&EPA
United States
Environmental Protection
Agency
Office of Radiation and Indoor Air
National Air and Radiation
Environmental Laboratory
EPA 402-R-12-007
August 2012
www.epa.gov/narel
          Uses of Field and Laboratory
          Measurements During a
          Radiological or Nuclear Incident

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                                     EPA 402-R-12-007
                                    www.epa.gov/narel
                                         August 2012
                                          Revision 0
  Uses of Field and Laboratory
     Measurements During a
Radiological or Nuclear Incident
       U.S. Environmental Protection Agency
           Office of Air and Radiation
         Office of Radiation and Indoor Air
  National Air and Radiation Environmental Laboratory
             Montgomery, AL 36115
                                        Recycled/Recyclable
                                        F^nsed Ktith Ssy.i'Canola hk on papec t
                                        ccinteins at Isasf KF4 rec^rled fib^r

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This report was prepared for the  National Air and Radiation Environmental Laboratory of the Office of
Radiation  and  Indoor  Air,  United  States  Environmental  Protection  Agency.  It was prepared  by
Environmental Management  Support, Inc., of Silver Spring, Maryland, under contract 68-W-03-038, work
assignment 35, and EP-W-07-037, work assignments B-33 and 1-33, all managed by David Carman and
Dan Askren. Mention of trade names or specific applications does not imply endorsement or acceptance by
EPA.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


                                       PREFACE

In the aftermath of a major release of radioactivity to the environment, such as the detonation of
multiple radiological  dispersal  devices ("RDDs" or "dirty bombs") or  an improvised nuclear
device (IND), hundreds of thousands of environmental samples will be  collected and analyzed
during the first year. In addition, a large number of field measurements will be made following a
major radiological or nuclear incident. Immediately following the initial response, many of the
cleanup and response decisions will be based on the results of measurements made with  hand-
held or field-portable equipment while others will require collection of individual samples from
various media and surfaces for analysis at radiochemistry laboratories. This document describes
the interrelationship among field  and laboratory  radiological  analytical  measurements, their
respective  advantages and disadvantages,  and  the planning and analytical  considerations
necessary to obtain data of known and defensible quality for use  by decisionmakers, primarily
during the recovery phase. Key to this understanding is the metrological concept of measurement
uncertainty. Both field and laboratory measurements will play significant  and  complementary
roles during the recovery operations  and  subsequent cleanup. This guide is intended to provide
decisionmakers, response and remediation managers, and field and laboratory personnel with the
necessary understanding to obtain technically  adequate  and defensible data in a timely and
effective manner.

The need to ensure adequate laboratory infrastructure to support response and recovery actions
following a major radiological or nuclear incident has been recognized by  a number of federal
agencies. The Integrated Consortium of  Laboratory Networks (ICLN),  created in  2005 by  10
federal agencies,1  consists  of existing laboratory networks  across the federal government. The
ICLN is designed to provide a national infrastructure with a coordinated  and operational system
of laboratory  networks that provide timely, high-quality, and interpretable results for early
detection and effective consequence management of acts of terrorism and other events requiring
an integrated  laboratory response. It also  designates responsible federal  agencies (RFAs) to
provide laboratory  support for chemical, biological, and radiological agents across all of the
response phases.  To  meet its RFA responsibilities  for  environmental  samples, the U.S.
Environmental Protection  Agency   (EPA)  has  established  the  Environmental  Response
Laboratory Network  (ERLN) to address chemical, biological, and  radiological  threats. For
radiological agents, EPA  is the RFA for monitoring, surveillance, and remediation, and will
share responsibility for overall incident response with the U.S. Department of Energy (DOE). As
part of the ERLN, EPA's Office of Radiation and Indoor Air is leading  an  initiative to develop
tools  and training to aide environmental radiological laboratories in the role of supporting
cleanup and remediation activities following a major radiological or nuclear incident.

EPA's responsibilities following a major radiological  or nuclear incident, such as  a terrorist
attack, include response and recovery actions to detect and identify radioactive substances and to
coordinate  federal  radiological monitoring and assessment activities. This  document was
developed to provide guidance to those who will support EPA's response and recovery actions
following a radiological or nuclear incident.
1  Departments of Agriculture, Commerce,  Defense, Energy, Health and Human Services, Homeland Security,
Interior, Justice, and State, and the U.S. Environmental Protection Agency.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


The use of procedures, developed in advance, for performing field and laboratory measurements
to  assess radioactivity levels  of  samples that contain significant  quantities of radioactive
materials  will ensure  that the radioanalytical  data  produced will  be of known  quality and
appropriate for the intended incident response decisions. This guide will provide perspectives
that may help field  and laboratory personnel have confidence that  their measurements of
radiation and radioactivity will be of adequate quality to support cleanup decisionmaking.

As with any  technical endeavor,  a radiological  or  nuclear incident may necessitate use of
particular methods or techniques to address specific data quality objectives and measurement
quality objectives. This document  does not catalog analytical methodologies or radionuclides,
nor does  it intend to prescribe or preclude the  use of particular  methodologies as long as
protocols selected  satisfy incident-specific data  quality objectives  and  measurement quality
objectives. A list  of  radionuclide-specific  methods to support  response  and recovery actions
following a radiological or nuclear incident  can be found in Standardized Analytical Methods for
Environmental Restoration Following Homeland Security Events - SAM 2010 (EPA 2010).

Detailed guidance on recommended laboratory radioanalytical  practices  may  be found in the
Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP 2004), which
provides detailed radioanalytical guidance  for project planners,  managers,  and radioanalytical
personnel based on project-specific requirements. Additional guidance may be found in the
Multi-Agency Radiation  Survey  and Assessment  of Materials   and Equipment  Manual
(MARSAME 2009).
	            9
This document  is one in  a planned  series designed  to  present  radioanalytical laboratory
personnel,  Incident Commanders, and other field  response personnel  with  key laboratory
operational considerations and likely radioanalytical  requirements, decision paths, and default
data quality and measurement quality objectives for samples taken after a radiological or nuclear
incident, including incidents caused by a  terrorist attack. Companion guides published  or in
preparation include:

•   Radiological Laboratory Sample Analysis Guide for Incidents of National Significance -
    Radionuclides in Water (EPA 402-R-07-007, January 2008)
•   Radiological Laboratory Sample Analysis Guide for Incidents of National Significance -
    Radionuclides in Air (EPA 402-R-09-007, June 2009)
•   Radiological Laboratory Sample Screening Analysis Guide for Incidents of National
    Significance (EPA 402-R-09-008, June 2009)
•   Method Validation Guide for Qualifying Methods Used by Radiological Laboratories
    Participating in Incident Response Activities (EPA 402-R-09-006, June 2009)
•   Guide for Laboratories - Identification, Preparation, and Implementation of Core
    Operations for Radiological or Nuclear Incident Response (EPA 402-R-10-002, June 2010)
•   A Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological
    or Nuclear Incident (EPA 600/R-l 1/122, October 2011)
   All   the  documents  in  this  series   are  available  at   www.epa.gov/erln/radiation.html  and  at
www.epa. gov/narel/incident guides.html.
                                            11

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


•  Guide for Radiological Laboratories for the Control of Radioactive Contamination and
   Radiation Exposure (EPA 402-R-12-005, August 2012)
•  Radiological Laboratory Sample Analysis Guide for Radiological or Nuclear Incidents -
   Radionuclides in Soil (EPA 402-R-12-006, September 2012)

Comments on this document, or suggestions for future editions, should be addressed to:

Dr. John Griggs
U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
National Air and Radiation Environmental Laboratory
540 South Morris Avenue
Montgomery, AL 36115-2601
(334)270-3450
Griggs.John@epa.gov
                                          in

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


                               ACKNOWLEDGMENTS

This guide  was developed by  the  National  Air  and Radiation Environmental Laboratory
(NAREL) of EPA's Office of Radiation and Indoor Air (ORIA). Dr. John Griggs was the project
lead for this document. Several individuals provided  valuable support and input to this document
throughout its  development.  Special acknowledgment and appreciation are extended to  Ms.
Schatzi Fitz-James, Office of Emergency Management, Homeland Security Laboratory Response
Center; and Mr. David Garman, ORIA/NAREL. We also wish to acknowledge the  external peer
reviews conducted  by Mr. Edward  Walker and other external reviewers, whose thoughtful
comments contributed greatly to the  understanding  and quality of the report. Numerous other
individuals inside EPA provided internal peer reviews of this document, and their suggestions
contributed greatly to the quality and consistency of the final document. Technical support  was
provided by Mr. Robert Shannon , Dr. N. Jay Bassin, Dr. Anna Berne, Mr. David Burns, Dr. Carl
V.  Gogolak, Dr. Robert Litman, and Dr. David  McCurdy of  Environmental  Management
Support, Inc.
                                    DEDICATION

This report is dedicated to the  memory of our friend and colleague, David Garman. Dave
administered nearly three dozen separate contracted radiochemistry projects for EPA dating back
nearly 17 years, beginning with the Multi-Agency Radiological Laboratory Analytical Protocols
(MARLAP)  in  1994.  Dave put up  with  countless changes of prime contractors, priorities,
subcontractors, and budgets, all with good cheer, diligence,  and all while keeping up  with his
"day job" as counting room lead for alpha-spectrometry analysis at NAREL.

Dave started with EPA's National Air and Radiation Laboratory in 1992. He left many friends
throughout EPA and the radioanalytical community, and he will be greatly missed.
                                          IV

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


                                     CONTENTS

Acronyms, Abbreviations, Units, and Symbols	vii
Radiometric and General Unit Conversions	x
1.  Scope and Purpose	1
2.  Introduction	2
3.  Impact of Source Term and Measurement Conditions on MQOs and Selection of
   Measurement Technologies	5
   3.1 The Impact of Source-Term Radionuclides on Measurement Approach	5
   3.2 Key Concepts: Surface Contamination vs. Volumetric Contamination	6
   3.3 Impact of Ambient and Intrinsic Background on Measurements of Radioactivity	7
   3.4 Applying the Directed Planning Process to Radionuclide Measurements	9
       3.4.1 Action Levels for Incident Response	9
       3.4.2 Data Quality  Objectives Process	10
4.  Metrology, Quality Systems, and QA/QC	15
   4.1 Why is Metrology Important?	15
   4.2 The Principles of Metrology	16
   4.3 Quality Systems	17
   4.4 Quality Systems Standards - Quality Assurance and Quality Control of Measurement
       Systems	17
       4.4.1 Quality Systems Standards, QA and QC for Field Measurements	18
       4.4.2 Quality Systems Standards, QA and QC for Laboratory Measurements	21
   4.5 Quality Assurance Project Plan	24
   4.6 Uncertainty Estimates and the Measurement Process	24
       4.6.1 Uncertainty Estimates and Field Measurements	25
       4.6.2 Uncertainty Estimates and Laboratory Measurements	26
5.  Considerations on the Capabilities and Limitations of Radioanalytical Measurement
   Techniques in the Field and Laboratory	27
   5.1 The Impact of Background Radiation on Radioanalytical Measurements	27
       5.1.1 The Impact of Background Radiation on Field Measurements	27
       5.1.2 The Impact of Background Radiation on Laboratory Measurements	31
   5.2 Types of Measurements of Radioactivity	32
       5.2.1 General Considerations Regarding Field Measurements	33
       5.2.2 General Considerations Regarding Laboratory Measurements	41
   5.3 The Effect of Measurement Geometry on Detector Calibration	46
       5.3.1 Measurement Geometry and Field Survey Instrument Calibrations	47
       5.3.2 Measurement Geometry and Field Spectrometry Measurements	49
       5.3.3 Measurement Geometry and Laboratory Survey and Gross Activity Measurements
              50
       5.3.4 Measurement Geometry and Laboratory Spectrometry Measurements	51
6.  Comparison and Applicability of Field and Laboratory Measurements	52
7.  Conclusions	61

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


   7.1 Conclusions and Recommendations Generally Applicable to Field and Laboratory
       Measurements	61
   7.2 Conclusions and Recommendations Specific to Field Measurements	62
   7.3 Conclusions and Recommendations Specific to Laboratory Measurements	63
   7.4 Summary	64
8.  References	64
Appendix I: Case Study on the Use of Field Spectrometry Instruments for Remediation at
   Rocky Flats Environmental Technology Site (RFETS)	69
Appendix II: Applicability of Selected Field and Laboratory Measurement Techniques	73
Appendix III: Example Scenarios: Approaches to Integrating Field and Laboratory
   Measurements During Response to a Radiological or Nuclear Incident	80
                                      FIGURES

Figure 1 -Uncontrolled Decision Error at the AAL	13
Figure 2 - Controlling the Probability of Decision Errors with the ADL and WMR	14
                                      TABLES

Table 1 - Comparison of Non-Spectrometric Field and Laboratory Measurements of
     Surficially Deposited Activity	54
Table 2 - Comparison of Non-Spectrometric Field and Laboratory Measurements for
     Volumetrically Deposited Activity	56
Table 3 - Comparison of Spectrometric Field and Laboratory Measurements for Surficially
     Deposited Activity	58
Table 4 - Comparison of Attributes of Spectrometric Field and Laboratory Measurements for
     Volumetrically Deposited Activity	60
Table 5 - Applicability of Selected Field Measurement Techniques for In Situ Measurements
     of Surface Activity / Concentrations of Radionuclides	76
Table 6 - Applicability of Selected Field Measurement Techniques for In Situ Measurements
     of Volumetric Activity / Concentrations of Radionuclides	77
Table 7 - Applicability of Selected Laboratory Measurement Techniques for Determining
     Activity / Concentrations of Radionuclides	78
Table 8 - Summary of Measurements for Scenario #1	82
Table 9 - Summary of Measurements for Scenario #2	85
Table 10 - Summary of Measurements for Scenario #3	87
Table 11 - Summary of Measurements for Scenario #4	89
Table 12 - Summary of Number of Scenario Measurements by Nuclide, Measurement Status,
     and Detection Status and Test	90
                                          VI

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
                   Acronyms, Abbreviations, Units, and Symbols
                            (Excluding chemical symbols and formulas)
a	alpha particle
a	probability of a Type I decision error
AAL	analytical action level
ADL	analytical decision level
ANSI	American National Standards Institute
ASTM	American Society for Testing and Materials
P	beta particle
ft	probability of a Type II decision error
BEGe	broad energy germanium [detector]
Bq	becquerel (1 dps)
CDC	Centers for Disease Control and Prevention
CFR	Code of Federal Regulations
Ci	curie
cm	centimeter
cpm	counts per minute
CRCPD	Conference of Radiation Control Program Directors
D&D	decontamination and decommissioning
DHS	United States Department of Homeland Security
DL	discrimination level
DOD	United States Department of Defense
DOE	United States Department of Energy
DOECAP	Department of Energy Consolidated Audit Program
DOT	United States Department of Transportation
dpm	disintegration per minute
dps	disintegration per second (Bq)
DQO	data quality objective
8	electron capture
EPA	United States Environmental Protection Agency
ERLN	Environmental Response Laboratory Network
FDA	United States Food and Drug Administration
FIDLER	Field Instrument for the Detection of Low-Energy Radiation
FSMO	Field Sampling and Measurement Organization
y	gamma ray
g	gram
GIS	geographic information system
G-M	Geiger-Miiller [detector]
GUM	Guide to the Expression of Uncertainty in Measurement
h	hour
HPGe	high purity germanium [detector]
HVAC	heating, ventilation, air conditioning [system]
1C	Incident Commander
ICLN	Integrated Consortium of Laboratory Networks
ICRU	International Commission on Radiation Units and Measurements
                                          vn

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


LEG	International Electrotechnical Committee
IND	improvised nuclear device (i.e., a nuclear bomb)
ISGS	in situ gamma spectrometry
ISO	International Organization for Standardization
ISOCS™	In-Situ Object Counting System
k	coverage factor
keV	kiloelectronvolt (103 electronvolt)
L	liter
LSC	liquid scintillation counting/counter
m	meter
MARLAP	Multi-Agency Radiological Laboratory Analytical Protocols [Manual]
MARSAME	Multi-Agency Radiation  Survey  and Assessment of Materials and Equipment
               [Manual]
MARS SIM	Multi-Agency Radiation Survey and Site Investigation Manual
MDC	minimum detectable concentration
MeV	megaelectronvolt (106 electronvolt)
uCi	microcurie (10 6 Ci)
ug 	microgram (1CT9 kilogram)
min	minute
MQO	measurement quality obj ective
mrad	millirad (1CT3 rad)
mrem	millirem (1CT3 rem)
Nal(Tl)	(thallium-activated) sodium iodide [detector]
NAREL	National Air and Radiation Environmental Laboratory
nCi	nanocurie (10 9 Ci)
NCRP	National Council on Radiation Protection and Measurements
NELAC	National Environmental Laboratory Accreditation Conference
NIST	National Institute of Standards and Technology
NRC	United States Nuclear Regulatory Commission
ORIA	Office of Radiation and Indoor Air
PAG	Protective Action Guide
                           1 9
pCi	picocurie (10"   Ci)
PT	proficiency testing
QA	quality assurance
QAPP	quality assurance proj ect  plan
QC	quality control
QSAS	Quality Systems for Analytical Services
RCRA	Resource Conservation and Recovery Act
ROD	radiological dispersal device (i.e., "dirty bomb")
rem	roentgen equivalent: man
RFA	responsible federal  agency
RFETS	Rocky Flats Environmental Technology Site
s	second
SI	International System of Units
SOP	standard operating procedure
SRM	standard reference material
                                          Vlll

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


Sv	sievert
TNI	The NELAC Institute
WMR	required method uncertainty
V&V	verification and validation
ZnS	[silver activated] zinc sulfide [detector]
                                           IX

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
                    Radiometric and General Unit Conversions
To Convert
years (y)
disintegrations per
second (dps)
Bq
Bq/kg
Bq/m3
Bq/m3
microcuries per
milliliter ((iCi/mL)
disintegrations per
minute (dpm)
cubic feet (ft3)
gallons (gal)
Gray (Gy)
roentgen equivalent
man (rem)
To
seconds (s)
minutes (min)
hours (h)
days (d)
becquerels (Bq)
picocuries (pCi)
pCi/g
pCi/L
Bq/L
pCi/L
jiCi
pCi
cubic meters (m3)
liters (L)
rad
sievert (Sv)
Multiply by
3.16xl07
5.26xl05
8.77xl03
3.65xl02
1
27.0
2.70xl(T2
2.70xl(T2
1(T3
109
4.50xlO~7
4.50X10"1
2.83xlO~2
3.78
102
io-2
To Convert
s
min
h
d
Bq
pCi
pCi/g
pCi/L
Bq/L
pCi/L
pCi
jiCi
m3
L
rad
Sv
To
y
dps
Bq
Bq/kg
Bq/m3
Bq/m3
(iCi/mL
dpm
ft3
gal
Gy
rem
Multiply by
3.17xl(T8
1.90xl(T6
1.14x10^
2.74xlO~3
1
3.70xl(T2
37.0
37.0
IO3
io-9
2.22
2.22xl06
35.3
0.264
io-2
IO2
NOTE: Traditional units are used throughout this document instead of the International System of
Units (SI). Protective Action Guides (PAGs) and their derived concentrations appear in official
documents in the traditional units and are in common usage. Conversion to SI units will be aided
by the unit conversions in this table.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


1.  Scope and Purpose

This document explains the importance and interrelationship of field and laboratory measure-
ments following a radiological or nuclear incident. Understanding and delineating the purpose of
each field  or laboratory  measurement process,  and implementing the measurements in a
controlled, well-documented manner, are critical  to ensure that data generated in response to a
radiological or nuclear incident in the field and in the laboratory are both technically and legally
defensible.

Section 2 provides a foundation for subsequent discussion of the document by discussing the
radionuclide(s) contaminants associated with a radiological or nuclear incident and the manner in
which they are deposited. These are critical elements to consider when determining which field
and lab measurement  techniques (or combinations of the two) can most  effectively be used to
address measurement challenges associated with an incident.

Section 3 of the  document addresses  key considerations for project planning. Measurement
quality objectives (MQOs) must be developed for the contaminant(s) of concern to ensure that
the measurement methods selected will be able to reliably meet project  data quality objectives
(DQOs). Once the analytical requirements have been established  and appropriate measurement
technologies identified, measurements can be carried out.

Section 4 addresses the  importance of the fundamental principles of metrology to  ensure that
measurements will be  traceable to national standards and reported in association with defensible
estimates of uncertainty. It also discusses the need for a quality systems approach to ensure that
measurements are conducted in a  controlled manner using validated  methods,  by  trained,
qualified personnel, and that all analytical operations  are well-documented  to preserve their
defensibility over time.

Section 5 of the  document identifies the respective capabilities and limitations of field and
laboratory measurement techniques and attempts to demonstrate the complementary nature of the
two  during the days  and months  following  an  incident. Factors impacting  calibrations and
background corrections are addressed in this section.

Section 6 contains tables that summarize and compare the respective strengths and limitations of
laboratory and field  measurements  for different types  of radionuclides  and measurement
conditions.  Section 7 provides  conclusions  and recommendations for field  and laboratory
measurements as well as an overall summary of this document.

Three appendices  follow the main body of the document. Appendix I presents a case study of
how in  situ  gamma  spectrometry  (ISGS) was  used  during  the   decontamination  and
decommissioning  (D&D) of the Rocky Flats Environmental  Technology  Site. The tables in
Appendix II show the applicability of a number of different instrument types for measurement of
a list of radionuclides and activity levels. Finally,  Appendix III uses several scenarios to explore
how the DQO/MQO process  can be  applied  to  field  and  laboratory measurements,  and
demonstrates  how field and laboratory measurements can be used in a complementary manner
during  a response to a radiological or nuclear incident.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
While most of the material in this document applies to all phases of an incident, the primary
focus  of the  document  will be the  recovery phase,  because this phase is EPA's primary
responsibility.

2.  Introduction

Immediately following  a  radiological or  nuclear  incident,  prompt feedback  of real-time
measurement results will  be crucial in supporting decisions regarding the health and safety of the
public. Field measurements used for this assessment will be invaluable  because they provide
real-time data to decisionmakers for determining the presence of a general hazard, and whether
or not the radiation exposure poses an imminent danger.

During the initial phase of an incident, responsible agencies and first responders must determine
the following as rapidly as possible:

  • Radionuclide(s) in the source device;
  • Levels  of gross activity present on contaminated surfaces, and  in  the air, water, soil, and
    other potentially contaminated areas, items or media;
  • Extent of the areas affected by contamination;
  • Levels of radiation exposure; and
  • What actions may be required based on Protective Action Guides (PAGs).

Estimates of the number  of laboratory samples required and the expected time frame to respond
to a radiological dispersal device (RDD or dirty  bomb) incident have been developed based on
White House Security Council Planning  Scenario  #11.3 These assessments  conclude that,
following a single incident in one metropolitan area with only one radionuclide (regardless of the
radiation emission type  from this radionuclide), well  over 350,000 measurements would be
required within a one-year period. More information on this scenario  can be found in EPA's
Assessment of Nationwide Laboratory Surge Capacity Required to Support Decontamination of
Chemical, Biological and Radiochemical-nuclear Agents (ICLN 2007) and The Current Gap in
Environmental Radioanalytical Laboratory Capacity.4

The responsibilities of various federal, state, and local agencies to address the possible health and
environmental consequences of a radiological or  nuclear incident properly fall at different times
in the recognized timeline of an incident. These agencies (e.g., the Department of Homeland
Security  (DHS),  Food and  Drug Administration (FDA), Centers for  Disease Control  and
Prevention (CDC), Department of Energy  (DOE),  EPA, state  and  local government) must
respond with technologies that are appropriate to their missions and responsibilities.

From the radioanalytical perspective,  an RDD scenario  involving a single gamma-emitting
radionuclide is perhaps the simplest scenario possible. Measurements in the field and in the
laboratory become more complicated when a mixture of alpha, beta, or gamma emitters, or pure
 1 http://cees.tamiu.edu/covertheborder/TOOLS/NationalPlanningSen.pdf
 lThe  Current Ga\
currently in draft.
4The Current Gap in Environmental Radioanalytical Laboratory Capacity, prepared for EPA in March 2007,

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


alpha- or beta-emitting radionuclides are  present.  The  destructive capability and radiological
impact of an improvised nuclear device (IND) would be considerably greater than that from an
RDD. Despite differences in the magnitude of the event, either of these scenarios would quickly
overwhelm resources  in  the  field and  at laboratories, making  optimal  use of  all available
resources essential.

Samples resulting from any radiological or nuclear incident will consist of a variety of matrices
and will originate from different geographic locations and environmental conditions. The data
quality  objectives and measurement  quality objectives5 for an incident will be tailored to the
phase of the incident and  will  address issues specific to  the radionuclides and matrices of
concern, and the locations and environmental conditions in and beyond areas directly impacted
by the  event. For example, measurements of building surfaces  in the early phase would be
expected to focus primarily on detecting levels of radioactivity that could result in short-term
exposures in excess of levels stipulated by protective action guides.

As the  event progresses  into the intermediate and recovery phases, efforts will  shift toward
identifying progressively  lower levels of  contamination. Large areas  will need to be quickly
characterized and cleared for longer-term use and habitation. Accordingly, the DQOs and MQOs
needed  to  support decisionmaking will  become increasingly  more  demanding of analytical
measurements.  A number of methods may be available for measuring radionuclides and their
radioactive emissions. The methods selected must be capable of reliably meeting the established
MQOs (i.e., a performance-based approach). This includes selecting and validating appropriate
techniques for sampling and analysis.

Measurements using field instruments will likely predominate in the earlier stages of an incident
when preliminary estimates of the type of radiation and activity levels present must be rapidly
determined so that protective  actions can be implemented effectively and without delay. Early
measurements  may  not  be   radionuclide-specific  or even  capable of  reliably  detecting
radionuclides with weakly penetrating radiations. Field crews also may need to gather samples
and  send them  to radiochemistry laboratories for rapid, unambiguous  confirmation of field
measurements  when these have  high  or  unknown  levels  of uncertainty. Radiochemistry
laboratories also may be  called on to provide  sensitive  and accurate measurements of specific
radionuclides in order  to meet  measurement quality objectives for detection  capability and
uncertainty needed to support decisionmaking by the Incident Commander (1C) or designee.

Following the initial  response phase of the incident, EPA, at a minimum, will be responsible for:

  • Delineating the ultimate  extent of contamination;
  • Assessing potential doses  from  various exposure pathways where  low-level radioactive
   contamination persists;
5"Data quality objectives (DQOs) are qualitative and quantitative statements that clarify the study objectives, define
the most appropriate type of data to collect, determine the most appropriate conditions from which to collect the
data, and specify tolerable limits on decision error rates. ... Measurement Quality Objectives (MQOs) can be viewed
as the analytical portion of the DQOs and are therefore project-specific." [MARLAP (2004), Section 1.4.9] See also
Section 4 of this document for further discussion of the directed planning process.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


  • Reassuring the  public  that  facilities,  property,  or homes  have  been  decontaminated
   effectively;
  • Determining that the disposition of contaminated equipment,  materials, environmental
   matrices, or facilities has been correctly and safely performed; and
  • Conducting ongoing monitoring.

Field measurements are valuable as they will be used to guide the process of exposure control
and remediation on a timely basis, especially in the earlier phases of an incident. As the response
to the  incident progresses through the intermediate and recovery  phases,  action levels  will
become progressively lower as decisions are based on longer-term goals. There will be a need for
increasingly  sensitive,  accurate,  and  radionuclide-specific  analyses,  and  expectations  for
stringent measurement  quality will  increase  accordingly. Laboratory determinations will be
needed to provide critically needed measurement capabilities and capacity.

Throughout the incident response, quality systems  are needed to provide the framework for
quality assurance and quality control (QA/QC) programs. Properly implemented quality systems
will provide the basis for defensible and informed decisionmaking under the stressful conditions
that  will be encountered during an  incident  response. Integrated internal QC measures and
external measurement intercomparisons will  demonstrate and document that measurements meet
established  MQOs.  Management structures  and independent internal  and  external  quality
oversight will  ensure that the quality  system is being implemented consistently and adequately.
All measurement techniques will be validated, and testing will be performed only by adequately
qualified and trained analysts following documented procedures.

Quality  systems  for laboratories  have  been  addressed  in  detail  by consensus  standards
development organizations.  Standards include  documents  such as  ISO 17025 (International
Organization for Standardization [ISO]/ International Electrotechnical Committee [IEC] 2005)
and The National Environmental Laboratory Accreditation Conference (NELAC) Institute (TNI)
Standard (NELAC, 2003). Although the TNI Standard theoretically applies to field sampling and
measurement  organizations,  quality  systems  and  associated certification  and accreditation
programs have just begun to be  implemented  on  a  limited scope for several  field parameters
(TNI 2007).

In March 2011, EPA's  Forum  on Environmental Measurements directed that  "...organizations
(e.g., laboratories,  field sampling and measurement)  generating  environmental data through
measurement  under Agency-funded  acquisitions  must  submit   documentation  of  their
competency, which  may include participation in applicable  certification and/or accreditation
programs." At present, however, this  directive has yet to be generally applied to measurements
of radioactivity in the field. As  such efforts proceed,  however,  similar levels of data quality  may
be expected of measurements from laboratory and field sampling and measurement organizations
(EPA 2011 a).6
6"Laboratories that perform field sample analysis are required to comply with rigorous quality systems standards.
Compliance with such standards provides the basis for accreditation by state regulatory agencies. Yet similar
standards do not exist for all field activities. Organizations conducting these activities are not required to meet a
quality system standard, do not need an accreditation for the work being performed and rarely are subjected to
routine oversight inspections. This inconsistency jeopardizes data usability and compromises the overall objective of

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Finally, field and laboratory measurements need to be coordinated in a manner that will ensure
that appropriate decisions can be made based on the phase of the incident and the action levels
and concentrations of the radionuclides that need to be analyzed. The abilities and strengths of
the various types  of field measurements coupled with  laboratory measurements  are explored
further in this document.

3.  Impact of Source  Term and Measurement  Conditions on MQOs  and  Selection of
    Measurement Technologies

The  source-term radionuclides for a  nuclear or radiological  incident will have  a  significant
impact on the most effective measurement approaches used following an incident. For example,
the RDD incident  described in White House Security Council Planning Scenario #11 involves a
single, medium-energy, beta-gamma-emitting radionuclide that emits gamma radiation readily
amenable to non-destructive field radioassay techniques. Medium- to high-energy gamma rays
penetrate through matrix materials to produce a  characteristic gamma ray signature, thus largely
eliminating the need for extensive laboratory work for the qualitative identification of gamma
emitters that may be present. When gamma-emitting contamination is deposited on the surface of
objects, field instrumentation techniques are  capable of generating data that can be used  for
defensible  incident response decisionmaking. Thus,  137Cs represents a best-case radionuclide
from the standpoint of rapid  and reliable measurement and remediation since responders can
most effectively utilize non-destructive field radioassay techniques. In the case of pure alpha,
beta, or low-energy gamma emitters,  the selection of viable field measurement alternatives is
more limited, and laboratory analysis may be needed to provide data of sufficient  quality  for
decisionmaking, especially for lower activity measurements in the later phases of an event.

3.1  The Impact of Source-Term Radionuclides on Measurement Approach

When  planning measurement approaches that  will  be  used  to  respond  to an incident, it is
important to consider that other less optimal,  yet likely, scenarios are possible that are  not
conducive to rapid, accurate field measurements. By their very nature, in situ measurements can
detect a radiation only after it is emitted from an object.  The radiation may  need to penetrate an
unknown amount  of matter before it reaches the surface of the object, is  emitted, and can be
detected. The type of radiation impacts its transmission  through matter. This, together with  the
depth of penetration into the object, will significantly affect the detectability of radiation emitted
from the object. Measurements of alpha  and beta particles  and low-energy photons that have
very short  ranges  in matter will almost always be subject to significant self-absorption  effects,
whereas  more highly penetrating, more energetic gamma rays will be less strongly attenuated
and will be more reliably detectable until  the  radionuclides  have penetrated deeper into  the
the data generation process. [...] Regulatory agencies have become sensitive to the negative impact that the absence
of an FSMO [Field Sampling and Measurement Organization] quality system standard may have on critical data.
This includes acknowledging that the quality of samples and field data that go to the laboratory is as critical to the
process as the quality of data generated by the laboratory. In response, such agencies have initiated steps to establish
quality system requirements  for field sampling and measurement organizations." From: David N.  Speis, Guest
Dialog: Improving Field  Sampling Quality  Control Pollution Engineering; August  1, 2004;  Available at:
www.pollutionengineering.com/Articles/Column/63ead7de8fd68010VgnVCM100000f932a8cO.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


surface being measured. When it is known that alpha- and beta-emitting contaminants are freshly
deposited, or that they have been deposited on hard, relatively impermeable surfaces, accurate
measurements in the field are practicable. If the radionuclides have penetrated into the surface,
field measurements of alpha or beta emitters may not be possible, while accurate measurements
of medium- to high-energy gamma-emitting radionuclides are possible even when the radionuc-
lides of concern have penetrated 1-2 cm or more into the object being measured.

