&EPA
United States
Environmental Protection
Agency
Office of Radiation and Indoor Air
National Air and Radiation
Environmental Laboratory
EPA 402-R-12-005
August 2012
www.epa.gov/narel
Guide for Radiological
Laboratories for the Control of
Radioactive Contamination and
Radiation Exposure
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EPA 402-R-12-005
www.epa.gov/narel
August 2012
Revision 0
Guide for Radiological Laboratories for
the Control of Radioactive Contamination
and Radiation Exposure
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
printed '»ih Soyj'Canoia hk on papet :hat
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
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 contracts 68-W-03-038, work
assignment 35, and EP-07-037, work assignments B-33 and 1-33, all managed by David Carman.
Mention of trade names or specific applications does not imply endorsement or acceptance by EPA.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
PREFACE
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 across response phases for chemical, biological, and radiological
agents. To meet its RFA responsibilities, EPA has established the Environmental Response
Laboratory Network (ERLN) to address chemical, biological, and radiological threats during
nationally significant incidents (www.epa.gov/erln/). EPA is the RFA for monitoring,
surveillance, and remediation of radiological agents. EPA will share responsibility for overall
incident response with the U.S. Department of Energy (DOE).
This document is one of several initiatives by EPA's Office of Radiation and Indoor Air
designed to provide guidance to radiological laboratories that will support EPA's response and
recovery actions following a radiological or nuclear incident, such as the detonation of an
improvised nuclear device (IND) or a radiological dispersal device (RDD) ("dirty bomb").
During the response to such an incident, a radiological laboratory may need to process much
greater numbers of samples, some of which are likely to have higher levels of radioactivity than
the laboratory is accustomed to handling. This guide describes the likely radioactive
contamination control and challenges that would face personnel at the laboratory following such
an incident, and offers suggestions for preparing for these challenges.
Advance planning by the laboratory to control radioactive contamination and radiation will be
critical to ensure the rapid delivery of radioanalytical results that meet the required data quality
objectives associated with the protection of human health and the environment.
This guide identifies key topics for consideration by the laboratory and presents various
suggestions on which the laboratory may base its decisions regarding the establishment of
operational protocols. Specifically, the guide discusses the need to prepare the laboratory to
participate in the incident response by defining and establishing discreet work areas and
operational guidelines for the various laboratory activities, based primarily on the levels of
radioactivity being processed and the flow of radioactive material through the laboratory, and by
establishing customized laboratory-specific protocols for the key activities that are likely to have
a significant impact on contamination and radiation control.
As with any technical endeavor, the establishment of effective contamination and radiation
control for radiological or nuclear incident response in a radiological laboratory will require each
laboratory to develop practices and protocols that address the unique needs of its facility. This
guide provides examples of practices and descriptions of work areas that are intended to serve as
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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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
a starting point for the laboratory to consider in the development of its own solutions to the
issues presented. The guide does not address a complete catalog of control methodologies or
potential situations.
9
This document is one in a planned series designed to present radioanalytical laboratory
personnel, Incident Commanders (and their designees), 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 analysis of samples taken after a
radiological or nuclear incident, including incidents caused by a terrorist attack. Documents
currently completed 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)
Uses of Field and Laboratory Measurements During a Radiological or Nuclear Incident
(EPA 402-R-12-007, 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
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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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
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 Dr. Keith
McCroan, ORIA/NAREL; Dr. Lowell Ralston and Mr. Edward Tupin, CHP, both of ORIA/
Radiation Protection Division; and Mr. David Garman, ORIA/NAREL. We also wish to
acknowledge the external peer reviews conducted by Ms. Dawn Cermak, Dr. J. Stanley Morton,
Mr. Sherrod L. Maxwell, Dr. Shiyamalie Ruberu, and Ms. Carolyn Wong, 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. David Burns, Dr. N. Jay Bassin, Dr. Anna Berne, Dr. Carl V. Gogolak, Dr.