The physical and chemical form of each radionuclide, the matrix material, and the manner in
which  a radionuclide is distributed in the  matrix material will impact measurements of radiation
and radioactivity.  An RDD may be  constructed  using radionuclides in  a  very insoluble,
refractory form. Extreme temperatures, pressures, and chemical and physical interactions with
surrounding materials also will affect the physical and chemical form of radionuclide(s) resulting
from the detonation of an IND or RDD.  Once contaminants are deposited in the environment,
changes in the physical and chemical form of contaminants and the matrices with which they are
associated occur as contaminants weather. The depth profile of radionuclides may change if they
migrate into the matrix. Such  effects will generally be more pronounced with porous matrices
such as soil since water can readily transport contaminants into the material on which they were
deposited. Field measurements may thus be complicated, especially if assumptions about self-
absorption cannot be defended without performing secondary measurements, or if varying rates
of adsorption  and  differential  transport of source-term radionuclides limit the use of marker
nuclides to model the distribution of source-term radionuclide mixtures.

3.2  Key Concepts: Surface Contamination vs. Volumetric Contamination

Attenuation effects  may interfere with accurate, non-destructive measurements of radioactivity
when  contaminants are not deposited in  a  regular,  thin layer on  a smooth  surface. Once
radionuclides penetrate an object, the  radiation emitted may be  self-absorbed by the matrix
material before it can escape the surface and be detected. When the degree of attenuation is high
or  not well-known,  unbiased measurements of  radioactivity and reasonable  estimates of
measurement uncertainty are generally not practicable, and the feasibility of field measurement
techniques for generating definitive results for  decisionmaking may be limited.

The concepts of  surface  versus  volumetric contamination have  been  the topic of much
discussion. A thorough understanding of these concepts and their impact on measurements of
radioactivity  is  key  to subsequent discussions.  The  Multi-Agency Radiation Survey  and
Assessment of Materials and Equipment Manual (MARSAME 2009) defines the two concepts as
follows:

  • Surficial Radioactive Material is radioactive material distributed on any of the surfaces of a
    solid object. Surficial radioactive material may be either removable by non-destructive means
    (such as casual contact, wiping, brushing, or washing) or fixed to the surface.
  • Volumetric Radioactive Material is radioactive material that  is  distributed throughout or
    within the materials or equipment being  measured, as opposed to a Surficial  distribution.
    Volumetric radioactive material may be homogeneously (e.g., uniformly activated metal) or
    heterogeneously (e.g., activated reinforced concrete) distributed throughout the materials and
    equipment (MARSAME 2009).

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
ANSI N13.12 defines surface contamination as "[rjadioactive contamination residing on or near
the surface of an item," and volume contamination as "... contamination residing in or throughout
the volume of  an  item."  It further differentiates between the two, stating  that "[v]olume
contamination can  result  from neutron  activation  or  from the  penetration of radioactive
contamination into  cracks or interior surfaces within the interior matrix of an item" and that
surface "...contamination can be adequately quantified in units of activity per unit area"  (ANSI
1999).

In an attempt to  address the issue in an operationally useful manner, this guide will address the
concepts  of surficial  contamination  or surface  contamination,  and  that of  volumetric
contamination,  pragmatically. The term  "surface"  is used  in  this document when  reliable
measurements of the radioactive contaminants deposited on an object are practicable. When a
reference is made to a "surface," this refers to contamination deposited in a thickness of material
near the surface  of an object for which self-absorption effects are minimal enough that they do
not impart uncorrectable bias or unknown amounts of uncertainty into the  measurement of
radioactivity in that surface. In contrast to this, measurements of radioactivity that are distributed
throughout the volume of an object are  considered to be volumetric contamination. Depending
on the uniformity of their distribution, accurate measurements of radioactivity in that object may
or may not be practicable.

Given strictly   surficial or homogenously  distributed  volumetric contaminants,  accurate
measurements of radioactivity  and  estimations  of measurement uncertainty are possible.
Considering the  realities of contamination in the environment, permeable and rough materials
such as soil, concrete, asphalt, fabric, and wood are the rule and not the exception, and it is
generally not known how deeply into the object the radioactive material has penetrated.  This
very significantly complicates accurate measurement of contamination. As time proceeds after an
incident, processes such as weathering set in, and radionuclides further permeate the materials on
which they were deposited. The depth of penetration  may be such that levels of attenuation and
self-absorption are poorly predictable and that they reach a point where radioactive emissions
cannot reliably be detected at all by field measurements.

Even when corrections are  made by assuming the depth of penetration, these assumptions may
lack documented, defensible technical basis and may not lend themselves to realistic estimates of
uncertainty. Lacking the key characteristics  of a defensible measurement, such results, beyond
limited applicability to scoping studies or the identification of obvious hot spots, are  not of
sufficient quality to support the decisionmaking process, and can be considered only qualitative
in nature.

3.3   Impact of Ambient and Intrinsic Background on Measurements of Radioactivity

Levels of naturally occurring radioactivity  intrinsic to the material being  measured may be
elevated or variable and may negatively impact the  reliability or the ability of low-level  field
measurements to demonstrate that an area has not been impacted or that it has been adequately
decontaminated to levels that will permit reoccupation. Similarly, ambient levels of background
radiation from naturally  occurring radioactivity or incident-related contaminants may interfere

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


with low-level measurements of radioactivity. For example, in one study of building materials
from  a single region, background  dose rates from the natural  radioactivity intrinsic to the
building materials ranged from 2.5 to 14 uR/h (Abbady 2006).  Significant local variations in
gamma background due to non-homogeneous areal distribution of contaminants associated with
the event itself may also interfere  with reliable  low-level in situ gamma measurements in
locations adjacent to contaminants. In the presence of elevated background activity, extended
count times (or even radiochemical  processing at a laboratory) may be required to  differentiate
between background activity and signal from contaminant radionuclide(s), especially at many of
the lower activity levels that likely will be applicable for recovery operations.

An incident  involving pure  alpha-  or beta-emitting  radionuclides such as  238Pu  or  90Sr, or
mixtures of pure alpha- or beta-emitting  radionuclides with other radionuclides,  would present
significant challenges to field instrument measurements not envisioned by White House Security
Council Planning Scenario #11. Earlier in the incident where higher-activity DQOs apply, field
measurements may  be used to guide remediation and, with laboratory  confirmation of the
underlying assumptions,  field measurements  often may be used effectively to address certain
lower-activity late-phase DQOs. For pure alpha emitters, and less energetic beta emitters, or
where significant weathering has occurred, however, laboratory measurements generally will be
needed to obtain radionuclide measurements of sufficient sensitivity and accuracy to meet low-
activity late-phase MQOs and final survey decisions.

In contrast to field measurements, there are fewer factors that interfere with laboratory analyses
because the laboratory environment is so carefully controlled and measures are employed to
address concerns  that could  adversely  impact a field measurement.  In  the laboratory, for
example, concerns about interference from  ambient background are addressed by  heavily
shielding potentially affected instrumentation.  Concerns about the intrinsic background activity
of the matrix  materials  remain  a common  challenge  to both to field and laboratory
measurements. The activity and expected variability of radionuclides present in the background
must be well-known in order to differentiate between signal from the background radioactivity
and low activities of naturally occurring radionuclide contamination.

Concerns about non-uniform distribution  of alpha-  and beta-emitting contaminants  can  be
addressed  in the  laboratory  by  homogenizing and  careful   subsampling to  ensure  the
representativeness of results. Laboratories routinely employ digestion and fusion techniques to
address intractable matrices.  Chemical  separation methods are  used to purify  and  isolate
elements of concern  from substances or other radionuclides that interfere with sensitive and
accurate measurements. Samples are measured in heavily shielded instrumentation with low and
stable backgrounds, which minimizes the variations in background activity that are problematic
in field  measurements.  When coupled  with low backgrounds  and  spectrometric detection
techniques, physical preparation and chemical separation steps permit sensitive radionuclide-
specific measurements of individual alpha- and  beta-emitting  radionuclides in  mixtures of
radionuclides and complex matrices. As a result, laboratories can minimize and more accurately
estimate uncertainties associated with single measurements than is generally possible in the field.
Rigorous quality programs at laboratories require  extensive validation of methods and quality
control, and ensure consistent documentation  of processes so that the  quality of measurement
results is highly defensible.

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Laboratory measurements have their limitations as well. Although laboratory turnaround times
have improved dramatically over the past decade and results often are available as quickly as
several  hours or days,  samples must  still be taken  and shipped to the laboratory. Thus,  a
laboratory process can never provide real-time results, as  is possible with field measurements.
Time and  effort are  required  in  the  field for  collecting samples  of surface or  volumetric
contamination to send to the laboratory. Because  laboratories  generally measure  and report
results  in  terms of the  massic or volumetric activity  of samples  (i.e.,  pCi/g  or pCi/L),
accommodations must be made to relate these units on a "activity per sample" basis, or to the
corresponding value in terms of areal activity (e.g., pCi/cm2).

Perhaps the most significant limitation associated with laboratory analysis relates back to the
number of in situ measurements and grab samples needed to characterize an area.  While for
alpha and  beta  emitters, there  is no  substantial  difference between  the number of  in situ
measurements or grab samples needed, when medium-  to high-energy  gamma emitters are
concerned  and when the areal distribution  of  the contaminant radionuclides  may be  non-
homogeneous, more grab samples may be needed  than in situ  measurements to have  a high
degree of confidence  that hot spots  will not be  overlooked. Similarly, the overall uncertainty
associated  with  collecting multiple  grab samples,  as opposed  to  performing a single ISGS
measurement of a larger  area, may require that more samples be collected and measured. Even
so, this may still result in higher overall combined measurement and sampling uncertainties, and
in a higher risk of not detecting activity even though it may be present in detectable quantities.

3.4  Applying the Directed Planning Process to Radionuclide Measurements

As the  event progresses into the intermediate and recovery phases, efforts will shift  toward
identifying progressively  lower  levels  of contamination. Large  areas will need to  be quickly
characterized and cleared for longer-term use and habitation. Incident-specific action levels will
be set to support the tasks of:

  • Reassuring the public  that  facilities,  property,  or  homes have been  decontaminated
   effectively; and
  • Determining that  the disposition  of contaminated equipment, materials, environmental
   matrices, or facilities has been correctly and safely performed.

3.4.1   Action Levels for Incident Response

Undoubtedly a key factor will  be public acceptability, which  may in fact be  more accurately
characterized as  intense public demands and expectations. In terms of reoccupancy or continued
occupancy  of impacted  or  possibly  impacted  areas, including  places of work, schools,
playgrounds, day care centers, hospitals, places of worship, etc., the public will  very likely insist
that  these  places  be  returned  to the  public's  perceived "radiation free"  status. This  may
effectively translate into public  demand that action levels be  set at a  fraction of the ambient
background for  certain radionuclides,  or at zero for  source-term radionuclides  not originally
present  in these locations. The public  demand for extremely low action levels could result in

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


significant measurement challenges, ultimately requiring very low detection capability coupled
with great precision (very small uncertainties).

While the Agency will certainly need to educate the public regarding the technical  challenges
involved with extremely  low action levels, the public will  still likely demand the most well-
established, sensitive, and precise measurements possible.  In addition, while the general public
may not  be familiar with  the  technical aspects  of data verification and  validation,  quality
assurance, and  quality control,  the  public  will  almost certainly  demand a high  degree of
demonstrated certainty for  the  data, as well as some type of rigorous technical review and
evaluation of the data prior  to Agency decisions. Given these likely public demands, as well as
lessons learned from the World Trade Center recovery  efforts, the Agency will need to employ
well-established measurement  processes capable  of precisely measuring low levels of select
radionuclides. These measurement processes will need  to be supported by well-established and
robust quality control procedures and practices that will  provide sufficient information and
documentation to allow for defensible data verification and validation.

3.4.2  Data Quality Objectives Process

The DQO  process  is  used to  define  specific data  requirements  for field and  laboratory
measurement programs to ensure that the analytical measurements will be of sufficient quality to
defensibly support the decisionmaking process. DQOs also are used to develop the performance
and acceptance  criteria for sampling and measurement criteria  activities documented in the
quality assurance project plan (QAPP). The output  of the DQO  process will specify the number
of measurements needed, their locations,  and any specific analytical requirements. The frequency
of measurements and number of locations will depend on the degree of variability and amount of
radioactivity compared with the established action level.

3.4.2.1 Decision Rules

One essential  aspect of the  DQO process is the specification of a decision rule.  Decision rules
may be qualitative or quantitative. They  contain alternative actions to be taken depending on the
decision about whether the result indicates there is sufficient probability that the analytical action
level (AAL) has been exceeded or not. The decision that will be made is expressed in a
hypothesis test.

A null hypothesis, HO,  is defined by initially assuming that the true concentration is either above
or below the AAL. We assume that the null hypothesis is true unless the result of a measurement
allows us to reject the null hypothesis. For most environmental measurements the consequences
of exceeding an action level are greater than not  exceeding it.  Thus, the null hypothesis most
frequently selected will protectively state that an AAL is exceeded unless data are available that
demonstrate with high probability that the activity is less than the AAL.7  By  incorrectly
deciding to reject the null hypothesis when it is indeed  true we  commit a Type I decision error.
7 There are occasions where it would be appropriate to assume that a result is below an action level unless the
contrary can be demonstrated. For a more complete discussion of decision rules, see MARLAP or Appendix VI in
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance—Radionuclides in Water,
(EPA 2008).


                                            10

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


By incorrectly failing to reject the null hypothesis when it is indeed false, we commit a Type II
decision error.

There is uncertainty  associated with every measurement. When the result of a measurement is
used to make a decision, there is a probability that a decision error may occur. Given an example
where the true concentration is equal to the AAL, by definition action should be taken. A single
measurement is performed with the plan to compare that result to the AAL to decide whether the
concentration is less than the action level. Since the result of each measurement varies according
to its uncertainty, half of all possible measurements will fall  below the AAL and half will be
equal to or greater than it. Using this approach to making decisions, we commit a Type I decision
error fifty percent of the time when the our measurement falsely indicates that the concentration
is less than the AAL.

The DQO process places limits on the probability of making such  decision errors. The limit for
the probability of making a Type I error (denoted a) is specified at the AAL. The probability of
making  a Type II error (denoted /?) is  specified generally at a lower concentration called the
discrimination level (DL).  The discrimination  level  is a  concentration  at which the null
hypothesis is false (i.e., a concentration below the AAL) and  at the same time, a concentration
which we need to be able to reliably distinguish from the  AAL. For example, suppose the
contaminant of concern is 226Ra, and we know that 226Ra is present in the background. Then by
establishing  the  discrimination level equal to the background concentration of 226Ra in the
sample will  minimize the probability that background concentrations  of radium may be falsely
identified as 226Ra present at the AAL.

The  AAL and  the DL together bound the "gray region"  an area in which  decision  error
probabilities are not  controlled as tightly as outside of it. When measurement results fall in the
gray region,  there is a higher risk that we will commit decision errors. The width of the gray
region is defined as:
                                   A = | AAL - DL .

3.4.2.2  Measurement Quality Objectives

MARS AME (2009) and the Multi-Agency Radiological Laboratory Analytical Protocols Manual
(MARLAP  2004) contain guidance on developing MQOs  from the applicable DQOs for
measurements of radiation and radioactivity at laboratories and in the field. MQOs are generally
quantitative  data requirements that evaluate the quality of the measurement against the  criteria
upon which decisions will be based using those data.

By specifying the required method uncertainty  (MMR) at the AAL, it  is possible to ensure that
decision errors will not exceed the levels deemed appropriate by the DQOs for defensible project
decisionmaking. Ensuring  that measurements are  of sufficient quality for decisionmaking also
will minimize effort, time, and money spent on making measurements, all key driving factors in
an incident response situation.
MARLAP considers the required method uncertainty at the AAL, WMR,  to be  a  fundamental
MQO. For decisions about whether a single sample exceeds the AAL, Z/MR can be calculated as
                                           11

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
                                     UMR ='
where the null hypothesis (Ho) is "the true sample activity is greater than the AAL," A = [AAL-
Discrimination Level] and
                   o
distribution function.
' l-a
and z 1 „  are the respective quantiles of the standard normal
Details and refinements for the determination of the required method uncertainty are given in
MARLAP Appendix C or Appendix VI of Radiological Laboratory Sample Analysis Guide for
Incidents of National Significance - Radionuclides in Water (EPA 2008).

In order to implement the use of the required method uncertainty, the laboratory must have in
place an  acceptable method  for  estimating measurement uncertainty.  MARLAP  (2004)
recommends the method presented in the Guide to Expression of Uncertainty in Measurement,
also referred to as "the GUM" (ISO Guide 98, 1995). No measurement  of radioactivity should
ever be determined or reported without an associated  uncertainty and its associated coverage
factor, k. Simply reporting "counting uncertainty" is incomplete and for high-activity samples,
may  result in  significantly  underestimating  the  combined  standard  uncertainty of  the
measurement.

3.4.2.3  Controlling the Probability of Decision Errors with Analytical Decision Level

The AAL is the dividing point for  a  choice  between  two alternative actions. The  quality of
measurements of radioactivity  should be driven by the need to make informed,  defensible
decisions about whether the AAL has been exceeded with acceptable limits on the probability of
a decision error. Failure to take the variability of results and the magnitude of the measurement
uncertainty into account will result in unacceptably high error rates for decisions, or in excessive
time and effort invested in performing measurements with quality that exceeds levels needed for
decisionmaking. High and uncontrolled probabilities of false  decisions are not compatible with
defensible  decisionmaking, will  result in less effective use of  analytical  resources  during
response, and will increase the time needed to complete recovery from the incident.

It  is often  important to correctly identify samples  whose true activity  exceeds an  AAL.  For
example, when prioritizing samples to be sent to a laboratory, sending low-activity samples to a
high-activity laboratory would  be less problematic (for the laboratory at least) than risking
contamination of a low-activity  laboratory. By selecting the null hypothesis that the true sample
activity  exceeds the AAL, we protect against  a Type I error of incorrectly deciding that true
sample activity is below the AAL when it is actually above the AAL. We also want to be sure
  Values of zl.a (or z^) for some commonly used values of a (or /?), taken from tables of the cumulative normal
distribution (MARLAP 2004, Appendix G, Table Gl), are:
a or/?
0.001
0.01
0.025
0.05
z^Corz^)
3.090
2.326
1.960
1.645
a or/?
0.10
0.20
0.30
0.50
z^or^)
1.282
0.842
0.524
0.000
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


that if the sample activity is significantly below the AAL, it is correctly identified, avoiding a
Type II error of incorrectly deciding that the sample activity is above the AAL when it actually is
below.9

Figure 1  is a graphical representation of a smoothed  distribution from an infinite number of
measurements of a sample or object where the true  activity is equal to the established AAL. In
the figure,  the  AAL is the mean  of the distribution of measurements. Variability  due to
uncertainty in the measurement will cause one-half of all  possible measurements to fall below
the AAL, and one-half at or above the AAL. Based on a single measurement, a decision must be
made about whether or not activity is present above the AAL.
                             Sample at Ambient
                               Background
                 0.1  0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9
                                     Concentration (nCi/g)
                                                         1.1  1.2  1.3  1.4  1.5  1.6
                       Figure 1 - Uncontrolled Decision Error at the AAL

If the measured result is compared directly to the AAL to decide whether the activity is equal to
or above the AAL, there is  a 50% probability that the measurement will result in an incorrect
decision that the true activity is below the AAL (this  case corresponds to the solid area below
the AAL).

The  magnitude of the  measurement uncertainty affects  the ability of  a  method to tell the
difference  between background  activity and contaminant at the AAL. Without establishing a
control on the measurement uncertainty,  it may  not be  possible to  discriminate  ambient
background activity from contaminant activity at or above the AAL (this case corresponds to the
cross-hatched area above the AAL).

It is  possible to control the  probability of decision errors by comparing measured results with
specified limits on uncertainty to an analytical decision level (ADL).
9 In a case where there would be greater consequences associated with falsely concluding that activity is present
when it indeed is not, the most appropriate null hypothesis would be,  "The measured activity is below the action
level." Because this case is less frequently applied for environmental analyses, it will not be presented here. For
details,  see Appendix VI of the Radiological Laboratory Sample Analysis Guide for Incidents of National
Significance - Radionuclides in Water (EPA 2008).
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Assume that the null hypothesis is that the true activity of the sample exceeds the AAL. We can
calculate an analytical decision level as ADL= AAL - Zj_a WMR.

This means that before deciding that activity is not present at or above the AAL, the result of a
measurement must fall below the AAL by a margin corresponding to the tolerable probability of
falsely rejecting the null hypothesis that the true concentration is above the AAL.

The DL is the concentration for which the null hypothesis is considered to be false but at which it
is important to be able to distinguish the concentration from that of a sample at the AAL. The
AAL and DL together bound the "gray region" in which decision error probabilities are not
controlled as tightly as outside of it.

Consider the hypothetical situation shown  graphically in Figure  2.  Assume that a DQO  is
established that stipulates that the null hypothesis is that the true activity of the sample exceeds
the AAL, with tolerable Type I and Type II error rates of 5% and 10% respectively.10
                  01  0.2  0.3  0.4  0.5  0.6  0.7  0.8 0.9
                                      Concentration (nCi/g)
                                                        1.1  1.2  1.3  1.4  1.5  1.6
          Figure 2 - Controlling the Probability of Decision Errors with the ADL and UMR

The AAL for the screening process is 1.0 nCi/g. Samples with activity above 1.0 nCi/g may not
be sent to the low-level laboratory.

A discrimination level of 0.5 nCi/g is selected since the matrix being measured contains naturally
occurring background  activity of 0.5 nCi/g, and there is  concern that this  activity will  be
mistaken for the contaminant of concern.  The gray region (A) is the area between the AAL and
the discrimination level. For  a  sample with true  activity in  the gray  region,  there is  a high
probability of a decision error.  The width of the gray region, delta, is calculated as:
                        A = IAAL - DL  = |i.o - o.5| na/g = 0.5 nci/g.
10The probability of making Type I error is chosen to protect against the greater risk associated with incorrectly
deciding that the sample activity is  below the AAL when in fact it is greater than the AAL. The larger Type II
decision error means that there are lower consequences—and thus greater tolerance—to falsely concluding that
activity is present, even though it may be attributable to background activity.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
The required method uncertainty ensures that the rate of Type I and Type II decision errors is
maintained within the specified limits and is calculated as follows:

                                  A        0.5nCi/g     ft1_   _..
                                                          17nCl/g
                              z^+Zj.p   1.645 + 1.282

See footnote 5 for the values of z^ and z^. The ADL, which is used as the decision criterion, is a
function of the uncertainty of measurements of a sample at the AAL and is calculated as:
            ADL = AAL -zi-a Z/MR = 1.0 nCi/g - [1.645x0.17 nCi/g] = 0.72 nCi/g.

The curve centered  about 1 nCi/g in Figure 1 represents the distribution of all possible measure-
ments of a sample with a true activity equal to the AAL. In figure 2, consistent with established
DQOs,  only 5% of this distribution (a ) falls below  the ADL. The curve, centered about 0.5
nCi/g,  represents the distribution of all possible measurements  of a  sample containing only
naturally occurring background activity (equal  to the  discrimination level).  Consistent with
DQOs, only 10% of this distribution (/3) may exceed the ADL.

Thus, only measurements that fall significantly below the AAL (I.e., less than the ADL) will lead
to rejection of the null hypothesis, and thus reliably support the conclusion that the true activity
of the  sample has not exceeded the  AAL. At the same time, the required method uncertainty,
MMR, is kept small  enough to  ensure that the AAL will  be differentiated reliably  from the
naturally occurring  background activity  at the  discrimination level. In contrast to decision error
rates  of 50% that  may result  from comparing measurements  directly to  the action  level,
comparing a measurement to the ADL will ensure that decision errors are maintained at the rates
consistent with DQOs.

4.  Metrology, Quality Systems, and QA/QC

An effective quality system is vital in assuring the quality  of any radioanalytical measurement
used for incident response decisionmaking. It ensures, among other things, that all measurements
are traceable to national standards and provides defensibility  against data challenges. The rigor
and detail of one aspect of the quality system,11 its  QC requirements, will likely need to be
increased from the  initial response and  final recovery phases and be the most stringent during
final status surveys. A graded approach may be applied to  reflect changing DQOs, MQOs,  and
needs for analytical quality. The QA/QC protocols used should always provide clear assurance
that data is of sufficient quality to support the decisionmaking process. This section addresses
some of the fundamental concepts of metrology, quality  systems, and their importance in field
and laboratory measurements for incident response.

4.1  Why is Metrology Important?

The  International  Vocabulary  of Metrology  (VIM;  IBWM 2008) defines metrology as the
"...science of measurement and its application.  [...] Metrology includes all theoretical  and
11 See section 4.3 for a more complete discussion of quality systems.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


practical  aspects of  measurement,  whatever  the  measurement  uncertainty  and field of
application."

Radiation and  radioactivity measurements can be complex, and establishing traceability for
instrument calibrations for complex field measurements may pose technical challenges. Some
practitioners may be uncomfortable in setting up equations for the various measurement models,
or in developing them into expressions of uncertainty.

Failing to consider and  apply  the fundamentals  of  metrology,  however,  will  result in
measurements of unknown and very possibly substandard quality. Without meaningful estimates
of measurement uncertainty, or traceability of measurements to national standards, it is not
possible to demonstrate defensibly that a measurement possesses sufficient quality to reliably
address DQOs applicable to incident response, or even to reasonably compare it to that taken by
another analyst or organization.  Since this could result in potentially serious consequences to the
decisionmaking process, it is vital that the  fundamental principles of metrology be understood
and adequately incorporated into measurements of radiation and radioactivity.

4.2   The Principles of Metrology

The  core  approach to performing any measurement,  whether it is a radiological measurement
performed in a field or laboratory  setting, rests on  the basic principles of metrology. Every
measurement is a comparison to a standard. The degree to which reference materials provide a
universal  reference depends on  the quality  of the link of those measurements to the applicable
reference  standards. ISO  1993a and MARLAP (2004)  define traceability as a "property of the
result of a measurement or the value of a standard whereby it can be related to stated references,
usually national  or international standards, through an unbroken chain of comparisons all
having stated uncertainties" (ISO 1993b).

Measurements  of radiation and radioactivity must  be traceable to  national radiation or
radioactivity  standards (e.g., a  Standard Reference Material  from the National  Institute of
Standards and Technology). The definition of traceability also recognizes that the uncertainty of
a measured value is an integral component of its traceability. This is because the uncertainty
indicates the degree of confidence that can be placed in a measurement.

It is important that measurement results be reliable, and that results from different organizations
be comparable, and objectively and confidently accepted as  such among all those likely to use
that  data. Not  only  must instrumentation be  calibrated,  but  measurements must also be
performed, and quality control protocols that preserve, validate, and document the traceability of
each  measurement to the national  standard  must  be available.  This  applies  equally to
measurements made in the field  and to those performed in a laboratory setting.

Factors that may affect the quality of measurements include reference materials used, equipment
calibration, and chemical treatment (e.g.,  extraction, digestion). These measurements  can be
strongly dependent on the source material or sample matrix, whose exact composition is almost
never completely known. This limits the degree to which the measurement environment can be
defined and controlled.
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      Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
 Some fundamental steps of metrology that should be followed in measurements of radioactivity
 are:

  • Develop/define DQOs and MQOs;
  • Choose or develop the appropriate measurement method to meet the MQOs;
  • Understand a method and its strengths and limitations;
  • Choose suitable National Institute of Standards and Technology (NIST)-traceable certified
    reference materials and use them properly;
  • Validate the method to demonstrate that the method will meet the  MQOs; demonstrate and
    confirm it;
  • Identify the sources of uncertainty in the method;
  • Derive a model  or  an equation  for the measurement that allows the combined standard
    uncertainty to be determined;
  • Evaluate the uncertainty of each measurement using a recognized approach;
  • Clearly establish and document that results are traceable to a national standard; and
  • Report the results, the associated combined standard uncertainty with the appropriate units,
    the number of significant digits, and the coverage factor.

 4.3   Quality Systems

 A management system for quality must precede the design of any QA program. ISO/IEC 17025
 provides guidance for developing an overall management system for quality, administrative, and
 technical operations. Similarly, the EPA has provided Guidance for Developing Quality Systems
for Environmental Programs (EPA QA/G-1,  2002a). The  scope and  purpose statement for
 QA/G-1  describes a quality  system as  "...the means by which  an organization  manages its
 quality  aspects  in a  systematic, organized manner.  It provides a framework for planning,
 implementing, and assessing  work performed by an organization and for carrying  out required
 quality assurance (QA) and quality control (QC) activities. It encompasses a variety of technical
 and administrative  elements,  including  policies  and objectives; organizational  authority;
 responsibilities;  accountability; and procedures  and practices." The document also stresses that a
 successfully implemented quality system will  reduce  vulnerabilities and improve  an organiza-
 tion's ability  to make  reliable,  cost-effective, and defensible decisions.  The  quality  system
 approach will help ensure scientific data integrity and  produce  well-documented data of quality
 appropriate for the purposes intended. It also will reduce the risk of embarrassing surprises and
 data challenges while improving  on-time delivery of data and reducing expenditures by reducing
 the need to repeat measurements unnecessarily.

 4.4   Quality Systems Standards - Quality Assurance and Quality Control of
      Measurement Systems

 Radioanalytical  measurements will play a vital role in  rapidly and reliably  characterizing the
 type and extent of contamination following a radiological or nuclear incident.  They are also key
 components needed to efficiently and effectively remediate  any contamination identified.  The
 production of data of known and sufficient quality to support long-term decisionmaking requires
 a  well-implemented QA  program  containing elements stated in guidance documents  from
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


various quality standards organizations. The elements defined in these programs address in detail
every aspect of measurement operations, including:

  • Effective, consistent, and well-documented oversight of the analytical process;
  • Receipt, tracking, and management of samples;
  • The procurement of supplies and equipment;
  • The qualifications  and training of personnel;
  • The setup, maintenance, and calibration of instruments and support equipment;
  • Quality control of all measurement processes;
  • Selection, validation, and proceduralization  of analytical methods;
  • Results' traceability to national standards (e.g., NIST);
  • Creation, maintenance, and archiving of records and documents;
  • The reporting  and review of results and  independent QA oversight of all measurement
   processes; and
  • Review of analytical output.

Any measurement program that will  be  used as the basis for  key decisions  also must be
supported by a substantial and robust QC program if it is to generate reliable, verifiable, and
defensible results and  uncertainty estimates. An effective QC program will empirically measure,
control, and document the precision, accuracy, representativeness, and comparability of results.
Lacking a comprehensive QA/QC program, the quality of data generated may be inadequate to
support the generation of large data sets that can be validated to levels that will withstand the
scrutiny of public or legal inquiry.

4.4.1   Quality Systems Standards, QA and QC for Field Measurements

Traditionally, it has been recognized that there are  limits to the detail and the quality of testing
for  radioactivity  that  is practicable  in  the  field. This  has  included   requirements  for  the
traceability of measurements, formalized QA, maintenance of constant test conditions, and
implementation of effective QC requirements and oversight to ensure that the quality of results
will meet DQOs/MQOs. As a result,  fixed laboratories have traditionally been called upon to
perform many of the most critical, complicated, and sensitive measurements. Fixed laboratories
also have been required to maintain sophisticated quality systems commensurate with the higher
quality of measurements being performed.

Over time, innovative field measurement techniques have become increasingly more available,
and increasingly more sophisticated measurements can now be performed in the  field. Since
these  measurements support the same decisions that traditionally  required the quality of fixed
laboratory data,  field programs need to consider the same quality concerns that have been
applied at fixed laboratories for many years.

Field  sampling program QA/QC has not focused on addressing the analytical process, since this
role was so frequently relegated to the fixed laboratory. Rather, it tended to address areas such as
the tracking, management, and receipt of samples; preservation of samples; sampling techniques
for various matrices; and procurement of supplies and equipment. Guidance  on the performance
of field measurement parameters (e.g.,  conductance, pH, radiation dose rate) and the  operation of
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


field instruments has been provided by instrument manufacturers. A limited number of standard
practices are  available from  standards organizations  that  address  field measurements and
associated QA/QC in detail. Based on available guidance and best practices, standard operating
procedures are designed for use by field analysts. Thorough guidance is needed for field
programs to  ensure  that sufficiently detailed  direction is given to designing  and effectively
implementing a quality system  for  field  measurements. This  can best  be accomplished by
providing detailed analytical protocol specifications in  quality assurance project plans, and by
allowing for time to focus and implement QA/QC  measures in advance of deployment.

Broad ranging formalized quality system standards  and  certification/accreditation and oversight
programs have yet to  be  implemented that effectively address field measurement programs.
Although  two  volumes  of The NELAC Institute Standard  apply to  field  sampling and
measurement organizations (TNI 2007),  implementation  of these  quality system standards,
adopted in 2007,  and associated  independent accreditation is limited to field determinations of
non-radioactive lead (Pb). The scope and timing  of additional implementation  has not been
determined at this time. The Multi-Agency Radiation  Survey and Site Investigation Manual
(MARSSIM  2000)  provides  only  general  direction  on QA  measures  applicable  to field
instruments. For example, in situ measurements,  particularly those performed using efficiency
modeling techniques, generate results that are not  traceable to national standards (e.g., to a NIST
Standard Reference Material). This critical  fact often is overlooked and represents a huge divide
between the standards of analysis needed to create accurate and defensible data and those that are
sometimes applied in the field.

Training of field personnel is a second area that is difficult to address, especially for an incident
response. Due to the nature  of  an  incident response,  there is  little if any time available to
effectively train a large number of instrument analysts and operators prior to mobilizing for the
field. Training classes would be  short and  provide  only generalized mechanical instructions on
operating an instrument. A thorough  knowledge of how matrix and geometry affect the measure-
ment process cannot be taught  during the pressure  of responding to an incident. Cursory
instruction  cannot substitute for the expertise  that results from long-term  experience and
documented historical performance running an analytical technique or instrument. Once  in the
field, oversight of relatively inexperienced analysts would be difficult to perform and to  docu-
ment. Additionally, each incident will have  specific matrix and field sample geometry issues.

A third area of concern surrounds the defensibility of the precision  and accuracy of results.
Given the variability in measurement conditions and the characteristics  of the  objects  to be
measured, innovative, empirical  quality control measures are needed to provide assurance that
the measurement process and individual measurements consistently meet MQOs. Quality control
measures  for field measurements are  not generally as robust as those routinely used  for
laboratory measurements. This is due in part to the nature of the measurement, and the challenge
of constructing QC protocols for in  situ measurements that  demonstrate empirical monitoring
and quality control of field measurements. One or more measures could be  implemented that are
appropriate to specific concerns  surrounding the type of measurement being performed. Such
measures might include:
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


   •   Routinely analyzing independent confirmatory grab samples at a laboratory to measure
       and control the bias and precision of the process;
   •   Analyzing in situ blanks to control absolute bias  in each area where measurements are
       conducted by repeating the measurement in the same location and rotating the instrument
       180° in the horizontal plane;
   •   Performing redundant measurements that validate the process using modified analysis
       parameters, for example, by:
       o  Measuring the same  object from  different angles and  distances to show adequate
          implementation of efficiency modeling and to help validate estimates of uncertainty;
       o  Having a different person repeat the measurement;
       o  Using a different instrument and/or software to repeat the measurement; or
       o  Repeating the  measurement after  breaking  down the equipment,  leaving the area,
          coming back, and setting up the equipment and instruments again.
   •   Analyzing known reference samples to measure and control the accuracy of the process;
   •   Participating in regular external proficiency testing programs that provide  independent
       empirical evidence of the accuracy and intercomparability of measurements;12 and
   •   Utilizing independent verification contractors to ensure that the cleanup has achieved its
       stated goals.

During conventional clean-up and remediation activities (for example Resource Conservation
and  Recovery  Act  [RCRA]  sites),  a  final  status report  is  written  at the completion  of
decontamination/removal  tasks that  summarizes the measurement data  and discusses  how a
decision is made that the data are adequate to satisfy the DQOs. In the case of structures and land
areas, the database that supports this  consists of in situ measurements supported by  independent
confirmatory lab analysis of random and judgmental (i.e., "biased")  samples. For regulated
activities (U.S.  Nuclear Regulatory Commission [NRC],  DOE,  agreement states), confirmatory
split sampling  by regulators and independent inspection and oversight are  performed by  an
independent verification contractor responsible to the applicable regulatory authority.

Validating  the  methods/procedures  to  be used  to conduct  field  measurements is  another
important practice that  empirically demonstrates  the  accuracy,  precision,  comparability,
specificity, and robustness provided  by a method.  If a field measurement technique is used in
support of the decisionmaking process, validating  it will help ensure that measurement biases
and uncertainties for various geometries are known  and that its capabilities are empirically tested
and well-documented prior to its use.

Techniques used for determining field measurements often rely on assumptions that are difficult
or impossible to verify (e.g., self-absorption effects, the impact of background on low-level
measurements,  or the  assessment of complex measurement situations).  Efficiency modeling
techniques rely considerably on the judgment of instrument operators and their ability to set up,
calibrate, check performance of, and use instruments and procedures to perform processes  such
as scanning surveys.
12 Small demonstration programs have been carried out in the past, but there are currently no ongoing external
programs that are designed to empirically assure the intercomparability of results produced under conditions that
approximate those encountered in the field.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


During  an incident, the level  of oversight  and number of personnel available to  support
operations  will  presumably  be stretched  to  the  limit.  Conditions in the  field  may vary
significantly from measurement to measurement. The level of experience available may not
guarantee that the  level of documentation and  review  is  adequate to verify all the critical
conditions  and assess the  impact of decisions  made during the performance of an in situ
measurement. Analyst judgment, for  example, is crucial  in complex in situ measurements, yet
judgment is difficult to quantify  and may vary depending on the knowledge, experience, and skill
of instrument operators and the specific challenges of the measurement.

Careful  and complete documentation,  effective prompt review, and retention of sufficient records
to assure unambiguous recreation of a result are  critical elements provided under a quality
systems approach. Lacking  effective technical oversight and experienced independent reviewers,
an individual may be asked to self-perform quality-related functions that should be completed
independently, a  situation  that  would not be  allowed under laboratory QA  programs where
independent review and oversight are required prior to release or utilization of results.

A very  effective  external QC measure, confirmatory sampling, should be incorporated as a
routine QC measure into field sampling and analysis plans. Comparing field measurement results
to radiochemical  analyses  of samples using  recognized, independent, quantitative laboratory
techniques  provides empirical evidence of the effectiveness of the field measurement process.
Integrating such quality control measures into the field measurement process lends a large degree
of defensibility to field measurements as long  as it is performed  at intervals frequent enough to
provide meaningful statistical  feedback on the adequacy and implementation of the measurement
program in  all of its  unique  measurement  situations. When the scope  of the QC program  is
relatively limited, or when  results are received long after the field efforts are  complete  and the
decisionmaking is  complete, the program  will  do little to provide meaningful  controls  on
measurements.

4.4.2  Quality Systems Standards, QA and QC for Laboratory Measurements

EPA's G-series QA documents provide extensive guidance on topics applicable to measurement
projects, including the development (EPA QA/G-1, 2002a) and assessment (EPA QA/G-3, 2003)
of quality systems; on systematic planning using the DQO process  (EPA QA/G-4, 2006; EPA
QA/G-5M, 2002c); the development  of quality assurance project plans (EPA QA/G-5, 2002b)
and  standard operating procedures (EPA QA/G-6, 2007);  and on audits and assessments (EPA
QA/G-7, 2000).

Laboratories and  their operational systems have  a  history of maintaining quality systems that
allow them to comply with extensive and elaborate  quality requirements. These quality systems
prescribe in detailed fashion the  elements needed to  generate and  document usable data from the
initial procurement of an instrument, through setup and calibration to data evaluation, reporting,
and  interpretation. The laboratory must maintain management structures that ensure adequate
resources and oversight are available to perform  the testing  required of them.  The laboratory's
ability to generate analytical results must be validated for all measurements. The laboratory must
routinely perform reliable and defensible QC that demonstrates that all measurement systems are
in control and thus capable  of meeting and producing data that meet MQOs. The laboratory also
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


must completely and unambiguously document all activities associated with measurements such
that all results can be recreated from available records. Such programs and  standards cited are
written  with the  laboratory process  of QA/QC and instrument calibration in mind.  No
comparable  or comprehensive nationally  accepted and nationally implemented quality systems
programs are currently available for field measurements.

Radiochemistry laboratories operate under comprehensive laboratory quality systems standards
such as the TNI Standard (NELAC 2003), Department of Energy Consolidated Audit Program's
Quality Systems for Analytical Services (DOE 2009), the Department of Defense Quality Systems
Manual (DOD, 2009), ANSI N42.23-1996 (ANSI, 2004a), and ISO/IEC 17025 (2005). One key
example of  the many elements addressed by  laboratory quality programs is the calibration of
detectors. Excerpts from several consensus standards regarding standardization and calibration
are cited here to  provide an example of the detail and broad influence of such documents on the
overall process and the quality and defensibility of measurement results.

For example, laboratories are accredited by any number of organizations to standards such as the
TNI Standard (NELAC 2003).  The TNI Standard is  a comprehensive quality  standard that
addresses, among other things, issues of traceability for laboratories conducting definitive
environmental measurements:

       "...   [T]he  essential elements that shall define  the  procedures and  documentation for
       initial instrument calibration and continuing instrument calibration verification to ensure
       that  the data must be of known  quality  and be appropriate for a given regulation or
       decision."

       "[A]ll initial  instrument calibrations must be verified with  a standard obtained from a
       second manufacturer or lot  if the lot can be demonstrated from the manufacturer as
       prepared independently from other lots. Traceability shall be  to a national standard, when
       commercially available."

The American Society for Quality Standard E4 (ASQ E4), Quality Systems for Environmental
Data and Technology Programs-Requirements with Guidance for  Use (ANSI 2004b), states, for
example, that for measurement devices, "Traceability to  nationally  recognized performance
standards should be maintained when they are used for critical  or sensitive items and activities."
American Society for Testing and Materials (ASTM D7282 2007), provides detailed guidance on
the setup, calibration, and quality control of instruments used for radioactivity measurements.
MARLAP (2004) Chapter 15,  "Quantification of Radionuclides," provides  guidance on the
importance of standardized calibration techniques using sources of known and traceable activity.
Specifically,

       "The goal of calibration- or test-source preparations is  to maximize detection capability
       while minimizing the introduction  of bias and uncertainty into the measurement process.
       To achieve this goal, calibration sources  should be prepared in a manner that provides
       comparability to test sources with respect to geometry, composition,  and distribution of
       the test-source material within a container or on a source mount."
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


Furthermore, it states that:

       "Proper  instrument  calibrations  are  essential  for  the  proper  identification  and
       quantification  of radionuclides  in  samples.  It is important to initially  calibrate  the
       instruments with calibration sources that are traceable to a national standards body. Once
       calibrated, the continuing validity of calibrations should be checked on a periodic basis
       (Chapter 18, Laboratory Quality Control) as specified in a laboratory's quality manual."

The QC measures taken to verify proper instrument calibration and use are another required
component of a defensible measurement process. These  measures include  instrument stability
and background checks, as well as quality control sample analyses that empirically demonstrate
the validity  of measurements. These elements are addressed, for  example, in the Nuclear
Regulatory  Commission's  Regulatory  Guide 4.15, Quality  Assurance for  Radiological
Monitoring Programs (Inception through Normal Operations to License  Termination)—Effluent
Streams and the Environment  (NRC 2007), and include routine analysis  of control  samples,
duplicates, blanks,  and matrix spikes. Such QC samples often are not performed in an equivalent,
formalized manner when making field measurements as would be required  under an accredited
laboratory's quality system.

Unlike laboratory systems, field operations are more transitory and are not  as readily amenable
to formalized audits. Accrediting authorities routinely audit laboratories to ensure compliance
with  the requirements  of quality  systems  standards.   Laboratories   participate  in  routine
independent  proficiency  testing  (PT)  studies  to  demonstrate  satisfactory performance  of
laboratory methods. These PT studies  are quantifiable measures of assurance that analytical
systems are working properly to produce reliable and defensible data and that offer opportunities
to make improvements when they do not.

In contrast, a field measurement team for an incident response may be made up of personnel who
have been pulled together for that specific project. They  may  not have been routinely audited,
nor are they as likely to have a documented record of compliance with a quality standard or
standard operating procedures (SOPs). The use of different instruments in  varied settings, and
the implementation of guidance that varies from what they are accustomed to may necessitate
additional QA/QC  measures to ensure that measurements are defensible.

Regular blind intercomparison programs generally are not viable options for field sampling and
measurements organizations due to practical challenges such as the preparation of test plots or
the need to transport field crews to a facility where such plots are available. The benefits of using
field calibration facilities,  such as the large area calibration pads at Walker Field Airport in
Grand Junction, Colorado (Leino et a/., 1994; Novak, 1998), could be substantial because they
would allow validation of in situ measurement technologies and training of field personnel prior
to mobilization.

Quality systems standards address another parameter key to performing quality measurements in
any setting.  Variability  in  ambient conditions such as  temperature,  humidity,  and ambient
background  could  affect analyses  and challenge notions of consistency and repeatability that
form the basis for setting up, maintaining, and operating analytical instrumentation in laboratory
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


settings. Careful storage and control of samples generally allow reanalysis of a sample, should
problems arise that could impact the quality or integrity of analyses.

Finally, laboratories maintain detailed records and generate extensive data deliverables that allow
each individual measured parameter to be recreated in detail and the measurement data to be
independently verified and validated. Based on the documentation produced, analytical results
can be independently verified, validated, and assessed from the deliverables and from archived
records. Comparable documentation for field measurements is more challenging because of the
fluid field conditions compared to those in the more controlled laboratory environment.

4.5  Quality Assurance Project Plan

A QAPP supplements the default quality system by providing a blueprint of where, when, why,
and how a particular measurement  project will  achieve data of the type and quality needed and
expected. A QAPP can form the basis of a QA program (EPA QA/G-5, 2002b). This document
should address:
       Personnel training and qualifications;
       DQOs and MQOs;
       SOPs, or schedules for the implementation of the QA program;
       Acquisition and maintenance of materials and supplies;
       Calibration;
       QC of instrumentation (including traceability of calibration sources);
       QC of routine measurements;
       External intercomparison programs and internal audits;
       Training of measurement personnel;
       Verification and validation (V& V) of data;
       Audits, corrective actions;
       Control and documentation of procedure revisions;
       Field logs (describing environmental conditions);
       Records of measurements (e.g., the time, date, location, instruments, and procedure used;
       personnel, etc.) with sufficient  detail to permit results to be  unambiguously recreated
       from data retained;  and
   •   QC  records  for  radiation  measurement instrumentation  (including  the  results  of
       instrument checks,  calibrations, instrument background determinations,  and maintenance
       activities that could affect equipment performance).

4.6  Uncertainty Estimates and the Measurement Process

MARS SIM  recognizes  the  importance  of minimizing  the  uncertainty  of data used  for
decisionmaking and stresses that "[s]ite surveys should be performed in a manner that ensures
results are accurate and sources of uncertainty are identified and controlled" (MARSSEVI 2000,
Section 4.9). MARLAP (2004, Appendix B) discusses the sources and impact  of uncertainty in
the measurement process:
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


       "The uncertainty of the measurement process involves not only  an instrument and its
       reproducibility, but also the representativeness of the sampling. There will be sampling
       uncertainty, due to spatial and temporal variability in concentrations across the site and
       from one sample to the next. There will also be analytical measurement uncertainty due
       to the variability in the  measurement process itself. Since it is impossible to eliminate
       uncertainty, basing decisions on measurement  data opens the possibility  of making a
       decision error.  Recognizing that decision errors are possible because of uncertainty is the
       first step in controlling them."

It goes on to state that:

       "...sampling uncertainty can  be reduced by  collecting a larger number  of samples.
       Measurement uncertainty can be reduced by analyzing  individual  samples several times
       or using more precise laboratory methods. Which uncertainty is more effective to control
       depends  on their relative magnitude.  For much  environmental work,  controlling
       [reducing] the  sampling uncertainty error by increasing the number of field samples is
       usually  more   effective than   controlling  measurement uncertainty  by repeated
       radiochemical analyses." (MARLAP 2004, Appendix B, B-ll and B-14)

4.6.1   Uncertainty Estimates and Field Measurements

When using field survey instruments to perform large-scale radioactivity measurements, there
are several factors that affect representativeness of sampling. These factors include:

   •   Non-uniform dispersion of radioactive material in the area being measured;
   •   Variability of ambient background radiation in and adjacent to the area being measured;
   •   Lack of knowledge about depth penetration of the radionuclide contaminant;
   •   Resuspension of some of the surface contamination during the measurement process;
   •   Weather conditions during and immediately prior to the measurement; and
   •   Robustness of the sampling and analysis plan.

In the field, it can be difficult to control and estimate these uncertainties.  Thus, field surveys of
structures and materials to be left in place may provide measurements of contamination with
poorly known uncertainties. Follow-up analyses using swipes  (to assess lower yet significant
levels of removable and  air-suspendable material), and surface  and sub-surface grab samples (to
assess volumetric contamination) can be used to confirm field measurements.

Another factor affecting  the uncertainty of reported field data is the correspondence between the
calibration geometry of the instrument and the actual geometric configuration of the radioactivity
in the field. Although  uncertainty estimates based  on sample density and shape  can be
mathematically computed, there is no uniform method  established for doing so. Guidance from
documents such as Guidance on Systematic Planning Using the Data Quality Objectives Process
(EPA QA/G-4, 2006), and the  GUM (ISO 1995) may be applied to field measurements. The
application of  these  methods  to  field surveys  of  materials  and equipment  is treated in
MARSAME (2000). The GUM procedures for calculating uncertainties do not always presume
that definitive estimates of each component of uncertainty are available, but provide a framework
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


for assessing the magnitude of such contributions given professional judgment and knowledge of
the measurement process. This allows planners to focus on those parameters that are most likely
to impact the overall uncertainty and affect decisionmaking.

The  concepts  of MQOs  and DQOs for field  measurements of radioactivity are not as well-
developed and implemented as they are for laboratory measurements. Similarly, uncertainty
analysis and its implication for the planning and decisionmaking  process  are  not nearly as
advanced as for laboratories. While MARSAME addresses many such concerns, it has only
recently been published, and there has been little training available in its use. Promulgating these
ideas into the field setting will require significant time, validation of the methods, and training of
the analysts who will perform these measurements.

4.6.2  Uncertainty Estimates and Laboratory Measurements

MARLAP  provides  guidance  on  calculating  uncertainty  and  measures used to minimize
uncertainty in sample measurement processes in the radioanalytical laboratory.  The guidance
provided in MARLAP supports the concepts for detailed measurement uncertainty estimates. By
placing each sample in a reproducible geometry within a shielded detector,  laboratories create a
controlled and predictable  environment in which measurements will be performed (including
stable, low,  and well-characterized  backgrounds). Samples  are prepared to ensure congruence
between the sample test source and the  calibration geometry. While this is clearly advantageous
in terms of minimizing measurement  bias,  it also minimizes measurement uncertainties  and
makes it easy to assess the contribution to the uncertainty from the measurement process.

The  treatment of measurement uncertainties and their  relationship to MQOs and DQOs have
been thoroughly addressed in MARLAP for radioanalytical chemistry measurements in the
laboratory.   The basic principles  underlying these  methods  are  outlined  in  Guidance  on
Systematic Planning  Using the Data Quality Objectives Process, the GUM, and other guidance
documents.  The methods  for estimating measurement uncertainties  are not  limited to  the
applications cited  in these  references  but  are equally  appropriate for virtually any type of
measurement.

Determination and reporting of uncertainty  for radioanalytical laboratory  measurements have
been routine at laboratories for  many years. There  have been  volumes of publications  on
uncertainty in radioanalytical measurements. ISO  17025 and  NIST traceability requirements
have increased the focus on determining and reporting measurement uncertainty and made
uncertainty  analyses very familiar  in  the laboratory  setting. MARLAP  Chapters 19 and  20
provide  detailed  guidance  and  examples  of  estimating  uncertainty   in  radioanalytical
measurements. Training in the use  of  these specific  methods has been provided at numerous
MARLAP training classes since 2005 and at nationally recognized radiochemistry conferences
for substantially longer periods of time.13

When considering the relative merits of in situ versus laboratory measurements, it is important to
keep in mind that the overall uncertainty of an ISGS measurement of surface activity may be less
13 See program  descriptions  for the 52nd and 53rd Annual Radiobioassay and Radiochemical Measurements
Conference www.lanl.gov/BAER-Conference/.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


than the combined uncertainty of laboratory measurement due to the uncertainty associated with
sampling. It is for this reason that ISGS measurements are attractive options.

Nonetheless, before  a program can rely on any  measurement, be it  from the  field or from a
laboratory, the quality of the measurement must be assured. This would include a demonstration
that  its estimate of measurement uncertainty is reliable and defensible and that it can satisfy
applicable MQOs. If experience,  guidance,  and programmatic support for  this are weak or
lacking, or conditions are variable such that inputs into the uncertainty model are poorly known,
field  measurements   should be verified  on a  routine  basis  using confirmatory  laboratory
measurements to demonstrate that MQOs have been satisfied.

5.  Considerations  on the Capabilities  and Limitations  of Radioanalytical Measurement
    Techniques in the Field and Laboratory

Field and laboratory measurement techniques each have their strengths and weaknesses, but they
may be used  together in a  complementary fashion during the days and months following an
incident.   This section  addresses  some of  the  key factors  impacting  the  effectiveness of
measurement  techniques as they are used in  the field  and at the laboratory  for  measuring
different  types of radiation and radioactivity. Among the key factors are the ability to accurately
calibrate  equipment for a given purpose, and to measure and apply corrections for background
such that the bias  and uncertainty  of the  measurements are controlled at  levels  that are
appropriate  for  decisionmaking.  An  understanding of these   factors  will  help  Incident
Commanders  identify appropriate measurement techniques and take  optimal advantage of the
respective strengths of the variety of field and laboratory measurement options available to them.

5.1  The Impact of Background Radiation on Radioanalytical Measurements

Ambient radiation can have a significant  impact on analytical measurements of low levels of
radioactivity. When low action levels are encountered, as would likely  apply during the recovery
phase of  an incident and during final status surveys, background activity must be accurately
measured and subtracted from measurements to ensure the quality and defensibility of results.
Inaccurate measurements of background activity  will  result in  biased measurements  and
underestimation of uncertainty, and may potentially lead to incorrect decisions. The following
section addresses the impact of background  radiation on radioanalytical  measurements in the
field and in the laboratory.

5.1.1  The Impact of Background Radiation on Field Measurements

Most radiation detection instrumentation responds to one type, or to  a combination of several
types, of radiation. Field instrumentation  generally  provides results as gross  activity14 (e.g.,
counts) or dose or exposure (e.g., mrad or roentgens) for  the particular type(s) of radiation.
Because field  detectors are built to be portable, they may not be heavily shielded and respond to
any  source  of radiation that  impinges on  the active  volume  of  the  detector.  Significant
14 The expressions "gross activity," "gross alpha," "gross beta," and "gross gamma" will be used in this guide to
refer to non-specific measurements of alpha, beta, or gamma radiation. These will be contrasted with measurements
of radioactivity, spectrometric or otherwise, that are specific enough to be attributed to a specific radionuclide.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


contributions from the ambient background radiation beyond the area of measurement may limit
the accuracy of field measurements adjacent to  other  contaminated  areas. According to  the
International Commission on Radiation Units and Measurements (ICRU) 53, "[a]t a detector
height of 1 m, about 30% of the total fluence rate measured comes from beyond a 3-m radius for
137Cs that is  uniformly distributed with depth in the soil." For a surface source distribution, about
half the fluence  comes  from  "beyond  10 m"  (Reginatto  et a/.,   1997).  Light shielding
(collimation) often is  used to reduce (but not eliminate) shine from  beyond the immediate area
being measured.  Unfortunately, cylindrical  shielding also reduces  the field of vision of the
detector and increases the number of measurements needed to characterize an area.  This impact
of ambient  sources of background has been reduced and the "field-of-vision" of  the detector
improved by using a downward-looking bell-shaped shield  with  a detector  mounted in  the
"neck" of the bell mounted on a wheeled frame for ease of movement.15

Sources of ambient radiation, such as cosmic radiation and naturally  occurring radioactivity, are
ubiquitous  in the environment. Naturally occurring radioactive materials  such  as uranium,
thorium, their decay  progeny,  40K,  and others,  represent significant  sources of  background
radiation in  soil, air, water, and construction materials (e.g., concrete, stone, wood, shingles, etc).
For example, the National Council on Radiation Protection and Measurements (NCRP) lists the
mean specific activities for several key naturally occurring radionuclides in soil as: 0.67 pCi/g
238U; 10 pCi/g 40K; 0.8 pCi/g 226Ra; and 0.65 pCi/g 232Th (NCRP 1976). Uranium,  radium, and
thorium decay through radon (an inert gas) into a number of radioactive decay products. As a
gas,  radon  and its shorter-lived progeny are transported through the air and  may deposit on
surfaces  and  impact measurements of radioactivity  on  and   around  those  surfaces in an
unpredictable manner.

In addition to naturally occurring radioactivity, anthropogenic sources of radionuclides,  such as
137Cs or 90Sr, are widely present in the environment as a result of fallout from the  atmospheric
testing of nuclear weapons.  Typical global  concentrations of  137Cs  and 90Sr in  surface soil
samples may range up to 0.4 pCi/g and 0.3 pCi/g, respectively.16

The  observed magnitude of the ambient background varies significantly in amount from location
to location  and over time. For  example, background dose levels due  to gamma radiation
(excluding   222Rn)  can vary substantially  but  commonly range  between 40-100 mrem/y.
Outdoors, the beta dose rate from soil one  meter above the  ground is about  one-third of the
gamma dose. Beta/gamma exposure rate measurements, using field  instruments that have only
minimal shielding, may be impacted by variations in terrestrial radionuclide concentrations and
the various effects of cosmic radiation, depending upon altitude (NCRP 1992).

If in situ measurements of alpha, beta, or gamma activity are  to  be  considered unbiased and of
known uncertainty, they may require adjustment to correct for the contribution from  the intrinsic
detector background activity, and for ambient radioactivity. As levels of residual radioactivity
and  MQOs  approach  background levels, the impact of ambient background on the quality of
15
  Personal communication with Edward Walker, 2010.
16 Based on population-weighted average cumulative deposition density values (world) for 137Cs and 90Sr for the
year 1999; fromUNSCEAR 2000, Annex C, Table 11. Conversion from cumulative area! deposition values assumes
                                                3
deposition in the top 5 cm of soil, and a soil density of 1.6 g/cm .


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


field measurements will become much more critical. Accurate and  precise measurements of
detector  background  activity  and corrections  for background activity are  possible in well-
controlled  environments  where the  detector  and ambient background can  be  determined
separately from the object being measured.

If the ambient background radiation level cannot be characterized accurately, measurements of
radioactivity  may  be  biased and measurement uncertainties difficult to estimate, resulting in
measurements of unknown quality. If decisions about reoccupying  space are based on such
results, the amount of contaminant present in an area could be underestimated and result in a
negative  impact to public health. Conversely, unreliable background measurements could result
in the overestimation  of contaminant present, and the  duration and costs of recovery operations
could be  increased unnecessarily. No matter what approach is taken, the accuracy of background
correction factors should be established for different measurement situations and confirmed as a
periodic QC measure by periodic confirmatory sampling.

5.1.1.1  The Impact  of Background Radiation on Gross Measurements of Alpha and Beta
        Radioactivity in the Field

Typical hand-held  survey meters, such as thin-window Geiger-Muller detectors, respond to alpha
and beta particles and  gamma rays but may not be sensitive enough for reliable measurements of
alpha and beta/gamma contamination at activities close to ambient background levels. Detectors
specific  to  certain types of radiation,  such  as  alpha  scintillation  detectors, often have
backgrounds  that  are  low enough to perform  reliable surface measurements  of pure alpha
emitters at relatively low  activity levels.17 When levels of radiation being measured are clearly
above ambient background levels, as may be the case during the earlier phases of an incident, the
contribution of background to the measurement may be small to negligible. As lower and lower
levels of radioactivity are measured,  as will be the  case as an incident  response progresses,
differentiating  between  background   and  signal  from  the  analyte  becomes  increasingly
challenging and techniques that played a role early in the response may no longer be effective.
Thus, it  is important  to  account for sources of background activity when performing field
measurements of radioactivity.

Ambient background  due to beta and gamma radiation will vary significantly by location  and
over time when using  unshielded detectors in the field. The use of counting statistics as the basis
for  detection decisions  may  not adequately  reflect this  variability and  could lead  to  an
underestimation of the overall uncertainty of a measurement. Unreliable measurement results and
underestimates of uncertainty may lead to incorrect  detection  decisions or a  false sense of
security about the  quality of data obtained. Thus, it is critical to ensure that each measurement
technique used is  appropriate  for conditions  under which measurements will be performed.  It
should take into account variability in the background and demonstrate that  a technique is  still
capable of meeting quantitative and qualitative MQOs.
17It should be emphasized that this statement is applicable only when the contamination is present directly on the
surface of the object being measured such that self-absorption does not decrease the effective response of the
detector and the magnitude of analyte signal relative to the background.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


Matrix materials (soil, asphalt, building  materials,  etc.) may contain intrinsic  background
radioactivity from naturally occurring radionuclides present in the matrix prior to the incident.
This intrinsic radioactivity contributes to gross activity measurements and, unless appropriate
corrections are made, may be significant enough to result in incorrect decisions about whether
contamination is present. Similar to ambient background, this effect becomes most significant as
the incident response progresses toward later stages and the activities of concern  approach
background levels. The intrinsic radioactivity  of a  matrix material may  be determined by
analyzing a representative  uncontaminated  sample of the  materials using the technique  of
interest. This information can be used  to  determine the  expected  distribution gross activity
measurements of uncontaminated background samples and  thus the levels at which one can
identify, with confidence,  situations  that deviate from background.  Depending on the natural
background, the technique involved, and DQOs, it may or may not be possible to identify when
contamination exceeds project DQOs. If action limits or corrections are derived without regard to
the variability normally encountered under measurement conditions, systematic low or high bias
may result  and may lead to an unacceptably high rate of false decisions regarding the presence
and the magnitude of contaminants.

While it may be possible to derive matrix-specific  background corrections and estimates  of
associated  uncertainty, sometimes it may  be beneficial to seek out  more  robust  detection
techniques  (e.g., when the analyte signal at the  action level is  less than five to 10 times the
combined uncertainty of the sum of the ambient, intrinsic, and instrument backgrounds). For
example, if a radionuclide  is not present in significant concentrations in  the environment,  a
spectrometric  measurement technique  such  as high  purity  germanium  (HPGe)  gamma
spectrometry might discriminate quite effectively against naturally occurring radionuclides that
would  interfere  with  the  ability  of a  non-spectrometric  technique  (i.e.,  a  gross activity
measurement) to provide meaningful measurements at  lower activity levels.

When gross activity results are corrected for contributions from ambient background activity, the
accuracy and uncertainty of correction factors should  be validated under differing measurement
situations. It also is recommended that field survey measurements be verified on a periodic basis
as a QC  measure (e.g., grab  sampling with confirmatory analysis at  a fixed  laboratory).
Empirically validating measurement  methods prior to use under real measurement conditions
will allow defensible  statements of applicability to be made  about the measurement technique,
and will demonstrate that the technique is capable of  effectively  meeting the DQOs and MQOs
needed for incident response  decisionmaking while  minimizing  vulnerability  to future  data
challenges.

5.1.1.2  The Impact of Background  Radiation   on  Field  Measurements of  Gamma
        Radiation

Gamma rays are the most penetrating form of radiation and have the longest range in materials
compared to the  other radiations (e.g., alpha and beta) commonly measured in the environment.
Thus, concern about interference of gamma rays with  the measurement is not limited just to the
radioactive materials intrinsic to objects being measured. For example, a gamma measurement of
a wall surface in a building interior will have some component contributed by sources in the area
other than those  in the expected field-of-vision of the detector. When detectors are only lightly
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


shielded or collimated, gamma rays from every part of the room and beyond can impinge on the
detector and contribute to the measurement. Gamma ray sources outside the area being measured
may significantly impact readings. For example, measurements taken inside a building in the
vicinity of a nuclear facility show variations in "background" that correspond to the amount of
radioactivity emitted from that facility.

When counting with a gamma spectrometer, background corrections may not be necessary if the
radionuclide  of concern is not present in the background of  the  area where  the  sample
measurement is taken. While naturally occurring radioactivity is ubiquitous, most anthropogenic
radionuclides are rarely encountered in significant concentrations in the environment. In the  case
of an incident  response, however, radionuclides associated with the incident will be widely
distributed in impacted areas, and may thus become a component of ambient backgrounds and
interfere with measurements prior to remedial activities.

If background subtractions are applied to low-level  in situ measurements, the background and
especially its variability  (i.e., uncertainty) need  to  be  well-characterized  and  reflected in the
measurement results or their evaluation. Where possible, the effect of background on sample
measurements may be minimized (but not  likely  eliminated) by  shielding the  detector.  The
measurement process should include a careful consideration of whether variability in background
activity is adequately reflected in the uncertainty of the background corrected  result to ensure
that  measurements will  be capable of meeting  established MQOs. If non-specific  gamma
radiation (i.e., gross gamma) is  being measured, local  and temporal variations in  background
may make it difficult, or even impossible, to accurately and  reliably determine the  background
activity (or its  uncertainty). No matter what approach is taken,  the accuracy of  background
correction factors should be established for different measurement situations and confirmed as a
periodic QC measure by periodic confirmatory sampling.