Robert Litman, Dr. David McCurdy, and Mr. Robert Shannon 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.
in
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Contents
Preface i
Acknowledgments iii
Dedication iii
Acronyms, Abbreviations, Units, and Symbols vii
Radiometric And General Unit Conversions ix
1. Introduction 1
1.1 Purpose and Scope 3
1.2 Limitations and Regulatory Considerations 4
2. Preparing the Laboratory 5
2.1 Defining Types of Operational Areas and Other Areas Affected by Laboratory
Operations 6
2.1.1 Unrestricted Public Areas 6
2.1.2 Buffer Zones 6
2.1.3 Operational Areas 7
2.2 Establishing Acceptable Levels of Radioactivity and Radiation 13
2.2.1 Action Levels: AAL, Required Method Uncertainty, and ADL 14
2.2.2 Establishing Analytical Action Levels for Contamination Control AAL(C) 15
2.2.3 Limiting the Method Uncertainty, MMR 20
2.2.4 Determining the Analytical Decision Level 21
2.2.5 Establishing Appropriate Corrective Action when the ADL(C) is Exceeded 22
2.3 Additional Comments Regarding Radioactivity and Exposure Limits 24
2.4 Determining Appropriate Levels of Personal Protective Equipment 26
2.5 Laboratory Layout and Process Flow 26
2.6 Additional Planning Considerations 27
2.6.1 Controlled Entry/Egress Points 27
2.6.2 Step-Off Pads 27
2.6.3 PPE Donning/Doffing Areas 28
2.6.4 Frisking Stations 28
2.6.5 Personnel Decontamination Stations 29
2.6.6 Spill Response/Surface Decontamination Equipment 29
2.6.7 Contamination Follow-Up Protocol 30
2.6.8 Additional Shielding Material 30
2.6.9 Glove Boxes 30
2.7 Changing the Work Area Designation During an Incident Response 31
3. Radioactive Contamination Control 32
3.1 Sample Handling Protocols 33
3.1.1 Initial Receipt of Radioactive Materials 33
3.1.2 Opening, Transferring, and Aliquanting Sample Material 34
3.1.3 Isolating Reduced Fractions for Transfer to Lower-Level Work Areas 35
3.1.4 Sample Preparation and Chemical Separation Processes 35
3.1.5 Instrumentation and Radioanalytical Controls 36
3.2 Movement Between Laboratory Areas (Entry/Egress) 37
IV
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
3.2.1 Entry Into a Higher-Activity Area 38
3.2.2 Egress Into a Lower-Activity Area 39
3.3 Laboratory Contamination Monitoring and Control 39
3.3.1 Surveillance of Laboratory Surfaces and Equipment 41
3.3.2 Decontamination of Laboratory Surfaces and Equipment 43
3.4 Personnel Contamination Monitoring and Control 43
3.4.1 Personnel Contamination Prevention 43
3.4.2 Personnel Contamination Surveillance 44
3.4.3 Personnel Decontamination 45
4. Exposure Control And Radiation Shielding 46
4.1 ALARA Principles 46
4.2 General Shielding Information 46
4.2.1 Alpha Shielding 48
4.2.2 Beta Shielding 48
4.3 Gamma Shielding of Storage Areas 49
4.3.1 Use of Buffer Zones and Other Unoccupied Spaces 49
4.3.2 Consideration of the Occupancy of Affected Areas 50
4.3.3 Strategic Placement of Gamma Shielding Materials 51
4.3.4 Consideration of Multi-Level Facilities 52
4.4 Gamma Shielding of In-Process Materials 52
5. Summary 54
6. References 55
Appendix A: Planning Considerations for Laboratory Layout and Process Flow 56
Appendix B: Initial Receipt of Radioactive Materials 63
Appendix C: Opening, Transferring, and Aliquanting Sample Material 68
Appendix D: Isolating Reduced Fractions for Transfer to Lower-Level Areas 72
Appendix E: Entry Into a Higher-Activity Area 75
Appendix F: Egress Into a Lower-Activity Area 76
Appendix G: Active Radiological Monitoring Program for Contamination Control 80
Appendix H: Surveillance of Laboratory Surfaces and Equipment 93
Appendix I: Decontamination of Laboratory Surfaces and Equipment 98
Appendix J: Establishing MQOs for Sample Screening Measurements 100
Appendix K: Establishing MQOs for Sample Exposure Rates 104
Figures
Figure 1 - Example of Shielding Considerations in Sample and Waste Storage Areas 50
Figure 2 - Three-Dimensional Shielding Considerations 52
Figure 3 - Alternate Shielding Configurations 53
Figure 4 - Conceptual Layout of the Laboratory and Associated Areas 56
Figure 5 -Process Flow in the Sample Receiving Area 58
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Figure 6a-Process Flow in the Screening Areas 59
Figure 6b -Process Flow in the Screening Area with a Single Entryway 60
Figure 7 -Process Flow in the Routine Work Areas 61
Figure 8 - Example of Radioactive Materials Shipments Initial Survey Results 65