5.1.2  The Impact of Background Radiation on Laboratory Measurements

By  its  nature, the laboratory provides  an  environment where  factors affecting radioanalytical
processing and  measurements can  be very carefully  managed  and  controlled.  Laboratory
instruments are  housed in permanent locations within  a building with controlled operations,
structure, temperature,  and humidity. The detectors used for measurements  are heavily shielded.
The  shielding not only reduces the levels of the ambient background radiation impinging on the
detector  surface, but it  also  helps  to ensure that detectors  are exposed to consistent  and
reproducible background radiation levels. As measurement requirements approach lower levels
(as is the case in the recovery phase of a radiological or nuclear incident), the highly controlled
background   environment  of the  laboratory  setting  allows more  sensitive  and  precise
measurements and ensures quality and dependability of the data.

In instances  where levels of contaminant radioactivity are very high,  having  a controlled
background environment is less vital. In fact, analysis of large numbers of samples of very high
radioactivity  levels may  create problems of cross-contamination and  elevated  or  variable
background in the laboratory (despite the available shielding). Thus, during  the early phase of an
incident,  the number of samples of high activity sent to a laboratory to be analyzed should be
minimized, and the purpose of the analysis focused on identifying the radionuclides that are

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


present,  establishing  an  upper  bound  on  their  concentration,  and  verifying  key  field
measurements.

Although there is generally a high degree of confidence that results measured in the laboratory
accurately reflect concentrations in any given sample delivered to the laboratory, the size of the
sample delivered to the laboratory is generally limited to the gram to kilogram range. This is a
much smaller effective sample size than is possible with ISGS measurements and might require
that more samples be taken and analyzed to obtain a similar level of confidence that an area is
adequately characterized and hot spots have not gone undetected.

The determination of intrinsic background in the sample matrix is an issue common to both field
and laboratory measurements. The activity of the matrix results from radionuclides present in the
matrix prior to the incident. Similar to the case discussed previously for field measurements,
intrinsic levels of radioactivity in the matrix may result in incorrect decisions that contamination
is present unless appropriate corrections are made to the measurement. For example, background
activity will  confound attempts to  identify alpha and beta emitters  at  activities  similar to
background when using gross activity measurement techniques. At the laboratory, in contrast,
chemical separations can be used to determine levels of radionuclides present  well below the
native gross activity of the matrix.

Similar to field measurements, the intrinsic background of the matrix must be well-characterized
to determine whether an area has been impacted.  Unless the signal attributable to the analyte at
the action level is less than five to 10 times the combined intrinsic backgrounds of the material
being measured and can  be  shown to be de minimis, empirical  matrix-specific background
corrections and estimates of associated uncertainty must be established. At these lower activity
levels, however, it is generally beneficial to seek out a more robust detection technique where
such is available. For example, for radionuclides not present in significant concentrations in the
environment, spectrometric techniques  may permit  effective  discrimination  against naturally
occurring radionuclides and allow non-spectrometric techniques (i.e., gross activity measure-
ments) to provide more accurate measurements at lower activity levels.

In contrast to many field measurements, ambient backgrounds in the laboratory  are quite stable
and  can be  well-characterized,  thus  minimizing  bias  and  uncertainty in  measurements.
Measurements  of detector background activity  and corrections for background activity are
possible  in well-controlled environments where  the  detector and ambient  background can be
determined separately from the object being measured.  The accuracy of background correction
factors applied in the laboratory is established and confirmed on a routine basis as a condition of
using an instrument.

5.2   Types of Measurements of Radioactivity

The subsequent discussion of instrumentation and measurements of radioactivity will address the
strengths, weaknesses, and general considerations  that  affect  the  capabilities of field  and
laboratory measurements.  In  the  most  general  sense,  a field survey  measurement  is  any
measurement used to conduct a radiation survey  in the field.  For  the sake of this discussion,
however, a distinction will be  made between field survey measurements and field spectrometry
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


measurements. Measurement techniques that measure gross activity will be classified  as field
survey measurements. These include measurements that measure gross alpha, beta, or gamma
radiation, but which are not capable of determining the energy of the radiation or the isotope that
emits the radiation. Field spectrometry measurements, on the other hand, refer to measurement
techniques that are capable  of analyzing the energy spectrum  of radiation of concern, usually
gamma radiation, and are thus capable of identifying the radionuclide(s) present.

For radiochemical analysis  at laboratories, a similar distinction  applies.  Chemical separations
followed by non-spectrometric measurements can achieve  definitive, radionuclide-specific
measurements at the lowest activity  concentrations. Thus, a distinction  will be made between
screening measurements and spectrometric measurements. Screening measurements will refer to
measurements of gross activity without determination of the specific radionuclide that led to the
emission of the radiation, whereas spectrometric measurements  will refer to those measurements
capable of radionuclide-specific determinations.

5.2.1   General  Considerations Regarding Field Measurements

Radioactive  emissions from  the surfaces of objects are measured using instrumentation sensitive
to the radiation of concern (alpha, beta, or gamma). A large number of factors vary from material
to material and impact the manner in which radiation is, or is not, emitted from the surface of an
object. Variability in any one of these  factors may significantly affect instrument response
relative to the source of the radioactivity (for further discussion,  see Section 5.3 below).

The accuracy and sensitivity of measurement are limited by knowledge about the measurement
situation and the assumptions made  about the  parameters that play a role in the emission of
radiation from  the  object  being measured to  the active volume of the detector.  Field
measurements are, by their very nature, measurements of radiation emitted from a surface. When
contamination is deposited directly on a surface,  its measurement is much easier than if it is
deposited more or less volumetrically within  an object. As discussed previously, surface activity
is radioactivity  deposited on  or  close enough  to  a  surface  that minimal  self-absorption
corrections are needed to effect a precise and unbiased measurement of that radioactivity. When
the depth profile of the radioactivity is not known, or cannot be accurately accounted for during
calibration of the instrument, accurate  measurements  of radioactivity are not possible. Due to
alpha- and beta  emitters'  limited range  in  matter, their measurement will be  significantly
impacted even following minimal penetration of contaminants into an object. In contrast, reliable
detection and  quantification of medium- to  high-energy  gamma emitters are possible even if
contaminants have penetrated several  centimeters into an object.

While spectrometric  measurements are sometimes considered to be of higher quality than gross
activity measurements, depending on  the specifics of the measurement situation (e.g., surface vs.
volumetric contamination), the quality of either type of measurement may range from screening
quality to an unbiased measurement of known uncertainty and may find differing levels of
applicability depending on questions at hand.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


5.2.1.1  Survey Measurements in the Field

First responders typically will use the latest technologies that rely on the detection of gamma
rays, x-rays, and beta and alpha radiation. The applicable technologies include a variety of
portable devices such as beta/gamma and alpha survey instruments in a variety of configurations.

Generally, gamma radiation above about 200 keV (medium- to high-energy gamma emissions) is
the easiest to  detect and accurately quantify with field measurements, because it is subject to
significantly less attenuation than  alpha, beta, and lower-energy photon emissions, and can thus
penetrate  several centimeters of material and  arrive at the detector with enough  energy to be
registered. Field measurements frequently provide results as uncalibrated instrument response,
such as counts per minute (cpm),  or in terms of dose or exposure (e.g., urad/h, uR/h) based on
                             1 &                                                 	
the particle flux at the meter.   For example, gamma survey meters,  such as Nal(Tl) detectors
and micro-R meters, are frequently calibrated using 137Cs or 60Co, perhaps due to the prevalence
of these nuclides at many nuclear sites and their relatively low cost, but also since these detectors
are optimally sensitive to radioactive emissions in this energy range. More recent generations of
instruments, however, may report activity results referenced to various radionuclides. The user is
strongly cautioned against  interpreting  such results  as  accurate measurements of  absolute
radioactivity (e.g., pCi or pCi/g)  unless  the instrument has  been calibrated for the particular
measurement situation since accurate quantitation is possible only after application of corrections
for factors such as  radionuclide(s) decay  type  and energy, matrix composition and density,
geometric  distribution of the contaminant,  attenuation due to surface roughness or overlaying
material, presence of multiple radionuclides, and variations in the contribution of activity from
radionuclides in the background.

Like any other instrument, field survey instruments must be calibrated prior to use if they are to
provide results that are traceable  to  national standards or intercomparable from instrument to
instrument. Most  field instrumentation used  to measure the concentration  of radionuclides
(instead of dose rate) detects total particle fluence rate with minimal regard to the energy of the
radiation.  Conversion of measurements of  count rate or dose (e.g., mrad per hour) to surface
activity (pCi/100  cm2)  or  volumetric/massic  activity  concentration   (e.g.,  pCi/g)  requires
knowledge of how radiation has been attenuated within the volume of the source and scattered
between the  source and detector.  Unless  calibrations  are  performed  that  reproduce  the
radionuclides and geometries and take into account self-absorption effects caused by the matrix,
the potential for bias and  unknown level of uncertainty in absolute  measurements of activity
cannot be discounted without additional sampling and analysis.

For direct,  static measurements of beta or alpha  radiation on  surfaces, the efficiency  of a
measurement can be viewed as a composite of two quantities:

 1) Instrument efficiency, which is a function of:
    •   Type of the radiation
18 While measurements of particle flux at the meter can be used to produce accurate estimates of dose, the use of
"uncalibrated  instrument response," that is instrument  net count rate, cannot be related to the activity of
radionuclides present (e.g., pCi or dpm) without applying an empirically determined values for detection efficiency,
i.e., cpm/dpm, of a specified radionuclide.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


     •   Energy of the radiation
     •   Detector type
     •   Position of the detector relative to the surface being measured
     •   Window size and thickness

 2)  Source efficiency, which is a function of:
     •   Type of the radiation
     •   Energy of the radiation
     •   Size and shape of the object
     •   Density of the object
     •   Physical composition of the object (i.e., average atomic number of constituents)
     •   Depth profile of radionuclides in the object
     •   Surface texture and roughness of the object
     •   Density of the material
     •   Current moisture  content in the object

Establishing the instrument efficiency, that is, the response of a detector to radiation incident
upon its active area, is a  relatively straightforward process if radioactive sources  are available
with the appropriate  radionuclides in the appropriate geometry.19 Accurately measuring the
source efficiency (i.e., the  fraction of radiation emitted from a surface relative to the total number
of decays taking place in that  surface) for each type  of object or surface to be measured,
however,  is a  much more complicated task  and  may not  be  practicable  without making
simplifying  assumptions. A number of factors determine the fraction of total radiation that will
be emitted from a surface with enough energy to be detected.20 Complex radiation transport
models and considerable  technical expertise may be needed  to generate accurate corrections.
Measurement geometries  are usually much more complicated in reality than approximations
based on  point sources or radioactivity  deposited homogenously  on a plane surface.  Detailed
knowledge about the measurement conditions is  required to derive corrections to the efficiency.
While  the density, physical composition, or even the surface texture can often be reasonably
estimated  for many objects encountered in the field, it is usually impossible to accurately gauge
the depth profile of radionuclide penetration into the surface of objects encountered in the field.
This single factor alone, if not properly accounted for, may seriously impact the accuracy of field
measurements.  This is particularly the case for weakly penetrating radiation such as alpha, low-
to-mid-energy beta emissions, and low-energy gamma and x-ray radiation.

If radioactivity can  be assumed to  reside "on the  surface"  of  an object  and the depth  of
penetration of the radionuclide(s) is shallow enough that radiation is not significantly attenuated
before it escapes from the object, accurate measurements with  known uncertainty are possible in
the field. As discussed earlier, this definition of surface is related to the range of the radiation in
matter and the  ability to make unbiased measurements of activity and associated estimates of
uncertainty. Listed in order of increasing range, alpha emissions  and beta emissions have the
shortest range, followed by x-rays and then gamma rays. Gamma rays are clearly a best case in
this  regard  assuming there is no contribution  from sources adjacent to the surface being
19 See ANSI standards N323A and N323B for calibration of portable instruments.
20 See NUREG-1507 and ASTM standard E1893 for typical correction factors for source efficiency.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


measured (e.g., a wall in another building or a storm drain beneath a sidewalk). Alpha particles,
low-energy beta particles,  and x-rays, in contrast, are worst cases because they are significantly
attenuated while passing though small amounts of matter or even by the  "roughness"  of the
surface from which they are emitted.

Sodium  iodide or HPGe  detectors,  or arrays  of  such detectors,  interfaced to a geographic
information system (GIS) can be used quite effectively to produce  radiation profile  maps of
gamma emitters for characterization and final status surveys. When combined with confirmatory
random and judgmental grab sample analyses at a fixed laboratory, these maps may be presented
in terms  of pCi/g or pCi/unit area. Typical setups incorporate a 2x2-inch detector used manually
to scan in  "swing" mode, 2x2-inch  shielded detector and electronics mounted on a  wheeled
frame for horizontal area coverage, and a large (5-8-inch diameter) Nal detectors mounted on a
motorized vehicle  or towed behind a vehicle for very large horizontal areas. This latter system
usually includes a multichannel analyzer for in situ spectrum analysis, which may reduce or
eliminate the need for lab  analysis for gamma emitters. The limited resolution of Nal detectors,
however, may limit the use of such techniques at lower activity levels because gamma emissions
from many radionuclide(s) of concern overlap those in the background. Thus, the applicability of
such techniques should be  evaluated and validated on a case-by-case basis.

For scanning measurements of beta or alpha radiation (where the survey meter is moved above
and across the surface), additional parameters such as the speed of the survey meter movement
and the  detector time constant must  be  considered to ensure  correct  results and detection
capability. The geometric distribution of radioactivity and the efficiency with which  the field
instrument can detect its radiations must be known. At a minimum, the effective duration of the
count must be  estimated using  assumptions about  radionuclides present,  source geometry, and
detector efficiency to ensure that significant amounts of radioactivity are not missed. Finally, the
technique used for scanning can be very operator-dependent, so this should be taken into account
when  setting  up and  validating the measurement method. NRC (1997)  presents Minimum
Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants
and Field Conditions. MARSSEVI (2000, Section 6.7.2), suggests approaches that can be used for
scanning surveys, and addresses the estimation of  sensitivity (detection capability)  of  scanning
survey measurements.

Given  these concerns, it is vital that field measurement protocols be validated relative to MQOs
prior to use to ensure that  survey instrument methodologies will be capable of producing data of
sufficient quality to support  DQOs  and decisions to  protect  public  health and safety. Field
measurement protocols should require correlated sampling and independent laboratory analysis
to empirically derive  factors  that  can  be  used to  correlate  raw  instrument  results with
radionuclide concentrations in the matrix in question. Confirmatory sampling also should be
performed  as  a routine quality  control measure to  provide evidence that field measurement
techniques  are being performed as  expected and that correlation factors are  accurate for the
measurement situations to  which they are being applied.

In the early  phase of an incident,  field  teams may  encounter higher  levels of radioactive
contamination that approach or exceed PAGs. By evaluating the impact of factors such as self-
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      Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident

                                                                                           91
absorption on detection efficiency in a manner that ensures that contaminants will be detected,
field teams may be able to use field survey instruments to rapidly provide protective results for
highly  contaminated  areas and  samples  such as  air, water, soil,  contaminated  surfaces  of
materials and buildings,  and swipes. Such results may find great utility in providing prompt,
conservative decisions regarding the health and safety of the public.  At this point in an incident
response, obtaining measurement results in real-time may outweigh  the need to obtain accurate
measurements of radioactivity and the potential dose it might cause.

During the intermediate  and recovery phases of an incident, field survey instruments may be
used  to make dose measurements and identify areas with levels of contamination  marginally
above the ambient background. However, field survey measurement techniques may not be well-
suited to  detecting and quantifying contamination as instrument signal approaches low  levels.
Field survey  measurements may not provide unequivocal results:

    •   Where analyte signal approaches the detection threshold of the detection technique, or
    •   Where complex physical monitoring geometries exist, or
    •   Where mixtures of radionuclides may be involved, or
    •   Where weathering or other processes have set  in and led to volumetric  contamination of
       materials.

Field survey  instrument measurements can, in most cases, provide general radiation information,
such  as indications  of the presence  of  radioactive contaminants,  but  lacking confirmatory
analysis, they generally may not  provide conclusive evidence of successful remediation  during
the intermediate and recovery phases of an  incident.

5.2.1.2  Spectrometric Measurements in the Field

Field spectrometric measurements are capable of  measuring  energy spectra and using these
characteristic spectra to provide for rapid  identification of radionuclides that  are present. One
example of a field gamma spectrometer is a radionuclide  identifier.  This is generally a sodium
iodide or high purity germanium  gamma detector interfaced with a multi-channel analyzer with
automated software  that  analyzes  characteristic  energy  peaks of gamma emissions.  The
Conference of Radiation  Control  Program  Directors (CRCPD) (2006) warns of the potential for
misinterpretation of data:

       fGJreat caution is advised, because no identifier is correct 100% of the time, and further
       analyses may be necessary for proper identification of a source.  Several radioisotopes
21 Deliberately biased assumptions regarding self-absorption may help improve the reliability of field survey
measurements. For example, by assuming a worst-case penetration profile for a known radionuclide contaminant,
biased correction factors for self-absorption and associated estimates of uncertainty may be generated that ensure
that concentrations of a radionuclide that exceed an action level  will be identified. Alternatively, a deliberately
biased ("judgmental") approach might be able to rapidly identify areas that likely exceed action levels, but which
will require additional characterization to  determine the  actual concentration prior to taking action. When biased
assumptions are applied, the technical basis for these assumptions must be clearly stated. The methods must also be
validated under the conditions of measurement using samples containing known concentrations of contaminants
(and interferences) prior to use. Once a method's limitations are  well-characterized, it can be incorporated into
standard operating procedures so that all measurements provide the required degree of protection.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


       emit gamma rays with energies that are similar or overlapping, or the radionuclide may
       not be available for comparison in the library.  These are delicate instruments that are
       sensitive to abrupt changes in temperature and humidity. Additionally,  radionuclide
       identifiers cannot identify a pure alpha or beta emitting radionuclide unless there is an
       associated gamma emitter from one of its decay products.  Consequently,  radionuclide
       identifiers may sometimes misidentify the radioisotope.

More sophisticated field spectrometry instruments  have been developed for decommissioning
nuclear power plants and radionuclide processing facilities at DOE  sites. Much of the above
discussion regarding the  limitations  of survey  instrumentation also  will  apply  to field
spectrometry detectors. Field spectrometry measurements are by their very nature measurements
of activity emitted from a surface and may be of limited benefit unless radiation is effectively
resident on the surface of the object being measured.

Alpha, beta, and low-energy gamma rays  and x-rays are much more rapidly attenuated than are
gamma rays when they  are emitted from material within an object's surface. Thus, alpha, beta,
and low-energy gamma- and  x-ray emitters do  not lend themselves in the field to accurate
spectrometric measurements of known uncertainty unless they are known to be deposited on the
contaminated  surface and thus are not subject  to self-absorption  effects. By contrast, the most
penetrating radiation, medium- to high-energy gamma rays, is less subject to attenuation effects.
Thus, unbiased field spectrometric measurements with known levels of uncertainty are possible
as long as the deposition  profile of the  radionuclides of  concern is predictable and can be
accurately accounted for during calibration of the instrument.

5.2.1.3  In Situ Gamma Spectrometry Measurements

The  most effective  field  spectrometry measurements  are  performed using collimated ISGS
detectors operated with  supporting software such  as In-Situ Object Counting System [ISOCS™]
or [ISOTOPICS™].    ISGS  units are  capable of  greater  specificity, and  depending on
measurement conditions and the analyte(s) of interest, of greater sensitivity than gamma survey
measurements. Under  the  appropriate conditions, ISGS  can  provide  significantly  greater
sensitivity than highly accurate laboratory gamma spectrometry measurements and decrease the
overall number of measurements needed to characterize potentially contaminated areas. This is
due to the large field-of-view and the much larger effective sample size that can be evaluated by
a single measurement. Extended road surfaces, or  large surface areas of walls, ceilings, or floors,
or even entire rooms can be evaluated with a single measurement,  reducing the need to collect
samples for definitive or confirmative analysis at a laboratory.

When evaluating ISGS  results, it is  important to  keep in mind that unless detailed information
about the  distribution of radionuclides in and around the objects being measured is well-known,
22ISGS should be differentiated from commercially available software packages such as ISOCS™ (Canberra
Industries) and ISOTOPICS™ (AMETEK Ortec). In this guide, ISGS  refers to the overall process of gamma
spectrometry measurements performed in situ, or in other words, without the need to destructively sample or disturb
the object or matrix in question. ISOCS™ and ISOTOPICS™' on the other hand, are proprietary techniques that
facilitate one aspect of ISGS by estimating gamma spectrometry detection efficiencies using mathematical modeling
of the counting geometries relative to a well-characterized detector.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


measurements will be qualitative, or associated with high levels of uncertainty, such that only an
identification  of radionuclides may be  possible.23 In  situ germanium  spectrometers  identify
gamma-emitting radionuclides of any gamma radiation incident on the detector. Assumptions
must be made about the geometric  distribution of the radionuclide activity surrounding the
detector even in cases where little knowledge about actual conditions may be  available. The
simplest approximation of geometric  distribution, for  example, would assume  that all of the
radioactivity in the field of view of the detector is concentrated at a single point source in the
most distant point in the area of measurement, say in the furthest corner of a room five meters
from the detector. The uncollided (unscattered, full energy) photon fluence rate  at the detector
position can then be calculated. Combining this fluence rate with that calculated based on a point
source calibration for the detector efficiency, a screening-level approximation of activity may be
obtained.  It  is important that assumptions regarding the distribution of activity lead to a result
that conservatively overestimates the true amount of activity present.

In reality, more detailed analyses are required to accommodate the complex counting geometries
that will be encountered in the field. These include models of volumetric sources of varying size,
shape,  and  spatial  distribution of the radioactivity within the source; knowledge of angular
dependence  of the photon fluence rate on detector response; and shielding effects resulting from
materials  between the source and the detector. While commercial products are available for
doing such calculations, they require  as input detailed models of the  physical characteristics of
the object being measured, including a geometric distribution  of radioactivity  in the  object.
Determining and documenting such information for each measurement situation, and performing
the necessary modeling, are  time-consuming and involve substantial technical  understanding.
Considerable  professional judgment  generally is needed to  accurately and  conservatively
estimate input parameters. Thus,  it is essential that these  analyses be carried out by a skilled,
knowledgeable, and experienced operator/analyst.

Absent a capable analyst,  errors may be made that are unlikely to be detected in a review of the
data or reflected in the reported uncertainty of the measurements. Lacking reliable estimates of
uncertainty of measurements, critical decisions may be based on data with unknown and possibly
substantial uncertainties. Decisions may not be adequately protective and could be called into
question.  Because of  this  fact,  ISGS  measurements  are  frequently  limited to real-time
applications such as guiding remediation or recovery operations where they can be used to very
rapidly identify  hot spots and gauge progress during  cleanup.  Final status  measurements and
periodic confirmatory samples are often analyzed at fixed laboratories at critical points in the
process to  provide  independent  assurance  that the results  obtained  are both accurate and
reasonable.  It also  is common for a  significant proportion of final status measurements to  be
produced  using definitive laboratory gamma  spectrometry testing (see  Appendix I  for  a
discussion regarding the limitations and successful use of ISGS measurements at the Rocky Flats
Environmental Technology Site).

Use of an in situ gamma spectrometer to collect reliable data requires that the instrument be set
up in the  area to be evaluated in a reproducible, consistent, and well-documented fashion. The
23Automated radionuclide identification routines  such as those used in radionuclide identifiers can misidentify
radionuclides present. Thus, even qualitative measurements should be evaluated by an expert gamma spectrometrist
and, where necessary, confirmatory laboratory analysis performed before results are considered final.


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


instrument software requires input of observed geometry parameters. Once the setup is complete
for an  individual  area,  an instrument  measurement (count) may  begin. Typically when
determining whether or not an area has contamination,  a count time of one hour is reasonable,
although  depending on activity  levels of concern, shorter  or longer measurements may be
required. Once the count is completed, the instrument may be  moved to the next location and the
process repeated.  If the  efficiency  model  is  established  prior to making  the  measurement,
unreviewed results are available immediately upon completion of the measurement. If modeling
is  not  complete prior to the measurement,  the spectrum will  require subsequent workup and
reporting before unreviewed results are available.

Performing  routine  definitive   field  spectrometry   measurements   is  a  relatively  newer
development.  In some cases, field measurements can  in fact  rapidly and effectively identify
contamination at levels needed to support characterization and recovery efforts. If alpha or beta
surface activity is accompanied by a unique gamma signature, it may be possible to quantify the
alpha or beta activity using in situ spectrum analysis, minimizing the need for laboratory analysis
of grab samples beyond periodic confirmatory samples. When the gamma signature is present
and detection  sensitivity  permits, beta and alpha scans coupled with in situ  gamma spectral
measurements may allow for rapid clearance of surfaces at action levels that would be typical of
the recovery phase.

There  also is  real concern about the  size of the pool of capable, trained operators for field
spectrometry instruments  This underscores the importance  of developing robust, formalized
protocols  for  calibrating and   operating  instruments and performing  QC  for the  field
measurements.

Although  ISGS units may  be able to provide sensitive gamma isotopic measurements, ISGS may
not always be a practical option for accurate evaluation of beta-gamma emitters on complex,
contaminated areas or  objects. Practical disadvantages and  limitations of using ISGS during an
incident response in a metropolitan area include:

   •   ISGS detectors  must be operated in the field at cryogenic temperatures. This may require
       field use of liquid nitrogen, or modern electrically cooled portable detectors.
   •   Breakdown, relocation, and setup of heavily shielded  collimated units can take time and
       effort and will practically limit the number of areas or surfaces that can be evaluated in a
       given period of time.24
   •   The  units  may have relatively  long  per-location  acquisition  times  for  low-level
       measurements,  especially  for lower-energy gamma-emitting radionuclides  due to  self-
       absorption effects when radionuclides are not deposited on the surface.
   •   Setup,  implementation, and interpretation of data from  an  ISGS unit (e.g., ISOCS™ or
       ISOTOPICS  )  require an  experienced  and technically  adept  operator (i.e., a specially
       trained spectrometrist), of which there are relatively few.25
24For certain applications, ISGS units have been very effectively implemented in a portable configuration.
25When performing an ISGS calibration (e.g., ISOCS™ or ISOTOPICS™), the operator must develop a mathematical
model that describes or approximates the solid geometry of the object being measured. Other required input values
are the elemental composition and density of the object, as well as the depth or penetration,  distribution, and
uniformity of contaminants in and on  the object, all of which must be measured or estimated. Depending on the


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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


    •   "False positive" (Type I error)  and "false negative" (Type II error) measurements can
       result from radionuclides that are naturally present as ambient background since varying
       ambient backgrounds are often difficult to predict in field settings.
    •   Calibration  methods for  ISGS measurements may not  meet the  rigorous  standards
       employed at fixed laboratories.26 ISGS generally involves mathematically modeling the
       counting geometry. The skill and experience of the operator/spectrometrist, and the time
       and  resources required to  document the circumstances of  the measurement, will be
       reflected in the reliability  and  accuracy of the calibration  and the magnitude  of the
       uncertainty.
    •   The level of QC  measurements routinely performed for in situ measurements generally
       does  not rise to the level of comparable  practices used  to perform QC  at fixed
       laboratories.27 (See discussion of quality control in Section 4 of this document.)
    •   Confirmatory  laboratory analysis is needed to  unequivocally verify the accuracy of
       efficiency models.
    •   Units must be checked based on documented  QA/QC protocols to ensure that they are
       operating properly each time they are moved to evaluate a new area or surface.

5.2.2   General Considerations Regarding Laboratory Measurements

A wide variety of instruments is used for sample measurements at laboratories. This discussion
of laboratory instrumentation will address some of the  strengths,  weaknesses,  and general
considerations that affect laboratory instrument capabilities.

Laboratories maintain instruments  that, similar to field survey equipment,  measure alpha and
beta emissions from samples without regard to  the energy of the respective radiations.  These
include low-background  gas proportional  (alpha-beta)  counters. Laboratories also maintain
spectrometric instrumentation that performs a  range of radionuclide-specific  measurements.
Examples include gamma spectrometers, alpha spectrometers, and liquid scintillation counters
(LSCs).

The initial contamination  resulting from a radiological or nuclear incident is expected to be
largely  removable or resuspendable as opposed  to fixed, surficial contamination of structures,
objects, roadways,  etc.  Although  they cannot readily discern between fixed and  removable
contamination unless a  sample is  removed and analyzed  separately, field measurements  are
capable of rapid and sensitive measurements of total surface radiation in an area. Laboratory
measurements of removable contamination may be used to complement field measurements and
complexity of the measurement, models may need to be developed specific to each measurement. While certain of
these components are based on measured values that can be documented, others must be based on estimates that may
be less well-documented.
26At fixed laboratories, all measurements are  traceable to a national standard (e.g., a NIST standard reference
material [SRM™]). Calibrations are performed by direct comparison of carefully prepared sample test sources to
controlled calibration sources traceable to the appropriate national standard. Prior to first use, calibrations for each
counting configuration are verified by comparison to a second independent traceable verification standard identical
to the sample test source.
27Quality controls for in situ measurements include review of documentation about the measurement and the
analysis.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


to free field personnel to perform critical measurements of total surface contamination and grab
and  confirmatory  sampling.  The laboratory offers  the  advantage of high levels of sample
throughput while maintaining accurate, sensitive, and radionuclide-specific results. The labora-
tory also is clearly best suited to the analysis of bulk samples for volumetric contamination.

Careful consideration of the complementary nature of field and laboratory measurements can
thus  ensure that data will meet DQOs/MQOs while meeting operational requirements for rapid
turnaround and high throughput.

5.2.2.1  Survey Measurements at the Laboratory

At a radiochemistry laboratory,  survey instrumentation is differentiated from more specialized
instrumentation  used  to conduct accurate and sensitive  radioanalytical measurements. At  a
radiochemistry laboratory, survey instruments are portable pieces of equipment used to support
laboratory operations, most frequently in the area of health physics and contamination control.
These  instruments are rarely, if ever, used to perform  sensitive  analytical measurements  of
sample activity.  Instead, they  find  relatively limited application  for  such applications  as
Department of Transportation (DOT) radioactive material receipt surveys, or health physics and
contamination  control  surveys. Survey  instruments  can rapidly identify  the  presence  of
significantly  elevated activities  of gamma  emitters.  They provide results of high or  poorly
estimated  uncertainty and are not able to reliably and accurately quantify concentrations  of
radionuclides in samples, particularly at the low activity levels that are of interest in the recovery
phase.

During an incident response, vast numbers of samples or measurements will need to be taken and
analyzed at radiochemistry laboratories.  Samples must be rapidly, effectively, and accurately
prioritized  for  subsequent handling and radionuclide analysis based  on gross  activity levels.
Gross activity measurements of samples in the field or immediately upon receipt, using similar
survey instrumentation, will identify and allow prioritization of samples containing the highest
levels  of gamma-emitting radionuclides. The majority of the samples, however, will contain
relatively  lower levels  of  activity  that  are  not effectively measured  with  an  unshielded
instrument.

5.2.2.2  Non-Spectrometric Measurements at the Laboratory

Depending on the event, the source term may be pure alpha- or beta-emitting radionuclides,
which  cannot be detected by hand-held instrument surveys of the sample containers (in the field
or in the laboratory). Alpha and beta emitters, or even lower levels of gamma activity that cannot
be detected with survey meters, are of great concern in a low-level radiochemistry laboratory
where  contamination control concerns in working with open samples are much greater than in
the field due to the very low levels of activity being handled and measured at the laboratory.

Radiochemistry laboratories  maintain  instrumentation  such  as  low-background  gas flow
proportional  detectors  that perform  non-specific measurements  of alpha and beta  radiation
analogous to those that might be performed in the field.  Although the instruments in the field
bear similarity to those in the laboratory, laboratory instruments are generally heavily shielded
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


with lead and actively shielded using guard detectors to minimize ambient background radiation.
The  sensitive instrumentation available at a laboratory would allow the laboratory to achieve
significantly better detection capabilities  relative to most field measurements with relatively
shorter  count times.  Since  the  laboratory  can  have  many instruments,  and  since  it can
simultaneously process many samples in parallel using batch processes, laboratories can achieve
very high levels of throughput with lower personnel demands than is generally possible in the
field.

Environmental  conditions  within a laboratory are designed to be optimal for measuring
radioactivity. Background radiation levels are stable, low, well-characterized, and not subject to
variation from changes in  measurement locale or to significant  fluctuations from  changes  in
environmental conditions. Power conditioners and line-voltage regulators are commonly used at
laboratories to minimize electrical supply disturbances to the detection systems. These measures
all ensure that measurements of backgrounds and samples will be optimally sensitive and that
associated uncertainties and detection  levels will be accurate and reliably determined. All  of
these parameters play key roles in ensuring the quality of low-level radioactivity measurements.

Laboratories also employ chemical separations  to enhance the capability of various instrument
measurement techniques. Chemical separations remove interfering matrices and radionuclides
and  minimize   self-absorption  effects that  degrade  instrument  response  and  resolution.
Laboratories  can isolate a single radionuclide from  a  mixture of radionuclides or from the
background  soup  of naturally  occurring  radionuclides  present  in nearly  any sample. When
combined with  the  appropriate chemical separations,  even  relatively  simple  gas-flow
proportional alpha-beta counters  are capable of a high  throughput  of  sensitive  and accurate
radionuclide-specific measurements for a broad range of radionuclides.

5.2.2.3  Spectrometric Measurements at the Laboratory

Laboratories  responding to  radiological  incidents  will  have  gamma spectrometers, alpha
spectrometers, and liquid scintillation  detectors. Rapid  screening measurements can be made
with laboratory instruments such as liquid scintillation counters and gamma spectrometers. These
measurements can help control widespread  contamination interfering with measurements, and
quick evaluation of an energy spectrum may provide a first qualitative hint of the identity of the
radionuclide contaminant. While these instruments can be used for gross  activity measurements,
their full benefit is gained in using them to conduct spectrometric  measurements  of specific
radionuclides.

In contrast  to  the majority of  field measurement  techniques,  spectrometric measurement
techniques available at the laboratory are capable of unequivocal, unbiased, and low uncertainty
determinations of specific radionuclides. In fact, these techniques are sometimes the  only viable
option for determining  low or  medium  activities  of certain  radionuclides.  Spectrometric
instrument measurements are more accurate and generally more  sensitive than determinations
that  are possible with corresponding  field  measurements. This  capability stems  from these
instruments'  ability to measure  energy  spectra,  and  to discriminate  between mixtures  of
                                           43

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident

                                                           9R
radionuclides  based  on their  characteristic  decay energies.    Laboratory spectrometers  are
operated in a very stable environment and can obtain low and reliable detection limits because of
low and stable backgrounds, and because they can discriminate  against background signal that
does not exhibit the characteristic energy signature of the radionuclides of concern.

When laboratories perform measurements using alpha spectrometers, they can address the whole
range of issues that prevent accurate measurement of alpha emitters in the field. Alpha particles
are significantly attenuated by sub-milligram amounts of matter (e.g., microscopic roughness of
surfaces). Most  samples contain  mixtures of radionuclides that emit alpha  particles with
overlapping decay energies. Many alpha emitters cannot be resolved unambiguously by an alpha
spectrometer due to their overlapping energies. However, at the laboratory, chemical separations
can be  used to eliminate interfering  matrix constituents  and radionuclides and  thereby  obtain
                                                                                      9Q
clean and well-resolved spectra for accurate determinations of alpha-emitting radionuclides   at
very low detection levels.

Although the liquid scintillation counter is capable of performing a wide range of spectrometric
measurements of alpha and beta emitters, its most common use in the radiochemistry laboratory
outside of screening  samples is for measurements of radionuclides that decay via low-energy
                                            QQ    r)A'\       1                             *—'•'
emissions, particularly beta  emissions such  as  Tc,    Pu,  or  H  or low-energy gamma or x-ray
emitters such as 125I or 103Pd. This application is possible because the radionuclide is dissolved in
a liquid that serves as a detector,  effectively eliminating the self-absorption effects that interfere
with detection of radioactivity in any solid  form.  Similar  to  alpha spectrometry,  chemical
separations  are used to isolate the element of concern prior  to measurement to ensure  the
specificity of the measurement. When combined with chemical separations, liquid scintillation is
often the only viable option for determining  a number of beta emitters.

The most versatile spectrometric  instrument in the laboratory is the gamma spectrometer  in that
it can be used for the determination of a very large number of radionuclides. Many  of the same
attributes of gamma emissions that make ISGS a powerful technique in the field are reflected in
the simplicity  and efficiency of  gamma  measurements at the laboratory.  Similar to field
measurements, the penetrating nature of gamma rays allows non-destructive measurements to be
made. This  allows very rapid and accurate  determinations to be made in the laboratory  with a
minimum of effort but under much more controlled conditions than are possible in the field.

Although ISGS is probably the most attractive option for quickly characterizing large areas for
gamma emitting contaminants due to its ability to cover large areas with a single measurement,
the discussion of field measurements in Section 5.2 points out several concerns that should be
addressed to ensure that the quality of data is defensible.  The first is the impact of potentially
high or spatially  variable  backgrounds  on measurements that may  interfere  with effective
operations in the immediate vicinity of areas  significantly contaminated by  the incident. It is
28One notable exception is in situ gamma spectrometry measurements which,  due to the large effective size of
samples, can obtain high sensitivity and minimize the likelihood of not detecting radionuclides that actually are
present at levels of concern. The downside of ISGS is that it tends to deliver semi-quantitative results that, ideally,
should bias "conservatively" high.
29Even amounts of residual matter as small as 25-50 ug/cm2 can degrade the resolution of the energy spectrum to a
point where differentiation between radioisotopes of an alpha-emitting element is not possible.


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notable, however, that this will be of less concern in later phases once remedial activities have
removed larger, contiguous  sources of contaminants, and thus the background associated with
them.

For freshly deposited gamma-emitting contaminants deposited over a large area, ISGS is a very
powerful  technique.  One  significant  concern with  in  situ measurements  involves limited
traceability of ISGS measurements to national standards. Although instruments are checked with
NIST-traceable sources to demonstrate their continued performance prior to use, they are  not
necessarily calibrated using reliable reference sources that match the area being measured. Thus,
the accuracy of the analysis is largely dependent on assumptions about conditions encountered in
the field.  These assumptions are used to derive factors that relate the gamma-ray flux at  the
detector to the activity concentration of the specific radionuclide being measured. They include
corrections for self-absorption effects related to the depth profile of contaminants in the solid
matrix and variable distribution of radionuclides. Assumptions also could also needed to address
the degree to which gamma-emitting marker nuclides are representative of pure alpha- or beta-
emitting  radionuclides in the  source-term mixture,  especially where weathering has occurred
after deposition. Such assumptions may be  readily confirmed by analyzing select random and
judgmental grab samples at the laboratory as  a regular, ongoing QC measure.

At the laboratory,  high  backgrounds are  not of concern since instruments are heavily shielded
(4"-thick lead shielding is routine). Similarly, variability  of the background is a minor concern
since instruments are maintained in the same configuration used for the sample measurements,
and backgrounds are relatively constant  and can be accurately measured and subtracted from
sample measurements.  As an additional control, the stability of backgrounds is tracked and
trended using control charts. The second significant concern about field gamma measurements
involved concerns  about the traceability of the field measurements to national standards and the
impact of assumptions  that are made regarding the geometry of the source being measured.
These  assumptions include the spatial distribution of gamma  emitters relative to the detector and
corrections for self-absorption within the material  being measured (affected by penetration
within the object and the density and average atomic mass or "Z" of the material). These issues
are routinely addressed at the laboratory by calibrating detectors for specific counting geometries
using certified radionuclide standards traceable to NIST. Prior to counting, samples received
from the field are homogenized and transferred into  counting containers so that the geometry of
the sample closely matches that of the calibration standard. Since the shape, volume, density, and
radionuclide  distribution in  the standard can be closely matched to that of the sample, very
accurate  and  precise calibration of the instrument and very  accurate  and precise sample
measurements are possible. Once the  detector is calibrated, it  is common practice to verify
calibration by counting a second standard  obtained from a  source independent of the one used for
the calibration.

In practice, there are also disadvantages to laboratory gamma spectrometry as opposed to field
gamma spectrometry. The first has to do with the relative  detection capability of field versus lab
measurements. Field gamma spectrometry measurements  have to rely on assumptions about the
measurement geometry and background. They may be associated with high or unknown levels of
uncertainty, and depending upon MQOs, the energy of the radiation and  deposition patterns, it
may be possible to make conservative assumptions so that  the results err protectively toward
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reliable  identification  of the presence  of contaminants  above  an action level.30  If  ISGS
measurements are conservatively biased  (or unbiased and of known uncertainty such that they
can be used for reliable measurements), the sensitivity and effectiveness of ISGS measurements
may exceed  that obtainable by measurement in the laboratory of grab samples taken from the
same area. In cases where deposition is non-uniform, ISGS can identify hot spots that would be
very difficult to find without a large number of grab samples. This  is primarily a function of the
effective size of the sample because in field measurements, the sample size is effectively very
large, whereas grab samples  generally represent an area of -100  cm  . For example,  effective
coverage of a  plane has  been obtained with  measurements performed one  meter above the
ground  using a  five-meter grid (Reginatto et al. 1997).  As  stated above,  although many
laboratory samples may be spared by using ISGS, it is generally important that the integrity of
ISGS measurements  and the  assumptions underlying them  be  confirmed  using correlated
laboratory measurements.31

Another disadvantage of laboratory gamma spectrometry measurements  is less technical  and
more practical in nature. Since samples must be taken and shipped to the laboratory, laboratory
analysis cannot offer  real-time results. Laboratories do, however, offer very  rapid turnaround
times for  gamma spectrometric measurements, when  needed, often providing results  within
hours of receiving a sample (depending  on MQOs). In compensation for this,  laboratories can
perform large numbers of measurements in a relatively short amount of time.

Measurements  made  in a laboratory  will  determine unequivocally which  radionuclides are
present in a particular sample  and can be used to address concerns that widespread contamination
could have compromised field ISGS measurements.

5.3  The Effect of Measurement Geometry on Detector Calibration

When using field survey  instruments  for any  type of measurement, the detector is generally
positioned relative to  a potentially contaminated object or surface to optimize coverage of the
area. In some cases, larger areas may be measured in a single measurement, thus minimizing the
number of measurements  and lowering the overall  time and effort required to characterize an
area. One of the challenges  that must be addressed  for  field measurements  is ensuring  that
instruments are adequately calibrated.  Once an instrument is calibrated, several questions should
be addressed. Does the calibration reflect the object or surface being measured? What are the
bounds  of the  measurement?  Given those bounds,  what is the  potential  for bias  in the
30Unless there is empirical evidence to support them, in situ gamma spectrometry measurements are generally
qualitative or associated with elevated levels of uncertainty. Nonetheless, they may be configured and effectively
used in a manner that is protective of health and environment. In this case, it is assumed that background corrections
will introduce no bias or that any bias introduced will be "conservative" (i.e., too little background will be subtracted
yielding a final result with a high bias). It is also assumed that any bias associated with assumptions made during
efficiency calibration or modeling will be "conservative" and thus produce results that always bias high. Since these
measurements should be biased, confirmatory sampling and analysis are needed to determine the extent of bias
introduced and to minimize unnecessary expenditures of resources and efforts in the recovery process.
31 As discussed above, there is a downside to the higher sensitivity of in situ measurements that also must be taken
into account. Given the large field of vision of the detector, the presence of a hot  spot within the field of view of the
instrument (even if it is beyond the direct area  of measurement) may bias  measurements.  Thus, confirming
measurements are often needed to isolate a hot spot. Nonetheless, ISGS would still outperform grab sampling
followed by laboratory analysis, which would be more likely to fail to identify a hot spot.


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measurement? Are personnel adequately experienced and trained to know how to perform the
measurements and recognize when conditions are inconsistent with assumptions underlying the
calibration?  Can a reasonable yet conservative  bound on the measurement  uncertainty  be
established that will provide needed assurance that MQOs will be met using this technique?

5.3.1   Measurement Geometry and Field Survey Instrument Calibrations

Field  measurements of gamma radiation are perhaps  the most powerful and  useful of field
techniques  available  during incident response. The instruments  are portable and  setup  is
relatively rapid. Consistent with this, minimal shielding is generally used,  often limited to a thin
collimator around the detector itself. Although a portion of the detector is shielded, the detector
will respond in varying degrees  to radiation from  all directions.  Thus, there is no way  to
completely avoid, or to  account  and correct  for, contributions from  materials beyond the
intended focus of the measurement. The calibration of field  survey  instruments is generally
performed using single radionuclide  sources in  fixed  geometries  or by using Monte Carlo
modeling. Although both of these approaches have been frequently used, lacking the ability  to
restrict the field-of-view of the instrument or to perfectly and accurately model the area within
the field of view of the detector means that there may not be a one-to-one correspondence
between the  assumed calibration  geometry  and  the  area  being  measured.  Significant
measurement bias may result,  and it may be difficult to accurately assign realistic estimates  of
uncertainty to the measurements.

ASTM D1893-08 (2008)  speaks of challenges  involved with  calibration of detection systems
used for in situ measurements of contamination.

       "The in situ measurement of the residual  activity distributed within a volumetric medium
       of interest shall be based on the photon  emission rate from that medium. The results  of
       the evaluations of this photon emission rate are normally expressed in units of picocuries
       per gram (pCi/gm)  or becquerels per gram (Bq/gm). This evaluation will be dependent on
       the background response of the detector and on  a conversion factor established for the
       medium  of  interest. Non-uniform  distributed  source  geometries can result  in  large
       interpretation errors of in situ measurements; therefore, caution should be used with these
       evaluations."

NCRP Report 112 (1991) also points out shortcomings of direct measurement techniques, among
which is a "limited ability to relate the reading of a survey meter to that of an alternative dose-
measuring instrument or device."  It stresses that "...proper calibration of the instrument and a
thorough understanding of its  response characteristics can reduce such discrepancies" and that
"[t]he selection  and use of radiation detectors  and instruments require detailed knowledge  of
their response characteristics as well as judgment in their application." The report also frames the
context of many in situ measurements:

       "For  purposes  of  common  radiation  control,  routine  measurements  of  surface
       contamination are made to fulfill  regulatory requirements and to provide semi quantita-
       tive information on which to base further action (e.g., decontamination). Under such
       circumstances,  a  sophisticated   and time-consuming   calibration  of  a  monitoring
       instrument  is  not  justified.  In   some  situations, e.g.,  the  release  of a  previously
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      Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


       contaminated  building  for unrestricted  use,  measurements  must provide  sufficient
       accuracy that regulators and others can make the proper decisions. In the latter instances,
       it is  desirable, and perhaps  necessary,  that  inaccuracies  in  measurements  yield
       conservative results. It is, therefore, important that the  variables that  affect instrument
       response be understood well  enough  to ensure  that  errors are  in  the  conservative
       direction."

Calibrating detectors for direct surface measurements of alpha- and beta-emitting radionuclides
in the field can be a greater challenge than for gamma. In order to physically calibrate a detector,
a calibration source is needed that is representative of the surface or object being measured. The
reality of field measurements is that there is considerable variability in surfaces being measured,
including the composition of materials  comprising the surface,  and their shape,  roughness, and
position relative to the detector.  Given the short range of alpha  and beta particles, and their
susceptibility to  attenuation  within  the  surfaces  being measured,  the  depth  profile  of
radionuclides within the surface will have a profound effect on attenuation of the radioactive
emissions,  and  thus  on the general validity  of the calibration  and its applicability to  the
measurement situation. When measuring radionuclides present on a surface, it is often assumed
that radionuclides are present  at the surface  of an object and  that self-absorption  is  either
negligible or constant. The most accurate results for alpha- and beta-emitting radionuclides can
be  obtained when  measuring freshly  deposited contamination on a smooth,  non-permeable
surface.  It  is extraordinarily difficult to predict the  penetration  of  alpha- and beta-emitting
radionuclides within a surface. Thus, field measurements of alpha- and  beta-emitting nuclides
should  be restricted to measurements  of surface contamination  on  relatively  smooth,  clean,
impermeable  surfaces where the activity may be  assumed to be uniformly distributed and
effectively resident on the  surface.32 Even in cases that approach the  ideal, surface texture can
impact instrument response. It may not be possible to obtain representative, traceable calibration
sources  that  conservatively  match conditions expected  in the  field.  This may necessitate
application  of additional correction factors, which must  be determined empirically or by best
judgment. If a detector cannot be reproducibly positioned relative to the surface being measured,
calibrations might also be affected.

MARSSEVI (2000) addresses this concern:

       "In  many facilities, surface contamination  is assessed by converting  the  instrument
       response (in counts per minute) to surface activity using  one overall total  efficiency. The
       total efficiency may be considered to represent the product of two factors, the instrument
       (detector)  efficiency, and the source  efficiency.  Use  of the  total  efficiency  is  not a
       problem provided that the  calibration source exhibits characteristics similar to the surface
       contamination  (i.e., radiation  energy,  backscatter  effects,  source  geometry, self-
       absorption).  In practice, this is hardly the case; more likely, instrument efficiencies are
       determined with a clean,  stainless steel source, and then those efficiencies are used to
       determine the level of contamination on a dust-covered concrete surface."
32In the  sense used here, "surface" refers to a thickness of material that will not significantly attenuate the
radioactive emissions.  This varies according to the material in question and the type and energy of radioactive
emissions being measured. Clean refers to the surface being free of dust, debris,  or other material that would
requiring attenuation corrections. Quantitative measurements are not possible if the penetration profile is unknown.


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MARSSIM also points to methods that can be used to minimize these effects. For example, it
refers to NRC  (1997)  for typical  source  efficiencies for  common  surface materials  and
overlaying material. The text also lists factors that impact efficiency:

       "Instrument efficiency may also be affected by detector-related factors such as detector
       size (probe surface  area),  window density thickness,  geotropism, instrument response
       time, counting time  (in static mode), scan rate (in scan mode), and ambient conditions
       such as temperature, pressure, and humidity. Instrument efficiency also depends on solid
       angle  effects, which include  source-to-detector distance and source geometry. Source
       efficiency may be affected by source-related factors such as the type of radiation and its
       energy,  source uniformity,  surface roughness and coverings, and surface composition
       (e.g., wood, metal, concrete)" (ISO 1988).

It is critical that measurement geometries be well-characterized and well-defined. Measurement
procedures  should consistently define the conditions that must apply for a calibration to be valid
and also ensure that all calibrations and measurements proceed according to these considerations.
Prior  to  use  in the field,  empirical validation  should  be conducted  to  demonstrate  that a
measurement technique, as implemented in  the field,  will be capable of meeting pre-defined
MQOs.  Periodic  QC  measures,  such as confirmatory sampling, should then be used  on an
ongoing basis to demonstrate that the measurement system is operating as planned.

Unless the bounds on such measurements  are well-defined,  and the methods  validated and
carefully implemented,  bias may result and the  uncertainty  of  the  measurement may be
underestimated or worse, not taken into account when evaluating the applicability of a technique
for the required measurements. This could provide a false sense of security regarding the quality
of the measurements being performed.

5.3.2   Measurement Geometry and Field Spectrometry Measurements

Several different types of field spectrometry instruments are commercially available.  The most
powerful and commonly used instruments are high-purity gamma spectrometers similar to those
found in  analytical laboratories. These instruments are ruggedly constructed to be used in harsh
environments. They do  have certain disadvantages because they are used directly in the
environment they are monitoring. One such disadvantage is the  concern about the introduction of
bias by ambient background from gamma emitters adjacent to areas being characterized.

A  detailed discussion of one example of the use and limitations in the use of field spectrometry
measurements during the cleanup  of Rocky Flats Environmental Technology  Site can be found
in  Appendix I. See also Tables 3, 4, and Table 5 in Section 6, which summarize the applicability
of several  field instrumentation  techniques  for  the determination  of  a  select  group of
radionuclides important to incident response.

Assuming that the absolute  geometry of the measurement is known, accurate, precise, and very
sensitive, in situ measurements of gamma emitters are possible in the field. Specifically, this
requires knowledge of the areal distribution and the depth profile of radionuclide contaminants,
the elemental composition and physical makeup  (e.g., density) of the matrix material, and the
ambient contribution from the contaminant of concern in the vicinity of the measurement. When
all of these factors are  well-known,  in situ measurements of gamma emitters are clearly the


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fastest and  most  sensitive  techniques  available for the characterization  of gamma-emitting
contaminants. The long range of gamma rays and the resultant wider field of vision for gamma
detectors allow measurement of relatively large areas. Not only does this increase the effective
size of the "sample" measured and the sensitivity of the measurement as compared with grab
sampling techniques,  but ISGS techniques also  are able to measure  larger areas in  a  single
measurement. This dramatically reduces the number of measurements needed to characterize an
impacted area with confidence that hot spots will not be overlooked.

It is necessary that the limitations of ISGS measurements be carefully considered and addressed.
Questions about the geometry, the composition of matrix materials, or the impact of ambient
background  on the  field  measurement  almost  always  exist.33  Without  regular  periodic
confirmation of the assumptions that underlie the measurement, the accuracy and especially the
estimates of measurement uncertainty of the in situ measurement should be called into question.
Even when the technique is used  for qualitative or approximate measurements, such as clearing
hot  spots in  an  area,  it  is vital that  confirmatory measures  be routinely employed  that
demonstrate  the adequacy  of  the  model  and  the  competency of the operator used for the
measurement. The most effective  QC measure  that can be used involves  routine,  periodic
confirmatory measurements of grab samples under very controlled conditions in a laboratory.

5.3.3  Measurement Geometry  and Laboratory Survey and Gross Activity Measurements

Laboratories  utilize survey instruments that in many cases are similar or identical to those used
for field survey measurements. These portable instruments are used almost exclusively for the
least formalized laboratory measurements,  such as those performed during sample receipt. The
calibration  and measurement protocols for such laboratory survey instrumentation do not vary
substantially  from those used for field survey measurements and do not result in substantially
different measurement quality than what is available for similar instrumentation in the field.

More elaborate screening instrumentation available at radiochemistry laboratories can be used to
perform rapid screening measurements of gross activity. Examples of screening instrumentation
used  at laboratories include low-background  gas proportional  counters,  liquid scintillation
counters, and sodium iodide gamma counters operated in gross activity mode. As used here,
screening refers to measurements of "gross" activity in a sample that are potentially biased and
have high levels of uncertainty.  In other words, this measurement is not specific to a radionuclide
and cannot differentiate  between a mixture of radionuclides that emit the  same radiation type
(i.e., alpha, beta, or gamma). These laboratory instruments tend to be heavily shielded and can
provide much more sensitive and reliable results than do survey measurements performed with
hand-held field or laboratory instruments, especially at lower activity levels such as those that
typically would be experienced in the later phases of an event. Often these laboratory screening
measurements are preceded by a simple preparation  step, such as drying, grinding,  digestion, and
a source preparation step to create a sample test source geometry that very closely matches that
33Assuming mean specific activities as quoted in NCRP Report No. 50, Table 2-6 (i.e., 0.67 pCi/g 238U with seven
alpha-emitting progeny in equilibrium, and 0.65 pCi/g 232Th with five alpha-emitting progeny in equilibrium), the
mean alpha activity of geological materials would approach 10 pCi/g with higher levels routinely encountered in a
number of natural construction materials. Unless the background matrix has been very precisely characterized, it
would be  inadvisable to attempt to detect  contaminants using gross activity measurements  until the activity
significantly exceeds these values.


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of the applicable calibration source. Stable, low, and well-quantified backgrounds, and extended
count times  facilitate more sensitive measurements at lower activity levels than can be achieved
with field or laboratory survey  instruments. When combined  with  more stringent  quality
assurance and quality control measures routinely practiced in the laboratory, these techniques
reliably provide very reproducible and defensible determinations of gross  alpha, beta, or gamma
radioactivity in samples received from the field. If a single radionuclide is  involved, especially at
levels  well  above  background, screening information  can often provide very  accurate  and
reproducible estimates of the activity  of the contaminant in the sample. Thus, within minutes to
hours of receiving a sample, information of high quality not otherwise available in the field can
be made available to an Incident Commander.

5.3.4   Measurement Geometry and Laboratory Spectrometry Measurements

As time progresses during the intermediate  and recovery phases, an increasing  proportion of
samples will require radionuclide-specific analysis  at successively lower levels. This will be
necessary to satisfy DQOs and  MQOs  for cleanup  criteria  and to reassure the  public  that
facilities, private property, public spaces, and personal residences have not been contaminated or
that they have been successfully decontaminated.

In  the  laboratory, environmental conditions such as  temperature,  humidity,  background,
electrical line voltage,  and contamination  are very  carefully  managed to ensure reliable
measurements of radioactivity,  especially at the lowest activity levels. The combination of low,
stable, and well-characterized backgrounds;  extended count times; robust chemical  separation
methods (incorporating  chemical yield carriers and  tracers to substantially reduce or eliminate
measurement  biases  relative  to  direct measurements);  careful  source  preparation;  and
spectrometric detection  methods all allow these techniques to unambiguously differentiate and
accurately measure very low activities of contaminant radionuclides.

For example, alpha spectrometers can, using chemical separations, routinely and very accurately
determine the activity of alpha emitters present at 0.1  pCi level and below. Liquid scintillation
and gas-flow proportional  counters  can accurately determine beta-only emitters following
chemical  separation at concentrations commensurate with 1CT6 risk levels and below.34  Given
progress in  practical chemical  separation techniques over the last five to 10 years, processing
times that were previously measured in weeks have decreased to days or even hours. While there
are no real  analogs to laboratory  capabilities for radionuclide-specific determinations of pure
alpha and beta emitters  in the  field,  sensitive  spectroscopic measurements of gamma emitters
using high resolution gamma spectrometers are possible without  chemical separations, both in
the field and in the laboratory.

While gamma ray  analysis at the laboratory may  not match the effectiveness and availability of
real-time results possible with in  situ measurements, the more  controlled conditions in the
laboratory are conducive to producing highly accurate measurements of known uncertainty. At
the laboratory,  samples  are carefully homogenized  and sample-to-detector geometries  closely
reproduced  to  ensure that measurements  are traceable  to  national radionuclide  standards.
34Although gas-proportional counters possess limited energy discrimination capabilities, they are not spectrometers.
They are mentioned in this section, however, since when combined with element-specific chemical separations, they
can be used to perform very accurate and reliable low-level measurements of pure beta-emitting radionuclides.


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Measurement  uncertainties  associated  with  calibration,  moisture,  density,  and  sample
homogeneity can  be more accurately  estimated. The laboratory  also  can very accurately
determine and correct measurements for ambient background, thereby ensuring unambiguous
determinations of radioisotopes  even in the  presence  of contaminant or naturally occurring
radioactivity present in the background.

Thus, with relatively limited  exceptions (such as ISGS measurements in well-characterized
areas), field  measurements  do  not provide  the sensitivity, specificity,  and  reliability  of
radionuclide-specific measurements performed at  a laboratory. Significant questions regarding
the  intercomparability  of  field  data  may  arise,  whereas  the  controlled  environment,
standardization of radioanalytical  methods and practices  at  radioanalytical laboratories, and
regular participation in laboratory intercomparisons and proficiency testing programs ensure the
intercomparability of results between laboratories.

Section  5 of this  document  compares and contrasts various aspects of field and laboratory
measurements and addresses  their relative strengths and  weaknesses. Section  6 contains four
tables that  compare  performance characteristics of several field and laboratory measurement
techniques.

6.  Comparison and Applicability of Field and Laboratory Measurements

Table 1  compares performance  characteristics of non-spectrometric techniques for field and
laboratory  measurements  of  surficial  contamination.  Table  2  compares  performance
characteristics of  non-spectrometric techniques  for field and  laboratory  measurements  of
volumetrically contaminated objects. Analogous to  Tables 1  and 2, Tables 3  and 4 consider
performance characteristics for spectrometric measurements of surficially  and volumetrically
contaminated objects. These performance characteristics are differentiated according to the type
of radiation being measured (alpha, beta,  low-energy gamma ray, medium-  to high-energy
gamma rays) and the activity relative to background.

Tables 1  and 3 address surficial  contamination and assume that the contaminant radionuclides
are deposited homogeneously on a surface in such a manner that self-absorption corrections are
not needed to perform unbiased measurements with well-defined and defensible estimates of
uncertainty.  Tables 2 and  4  address volumetric contamination and assume that contaminant
radionuclides are  deposited within the  volume  of  an object  or matrix  material such that
corrections for measurement geometry and self-absorption can be effectively applied and that the
resulting  measurement does not exhibit significant bias  and reasonable estimates of uncertainty
can be performed.

In the case of  some field measurements, it may not be practicable to perform unbiased
measurements,  although measurements may be  configured in such a  manner that  allows
measurement quality objectives to be met defensibly. This specifically includes "judgmental"
(i.e., strategically biased) measurements as long as the combined bias and uncertainty provides
defensible and conclusive evidence that MQOs have been met.

These tables also presuppose that ambient sources  of background radioactivity beyond the
surface being  measured  (e.g., activity associated with volumetric  contamination  or inherent
radioactivity of the object in question) can be accurately determined and  subtracted from the


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measurements in a manner that results in minimal absolute bias and permits reasonable  and
accurate estimates of measurement uncertainty.

For field measurements, the tables further differentiate between in situ measurements of surface
contamination and in situ measurements of volumetric contamination. There is  only  a  single
table addressing laboratory measurement (Table 7 in Appendix II) because at the laboratory there
is no significant difference in how surface or volumetric measurements are conducted beyond the
units used to report results.

Note that when compared to field measurements, there are fewer permutations for laboratory
measurements.  Thus, there is minimal need to differentiate between emitter types, and there is
only a single description to address lab measurements at each activity level. This is  because
laboratories, by design, can  homogenize samples, perform chemical separations to  address
interferences, and carefully match  calibration  geometries to  samples. By taking control of
measurement conditions, there  is no need to differentiate between many situations that pose
different challenges to field measurements.

Given the variability of conditions in the field, independent confirmatory measurements of grab
samples at a laboratory should always be performed, in parallel with in situ measurements, on a
routine basis as a quality control  measure  to  demonstrate the integrity  of the  measurement
systems and to validate the accuracy of assumptions underlying the measurements.

Incident-specific  circumstances,  such as  radionuclides  of concern,   matrix,  interfering
radioactivity, random  circumstances surrounding the measurement, and DQOs and MQOs may
influence the viability of a specific  technique for a given situation.  Tables 1 through 4 of  this
section are complemented  by three tables in Appendix II, Tables 5, 6, and 7. These tables show
the applicability of specific field and laboratory measurement techniques for determinations of
different radionuclides of concern at low, medium, and high activity levels.  Tables  5, 6, and 7 do
not attempt to address  every possible measurement technology;  rather,  they serve as  a
comparative tool and a starting point for selecting appropriate field and laboratory techniques for
measurements of a variety of radionuclides at different activity levels.