Figure 9 - Work Flow Inside Fume Hood; Unpacking Samples 66
Figure 10 - Opening, Transferring, and Aliquanting Sample Material 69
Figure 11 -Example Layout of the Egress Area 77
Figure 12a - Hypothetical Environmental Laboratory Operating Under Normal Conditions 82
Figure 12b - Hypothetical Environmental Laboratory Operating Under Normal Conditions 83
Figure 13a - Hypothetical Environmental Laboratory Operating Under Incident-Response
Conditions 84
Figure 13b - Hypothetical Environmental Laboratory Operating Under Incident-Response
Conditions: Radiochemistry Laboratory Expanded View 85
Figure 14 -Example Survey Report Form, Front 94
Figure 15 -Example Survey Report Form, Back 95
Tables
Table 1 - Laboratory AALs for Contamination and Exposure Control: An Example of Maximum
Sample Activity, Exposure and Dose Rate, and Radioactive Contamination by Area Type
19
Table 2 - Laboratory ADLs for Contamination and Exposure Control: An Example of Routine-
Level Work Area MQOs 23
Table3 - Suggested PPE for Operational Areas 26
Table 4 - Summary of Major Changes Suggested for Radiological or Nuclear Incident Response
Operations 86
Table 5 - Target Areas, Techniques, and Frequency of Radiological Monitoring 90
Table 6 -Example Contamination Investigation and Action Levels 91
VI
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
ACRONYMS, ABBREVIATIONS, UNITS, AND SYMBOLS
(Excluding chemical symbols and formulas)
a alpha particle
a probability of a Type I decision error
AA atomic absorption (spectrometry)
AAL analytical action level
AAL(C) analytical action level for contamination control analyses
AAL(,S) analytical action level for field sample analyses
ADL analytical decision level
ADL(C) analytical decision level for contamination control analyses
ADL(,S) analytical decision level for field sample analyses
ALARA As Low As Reasonably Achievable
AMTLD area monitoring thermoluminescent dosimeter
ASHRAE American Society of Heating, Refrigerating, and Air-Conditioning Engineers
P beta particle
ft probability of a Type II decision error
Bq becquerel (1 dps)
CFR Code of Federal Regulations
Ci curie
C SU combined standard uncertainty
d day
DL discrimination level
DOE United States Department of Energy
DOT United States Department of Transportation
dpm disintegrations per minute
dps disintegrations per second
DQO data quality objective
DRP discrete radioactive particle
EPA United States Environmental Protection Agency
ERLN Environmental Response Laboratory Network
y gamma ray
g gram
GC/MS gas chromatograph/mass spectrometer
G-M Geiger-Miiller
GPC gas-proportional counting/counter
Gy gray
h hour
HEPA high efficiency particulate air [filter]
HPGe high purity germanium [detector]
HVAC heating, ventilation, air conditioning [system]
ICLN Integrated Consortium of Laboratory Networks
ICP inductively coupled plasma
IND improvised nuclear device (i.e., a nuclear bomb)
IRP Incident Response Plan
L liter
LSC liquid scintillation counting/counter
vn
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
|j,Ci microcurie (10 6 Ci)
|jR microroentgen (10 6 R)
m meter
MARLAP Multi-Agency Radiological Laboratory Analytical Protocols [Manual]
MARSAME Multi-Agency Radiation Survey and Assessment of Materials and Equipment
[Manual]
MDC minimum detectable concentration
mg milligram (10~3 g)
min minute
mrem millirem (10~3rem)
MQO measurement quality obj ective
Nal(Tl) thallium-activated sodium iodide detector
NEPA National Environmental Policy Act
NRC United States Nuclear Regulatory Commission
Ms.(C) required relative method uncertainty above the AAL(C) for contamination
control analyses
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
RADIOMETRIC AND GENERAL UNIT CONVERSIONS
To Convert
years (y)
disintegrations per
second (dps)
Bq
Bq/kg
Bq/m3
Bq/m3
microcuries per
milliliter (uCi/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
MCi
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
2.70xlO~2
io-3
109
4.50xlO~7
4.50X10"1
2.83xlO~2
3.78
IO2
io-2
To Convert
s
min
h
d
Bq
pCi
pCi/g
pCi/L
Bq/L
pCi/L
pCi
uCi
m3
L
rad
Sv
To
y
dps
Bq
Bq/kg
Bq/m3
Bq/m3
|jCi/mL
dpm
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
10~2
IO2
NOTE: Traditional units are used throughout this document instead of the International System of Units
(SI). Conversion to SI units will be aided by the unit conversions in this table.