Finally, Appendix  III presents four simple example scenarios that synthesize information
presented in this guide. They provide a simple  demonstration  of how the DQO/MQO process
combined with  a quality systems approach could be employed during response to  a radiological
or nuclear incident in an urban field  setting. Several permutations are explored, ranging from the
simplest  scenario of a single medium- to high-energy gamma emitter, to more challenging
scenarios with  pure alpha and beta emitters,  and mixtures  of radionuclides.  These simple
examples are not meant for specific use in the field;  rather, they identify how DQOs/MQOs,
validated measurement techniques, and a quality systems approach could  be applied in a field
setting, and  how field and lab  measurements can be  used in  complementary fashion  to most
expeditiously characterize areas potentially impacted by a radiological event. These scenarios
should serve as  starting  points  for developing  an  approach  to  DQO/MQO-focused field
measurements that are technically and  legally defensible and  as well-documented as measure-
ments performed in a fixed laboratory.
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                         Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
      Table 1 - Comparison of Non-Spectrometric Field and Laboratory Measurements of Surficially Deposited Activity
  Activity
   Level
  Emitter
   Type
                  Field Survey Measurements*
     Laboratory Screening Measurements*
   Gross
 activity at
 the action
    level
significantly
greater than
background
   levels
                 Single
                gamma
               emitter of
              medium- to
              high-energy

                Identity
                 known
             Ideally suited for rapid, real-time location of hot spots, and qualitative
             or approximate measurements of single, surface-deposited radionuclide
             of known identity. Risk of false non-detection is low to moderate. Large
             field-of-vision may reduce  sampling uncertainty and total number of
             required   measurements   relative   to   grab  sampling  techniques.
             Measurement bias and problems estimating measurement uncertainty
             increase  with depth of  penetration of contaminant in the surface.
             Confidence  in  measurements is significantly improved  by a routine
             program  of confirmatory  sampling and independent laboratory analysis
             that validates assumptions about deposition profiles of contamination on
             and in the object being measured.
Gamma or x-
ray emitters
  of low to
  medium
   energy

  Identity
   known
Similar attributes as for medium- to high-energy gamma-  and x-ray-
emitters except: Measurements are less rapid; risk of false non-detection
is moderate to high; rapid increase  in measurement bias and problems
estimating measurement  uncertainty with decreasing  energy of the
radiation  and increasing penetration of contaminant into the surface.
Confidence in measurements is  significantly  improved by a routine
program of confirmatory sampling and independent laboratory analysis
that confirms assumptions about deposition profiles of contamination on
and in the object.
              Single high-
              energy beta
                emitter

                Identity
                known
             Well-suited  for  rapid, real-time  identification  of hot  spots  and
             qualitative or approximate measurements of a single surface-deposited
             radionuclide. Risk of false non-detection and data quality depends on
             the adequacy of assumptions about serf-absorption, surface roughness,
             efficiency corrections,  and  estimates  of  measurement  uncertainty.
             Confidence  in  measurements is significantly improved by a routine
             program of confirmatory sampling and independent laboratory analysis
             that confirms assumptions about deposition profiles of contamination on
             and in the object.
Ideally suited for rapid, high throughput screening, or
unbiased, low-uncertainty measurements of a single
radionuclide of known identity. Also well-suited for
confirmatory  measurements.   Additional  effort is
needed in the field for grab sampling.
Laboratory  measurements are not completed in real-
time since  measurements follow sampling,  shipping
and preparation of test sources at the laboratory.
Results reported by laboratories in terms of activity
concentration (i.e.,  pCi/g or pCi/mL)  may not be
directly  comparable to field measurements prior to
conversion to  area! concentration (i.e., pCi/m2).
Analyses are performed  on prepared,  homogenous
aliquants representative of the sample provided to the
laboratory,  minimizing the  degree of concern about
false detection  and non-detection.  Low  and stable
backgrounds,   good  control   of  calibrations,  and
measurement  geometries minimize  introduction of
bias during  preparation and analysis  and allow
minimization and accurate estimation of measurement
uncertainty.  Well-defined,  rigorous  QC  protocols
provide  documented evidence supporting the quality
of results.
In  the  case  of  medium-  to high-energy  gamma
emitters, higher levels of uncertainty and increased
likelihood of false non-detection accompany the need
to take  multiple  samples to  characterize  an  area,
whereas in situ measurements of gamma emitters may
                                                                     54

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                         Uses of Field and Laboratory Measurements  During a Radiological or Nuclear Incident
  Activity
   Level
  Emitter
   Type
                   Field Survey Measurements*
     Laboratory Screening Measurements*
               Single low-
                to mid-
               energy beta
                or alpha
                emitter

                Identity
                known
             Very limited  applicability.  Can play  a  supporting  role in real-time
             identification of hot spots and approximate measurements of surface-
             deposited radionuclides. Risk of false non-detection is very significant
             for alpha and low- to mid-energy beta emitters.  Total number  of
             required measurements is  similar  to  grab measurement techniques.
             Problems with bias and uncertainty  estimates increase  rapidly with
             surface roughness  and when the  contaminant may have  penetrated
             below the surface of the object. Data quality depends on the accuracy of
             assumptions about serf-absorption and surface roughness and estimates
             of measurement uncertainty. Confidence in measurements may be weak
             unless a routine program of confirmatory  sampling and independent
             laboratory analysis  confirms that contamination is present only  on the
             surface of objects measured.
              Radionuclide
                mixtures

                Identity
                unknown
             Well-suited for rapid, real-time identification of hot spots. Applicability
             is highly dependent on specific  mixes; measurement conditions; ability
             to make accurate assumptions about the mixture, distribution, and depth
             profile of  radionuclides;   and  ability to accurately calibrate  survey
             instrumentation. High levels  of alpha emitters increase probability  of
             false detection and non-detection. Confidence in measurements may be
             weak  unless  a  routine  program  of  confirmatory  sampling  and
             independent laboratory analysis confirms that assumptions used during
             calibration match the conditions  of analysis.
                                                                   be able to characterize larger areas (e.g., up to 25 m )
                                                                   in a single measurement. As a result, more laboratory
                                                                   gamma measurements may be needed to characterize
                                                                   an area than would be required using ISGS.
                                                                   In contrast to gamma emitters, due to the short range
                                                                   of  the   radiations   in  matter,  the   number   of
                                                                   measurements required to characterize alpha-, beta-,
                                                                   and low- to mid-energy photon-emitting contaminants
                                                                   will be similar in the field and  in  the laboratory.
                                                                   Given significantly  better detection capabilities  for
                                                                   short-range radiations,  overall  higher  throughput  of
                                                                   measurements  may  be  possible   at   laboratories,
                                                                   allowing  more  effective used  of field personnel  to
                                                                   streamline recovery operations.
   Gross
 activity at
action level
 similar to
background
   levels
Alpha, beta,
 gamma, or
   x-ray
  emitters

  Identity
 known or
 unknown
Limited applicability. Low-level survey measurements with unshielded
instrumentation  do not  reliably  or accurately  detect  or  quantify
contaminants due to inability to distinguish signal  from background.
High risk of false detection/false  non-detection due to temporal and
spatial variability in background. Significant risk of false non-detection
of alpha and beta emitters with rough or porous surfaces due to assump-
tions  about geometry  and variable deposition profiles. Confidence in
measurements may be weak unless a routine program of confirmatory
sampling and independent laboratory analysis confirms that assumptions
used during calibration match the conditions of analysis.
Limited  applicability  but  more  sensitive,  well-
controlled measurements of gross activity are possible
than in the field. Requires grab  sampling, shipping
and  preparation of  sample prior to measurement.
Matrix  is  homogenized  prior  to  measurement.
Interpretation of results is limited when instrumen-
tation cannot distinguish between  analyte signal from
background. The accuracy with  which the  "back-
ground activity" of the matrix is known determines
usability of measurements.
    Unshielded beta/gamma and alpha survey meters.
    Laboratory Screening Measurements column applies to multiple emitter types. Laboratory screening includes gross alpha, beta, and gamma analyses for a variety of sample
    geometries. Instruments include shielded gas-proportional counters, gamma ray detectors, and liquid scintillation counters.
                                                                      55

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                         Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
   Table 2 - Comparison of Non-Spectrometric Field and Laboratory Measurements for Volumetrically Deposited Activity
Activity Level
Emitter Type
              Field Survey Measurements*
           Laboratory Screening Measurements*
    Gross
  activity at
 action level
 significantly
 greater than
 background
    levels
 Gamma and
x-ray emitters
Suitability ranges significantly depending upon measurement
conditions. Rapid, real-time measurements of a known single
radionuclide are  possible.  Can  be used  qualitatively  in
scanning mode to quickly localize hot spots. Relating surface
activity  to volumetric  activity  requires that assumptions
about the spatial distribution of contaminant  in  samples
relative  to  the  detector be taken  into  account  during
calibration of the instrument. Large  field-of-vision may
reduce sampling uncertainty and the total number of required
measurements relative to grab sampling techniques. Risk of
false non-detection, negative bias, and problems estimating
measurement  uncertainty   are  high.  Non-homogenous
distribution of contaminants within an object will impact the
accuracy of instrument calibrations. When this technique is
used to characterize  volumetric  contamination, a routine
program for confirmatory sampling and independent labora-
tory  analysis is needed to provide confidence  in the field
measurements by confirming the accuracy of assumptions
used during calibration.
               Alpha and

              Beta emitters,
               low-energy
                 photon
                 emitters
              Poorly  suited for any  volumetric  measurement  with the
              exception of qualitative identification of hot spots. Risk of
              false non-detection, negative bias, and problems estimating
              measurement uncertainty  are extremely high due to short
              range of alpha and beta particles in solids.
Ideally suited for rapid, high throughput screening, and unbiased
measurements of known uncertainty of a single radionuclide of
known identity. Well-suited for confirmatory  measurements at
the laboratory.
Additional  effort  is  needed in the  field  for grab sampling.
Laboratory  measurements are not  completed in real-time since
measurements follow sampling, shipping, and preparation of test
sources.
Low and stable backgrounds, good control of calibration  and
sample measurement geometries, and rigorous,  well-defined QC
protocols minimize concerns about false  detection and  non-
detection,   measurement  bias,  and  inaccurate  estimates  of
measurement uncertainty. Higher uncertainty and increased like-
lihood of false non-detection are associated with grab sampling.
The number of samples needed to address this  concern is higher
than what would be required for in situ measurements of mid- to-
high-energy gamma emitters. In contrast to gamma, the overall
number of measurements required to quantify alpha-, beta-,  and
low- to mid-energy photon-emitting contaminants is similar to
the number of field measurements required, but processing time
in the laboratory may be more rapid.
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                          Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Activity Level
Emitter Type
Field Survey Measurements*
Laboratory Screening Measurements*
    Gross
  activity at
 action level
  similar to
 background
    levels
               Gamma and
              x-ray emitters
              Limited  applicability.  In  most  cases,  low-level survey
              measurements  with unshielded  instrumentation  do  not
              reliably or accurately detect or quantify contaminants due to
              inability to  distinguish signal from background. High risk of
              false non-detection and false detection due to variability in
              background radioactivity.  Significant risk of false  non-
              detection of alpha, beta, and  low-energy-photon emitters
              when  measuring   rough  or  porous   surfaces  due   to
              assumptions  about  geometry  and   variable  depth   of
              contamination  that  underlie   calibrations.  When   this
              technique is used to characterize volumetric contamination, a
              routine program for confirmatory sampling and independent
              laboratory analysis  is needed to provide confidence in the
              field  measurements  by  confirming  the  accuracy   of
              assumptions used during calibration.
                Alpha and

              Beta emitters,
                low-energy
                 photon
                 emitters
              Field techniques  are  generally  poorly  suited  for  any
              volumetric measurement of alpha and beta emitters with the
              exception of the qualitative identification of hot spots. Risk
              of  false  non-detection,  negative  bias,   and  problems
              estimating measurement uncertainty are extremely high due
              to short range of alpha and beta particles in solids.
                                                                                     Limited applicability but more sensitive and controlled measure-
                                                                                     ments of gross activity are possible than in the field. Interpreta-
                                                                                     tion of results is limited when instrumentation cannot distinguish
                                                                                     signal  from  background.   The  accuracy  with  which  the
                                                                                     "background  activity"  of  the  matrix  is known  determines
                                                                                     usability of measurements. Requires grab sampling,  shipping,
                                                                                     and preparation of sample prior to measurement.
   Unshielded beta/gamma and alpha survey meters.
   Laboratory Screening Measurements column applies to multiple emitter types. Laboratory screening includes gross alpha, beta, and gamma analyses for a variety of sample
   geometries. Instruments include shielded gas-proportional counters, gamma ray detectors, and liquid scintillation counters.
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                        Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
        Table 3 - Comparison of Spectrometric Field and Laboratory Measurements for Surficially Deposited Activity
Activity Level
Emitter Type
             Field Spectrometry Measurements
    Laboratory Spectrometry Measurements*
                   Gamma
                   emitter of
                  medium- to
                  high-energy
Activity of the
radionuclide(s)
 of concern at
the action level
 significantly
 greater than
 background
    levels
               Ideally suited for rapid, real-time  determination of radionuclide
               identity and for approximate measurements of surface-deposited
               gamma-emitting  radionuclides.  Can  be  used  qualitatively  in
               scanning mode to quickly localize hot spots.  Risk of false non-
               detection is low-to-moderate.  Large field-of-vision may reduce
               sampling uncertainty  and the total  number of measurements
               required relative to grab sampling  techniques. Measurement bias
               and problems estimating measurement uncertainty increase with
               depth of penetration of contaminant into the surface. Confidence in
               measurements is significantly improved when a routine program of
               confirmatory sampling and independent laboratory analysis is used
               to  confirm that contamination is homogenously distributed and
               only present on the surface of the object.
 Gamma or x-
ray emitters of
low to medium
    energy
Similar attributes as for medium- to high-energy gamma and x-ray
emitters except: Measurements are less rapid; risk of false non-
detection is moderate to high; rapid increase in measurement bias
and   problems   estimating  measurement   uncertainty   with
penetration of contaminant into the surface and decreasing energy
of the radiation.  Confidence in measurements is  significantly
improved when a routine program of confirmatory sampling and
independent  laboratory  analysis  are used  to  demonstrate  that
contamination is homogenously distributed and present only on the
surface of the object.
                Alpha and beta
                   emitters
               There is very limited application to spectrometric determinations
               of alpha and beta emitters in the field. Similar information can be
               obtained using gross activity measurements.
Laboratory analysis of alpha, beta, and gamma emitters
is ideally  suited for rapid, high throughput, low-bias,
low-uncertainty measurements of radionuclides present
alone or in mixtures. Also well-suited for confirmatory
measurements at the laboratory.

Laboratory measurements are not completed in real-
time  since  the   measurements  follow  sampling,
shipping, and preparation of test sources.

Additional effort is  needed  in the  field for grab
sampling.  Results reported by laboratories in terms of
activity concentration (i.e., pCi/g or pCi/mL) may not
be directly comparable to field measurements prior to
conversion to areal concentration (i.e., pCi/m2).

Analyses  are  performed on  prepared, homogenous
aliquants representative of the sample provided to the
laboratory to minimize concerns about false detection
and  non-detection.  Use  of  tracers/carriers  during
chemical separation and analysis, low and stable back-
grounds,  good control of calibrations,  and measure-
ment geometries  minimize introduction of bias during
preparation and analysis and allow minimization and
accurate estimation of measurement uncertainty. Well-
defined and rigorous QC provides evidence attesting to
the quality of results.
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                       Uses of Field  and  Laboratory Measurements During a Radiological or  Nuclear Incident
Activity Level
Activity of the
radionuclide(s)
of concern at
the action level
significantly
greater than
background
levels
Activity of the
radionuclide(s)
of concern at
action level
similar to
background
levels
Emitter Type
Radionuclide
mixtures
Gamma
emitters of
medium to
high energy
Alpha, beta, or
low-energy
photon
emitters
Field Spectrometry Measurements *
Gamma emitters are effectively determined in the presence of
alpha and beta emitters. There is limited application to spectromet-
ric determinations of alpha and beta emitters in the field (see
above for respective discussions). If the activity of gamma emitters
relative to alpha and beta emitters has been characterized, it may
be possible to assume that the ratio holds, allowing mixtures of
radionuclides to be characterized with field measurements of
gamma marker nuclides. Confidence in measurements is
significantly improved when a routine program for confirmatory
sampling and independent laboratory analysis is used to demon-
strate that contamination is homogenously distributed and present
only on the surface of the object, and to verify assumptions about
ratios for radionuclide mixtures that have been subjected to
chemical processes such as weathering.
Similar attributes to measurements of gamma emitters in medium-
to high-activity settings, especially for non-natural radionuclides.
The power of the technique diminishes when measuring radionuc-
lides present in the matrix prior to the incident, or in areas where
there is significant target analyte shine from collocated contamina-
tion.
There is limited application to spectrometric determinations of
alpha and beta emitters in the field, especially for lower level
determinations (see above for respective discussions).
Laboratory Spectrometry Measurements**
In the case of gamma Spectrometry, there is higher
uncertainty and increased likelihood of false non-
detection associated with sampling than in field
measurements of gamma, which can characterize
larger areas. As a result, a larger number of samples
may be analyzed for gamma emitters at the laboratory
and more complex statistical analysis might be
required than would be the case for in situ measure-
ments of mid- to high-energy gamma emitters.
In contrast to gamma, the overall number of measure-
ments required to quantify alpha-, beta-, and low- to
mid-energy-photon-emitter contamination will be
similar to the number of field measurements required
to do the same.
Similar attributes to laboratory measurements above.
Detection capability for medium- to high-energy
gamma emitters may be less than that possible using
ISGS.
Similar attributes to laboratory measurements above.
Field Spectrometry equipment includes gamma spectrometers, Field Instrument for the Detection of Low-Energy Radiation (FIDLERs™-1, and radionuclide identifiers.
Laboratory Spectrometry measurements column applies to multiple emitter types. Laboratory Spectrometry instrumentation includes alpha and gamma spectrometers and
liquid scintillation counters, and non-spectrometric techniques that provide radionuclide-specific results when combined with chemical separations.
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                          Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
  Table 4 - Comparison of Attributes of Spectrometric Field and Laboratory Measurements for Volumetrically Deposited Activity
 Activity Level
  Emitter
   Type
                     Field Spectrometry Measurements
      Laboratory Spectrometry
          Measurements**
 Activity of the
 radionuclide(s)
  of concern at
 the action level
  significantly
  greater than
  background
      levels
Medium- to
high-energy
  gamma
  emitters
Suitability ranges significantly  depending upon conditions of the measurement.
Rapid, real-time identification of hot spots or approximate measurements of a single
radionuclide of  known identity are possible.  Levels  of uncertainty may  vary
significantly. Relationship of surface activity to volumetric activity assumes that
spatial distribution of contaminant in samples relative to the detector is well-known
and accounted for during calibration.  Large  field-of-vision may reduce sampling
uncertainty and the total number of required measurements relative to grab sampling
techniques. Risk of false non-detection,  negative bias,  and problems estimating
measurement uncertainty are  high. Contaminants may  be non-homogenously
distributed within objects, leading to a mismatch between calibration and  sample
geometries. When this approach is used,  a  routine  program  for confirmatory
sampling and independent laboratory analysis  is needed to provide confidence in the
field measurements by verifying assumptions used during calibration and analysis.
                   Alpha and
                     beta
                   emitters,
                  low-energy
                    photon
                   emitters
             Surface  activity measurements are poorly suited for volumetric  measurement of
             alpha and beta emitters. There is limited application for spectrometric determina-
             tions of alpha and beta emitters in the field beyond qualitative hot spot identifica-
             tion. In many cases,  similar information can be  obtained  using gross  activity
             measurements.
Similar   attributes   to   laboratory
measurements listed in the tables above
except that measurements need not be
converted to volumetric units.
Detection capability  for medium- to
high-energy gamma emitters  may be
poorer than that possible using ISGS.

In contrast  to  gamma,  spectrometric
analysis at the  laboratory may be the
only viable option for measurements of
pure alpha and beta emitters.
 Activity of the
 radionuclide(s)
  of concern at
   action level
    similar to
  background
      levels
Gamma and
   x-ray
  emitters
Similar attributes to measurements of gamma emitters in medium- to high-activity
settings,  especially  for  non-natural radionuclides. The  power  of the  technique
diminishes when measuring radionuclides present in the matrix prior to the incident,
or in  areas  where  there  is  significant  target  analyte shine  from collocated
contamination.
 Alpha and
   beta
 emitters,
low-energy
  photon
  emitters
Surface activity  measurements are poorly suited for volumetric measurement of
alpha and beta emitters. There is  limited application for spectrometric determina-
tions  of  alpha  and  beta  emitters  in the  field  beyond qualitative hot  spot
identification.  Similar  information often may be  obtained using gross  activity
measurements.
Similar   attributes   to   laboratory
measurements   above   except  that
measurements are generally reported in
units of volumetric or massic activity.

Approach is  well-suited  for sensitive,
accurate,  and   precise   radionuclide-
specific determinations.

In contrast  to  gamma,  spectrometric
analysis at the  laboratory may be the
only viable option for measurements of
pure alpha and beta emitters.
*  Field Spectrometry equipment includes gamma spectrometers, FIDLERs™, and radionuclide identifiers.
** Laboratory Spectrometry Measurements column applies to multiple emitter types. Laboratory Spectrometry instrumentation includes alpha and gamma spectrometers and liquid
   scintillation counters, and non-spectrometric techniques that provide radionuclide-specific results when combined with chemical separations.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
7.   Conclusions

7.1  Conclusions and Recommendations Generally Applicable to Field and Laboratory
     Measurements

       •  There will  be an unprecedented demand for radioanalytical capabilities following a
          radiological or nuclear incident. The Agency's decisions regarding re-occupancy of
          places of work, schools, playgrounds, day  care centers, hospitals, places of worship,
          etc., must be based on defensible data of demonstrated accuracy and quality.

       •  Much attention has been focused on planning based on the White  House Security
          Council Planning Scenario #11  involving a single gamma-emitting radionuclide. It is
          important to recognize that a Scenario #ll-type event is one of the simplest possible
          scenarios in terms of radioanalytical measurement. Planning exclusively for the
          simplest case runs  a significant risk of  not  being prepared  to address more
          challenging scenarios, including mixtures of radionuclides, especially those involving
          pure alpha- or beta-emitting radionuclides.  Such scenarios  would  place  extensive
          demands on available resources in the field and at laboratories, and would more
          quickly overwhelm available resources than would Scenario #11.

       •  Both field and laboratory radionuclide measurements will play critical roles following
          a radiological or nuclear incident. There are inherent tradeoffs between laboratory and
          field measurements in terms of reliability, repeatability,  uncertainty, turnaround time,
          cost,  and  throughput.  If  Incident  Commanders,  planners,  and  decisionmakers
          understand  the respective benefits and limitations of the two approaches, they will be
          able to decide under which circumstances one approach is favored over another, and
          where and   how the two  approaches may be used synergetically  to increase the
          effectiveness of the response  while ensuring the  reliability  and  defensibility  of
          measurements used for decisionmaking.

       •  In the intermediate and the recovery phases,  a  gradual transition to progressively
          lower action levels and  more demanding analytical  requirements will likely require
          increased reliance on field  spectrometry measurements and increased demand for
          laboratory measurements.

       •  DQOs and MQOs must be established to provide a defensible foundation for planning
          and  for defending  the types  and  quality  of measurements  used to support
          decisionmaking. They can  control the levels of  uncertainty  and minimize decision
          error rates for decisionmaking.

       •  All radioanalytical measurements rest on  the basic principles of metrology.  Every
          result used for critical decisionmaking should be traceable to  national radionuclide
          standards.
          o   Instrumentation must be calibrated, and measurements  performed to preserve
              traceability.
          o   Reasonable  and defensible estimates of measurement  uncertainty  must  be
              determined and reported with each result to indicate the degree of confidence that
              can be placed in that result.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


       •  The  credibility,  and ultimately the defensibility, of data depend on  data  being
          generated under a quality system framework.
          o  Quality systems, such as those envisioned by ISO 17025, or the TNI Standard, are
             critical in providing a solid framework for ensuring that all measurements used to
             support the decisionmaking process are accurate and of known uncertainty, well-
             documented, traceable to national standards, and generally technically and legally
             defensible. Several important components of a quality system include:
             •   Accreditation by independent authorities.
             •   Validation  of  measurement  methods  and  procedures   prior  to  use  to
                 demonstrate that they are capable of reliably meeting MQOs.
             •   All measurements performed by qualified and trained analysts.
             •   Routine blind performance evaluations against traceable standards in various
                 matrices.
             •   Internal quality  control measures  to demonstrate  the ongoing quality  of
                 measurements.
             •   Rigorously documented programs to ensure that data can be recreated and
                 independently validated and thus withstand possible data challenges.
          o  Although  the  concept  of quality  systems for field  measurements has been
             considered, implementation has yet to occur. The transitory nature of many field
             operations may be partially responsible for this.
          o  Creative, more formalized, and effective quality controls  could be implemented to
             support field measurements. These might range from implementing additional QC
             measurements in the  field, to  periodic independent confirmatory analyses  at the
             laboratory.
       •  Emissions from  naturally occurring radionuclides  in the background may interfere
          with measurements of contaminant using gross activity techniques. This challenge
          may be overcome by increased use of spectrometric measurement techniques for
          gamma emitters that can most effectively be performed in the field.

7.2  Conclusions and Recommendations Specific to Field Measurements

       •  Field measurements will play a predominant role in the early phase. They:
          o  Are ideally suited for generating real-time data for short-term protective action
             decisions involving medium- to high-activity levels.
          o  Can provide real-time results for rapid and effective decisionmaking.
          o  Can  provide  the  best   estimate  of  average activities  of  gamma-emitting
             radioactivity.
          o  Can minimize the risk of not identifying hot spots of gamma emitters.
   •   The value of using field calibration facilities cannot be underestimated. The  availability
       of such a facility, if used prior to deployment for an incident, would allow field sampling
       and measurement organizations to address potential weak points in their measurement
       systems to ensure that:
          o  Measurement technologies could be validated against reliable reference sources.
          o  Instruments could be calibrated against reliable reference sources.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


          o  Analysts could be  trained and qualified in a real-world  environment prior to
             deployment in the field.
       •   A number of technical and  practical considerations impact  the viability of field
          measurements in  providing  rapid,  unbiased,  low-uncertainty  measurements  of
          radioactivity.  Several of these  include:
          o  Control of measurement geometry to ensure defensible in situ measurements.
          o  The impact on calibrations and measurements of deposition patterns and mechan-
             isms and  self-absorption effects resulting from penetration of contaminants into
             solid  surfaces.  Gamma-emitting contaminants are the most  amenable to field
             measurement.  Alpha-  and  beta-emitting  contaminants   may  present  more
             challenges to field measurements and require confirmatory or primary laboratory
             analysis for their determination.
          o  If an incident involves pure alpha and beta emitters, or mixtures containing pure
             alpha and beta emitters, field measurements may be much more limited  in their
             ability to meet MQOs, especially in the later stages of an incident.
       •   The  effectiveness  and quality  of  field measurements  may be  limited  by the
          availability of equipment and experienced and trained operator/analysts.
       •   Confidence in the field data is significantly  increased by grab sampling with
          confirmatory analysis at a laboratory.

7.3  Conclusions and Recommendations Specific to Laboratory Measurements

       •   Laboratory measurements will play a limited role in the early phase. They:
          o  Identify the complete list of contaminants.
          o  Perform defensible confirmatory analyses for field measurements  and measure-
             ments in media such as water.
          o  Can be used to delineate the extent of impacted areas for  lower activity  air
             particulate and soil measurements.
       •   A number of technical  and practical considerations impact the viability of laboratory
          measurements in  providing,  rapid,  unbiased,  low-uncertainty  measurements  of
          radioactivity.  Several of these  include:
          o  Real-time measurements are not possible with laboratory measurements.
          o  Grab samples must be collected and shipped to the laboratory for preparation and
             analysis, which leads to a  delay in obtaining analysis results relative to real-time
             measurements in the field.
          o  Laboratories  can perform independent  final status measurements to  meet the
             highest data quality requirements.
          o  Laboratories  provide low-bias, low-uncertainty, and low-level measurements of
             alpha- and beta-emitting contaminants. Measurement geometries and calibrations
             are  carefully  matched,  controlled  environments  provide  low  and  stable
             backgrounds, and chemical separations may be combined with non-spectrometric
             and spectrometric measurement techniques to produce reliable measurements at
             the lowest activity levels.
          o  In spite of longer turnaround times of one to several days, laboratories  provide
             high throughput for less  time-critical, quality-assured measurements  of alpha,
             beta, and gamma emitters.
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          o  If sufficient  resources and expertise  are available  in the field to collect grab
             samples, combining laboratory and field capacity will result in an overall increase
             in analytical throughput and more rapid completion of recovery operations.
          o  Naturally occurring radionuclides in the matrix may interfere with measurements
             of contaminant using gross activity techniques. This challenge may be overcome
             by  increased use of spectrometric measurement techniques for alpha, beta, and
             gamma emitters, which are readily available at the laboratory. (Note  that this
             challenge is shared with field measurements.)
          o  For gamma spectrometry measurements, larger numbers of grab samples may
             have to be collected and analyzed in  the laboratory to obtain the  same level of
             confidence obtained using in situ gamma spectral measurements.

7.4  Summary

Ultimately, both laboratory and field measurements will be used in all phases of an event as part
of the recovery and remediation process. The  results of all measurements from these sources
should not only support the DQOs and MQOs, but also should be complementary to  each other.
This is an extremely important part of the data assessment process that will provide the basis for
a defensible decision. Whether measurements are performed in the field or the laboratory, the
data generated need to be technically defensible. Data need to be  obtained using rigorous and
well-documented  analytical  protocols within the context  of  a  robust  and well-implemented
quality management program. Ultimately, it is the responsibility  of the Incident Commanders
and their designees to ensure that  all analytical data produced will be of sufficient quality to
support decisionmaking.

8.  References

Abbady,  A. 2006. Radiological Hazard and Radiogenic Heat Production in Some  Building
   Materials in Upper Egypt. Journal of Radioanalytical and Nuclear Chemistry, Vol. 268, No.2
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American National   Standards  Institute (ANSI). 1999.  Surface  and  Volume  Radioactivity
   Standards for Clearance. N13.12. Health  Physics Society, American  National Standards
   Institute Health  Physics Society, American National Standards Institute (ANSI)  N13.12
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American  National   Standards  Institute  (ANSI).  2004a.  American  National  Standard
   Measurement  and Associated Instrument Quality Assurance for Radioassay Laboratories.
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   Available from: http://www.ansi.org/.

American National Standards Institute (ANSI).  2004b. Quality Systems for Environmental Data
   and  Technology Programs-Requirements with  Guidance for  Use.  American  Society for
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American Society for Testing and Materials (ASTM). 2008. Standard Guide for Selection and
   Use  of Portable Radiological Survey Instruments for Performing In Situ Radiological
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   Assessments  in  Support of Decommissioning.  ASTM D1893-08,  Section  5.3.  ASTM
   International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA.

American Society for Testing  and Materials (ASTM).  2007. Standard Practice for  Set-up,
   Calibration, and Quality Control of Instruments  Used for  Radioactivity Measurements.
   ASTM D7282-06. January. Available from: www.astm.org/.

Conference of Radiation Control Program Directors (CRCPD). 2006. Handbook for Responding
   to a Radiological Dispersal Device - First Responder 's Guide—the First 12 Hours. CRCPD
   Publication     06-6.     Frankfurt,     Kentucky,     September.     Available      at:
   www.crcpd.org/RDD Handbook/RDD-Handbook-ForWeb.pdf

U.S.  Department of Defense  (DOD).  2009.  Quality  Systems Manual  for  Environmental
   Laboratories (QSM).  Department of Defense.  QSM  rev.  4.1.  April. Available  at:
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U.S. Department of Energy (DOE). 2009. Quality  Systems for Analytical Services (QSAS).
   Department of Energy Consolidated Audit Program. QSAS rev. 2.5. November. Available at:
   https://doecap.oro.doe.gov/DOECAP Public/documentsLab.aspx.

U.S. Environmental Protection Agency (EPA). 2000. Guidance on Technical Audits and Related
   Assessments for Environmental Data Operations. Washington, DC. EPA QA/G-7, EPA-240-
   R-99-080. January. Reissued May 2006. Available at: www.epa.gov/quality/qa_docs.html.

U.S. Environmental Protection Agency (EPA). 2002a. Guidance for Developing Quality Systems
   for Environmental  Programs.  Washington,  DC.  EPA QA/G-1,  EPA-240-R-02-008.
   November.  Reissued January 2008. Available at: www.epa.gov/quality/qa_docs.html.

U.S. Environmental Protection Agency (EPA). 2002b. Guidance for Quality Assurance Project
   Plans. Washington,  DC.  EPA QA/G-5, EPA-240-R-02-009.  December.  Available  at:
   www.epa.gov/qualitv/qa docs.html.

U.S. Environmental Protection Agency (EPA). 2002c. Guidance for Quality Assurance Project
   Plans for Modeling. Washington, DC. EPA  QA/G-5M, EPA-240-R-02-007. December.
   Available at: www.epa.gov/qualitv/qa docs.html.

U.S. Environmental Protection Agency (EPA). 2003. Guidance on Assessing Quality Systems.
   Washington, DC. EPA QA/G-3, EPA-240-R-03-003. March. Available at: www.epa.gov/
   qualitv/qa docs.html.

U.S. Environmental Protection Agency (EPA). 2006. Guidance on Systematic Planning Using
   the Data Quality Objectives Process. Washington, DC. EPA QA/G-4, EPA-240-B-06-00.
   February. Available at: www.epa.gov/quality/qa_docs.html.

U.S. Environmental Protection Agency (EPA). 2008. Radiological Laboratory Sample Analysis
   Guide for Incidents of National Significance - Radionuclides in Water. Washington, DC.
   EPA 402-R-07-007. January. Available at: www.epa.gov/narel/incident_guides.html.

U.S. Environmental Protection Agency (EPA). 2009a. Method Validation Guide for Qualifying
   Methods Used by Radioanalytical Laboratories Participating in Incident Response Activities.
   Washington,  DC. EPA 402-R-09-006. June.  Available  at:  www.epa.gov/narel/incident_
   guides.html.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


U.S. Environmental Protection Agency (EPA). 2009b. Radiological Laboratory Sample Analysis
    Guide for Incidents of National Significance - Radionuclides in Air. Washington, DC. EPA
    402-R-09-007. June. Available at: www.epa.gov/narel/incident_guides.html.

U.S.  Environmental  Protection  Agency  (EPA). 2009c.  Radiological  Laboratory  Sample
    Screening Analysis Guide for Incidents of National Significance.  Washington, DC. EPA 402-
    R-09-008. June. Available at: www.epa.gov/narel/incident_guides.html.

U.S. Environmental  Protection Agency (EPA).  2010.  Standardized Analytical Methods for
    Environmental Restoration Following Homeland Security Events - SAM 2010. Revision 6.0,
    Washington,  DC.  EPA  600/R-10/122,  September.   Available  at:  www.epa.gov/sam/
    index.htm.

U.S.  Environmental  Protection Agency  (EPA).  201 la.  Policy  to  Assure  Competency of
    Laboratories,  Field  Sampling,   and  Other  Organizations   Generating  Environmental
    Measurement Data under Agency-Funded Acquisitions. Agency Policy Directive Number
    FEM-2011-01, March. Available at: www.epa.gov/fem/pdfs/fem-lab-competencv-policy.pdf.

U.S. Environmental Protection Agency  (EPA). 201 Ib. A Performance-Based Approach to the
    Use of Swipe Samples in Response to a Radiological or Nuclear  Incident. Revision 0. Office
    of Research and  Development, Cincinnati, OH,  and Office of Radiation  and  Indoor Air,
    Washington, DC. EPA 600/R-l 1/122,  October.  Available at:  http://oaspub.epa.gov/eims/
    eimscomm.getfile?p_download_id=504097.

International  Bureau of Weights  and Measures  (BIPM). 2008. International vocabulary of
    metrology — Basic and general concepts and associated terms  (VIM). Joint Committee for
    Guides in Metrology 200:2008. BIPM. Available at: www.bipm.org/en/publications/guides/.

Integrated Consortium of Laboratory  Networks  (ICLN).  2007.  Assessment of Nationwide
    Laboratory Surge Capacity Required to Support  Decontamination of Chemical, Biological
    and Radiochemical-nuclear Agents. Task 06-32,  Integrated  Consortium of  Laboratory
    Networks (ICLN) Capability Assessment. April 30.

International  Organization  for  Standardization   (ISO).   1988.   Evaluation   of  Surface
    Contamination - Part 1:  Beta Emitters and Alpha Emitters.  ISO-7503-1 (first edition).
    Geneva, Switzerland.

International  Organization  for  Standardization  (ISO).  1993a. Statistics  - Vocabulary  and
    Symbols  - Part  1:  Probability  and  General Statistical Terms.  ISO 3534-1. Geneva,
    Switzerland.

International Organization for Standardization (ISO).  1993b. International Vocabulary of Basic
    and General Terms in Metrology. ISO Guide 99, Geneva, Switzerland.

International Organization for Standardization (ISO) Guide 98. 1995. Guide to the Expression of
    Uncertainty in Measurement. Geneva, Switzerland. Available at: www.iso.org/iso/catalogue
    detail.htm?csnumber=45315.

International Organization for Standardization  (ISO/IEC). 2005. General Requirements for the
    Competence  of  Testing and  Calibration Laboratories.  Standard 17025,  International
                                          66

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


    Organization  for  Standardization/International  Electrotechnical   Commission.  Geneva,
    Switzerland. Available from: www.iso.org/

Leino, R.,  D.C. George, B.N. Key,  L. Knight, and W.D. Steele. 1994. Field Calibration
    Facilities for Environmental Measurement of Radium, Thorium, and Potassium,  Technical
    Measurements Center, Grand Junction Projects Office, Grand Junction, CO, U.S. Department
    of Energy.

Multi-Agency Radiological Laboratory Analytical Protocols (MARLAP) Manual. 2004. EPA
    402-B-04-001A, July. Volume I, Chapters 6, 7, 20, Glossary; Volume II and  Volume III,
    Appendix G. Available at: www.epa.gov/radiation/marlap.

Multi-Agency Radiation Survey and  Assessment of Materials and Equipment (MARSAME)
    Manual.  2009.  EPA  402-R-06-002.  Available  at:  www.epa.gov/radiation/marssim/
    marsame.html.

Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM).  2000. Revision  1.
    NUREG-1575 Rev 1, EPA 402-R-97-016 Revl, DOE/EH-0624 Revl. August. Available at:
    www.epa.gov/radiation/marssim/index.html.

National Council  on Radiation Protection  and  Measurements  (NCRP). 1976. Environmental
    Radiation Measurements, Report No. 50, December.

National Council  on Radiation Protection  and  Measurements  (NCRP). 1991. Calibration  of
    Survey Instruments Used in Radiation Protection for the Assessment of Ionizing Radiation
    Fields and Radioactive Surface Contamination. NCRP Report 112, pp. 4-5. Bethesda, MD
    20814.

National Council  on Radiation Protection  and  Measurements  (NCRP). 1992. Environmental
    Radiation Measurements. NCRP Report No. 50.

National Environmental  Laboratory Accreditation Conference (NELAC). 2003. 2003 NELAC
    Standard, EPA-600-R-04-003, June.  Available at:  www.nelac-institute.org/docs/2003nelac
    standard.pdf

Novak,  E.F.  1998.  Exposure-Rate Calibration  Using Large-Area Calibration Pads.  Grand
    Junction Projects Office, Grand Junction, CO, U.S. Department of Energy.

U.S. Nuclear Regulatory Commission (NRC) and Oak Ridge  Associated Universities. 1992.
    Manual for Conducting Radiological Surveys in Support  of License  Termination, Draft
    Report for Comment. NUREG/CR-5849. Washington, DC.

U.S. Nuclear Regulatory Commission (NRC). 1997. Minimum Detectable Concentrations with
    Typical Radiation Survey Instruments for  Various Contaminants and Field Conditions.
    NUREG-1507. Available at: www.orau.gov/ddsc/instrument/NUREG-1507.pdf

U.S. Nuclear Regulatory Commission  (NRC). 2006. Consolidated Decommissioning Guidance:
    Decommissioning Process for Materials Licensees. NUREG-1757 (Volume 1, Revision 2).
    Available at: www.nrc.gov/reading-rm/doc-collections/nuregs/staff/srl757/.

U.S.  Nuclear Regulatory  Commission  (NRC). 2007. Quality Assurance  for Radiological
    Monitoring Programs (Inception  through Normal Operations to License  Termination)—
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


   Effluent Streams and the Environment, Regulatory Guide 4.15, Rev. 2. July. Available at:
   http://adamswebsearch2.nrc.gov/IDMWS/ViewDocBvAccessi on.asp? AccessionNumber=M
   L071790506.

Reginatto, M., P. Shebell, and K.M. Miller. 1997. ISD97, EML-590 -A Computer Program to
   Analyze Data from a Series of In Situ Measurements on  a Grid and Identify Potential
   Localized Areas of Elevated Activity, Environmental Measurements Laboratory, New York,
   NY, October.

The NELAC Institute (TNI). 2007. Volume I: General Requirements for Field Sampling and
   Measurement Organizations; and Volume II: General Requirements for Accreditation Bodies
   Accrediting  Field Sampling and Measurement  Organizations.  The Field Sampling and
   Measurement Organization Sector of The NELAC Institute. May. Available at: www.nelac-
   institute.org/doclibrary.php.

United Nations  Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). 2000.
   Sources and Effects of Ionizing Radiation. Report Vol. I. Available at: www.unscear.org/
   unscear/en/publications/2000 1 .html.
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Appendix I: Case Study on the Use of Field Spectrometry Instruments for Remediation at
Rocky Flats Environmental Technology Site (RFETS)

At Rocky Flats Environmental Technology Site, in situ gamma spectrometry (ISGS) was one of
several  radioanalytical techniques  used to support the decontamination and decommissioning
(D&D)  process.  Given RFETS' historical mission, the majority of contamination  at  the  site
resulted from plutonium  processing and involved isotopes  of americium and  plutonium with
lesser amounts of uranium. Experience during the D&D  at RFETS showed that ISGS was a
valuable tool at the  radiologically  contaminated site. Given  the right  environmental conditions
and  the resources for physically characterizing objects being measured and performing  data
reduction via established  procedures, it was able to play  vital  and  complementary roles in
assessment and  remediation  activities. At  the same  time,  experience  showed that ISGS
applications have clear limitations and that these limitations may run counter to expectations that
large amounts of definitive radioanalytical data can be quickly and easily generated in the field,
especially if more complex mixtures of pure alpha and beta emitting radionuclides are present in
the source term.

ISGS found primary application at RFETS in situations where grab sampling was impractical
(e.g., large objects or areas) and results were needed in real-time. Specific applications included:

   •  Support of excavations  of contaminated areas and landfills (e.g., 903 Pad35);
   •  Identifying the extent of heavily contaminated areas;
   •  Safeguarding measurements of special nuclear materials in glove-boxes (i.e., "hold up");
   •  Tracking  progress  during  cleanup  and excavation to  provide  "go"  and  "no-go"
       determinations;
   •  Surveys of outdoor areas (soil, pads, or other potentially contaminated surfaces); and
   •  Characterization and   final  status surveys  in buildings  and outdoor  areas   during
       assessment.

Most critically, in order for ISGS to provide usable results, the isotope of interest must be a
gamma-emitting  radionuclide.  Alpha  and beta emitters  cannot be detected unless  they  also
possess a  secondary  gamma  ray  emission.  At RFETS,  this was nearly an  insurmountable
challenge because the primary contaminant at the site, plutonium, is an alpha emitter that emits
only very  weak  gamma and x-rays.  Thus,  plutonium is  not readily  detectable  using  gamma
spectrometry unless  very large amounts are present.36 ISGS would not have played a significant
35ISOCS™ was used at Rocky Flats in the remediation of the 903 Pad to help guide the progress of excavation in
real-time.  It might be misleading, however, to say that the measurements made at the 903 Pad using ISGS were
definitive  since  quantitative in situ  measurements of contaminants often are impossible  in  the presence of
confounding contaminants and the background activity associated with them. In such cases, samples must be taken
"destructively" and transported to an area where the background activity has been quantitatively determined. At the
903 Pad, for example, a fixed geometry approach was used for many of the measurements. Although ISOCS™ was
used, it was most frequently not applied in situ but rather in a manner more reminiscent of conventional gamma
spectrometry measurements with the exception that ISOCS™ measurement efficiencies were  modeled and results
generated  without direct comparison to a NIST standard. Although the results generated may have been reasonable,
they were  not traceable to a NIST standard as would be required of quantitative measurements.
36 While absolute detection thresholds for 239Pu were typically at the nanocurie level, exact detection thresholds
depend on ambient background, composition of the material being measured, depth and profile of deposition, area!


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role in the D&D effort at RFETS except for the fortuitous availability of accurate data on the
isotopic makeup of plutonium used at the plant. This, together with the latest date of plutonium
separation (beginning when production operations at  the  plant ceased), made it possible to
inferentially relate the 241Am present to the 241Pu. Despite this information about the source term,
extensive pre-survey and post-survey confirmatory sampling and radiochemical analysis at fixed
laboratories were needed to verify that the americium to plutonium ratios presumed from process
knowledge were  still valid and had not been changed due to chemical processes and transport
mechanisms following deposition of the contaminants in the environment.37

Although in situ techniques played an indispensable role in the rapid pace and ultimate success
of D&D at RFETS, it would be misleading to overlook the fact that ISGS results were qualitative
in nature, or associated with unknown  levels of bias and uncertainty. To perform an accurate
"calibration" for this technique, the following conditions must be met:

    •   Ambient background must be accurately determined, particularly for environmental and
       low-level  measurements where incident-related contaminants may be present adjacent to
       the location of the measurement.
    •   The physical  characteristics of  the  material or materials  comprising the object being
       measured must be accurately known, including their elemental composition and density.
    •   The shape of the contaminated objects and materials  of which they are  composed and
       their spatial relationship to the detector must be well known.
    •   The areal and volumetric distribution of the contaminants on and in the objects being
       measured must be very well known.
    •   All of these factors must be synthesized into a mathematical model that is representative
       of the measurement, which must be done by a gamma spectrometrist specially trained and
       experienced in the technique.

Given the number of critical factors underlying the application of ISGS in the real world (and the
assumptions generally necessary to estimate these factors), it is not surprising that in many cases
it is extremely difficult to realistically assign uncertainty to ISGS measurements. Similarly,  it
should not be overly surprising when realistic  assessments of measurement uncertainty  exceed
those obtained through fixed laboratory measurements.

Thus, for critical measurements  requiring reliable and defensible data (as opposed to "go" and
"no-go" measurements, such as those used to guide remedial  excavations),  samples were taken
and radiochemical analysis performed  under the carefully controlled conditions available in
radioanalytical  laboratories. Fixed laboratory analysis  was crucial  in situations where  in situ
measurements were technically or practically infeasible. This analysis also was used to develop
distribution of the contaminant, and location of the detector. 241 Am, which has a reasonably abundant gamma ray
emission, for example, would not meet the criteria specified in  10 CFR 835 Appendix D for removable surface
contamination with MDCs of -30-50 dpm/cm2 for an ideal geometry, a flat plane surface, and extended count times
between eight and 24 hours (based on personal experience and unreleased MDC data).
37 According to informal communications with several individuals, attempts to apply similar assumptions at other
DOE sites have met with limited success.
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correlation  factors used to guide in situ measurements,  and as a reliable  and defensible
confirmatory technique (i.e., "ground truth").

Additionally, accurate measurements  with ISGS are possible only when extensive and detailed
information  regarding the  distribution and  deposition characteristics of the  contaminant is
available. Even minor variations in the characteristics (e.g., variations in depth and profiles of
contaminant penetration due  to  porosity,  or even  due to  surface roughness) could introduce
significant errors into  measurements. The most accurate results are  obtained  in cases where
surface contamination was "fixed" on a flat surface by stabilizing the contaminant with paint. In
practice, though, confirmatory sampling followed by chemical separation and laboratory analysis
is necessary to validate the assumptions made during calibration of the  instruments. On a number
of occasions, traditional sampling and analysis indicated that the original assumptions made to
calibrate the ISGS were inaccurate and that the inaccuracy of measurements was not covered by
the reported uncertainty.

In the field (e.g., with soils or rough or porous surfaces), it became increasingly difficult to make
defensible assumptions and more frequent, extensive, and specialized analysis of grab samples
(e.g., radionuclide penetration analysis in cored or  scabbled samples) was necessary to  ensure
that ISGS measurements were accurate. Given the time, effort, and cost for the fixed laboratory
analysis, the need to synthesize this information gained, and the delay  in time needed to do this,
much of the perceived rapidity of analysis was lost.

Even if only 241Am is present and conditions are otherwise reasonably ideal (e.g.,  241Am-free
background, with the detector -30 cm from a plane surface), the sensitivity of the technique may
not be able to reliably measure 241 Am at the levels needed to detect surface contamination at the
limits established under 10  CFR 835 Appendix  D (20   dpm/100  cm2). For example, one
representative  minimum detectable concentration (MDC) study performed  at RFETS indicated
detection capabilities ranging from 30-50 dpm/100  cm2 for areal deposition of 241Am using a
broad energy germanium (BEGe) detector  even with extended count times of eight to 24 hours.
Another limitation of ISGS encountered at RFETS  involved  measurements  in contaminated
areas. Because the detector is only lightly shielded (using a collimator), ambient radiation in an
area cannot be reliably differentiated from analyte signal. As a  result, when contamination was
present in an area of concern at RFETS, often it was  not possible to determine the background
activity. This necessitated collecting grab samples for measurement under adequately controlled
conditions. For example, although many ISOCS  measurements were made during the 903 Pad
excavation, a large number of these samples were removed from the area and counted away from
the main  source  of  contamination  (in  a  quasi fixed-geometry situation  very similar to  the
traditional laboratory setting).

Finally, the experience at RFETS showed that while there are distinct advantages given the right
conditions, there are just as  distinct limits to sample throughput for ISGS (specifically ISOCS™)
measurements. Gamma spectrometrists specially trained and experienced in ISGS techniques are
needed to produce defensible data. Based on interviews with personnel intimately involved in
performing ISOCS   measurements onsite at RFETS, 15 to 60  minutes are needed to set up  a
gamma "shot." A highly experienced operator is required  who can very  carefully document
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conditions of analysis, prepare accurately  dimensioned sketches of the  area, determine and
document the composition of the object being  analyzed, and  identify conditions that could
impact very  subtle (and  subjective) factors in the analysis such as depth of  penetration  of
contaminants. Count times vary depending on the sensitivity of the measurement needed, but
even assuming a short count of 45 minutes, a single operator with a single instrument could  be
expected to perform a maximum of eight measurements in a day. If extended counts (8- to 24-
hours) are needed, throughput drops precipitously. Once the spectrum and associated data have
been  acquired,  data  reduction   and  analytical   results  are performed  by  an  experienced
spectrometrist. At RFETS, this required approximately 20  minutes  per  gamma  spectrum  in
routine  cases. Thus,  optimistically, four people would  be required  to produce  about  25
measurements per day. This  does not make any allowance for confirmatory sampling  or
integration of feedback from confirmatory sampling.

In summary, ISGS would not have been capable of detecting levels of plutonium  low enough to
support environmental and free-release criteria at RFETS without making assumptions regarding
ratios of plutonium relative to the marker isotope, 241Am. That it was used at all is due to the
fortuitous availability  of  historical isotopic characterization data for the  site's  plutonium.
Calibrating ISGS detection systems requires extensive knowledge that was not always available
to operators in the field. Varying and unknown levels of self-absorption in weathered settings
complicated the development of ISGS calibration models. As a result, extensive  pre- and post-
survey fixed-laboratory radiochemical measurements were needed to confirm and support the
assumptions used to generate the ISGS data. The ambient background activity of 241Am from site
contaminants often precluded use of in situ techniques  for measurements of 241Am. Instead,
where defensible analyses  were required (i.e., results traceable to NIST standards that would  be
used to make decisions of record), ISGS results  were not generally used;  rather, grab samples
were routinely taken and sent to fixed laboratories for alpha isotopic analysis.

In the case of a radiological or nuclear incident, it is foreseeable that even if a large amount  of
ISGS equipment is procured, similar  circumstances could  apply. Large numbers of expert,
experienced operators and spectrometrists would be needed to perform ISGS measurements, a
requirement that  would very likely cause  staffing shortfalls. The limitations of  assumptions
needed to develop models for calibration and elevated background from co-located contaminants
or natural background would require the coordination of field and lab resources  to balance the
need  for large numbers  of measurements with  the data quality  needed to support critical
decisionmaking.
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Appendix II: Applicability of Selected Field and Laboratory Measurement Techniques

Tables 5, 6, and 7 provide a comparative overview of the  applicability of various  detection
techniques for determining radionuclides at low, medium, and high activity levels in the field and
at the laboratory. The tables may help to provide  perspective on the relative applicability of
specific techniques for measurements of radionuclides conducted  at  different activity levels.
Incident-specific parameters, such as those listed below, will all affect the viability of a specific
technique for measurement of the radionuclides of interest:

   •   DQOs;
   •   MQOs;
   •   Matrices to be sampled;
   •   Deposition profiles of radionuclides in matrices;
   •   Interfering radionuclides or radiation;
   •   Non-radiological interferences;
   •   Need for rapid or even real-time measurements; and
   •   Relative availability of needed instrumentation, skilled and experienced analyst/operators
       or samplers, and laboratory capacity.

Clearly, incident-specific  circumstances  such as DQOs, MQOs, matrix, interfering radiation,
circumstances of the  measurement, etc.,  will influence the viability of a technique to a given
situation. Thus, these  tables  should be viewed only as a comparative tool and as a starting point
for comparing field and laboratory techniques for measurements of various radionuclides.

In the tables below, cases where a technique is generally well-suited to unbiased, low-uncertainty
determinations of a radionuclide contaminant at the respective activity level are marked with a
solid dot (•). Cases in which the test is deemed to be of marginal applicability, or cases  where
the technique is by its nature non-definitive, or where applicability is limited over a significant
portion of the range noted  are marked with an open circle (o). Where a technique is deemed to be
unsuitable for determining the radionuclide at the activity level in question, the slot is left blank.

For field measurements, the tables further differentiate between in situ measurements of surface
contamination and  in situ measurements  of volumetric contamination. There is  only  a  single
table  addressing  laboratory measurements because there is  no significant difference in how
surface or volumetric measurements are conducted beyond the units used to report results.

In  general,  instruments  that   have  high  or  variable backgrounds, such as  unshielded
instrumentation, will find  limited applicability unless the levels  of radioactivity of concern are
high enough  that analyte  signal can be  unambiguously differentiated from ambient radiation
levels. This clearly limits the applicability of many field techniques at the lowest activity levels.

When an uncontaminated sample matrix  contains elevated levels of background radioactivity
intrinsic to the uncontaminated matrix material, these will compete with or mask signal from the
analyte. This is commonly the case in measurements of radionuclides at low-to-medium activity
levels. Thus,  techniques based on the measurement of gross  activity  are viable only when the
activity of the  contaminant significantly exceeds the gross activity in the uncontaminated sample
                                           73

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


matrix. In the field, and in some cases at the laboratory, this will limit the applicability of most
non-spectrometric techniques to medium- to higher-activity levels.

In some cases,  the  analyte of concern itself is a radionuclide encountered in the ambient
background or in the uncontaminated matrix material, such as isotopes of radium, uranium, lead,
and polonium. In such cases, the intrinsic activity and associated uncertainty of the analyte in
uncontaminated  matrix material must be  determined by separately  analyzing  representative
uncontaminated  matrix material. The uncertainty with which competing background activity is
known will define the threshold for determining the presence or absence of contaminant.

Spectrometric techniques, especially gamma spectrometry, can discriminate against interfering
radiation while  specifically measuring the contaminant  even  when  significant  levels of
background  activity  are present. Gross  gamma measurements may not provide unambiguous
results at the low and medium activity levels, while gamma spectrometric measurements may
detect very low levels of radionuclides even in the presence of the ambient levels of interfering
radioactivity.

Radionuclide-specific measurements in the laboratory will nearly always produce  more accurate
results and reliable estimates of uncertainty at lower levels of activity than is  possible for field
measurements. Field measurements using lightly shielded or unshielded alpha,  beta, or dose rate
meters,  especially at low-to-medium activities,  will  not be  able  to  discriminate against  the
intrinsic background signal of the matrix.  This concern can be addressed at the laboratory by
combining chemical separations with heavily shielded alpha and beta measurement techniques to
provide radionuclide-specific  data with  lower detection  levels  and smaller  measurement
uncertainties. Controlled counting geometries, longer count times, and tighter QA/QC controls
also allow lower uncertainties and a higher degree of defensibility.

Field techniques can provide defensible results that meet MQOs given the proper conditions.
Most optimally,  when radionuclide(s) of known identity are freshly  deposited on smooth and
relatively  impermeable  surfaces,  bias due to  inaccurate  self-absorption  corrections is
significantly  minimized  to  a  point where it is non-problematic. In  most cases,  however,
radionuclides are deposited on permeable and irregularly shaped surfaces, where weathering may
have occurred requiring more  information  about measurement conditions to generate accurate
estimates of the detection efficiency and  its associated uncertainty.  Such information could
include the  size and shape of the  active  source,  information  about the  spatial distribution
(including depth of penetration for self-absorption corrections), the degree  of homogeneity of
contaminants within the source,  the elemental  composition of the  object,  and the ambient
background activity in the area of the measurement.

There is one notable exception where field measurement sensitivity may be significantly greater
than the corresponding measurements at a laboratory. ISGS is a very powerful  tool for real-time
field  measurement  of  medium-  to  high-energy  gamma  emitting  radionuclides.  If  the
measurement  geometry  is reproducible  and  well-controlled,   accurate   results  and  low
measurement uncertainties may be possible  at detection limits that are  much lower than may be
routinely available at the laboratory.  ISGS  measurements,  however,  often are  subject to
interference  from ambient background, which may introduce bias into results and increase  the
                                           74

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


uncertainty of the measurement. Laboratory gamma spectrometry measurements, on the other
hand, are made in an environment where background from ambient sources of radiation has been
effectively eliminated but tends to be limited by the size of the sample that can be measured.

Even when factors impacting instrument calibrations and background corrections are less well-
known,  a conservative set of assumptions may be applied to allow  ISGS measurements to be
used protectively for rapid characterization of large areas and detecting hot spots in the field with
a minimum of effort. Given the potential for mismatch between measurement conditions and the
assumptions underlying the gamma spectrometer calibrations, however,  assumptions should be
carefully applied  and operational  controls  established to  ensure  that  measurements  will
consistently err on the side of protecting human health and the environment (i.e., always have  a
positive bias).

Since in situ measurements may be biased or have high or unknown levels of uncertainty, they
should be clearly  qualified as such and used only very judiciously for decisionmaking. Positive
measurements that could be the result of bias in the measurement system, or for which estimates
of uncertainty may be unrealistically low, should be verified prior to taking significant action.
The  validity  of all field measurements  also should be routinely  confirmed by independent
measurement of samples  at laboratories since measurement conditions and bias are much more
carefully controlled in the laboratory setting  than is generally possible  in the field. These
confirmatory  data provide the program with high quality, traceable results and documented
evidence, thus providing solid support for decisionmaking during incident response.

Assuming there are further limiting technical issues, decisions about whether field or laboratory
measurement  techniques  (or both)  should  be  used  will be influenced by   operational
considerations such as: Is there a need for  rapid or real-time results? Are trained and experienced
sampling  personnel  and fixed  laboratory  capacity  available?  Are trained, experienced
operator/analysts and field instrumentation available for field analysis?
                                           75

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                            Uses  of Field and Laboratory Measurements During  a Radiological or  Nuclear Incident
Table 5 - Applicability of Selected Field Measurement Techniques for In Situ Measurements of Surface Activity / Concentrations of Radionuclides

1 ° Radiation
2° Radiation
241Am
a
7
X
244Cm
a
x(w)
238pu
a
X
239f40pu
a
X((0)
238U#
a
x(w)
235U
a
r
X
232Jh#
a
X
7 (a)
210p0
a
n/a
226Ra#
a
y(w)
x(w)
gosr
p
n/a
sssr
P
n/a
32p
P
n/a
"Tc
p
n/a
3H
p
(LE)
n/a
241pu
P
(LE)
n/a
125|
E
(LE)
7
(LE)
129|
P
(LE)
7
(LE)
13?Cs
P
7
x(w)
6°Co
P
y(o>)
103pd
E
(LE)
X((0)
(LE)
HPGe (ISGS - energy greater than 0.06 MeV)
Low Activity
Medium Activity
High Activity
o
•
•










o
•
o
•
•

o
o
Unshielded Geiger-Muller (G-M) (thin window non-specific ionizing radiation - gross al
Low Activity
Medium Activity
High Activity

o
•

o
•

o
•

o
•

o
•

o
•

o
•



I
o
•
























•
•
•
•
•
•



oha/gross beta)

o
•

o


o


o


o


o














o
•

o
•

o
•
Unshielded Nal(TI) (Gross Gamma )
Low Activity
Medium Activity
High Activity

o
•










o
•

o
•

o
•




o
•



















o
•

o
•

•
•

•
•

o
•
Alpha Scintillator (large-area in situ zinc sulfide (ZnS) detector- gross alpha)*
Low Activity
Medium Activity
High Activity
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•

































Unshielded Beta Scintillator (large-area in situ organic scintillator detector - gross beta, average energy greater than 500 keV) t
Low Activity
Medium Activity
High Activity



























o
•
•
o
•
•
o
•
•

o
•












o
o
•
o
o
•



Gas Proportional Counter (large-area in situ detector- discriminated gross alpha/beta)*
Low Activity
Medium Activity
High Activity
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•

o
o












o
•
•
o
•
•

o
o
Gas Proportional Counter (segmented large-area in situ detector - discriminated gross alpha/beta) t
Low Activity
Medium Activity
High Activity
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o

o
•

o
•

o
•


o













o
o
•
o
o
•

o
o
Thin Nal(TI) Low-energy Photon Detector (e.g., FIDLER - x-ray spectrometry specificity is limited, self-absorption prevents unbiased, low-uncertainty determinations unless surface deposited)
Low Activity
Medium Activity
High Activity
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•
o
o
•

























•
•

•
•

o
o

o
o

•
•
• - suitable for definitive (unbiased, low-uncertainty) determination; o - capable of screening quality measurements only;
Low activity refers to levels between -0.1- 10 pCi/g alpha or -1-100 pCi/g beta-gamma; Medium activity refers to levels between -10-500 pCi/g alpha or -100-5000 pCi/g beta-
gamma; High activity refers to levels greater than —500 pCi/g alpha and —5000 pCi/g beta-gamma (determinations with low uncertainty are possible at levels significantly above
background); * determination based on decay progeny if in equilibrium; a - alpha emission; P - beta emission; y - gamma ray emission, x - x-ray emission; & - electron capture
decay; LE - emission less than 100 keV; 
-------
                            Uses  of Field and Laboratory Measurements During  a Radiological or  Nuclear Incident
Table 6 - Applicability of Selected Field Measurement Techniques for In Situ Measurements of Volumetric Activity / Concentrations of Radionuclides

1 ° Radiation
2° Radiation
241Am
a
7
X
244Cm
a
x(w)
238pu
a
X
239f40pu
a
X((0)
238U#
a
x(w)
235U
a
7
X
232Jh#
a
X
r(w)
210p0
a
n/a
226Ra#
a
y(w)
x(w)
gosr
p
n/a
89Sr
p
n/a
32p
p
n/a
"Tc
p
n/a
3H
p
(LE)
n/a
241pu
p
(LE)
n/a
125|
E
(LE)
r
(LE)
129|
P
(LE)
r
(LE)
137CS
P
J
x(w)
6°Co
p
y(co)
103pd
E
(LE)
X((0)
(LE)
HPGe (ISGS - energy greater than 0.06 MeV)
Low Activity
Medium Activity
High Activity
0
0
•










0
o
0
•
•






I
•
•




















o


o
•
•
•
•
•
•


o
Unshielded G-M (thin window non-specific ionizing radiation - gross alpha/gross beta)*
Low Activity
Medium Activity
High Activity

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o

0
o













0
o

0
o



Unshielded Nal(TI) (Gross Gamma )
Low Activity
Medium Activity
High Activity

0
o










0
o

0
o

0
o




0
o




















o


o

•
•

•
•


o
Alpha Scintillator (large-area in situ ZnS detector- gross alpha)
Low Activity
Medium Activity
High Activity

o
0

o
0

o
0

o
0

o
0

o
0

o
0

o
0

o
0

































Unshielded Beta Scintillator (large-area in situ organic scintillator detector - gross beta, energy greater than 500 keV) *
Low Activity
Medium Activity
High Activity




























o
0

o
0

o
0

o
0












0
o
0
0
o
0



Gas Proportional Counter (large-area in situ detector- discriminated gross alpha/gross beta)*
Low Activity
Medium Activity
High Activity


0


0


0


0


0


0


0


0


0

o
0

o
0

o
0















0
o
0
0
o
0



Gas Proportional Counter (segmented large-area in situ detector- discriminated gross alpha/gross beta)*
Low Activity
Medium Activity
High Activity

o
o

o
o

o
o

o
o

o
o

o
o

o
o

o
o

o
o

o
o

o
o

o
o















0
o
o
0
o
o



Thin Nal(TI) Low-energy Photon Detector (e.g., FIDLER - x-ray spectrometry specificity is limited, self-absorption prevents unbiased, low-uncertainty determinations unless surface deposited)
Low Activity
Medium Activity
High Activity

0
o

0
o

0
o

0
o

0
o

0
o

0
o

























0
o

0
o

0
o

0
o

0
o
• - suitable for definitive (unbiased, low-uncertainty) determination; o - capable of screening quality measurements only;
Low activity refers to levels between -0.1- 10 pCi/g alpha or -1-100 pCi/g beta-gamma; Medium activity refers to levels between -10-500 pCi/g alpha or -100-5000 pCi/g beta-
gamma; High activity refers to levels greater than —500 pCi/g alpha and —5000 pCi/g beta-gamma (determinations with low uncertainty are possible at levels significantly above
background); * determination based on decay progeny if in equilibrium; a - alpha emission; P - beta emission; y - gamma ray emission, x - x-ray emission; & - electron capture
decay; LE - emission less than 100 keV; 
-------
                       Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Table 7 - Applicability of Selected Laboratory Measurement Techniques for Determining Activity / Concentrations of Radionuclides

1 ° Radiation
2° Radiation
241Am
a
7
X
244Cm
a
x(co)
238pu
a
X
239f40pu
a
x(a>)
238y#
a
x(co)
235U
a
7
X
232Th#
a
X
y((o)
210Po
a
n/a
226Ra#
a
7(<»)
x((o)
9°Sr
P
n/a
89Sr
P
n/a
32p
P
n/a
99Tc
P
n/a
3H
P
(LE)
n/a
241pu
P
(LE)
n/a
125|
S
(LE)
7
X
129|
P
(LE)
7
X
1"Cs
P
7
x(w)
6°Co
P
y(w)
103Rd
S
(LE)
x(w)
Unshielded G-M (thin window)
Low Activity
Medium Activity
High Activity

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0

0
0








0


0
0
0
0
0
0
0


0
Unshielded Nal(TI) (Gross Gamma)
Low Activity
Medium Activity
High Activity

0
o










0
o

0
o

0
o




0
o




















o


o

0
o

0
o


o
Shielded Nal(TI) (Gross gamma)
Low Activity
Medium Activity
High Activity
o
o
o
o
o
o


o


o
o
o
o
o
o
o
o
o
o


o
o
o
o



















o
o

o
o
o
o
o
o
o
o

o
o
Shielded HPGe Gamma Spectrometry - energy greater than 0.06 MeV)
Low Activity
Medium Activity
High Activity
o
•
•









o
o
•
o
•
•
o
o
•



o
o
•
























•
•
•
•
•
•



Low Background Gas Proportional Counting (gross alpha/gross beta screen)
Low Activity
Medium Activity
High Activity
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0







0
0

0
0
0
0
0
0
0
0

0
0
Low Background Gas Proportional Counting (chemical separation - element or radionuclide specific)
Low Activity
Medium Activity
High Activity
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•






















0
0
0
•
•
•
•
•
•
•
•

0
•
Liquid Scintillation Counting (a/p screen - direct analysis)
Low Activity
Medium Activity
High Activity
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
0
o
o
                                                                78

-------
                            Uses  of Field and Laboratory Measurements During  a Radiological or  Nuclear Incident

1° Radiation
2° Radiation
241Am
a
7
X
244Cm
a
x(a>)
238pu
a
X
239f40pu
a
x(a>)
238|J#
a
x(a>)
235U
a
7
X
232Th#
a
X
y((0)
210Po
a
n/a
226Ra#
a
y(a>)
X(0))
90Sr
P
n/a
sssr
P
n/a
32P
P
n/a
"Tc
P
n/a
3H
P
(LE)
n/a
241pu
P
(LE)
n/a
125|
s
(LE)
7
X
129|
P
(LE)
7
X
13?Cs
P
7
x(co)
60Co
P
y(co)
103Pd
s
(LE)
x(co)
Liquid Scintillation Counting (chemical separation - element or radionuclide specific)
Low Activity
Medium Activity
High Activity
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•






















































•
•
•
•
•
•
•
•
•
Alpha Spectrometry(following separations)
Low Activity
Medium Activity
High Activity
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

































 > - suitable for definitive (unbiased, low-uncertainty) determination; o - capable of screening quality measurements only;
Low activity refers to levels between ~0.1- 10 pCi/g alpha or —1-100 pCi/g beta-gamma; Medium activity refers to levels between —10-500 pCi/g alpha or —100-5000 pCi/g beta-
gamma; High activity refers to levels greater than -500 pCi/g alpha and -5000 pCi/g beta-gamma (determinations with low uncertainty are possible at levels significantly above
background); * determination based on decay progeny if in equilibrium; a - alpha emission; P - beta emission; y - gamma ray emission, x - x-ray emission; & - electron capture
decay; LE - emission less than 100 keV; o> - low intensity emission (between 0.1% and 5%); I - poorly resolvable gamma-ray interference.
* Interference from crosstalk may limit the effectiveness of beta measurement techniques when high activities of alpha activity are present, and vice versa.
                                                                            79

-------
     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Appendix  III:  Example  Scenarios: Approaches to  Integrating Field and  Laboratory
Measurements During Response to a Radiological or Nuclear Incident

This  section presents several  scenarios  that  illustrate
some of the challenges  that may be encountered, and
some of the benefits that  may  be gained, during an
incident response  by coordinating  field  and laboratory
measurements to rapidly and accurately characterize the
situation while making optimal use of limited resources
at the field and laboratory.
This section presents several simple
scenarios   to   help   show   how
radioactive   emission   type   and
energy, DQOs / MQOs, and the use
of non-spectrometric versus spectro-
metric measurement techniques all
have   an  impact   on  possible
approaches  to  characterizing  an
area. They also provide a taste of
how field and  laboratory  measure-
ments can be used in complement-
ary fashion for more  effective and
efficient characterization  of  indoor
spaces such as those in potentially
contaminated buildings.