IX
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
1. INTRODUCTION
Every radiochemical laboratory with a radioactive materials license must implement a radiation
protection program (RPP) that controls and minimizes radiation exposure and radioactive
contamination.3 The primary purpose of the RPP is to protect laboratory personnel and the public
from the effects of radiation resulting from laboratory activities. This guide assumes that such a
program is in place and is designed to address issues related to the routine operations of the
laboratory.
In the event of a radiological or nuclear incident, however, it is likely that many radiological
laboratories will be called upon to perform sample analyses in support of the various response
efforts taking place, and that the radioactivity concentrations of some of these samples may be
well in excess of those to which the laboratory is routinely accustomed. The numbers of samples
and the total quantity of sample material are also likely to be significantly increased. In addition,
the increased radioactivity levels in the standards and tracers required for analysis, waste
produced during analyses, sample test sources, and quality control (QC) samples will all
contribute to the increased radioactivity and radiation levels in the laboratory.
Elevated radioactivity levels in the labora-
tory may increase the risk of occupational
radiation exposure, may impact the quality
of radioanalytical measurements by
increasing instrument background count
rates, may increase the possibility of
cross-contamination among samples, and
may become a potential source of labora-
tory and environmental contamination.
The laboratory should make advance prep-
arations for receiving and handling the
samples in order to minimize radiation
exposure and radioactive contamination.
These advance preparations should be
clearly outlined in the RPP and in relevant
standard operating procedures (SOPs). The
advance preparations for a radiological or
nuclear incident should include an
assessment of the configuration of the laboratory, the resources available for the incident
response, and the sample and waste handling and contamination control procedures to be
implemented during the incident response.
In addition, the laboratory staff should be adequately trained to implement these measures
efficiently and effectively during a radiological or nuclear incident. These preparations, the RPP,
This section refers to both radiological and
radioanalytical contamination.
The general term radioactive contamination refers to
the contamination of the laboratory facilities or
personnel from radioactive materials. In some cases,
radioactive contamination may occur at levels that
pose a radiological health and safety concern.
The specific term radioanalytical contamination refers
to contamination of the sample material, instrument-
ation, or laboratory facility that leads to sample cross-
contamination or otherwise negatively impacts
radioanalyses.
While the laboratory's surveillance and control
measures for personnel protection and for the
prevention of radioanalytical contamination may
frequently overlap, the goals are sufficiently different
that they may be discussed separately in this guide,
when it becomes important to make the distinction.
10 CFR 20.1101, Radiation Protection Programs.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
the laboratory SOPs, and the necessary training are essential components of an effective
Radiological Controls Program (RCP).4
An effective Radiological Controls Program should eliminate, or at least minimize, the effects of
increased radioactivity and radiation levels on laboratory facilities, personnel, and data quality.
This may be accomplished through the development of procedures and practices to:
Control the radioactive materials being handled in the laboratory. This includes the
accurate assessment (screening) of the nature of the material and the establishment of
well-defined and effective procedures that will guide the physical handling of the
material and the movement of the material through the laboratory.5
Actively monitor radioactive contamination and radiation exposures, and establish
quantitative limits for contamination of surfaces, instruments, and personnel.
Proactively address the decontamination and shielding of laboratory personnel to
minimize occupational exposures and to prevent exceeding established quantitative
limits.
Programmatically address the decontamination of laboratory surfaces and equipment to
prevent the exceedence of established quantitative limits, thereby reducing instrument
backgrounds, and minimizing cross-contamination.
As with all other aspects of the laboratory's incident response activities, an RCP should
anticipate the unique challenges associated with various radiological or nuclear incident
scenarios and allow for rapid assessment of, and adjustments to, changing laboratory conditions.