These  examples  should  not  be
viewed as  limiting.  For  example,
scenarios  involving  complex  mix-
tures  of  alpha- and beta-emitting
radionuclides are possible and would
require  more  extensive  use  of
spectrometric techniques in the field
and heavier reliance  on laboratory
measurements  following  chemical
separations.
Scenarios #1 and #2 demonstrate the capabilities of ISGS
measurements.   When  compared  to  grab  sampling
followed by  laboratory  analysis, using ISGS  for  the
determination   of  gamma  emitters  can  significantly
decrease  the   number of measurements  needed  to
characterize an  area while significantly increasing  the
probability  that  contamination,  if  present,  will   be
detected. Using ISGS, where  possible,  may free  up
laboratory  capacity  to  perform  more sensitive  and
unbiased  gamma  spectral measurements  of  known
uncertainty such as periodic,  routine  confirmation  of
ISGS measurements.  ISGS is not without drawbacks,
however. The scenario demonstrates that an unshielded
in situ  detector will respond  to all incident  radiation,
even  if it  originates  from  beyond  the  presumptive
confines of the intended measurement.
Scenarios #3 and #4 involve pure alpha and beta emitters. These underscore the limitations of
alpha and beta measurements in the field. Given the very short range of this radiation, a much
larger number of samples is needed to demonstrate that an area has not been contaminated. In
these scenarios, not only are the testing techniques not sensitive enough to address the lowest
action limits for removable contamination, but pending empirical evidence of their efficacy, they
also should be recognized for what they are: screening tests.  Although results are calculated
using conservatively assigned attenuation factors to address potential geometry concerns (surface
penetration and texture), a certain fraction of results will be subjected to confirmatory analysis
using a technique at  the laboratory that  is capable of delivering  unbiased results of known
uncertainty.

Scenario  #1: Following an RDD event, Building #1 is to be assessed for 60Co contamination.
The building was downwind from the incident, and there is potential for contamination since the
heating, ventilation, and air conditioning (HVAC) was running during and after the incident as
the plume passed. As  is the case throughout the city, there is also the potential that people have
tracked contamination from other areas into the building. AALs have been established by the
                                           80

-------
      Uses of Field and Laboratory  Measurements During a Radiological or Nuclear Incident

   TO                      a                      fj                         f:s\
1C   at 7100  dpm/100 cm  and 710  dpm/100 cm  for total and removable  Co contamination,
respectively. The MQO for required  relative method uncertainty for screening measurements of
gross gamma or gross beta activity is 34% of the respective AALs of 7100 dpm/100 cm2 and 710
dpm/100 cm2. The corresponding analytical decision levels (ADLs)39  are 3100 and 310 dpm/100
cm2 respectively.

Cobalt 60 contamination will be assessed by in situ gamma counting  (non-spectrometric screen)
on each floor of the building. Given the long range of gamma rays, a single gamma measurement
can characterize a relatively large  area, minimize the risk  of false non-detection, and minimize
the total number of measurements required relative to measurements of alpha or beta radiation.
This could minimize the need to take multiple grab samples for analysis at the laboratory. Given
the better detection capabilities for beta radiation at the laboratory and the  relative ease of taking
swipes, it may be more effective to screen for higher levels of gamma and to assess removable
contamination by taking swipes and counting beta at a radiochemistry laboratory. This optimizes
limited field staff and equipment resources and significantly streamlines characterization efforts
in the field.

An unshielded in situ Nal(Tl) gamma detector is  set up in an elevated position in the center of
the room and a 1-hour count is performed. The  ISGS  gamma measurement is evaluated using
conservative  assumptions  about  the  geometry  (i.e.,  all contamination  is  assumed  to  be
concentrated at a distant point within the room but no more than 3 m  from the detector, and that
the radiations from 60Co are attenuated  by no more than  2 cm of intervening solid material).
There is no concern about "shine"  from outside the building since it is known  that ambient 60Co
levels outside the  building are low.  Therefore, no background  correction will  be  applied,
minimizing the risk of negative bias.
38 Actual AALs established for a specific incident would vary by incident. The AALs presented are provided here
for demonstration purposes only. These values are roughly equivalent to values shown in NRC (2006) Appendix B,
Table B.I  (Acceptable License Termination Screening  Values of Common Radionuclides for Building-Surface
Contamination). Per note a) of NUREG-1757, "[screening levels are based on the assumption that the fraction of
removable  surface  contamination is equal to 0.1. For cases when the  fraction of removable contamination is
undetermined or higher than 0.1,  users may  assume,  for screening  purposes, that  100 percent of surface
contamination is removable, and therefore the screening levels should be decreased by a factor of 10." Both total
and removable limits  must be met separately to satisfy criteria for free release. A single measurement of total
activity less than the ADL for removable activity can be used to demonstrate compliance with the AAL for
removable activity.  See Section 3.4.2 for a more  detailed discussion of MQOs, AALs, required method uncertainty
and ADLs.
39 The approach for determining MQOs is described in detail in Section VI  of A Performance-Based Approach to
the  Use of Swipe Samples in Response to a Radiological or Nuclear Incident (EPA 201 Ib). MQOs are derived from
DQOs consistent with MARLAP principles and ensure that decisions are  based on measurements of sufficient
quality to address the question at hand. The analytical decision level is  the level below which the measurement
provides sufficient confidence to reject the null hypothesis that "activity present on the surface  is greater than the
action level." In this case, the AAL for total 60Co contamination is established at 7100 dpm/100 cm2. For the gross
activity measurements, the DL is 0, the Type I tolerable error, alpha, 5%, and the Type II tolerable error, beta, 10%.
Thus, the required method uncertainty, MMR, is 2400 dpm/100 cm2 at the AAL and the ADL is 3,100 dpm/100 cm2.
Thus, any result greater  than the ADL of 3,100  dpm/100  cm2 would trigger appropriate corrective actions (e.g., a
more precise measurement, destructive sampling followed by lab analysis, or remediation). The values for the UMR
and ADL for removable  contamination using gross activity screens are proportional to the AAL (1/10  the level for
total contamination).


                                              81

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
If 60Co is detected in the gamma screening survey above the ADL for total contamination, a
confirmatory survey will be conducted at a new location in the room to verify the initial reading.
If 60Co is detected, gross beta surface measurements will be conducted in the room in question
with a large area beta scintillation detector and a portable 1><1" Nal(Tl) gamma survey. Swipes
also will be taken in the room and analyzed at the laboratory for removable beta contamination to
provide evidence to support achievement of removable AALs and to confirm survey results. If
60Co is detected in  the gamma survey, even at levels below the AALs, the default  sampling
frequency of one room per floor will be expanded as appropriate to minimize the risk of missing
contaminated rooms. Finally, swipes and a portable Nal(Tl)  survey will be taken in two rooms
and two locations in the hallway of each affected floor.

As  the  gamma  screening  measurement proceeds,  and after  the  technician has completed
assembling survey documentation (including maps and  QC), three random swipe samples are
taken from judgmentally biased locations in the room (e.g., dusty areas, air intakes, door knobs),
one each from two additional rooms on the floor, and one each in opposing  halves of the
hallway.  The gamma measurement meets all MQOs for sensitivity and uncertainty and activity
results are below the critical level. This supports the conclusion that 60Co is not present in those
locations at  levels that exceed the AAL. The swipes will be sent to a laboratory for sensitive
confirmatory counting for gross beta referenced to 60Co. The swipes are quick,  low-cost,  and
sensitive,  and  provide  confirming  evidence that  there  is no  indication  of removable
contamination above the AAL. The technician tags the room and floor  with a "survey results
pending" notice and moves on to continue the process  on  the next floor of the  building. The
survey will be finalized in two days after all of the data from the building, including the swipe
results, have been received back from the laboratory and independently assessed and approval is
granted.
                  Table 8 - Summary of Measurements for Scenario #1
Location
Bldg#l
RmlOl
Bldg#l
Rmlll
Bldg#l
Rml34
Bldg#l
1st floor
hallway north
Bldg#l
1st floor
hallway south
Radiation
Type
60 r*
Co
Beta-gamma
60 f^
Co
Beta-gamma
60 f^
Co
Beta-gamma
60Co
Beta-gamma
60Co
Beta-gamma
Primary
Measurement
1ISGS for total;
3 swipes for
removable beta.
1 swipe for
removable beta.
1 swipe for
removable beta.
1 swipe for
removable beta.
1 swipe for
removable beta.
Secondary
Measurement
n/a
n/a
n/a
Area survey with
lxl"NaI(Tl)
Area survey with
lxl"NaI(Tl)
Comment
Clear pending laboratory
analysis, data V&V, and
assessment.
Clear pending laboratory
analysis, data V&V, and
assessment.
Clear pending laboratory
analysis, data V&V, and
assessment.
Clear pending laboratory
analysis, data V&V, and
assessment.
Clear pending laboratory
analysis data V&V, and
assessment.
Scenario #2: This scenario is essentially the same as Scenario 1 except the analysis will be made
using ISGS instead of in situ gamma counting. Following an RDD event, Building #2 is to be
assessed for 60Co contamination. The building was downwind from the incident, and there is a
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


potential for contamination  since the HVAC was running during and after the incident as the
plume passed. As is the case throughout the city, there is also the potential that people have
tracked contamination from other areas  into the building. The MQO specifies that a relative
method uncertainty  of 30%  is required  at the respective AALs  for total  and removable
contamination of 7100 dpm/100 cm2 and 710 dpm/100 cm2. The ADL is 3600 dpm/100 cm2. The
MQO  for removable  contamination  is proportional  to  the  AAL, i.e.,  1/10*  those for total
contamination.40

60Co contamination will be assessed by ISGS in one room on each floor of the building. Given
the long range of gamma rays, a single ISGS measurement  can characterize a relatively large
area and minimize the risk of false non-detection and the total number  of measurements required
relative to  measurements of alpha or beta radiation. This  could minimize the need to take
multiple grab samples for analysis at the laboratory. On the other hand, due to the long range of
gamma rays and the wide distribution of 60Co contamination following the incident, gamma ray
activity for 60Co is present in the background,  and there is concern that 60Co detected in low-
level in situ measurements may come from a source beyond  the object being measured.  Given
better detection capabilities  for beta radiation at the laboratory, and the relative ease of taking
swipes, it will be more effective to screen for higher levels of total 60Co using ISGS and to assess
removable contamination by beta counting swipes at a radiochemistry laboratory. This optimizes
limited field staff and equipment resources and  significantly streamlines characterization  efforts
in the field.

An unshielded ISGS unit is set up in an elevated position above the center of the room, and a
spectrum is recorded for 3,600 seconds. The  ISGS  gamma measurement is evaluated using
conservative assumptions  about the geometry:  i.e.,  all contamination  is  assumed  to  be
concentrated at a distant point within the room  from the detector, which can be no more  than 3
meters from the detector, and 60Co is attenuated by  no more  than 2 cm  of intervening solid
material. In this case,  there is no concern about "shine" from outside the building since it is
known  that ambient  60Co  levels outside the building are low.  Therefore,  no background
correction will be applied minimizing the risk of negative bias.

If 60Co is detected in the ISGS survey above the  AAL for total contamination, a second survey
will be conducted at a new location in the room to verify the reading and to ensure that detector
placement did not bias the  measurement (e.g., due to shielding by furniture,  etc.). If 60Co is
detected, gross beta surface measurements with  a large area beta scintillation  detector and a
gamma survey will be conducted in the room in question using  a 1><1" Nal(Tl) detector.  Swipes
also will be taken in the room and analyzed at the laboratory for removable beta contamination to
provide further support and  confirmation of survey results. Finally, swipes and a 1><1" Nal(Tl)
survey will be taken in two rooms and two locations in the hallway of each affected floor. If 60Co
is detected in the ISGS survey, even at levels below the AAL, the default sampling frequency of
40 The incident command recognizes that the spectrometric measurement technique is of higher quality and evaluates
    and the ADL for total contamination using the following parameters: the DL is 0, the Type I tolerable error,
alpha, is 5%, and the Type II tolerable error, beta, is 5%. The required method uncertainty, MMR, is 220 dpm/100 cm2
at the AAL and the ADL is 360 dpm/100 cm2. Any result greater than 360 dpm/100 cm2 will trigger appropriate
corrective actions (e.g., a more precise measurement, destructive sampling followed by lab analysis, or remediation).


                                           83

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


one room per floor will be expanded as appropriate to minimize the risk of missing significant
levels of contamination.

Note: The building ventilation system was in operation during the incident, and contamination
was spread throughout the system. A hot spot exists in the HVAC system but has not yet been
identified. The  building has been unoccupied since the incident so there  is less concern that
routine building cleaning operations have moved contamination or that it has become fixed.

An in situ gamma spectrometer is set up in the center of the first room to be surveyed. After
performing QC checks to ensure that the instrument is operating properly,  the technician starts
the count and a spectrum is recorded over the space of an hour. The ISGS gamma measurement
will be evaluated using conservative assumptions about the geometry (i.e.,  all contamination is
concentrated  at a single point in the room, 3 m  from the  detector,  with less than 2 cm of
intervening solid material).

As the  ISGS  measurement  proceeds,  and  after the  technician  has  completed  survey
documentation  (including maps  and  QC),  three random  swipe  samples  are taken from
judgmentally biased locations in this room (e.g., dusty areas, air intakes, door knobs), one each
from two additional rooms on the floor, and one each in opposing halves of the hallway.

The measurement indicates that 60Co levels are high enough that they do not permit rejection of
the null  hypothesis that "levels of total 60Co in the  room  exceed the  action limit." 60Co is
somewhere within the field of view of the detector, which given the high energy of the gamma
rays in question, may extend beyond the four walls of the room. As soon as the first gamma ray
measurement has been completed and initial  results indicate potentially elevated levels of 60Co,
the technician moves  the instrument and prepares  to conduct a confirmatory count. After QC
checking the instrument, the technician initiates a second one-hour ISGS count.

As the second gamma count proceeds, the technician performs additional surveys of the room.
Based  on the identification of 60Co, static  counts with a 600 cm2 beta-scintillating detector are
initiated  at two random locations in the room. A scanning survey for gamma radiation is also
performed with a portable 1><1" Nal(Tl) detector. Although the gamma scanning measurements
are not  of  sufficient  sensitivity to "clear" the  room, they  often are  useful  for  hot spot
identification. It is important  to keep in mind that large  area measurements may effectively
"average" and  thus fail to identify hotspot activity. The technician notes  slightly elevated
readings  toward the center of the building in  front of air conditioning ductwork. A note is made
in the paperwork that the floor of the room is ceramic tile and that elevated gamma activity is
observed over the tile. Based on the  elevated  readings in the Nal(Tl) survey  in the vicinity of the
air conditioning duct, one additional static  count for gross beta  is taken adjacent to the AC vent
but no supporting beta activity is found. Based on available evidence, it appears that the source
of the activity may be outside the room. The technician will note this in the report and bring it to
the attention of the team leader.
The results of the  second in situ gamma count support those of the first and indicate that
detectable 60Co is present. Since the field of view for the detector extends beyond the room,
however, the detector may be responding to some source of contamination outside the room. The
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
static beta measurement in front of the air conditioning duct shows slightly elevated levels that
exceed action limits for removable contamination. The results of the gas proportional beta counts
in all non-ceramic locations meet specifications for sensitivity and measurement uncertainty, and
the results are low enough to support the conclusion that 60Co is not present at those locations at
levels that exceed the AAL for removable contamination. The beta survey  on the tile is
predictably very elevated, but the technician has seen this problem before and notes the concerns
about 40K in the log. Following  procedure, the technician takes four random swipes from the
tiled area, and one swipe from a judgmental (i.e.,  worst case) location on the wood floor and
queues these to be sent to the laboratory for confirmatory  gross beta counting. The  room is
tagged with a note stating "survey results pending" and the process is repeated in the next room.
                   Table 9 - Summary of Measurements for Scenario #2
Location
Bldg #2
RmlOl
Bldg #2
Rmlll
Bldg #2
Rml34
Bldg #2
North end of
1st floor
hallway
Bldg #2
South end of
1st floor
hallway
Radiation
Type
60Co
Beta-
Gamma
6UCo
Beta-
Gamma
6UCo
Beta-
Gamma
60Co
Beta-
Gamma
60Co
Beta-
Gamma
Primary
Measurement
2ISGSfortotal;
3 swipes for
removable beta.
1 swipe for
removable beta.
1ISGS for total;
3 swipes for
removable beta
1 swipe for
removable beta.
1 swipe for
removable beta.
Secondary
Measurement
3 static counts for gross
beta surface activity;
Nal(Tl) gamma survey
n/a
n/a
Area survey with 1x1"
Nal(Tl)
Area survey with 1x1"
Nal(Tl)
Comment
60Co results above ADL; source
not localized; laboratory swipe
data, V&V, and assessment
pending.
Laboratory analysis pending.
60Co below ADL; laboratory
analysis, V&V, and assessment
pending.
Laboratory swipe analysis,
V&V, and assessment pending.
Laboratory analysis, V&V, and
assessment pending.
Scenario #3: This is essentially the same scenario as Scenarios #1 and #2 with the exception that
the RDD  source term has been  identified  as pure  alpha-emitting 239240Pu. The  building  was
downwind from the incident, and there is reasonable potential for contamination since the HVAC
was running during and after the incident as  the plume passed. As is the case throughout the city,
there  is also the potential that people have tracked contamination from other areas  into the
building. AALs have been established at 50 dpm/100 cm2 and 5 dpm/100 cm2  for total  and
removable contamination respectively. The MQOs specify that a required method uncertainty of
24% is required  at the AAL. ADLs of 30 and 3.0 dpm/100 cm2 are  specified  for total  and
removable contamination respectively.41
41 Incident Command has established MQOs for MMR using the following parameters. The AAL for total alpha is 50
dpm/100 cm2. The DL is 10 dpm/100  cm2, (set at an assumed native gross alpha of 10 dpm/100 cm2), the Type I
tolerable error, alpha = 5%, and the Type II tolerable error, beta = 5%. The required method uncertainty, MMR, is thus
12 dpm/100 cm2 at the AAL and the  ADL is 30 dpm/100 cm2. Thus, relative low uncertainty measurements are
needed, and any result greater than 30  dpm/100 cm2 will trigger appropriate corrective actions (e.g., a more precise
measurement, destructive sampling followed by lab analysis, or remediation).
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


This scenario presents special challenges  since field surveys for low levels of alpha-emitting
contaminants are of limited effectiveness. Ambient levels of naturally occurring alpha emitters in
building materials and interference  from radon and decay progeny, for example, will prevent
MQOs for removable contamination from being determined  using in situ measurements. Wipe
samples will be analyzed at the laboratory by gross alpha and, when needed, isotopically (after
chemical separation  from other  alpha  emitters) to  determine  the specific  concentration of
239/240pu £ven if fi^d measurements, such as those conducted with a large area ZnS counter (600
cm2), are able to provide sufficient sensitivity to differentiate between the gross alpha natural
background (assumed to be 10 dpm/100 cm2) from the 50 dpm/100 cm2 AAL for total 239/240Pu
contamination, it is  important  that the technician be able  to identify situations  where self-
absorption may be a  confounding factor that undermines the  defensibility of the measurements.
Laboratory  analysis   of  grab  samples will  provide superior   detection  limits  and  lower
measurement uncertainties for gross  alpha, and thus minimize the risk of false non-detection.

Lacking techniques with  similar detection range to ISGS, incident-specific protocols for alpha
and beta detection specify that  an increased number of surveys  will be conducted in multiple
rooms on each floor of the  building. Large-area ZnS alpha detectors have been  shown to be
capable of rapidly identifying elevated levels  of beta-gamma emitters, and alpha- and gamma-
emitting  contamination from  226Ra (and  progeny)  on  impermeable  and  relatively smooth
surfaces.42 It is important, however,  to carefully evaluate the applicability of direct measurement
techniques for each surface. When  rough, dirty, or porous surfaces are involved, direct alpha
measurements using  a large-area ZnS detector may be "non-conservative"  and thus may be
suitable only for  identifying hot spots and  triggering  more aggressive follow-up  surveys.
Similarly, porous or rough materials, and materials known to contain elevated levels of intrinsic
naturally occurring alpha emitters (such as granites and some concretes), may not be amenable to
gross alpha screening.

Where problematic  surfaces predominate, or where  direct measurements  indicate  possible
contamination, field  instruments such as FIDLERs may  be  used to improve the reliability of
measurements, and certainly to perform real-time qualitative identification of hot spots, but they
cannot defensibly "clear" an area,  at least without confirming  measurements that verify the
assumptions upon which the  clearance measurements are based. Instead, accurate determinations
of 239240Pu are most effectively and defensibly determined by grab sampling  (e.g., scabbling or
coring) followed by isotopic analysis for 239/2 °Pu at a radiochemistry laboratory. Wipe samples
of removable contamination also can be  sent to a radiochemistry laboratory for  gross alpha
screening, with  potential alpha  isotopic determinations of  239 40Pu,  as  indicated. Finally,
confirmatory grab sampling  at a direct measurement location will be performed as a recurring
QC measure to confirm the  accuracy of the direct measurements. Since AALs are provided in
units of areal contamination,  sample  volumes must be recorded in terms convertible to equivalent
surface area and the laboratory instructed to calculate results in terms of activity per unit surface
area. If any of the laboratory results are positive for 239240Pu, data will be assessed and additional
action taken as deemed appropriate.

The technician  enters the first  room specified for surveying and sets  up two large area ZnS
detectors for a 30-minute static count of the tile floor and the welcome mat. As the counters
42 Personal communication with Dick Dubiel of Millennium Shonka, 2010.
                                           86

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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


acquire data, the technician proceeds to collect swipes from  five locations in room 101, and one
swipe  each from the north and south ends  of the hallway. When acquisition is complete, the
technician notes that uncertainty requirements have been met, but that the count on the welcome
mat exceeds the action limit for total alpha. In keeping with  protocol, he  surveys the area, cuts a
100 cm2 coupon from the area showing the highest survey results, and packages and labels this to
be  sent to the laboratory for confirmatory analysis. Once the work is complete, the technician
marks  the room as  "potentially  contaminated pending  confirmatory laboratory analysis" and
continues to room 111, where he initiates two more static counts for total  alpha activity. As these
data are being acquired, he collects five wipe samples each  from rooms  111  and  134. When the
static counts are finished, the technician verifies that the uncertainties will meet the MQOs and
determines  that both results are  low enough to  conclude that the activity will not exceed the
AAL. He  places a sign on the door indicating that laboratory analysis is pending and moves on to
the next floor.

                  Table 10 - Summary of Measurements for Scenario #3
Location
Bldg #3
RmlOl
Bldg #3
Rmlll
Bldg #3
Rml34
Bldg #3
North end of
1st floor
hallway
Bldg #3
South end of
1st floor
hallway
Radiation
Type
239/240pu
Alpha
239/240pu
Alpha
23y/24aPu
Alpha
239/240pu
Alpha
239/240pu
Alpha
Primary Measurement
2 static counts for gross
alpha total surface
activity;
1 sample taken -
"welcome mat coupon"
2 static counts for gross
alpha total surface
activity
n/a
n/a
n/a
Secondary
Measurement
5 swipes for
removable alpha
activity
5 swipes for
removable alpha
5 swipes for
removable alpha
1 swipe for
removable alpha
1 swipe for
removable alpha
Comment
Gross alpha above action limit;
sample taken for analysis.
Laboratory analysis, V&V, and
assessment pending.
Laboratory analysis, V&V, and
assessment pending.
Laboratory analysis, V&V, and
assessment pending.
Laboratory analysis, V&V, and
assessment pending.
Laboratory analysis, V&V, and
assessment pending.
Scenario #4: This is the same scenario as Scenario #2 except in this case, the RDD source term
is identified as 90Sr. AALs have been established at 87 dpm/100 cm2 and 8.7 dpm/100 cm2 for
total and removable contamination respectively. The MQO specifies  that a required method
uncertainty of 15% at the AAL. The ADLs are 65 and 6.5 dpm/100 cm2 for total and removable
contamination respectively.43
43 Incident Command has established AALs, MMR and ADLs using the following parameters to evaluate MMR and the
ADL. The AALs for gross beta screening are 87 dpm/100 cm2 and 8.7 dpm/100 cm2, for total and removable
activity. The DL = is l/i the respective AAL, the Type I tolerable error, alpha = 5%, and the Type II tolerable error,
beta = 5%. The required relative method uncertainty, MMR, is 15% of the AAL, and the ADLs are 65 dpm/100 cm2
and 6.5 dpm/100 cm2 for total and removable contamination respectively. Given the low levels that would be
required to demonstrate meeting levels for removable activity, they will be analyzed by taking swipes that will be
sent to a radiochemistry laboratory for analysis on a low background proportional counter, and where necessary,
verification of radioisotopic activity following chemical  separations.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident


Given the limitations of field surveys for very low levels of beta contamination, the superior
detection capability  at laboratories for gross  beta, and accuracy and reliability of laboratory
analysis for 90Sr, the approach will rely more heavily on laboratory analysis of swipes for non-
permeable surfaces and on grab samples for porous or other rough surfaces. Because 90Sr does
not emit any gamma rays, ISGS is not a viable alternative.  Lacking the detection range of ISGS,
protocols specify that surveys will be conducted in two rooms on each floor of the building. If
surfaces are impermeable and  relatively smooth (and significant levels of naturally occurring
radionuclides are not present), large area beta scintillation  detectors have been validated to
determine compliance with action limits for total 90Sr contamination on smooth and impermeable
surfaces. Due to the potential for  self-absorption of beta  emissions,  surface measurements on
porous or rough  surfaces  are  considered non-conservative screens  and are suitable  only  for
identifying  hot  spots  and triggering  more aggressive follow-up  surveys. Porous  or  rough
materials, or materials known  to contain elevated levels  of naturally occurring beta emitters
(such as  ceramic tile,  granites, and  concretes), will produce  high rates  of false  positive
determinations. Where  such  surfaces  are  predominant,   or  where  direct measurement has
indicated possible contamination, grab  sampling (e.g., coring  or scabbling) is required followed
              on
by analysis for   Sr at a radiochemistry laboratory. Confirmatory grab sampling also is required
at one direct measurement location at a frequency of one sample per building. Since AALs  are
provided in units of areal contamination, sample volumes must be recorded in equivalent surface
area and the laboratory instructed to calculate results in terms  of activity per unit surface area. If
any  of the laboratory results are positive for 90Sr,  data will  be assessed and additional  action
taken as deemed appropriate.

The technician  enters the first  room specified for surveying  and sets up both large  area beta
scintillation detectors for  10-minute  static counts. As the  counters acquire data, the technician
proceeds to  collect swipes from five locations  in room 101, and one swipe each from the north
and  south  ends of  the hallway.  When acquisition  is complete,  the technician notes  that
uncertainty requirements have been met and that both counts are low enough to conclude that the
action limit for total beta has not been exceeded. The technician marks the room as "pending
laboratory analysis"  and continues to room 111 to initiate two additional static counts for total
beta activity. As these data acquire, the technician collects five wipe samples each from  rooms
111  and  134. When  the static counts are finished, the technician verifies that the uncertainties
will meet the MQOs  and determines that both results are low enough to conclude that the activity
is not high enough to exceed the action limit and trigger laboratory confirmation. The technician
places a  sign on the door indicating "laboratory analysis pending" and moves on to  the next
floor.
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     Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
                 Table 11 - Summary of Measurements for Scenario #4
Location
Bldg #4
RmlOl
Bldg #4
Rmlll
Bldg #4
Rml34
Bldg #4
North end of
1st floor
hallway
Bldg #4
South end of
1st floor
hallway
Radiation
Type
90Sr
Beta
90Sr
Beta
yuSr
Beta
90Sr
Beta
90Sr
Beta
Primary
Measurement
2 static counts for
gross alpha total
surface activity
2 static counts for
gross alpha total
surface activity
n/a
n/a
n/a
Secondary
Measurement
5 swipes for
removable alpha
activity
5 swipes for
removable alpha
5 swipes for
removable alpha
1 swipe for
removable alpha
1 swipe for
removable alpha
Comment
Laboratory analysis
and V&V pending
Laboratory analysis
and V&V pending
Laboratory analysis
and V&V pending
Laboratory analysis
and V&V pending
Laboratory analysis
and V&V pending
Observations on the Four Scenarios: Table 12 summarizes the number of samples needed for
each of the above scenarios. Several general observations are noted:
   •   Gross measurements in the field may not be capable of reliably detecting radionuclide
       contamination at levels approaching background.
   •   Instrument detection capability does not guarantee that  a technique will be useful for
       measuring contamination.
       o  Bias due to self-absorption may not  permit  MQOs to  be met  and may require
          sampling and laboratory analysis.
       o  High background activity may interfere with measurements, or may lead to such long
          measurements being required that grab  sampling and laboratory  analysis may  be a
          more effective and efficient option.
   •   Alpha and Beta Emitters
       o  The risk  of false non-detection of alpha or beta emitters  is higher than for gamma
          emitters.
       o  Minimizing the risk of false non-detection for alpha and  beta emitters  must be
          accomplished using a robust sampling plan (e.g., MARSSEVI). A similar number of
          measurements are needed in the field and at laboratories.
   •   Gamma Emitters
       o  Gross gamma measurements may not be able  to effectively or efficiently detect or
          measure radionuclides at levels approaching the ambient background.
       o  Field measurements for gamma contaminants can significantly minimize the overall
          number of samples needed to characterize an area.
       o  Fewer measurements are needed to characterize gamma-emitting contamination than
          alpha- and beta-emitting contamination.
       o  ISGS  can detect contamination at levels below ambient background as long as the
          radionuclide of concern is not present in the background.
   •   Strategic use of laboratory and field measurements may speed up the overall recovery
       process by optimally using laboratory and field resources.
                                          89

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    Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
Table 12 - Summary of Number of Scenario Measurements by Nuclide, Measurement Status, and
                               Detection Status and Test
Radionuclide
Radiation
Type
60Co
Beta-gamma
60Co
Beta-gamma
239/240pu
Pure alpha
90Sr
Pure beta
Contain.
present?
N
Y
Y
Y
ISGS
1
2
n/a
n/a
Gross
Gamma
1
2
n/a
n/a
Gross
Alpha
0
n/a
4
n/a
Gross
Beta
0
3
n/a
4
Alpha Swipes
for
Laboratory
analysis
0
n/a
17
n/a
Beta Swipe
for
Laboratory
analysis
7
7
n/a
17
Laboratory
Nuclide
Specific
0
0
1
1
Comment
ISGS decreases
sample load
Survey detects
60Co but cannot
localize source
Survey detects
alpha - sample
to laboratory
Survey detects
beta - sample to
laboratory
                                         90

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