IMPORTANT NOTE
This guide contains numerous examples of procedures for the control of radioactive
contamination and radiation exposure. These examples are intended to provide guidance to
the laboratory in the formulation of its own Radiological Controls Program. Users are
strongly cautioned, however, that these are only examples, which may be used by the
laboratory to assess its own operations and to formulate procedures that address the
conditions and operations that may be unique to that specific laboratory. The examples are
not intended to be prescriptive or to address every situation that the laboratory might
encounter.
4 A broader discussion of effective Radiological Controls Programs is provided in the companion document Guide
for Laboratories - Identification, Preparation, and Implementation of Core Operations for Radiological or Nuclear
Incident Response (EPA 2010).
5 More detailed guidance for sample screening considerations is provided in the companion document Radiological
Laboratory Sample Screening Analysis Guide for Incidents of National Significance (EPA 2009b).
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
1.1 Purpose and Scope
The purpose of this guide is to assist the laboratory in developing specific parts of an RCP that
would enable the laboratory to safely and effectively participate in the response to a radiological
or nuclear incident. Specifically, this document provides guidance that is intended to assist in the
assessment of the physical layout of the laboratory, and to assist in the consideration of potential
changes in the laboratory design and work flow to prevent the incoming sample material from
compromising the analytical capabilities of the laboratory or exposing personnel to elevated
1 evel s of radi ati on.
This guide and its appendices also provide examples of procedures for sample handling; for the
surveillance, prevention, and control of radioactive contamination throughout the laboratory; and
for the control of radiation exposure both inside the laboratory and in the areas immediately
outside the laboratory that may be affected by laboratory operations. These examples are
intended to be illustrative of typical laboratory operations and to serve as suggestions with which
the laboratory might develop its own procedures.
This guide is separated into the following sections:
Section 2.0 (Preparing the Laboratory) describes potentially significant planning steps that
(a) define the types of operational areas that a laboratory might typically employ; (b)
establish acceptable radioactivity and radiation levels for those areas; (c) establish
appropriate protective equipment for those areas; and (d) give consideration to the laboratory
layout and process flow for radioactive materials. Other miscellaneous but important
planning considerations are also discussed.
Section 3.0 (Radioactive Contamination Control) addresses specific radioactive
contamination control measures that may be taken for both personnel protection and
radioanalytical control. As mentioned above, these two aspects of contamination control
frequently overlap, and control measures are taken with both goals in mind. Where particular
recommendations are intended to specifically address one over the other, clarification is
provided.
Section 4.0 (Exposure Control and Radiation Shielding) presents the protective measures of
time, distance, and shielding in the context of incident response activities in the laboratory,
with the primary emphasis on personnel protection. Some additional discussion of the
prevention of adverse instrument response from elevated activity and transient sources in the
laboratory is also provided.
The guide concludes with numerous appendices that may be useful by providing specific
examples for implementing the various recommendations. The laboratory is strongly
cautioned, however, that these are only examples. These examples are not intended to be
prescriptive or to limit the scope of the laboratory's preparation for an event, but are intended
to help the laboratory identify, select, and devise contamination control measures that are
tailored to its specific needs. Decisions regarding the designation of area types, activity
levels, appropriate personal protective equipment (PPE), work flow, and protocols are
decisions that must be made internally, on a case-by-case basis, specific to each laboratory.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
The examples are, however, intended to be applicable to a broad range of radiological
laboratories: large, small, streamlined, and complex. The specific procedures that a
laboratory develops to address contamination and exposure control will depend largely on the
available space, staffing, and other resources of the laboratory. In addition, those procedures
may need to be periodically reassessed and revised, depending on the changing nature of the
incident response efforts.
1.2 Limitations and Regulatory Considerations
In the event of a radiological or nuclear incident involving releases of significant quantities of
radioactive materials to the environment, only those laboratories already having the necessary
facilities and procedures will be capable of responding to the anticipated demand for analysis of
samples. Laboratories that either intend to develop segregated contamination and radiation areas
in their laboratories, or already have them and wish to evaluate them, may find the
recommendations for physical layout and organizational procedures for laboratories contained in
this report useful. Laboratories with limited physical infrastructure or a very narrow scope of
operations may not be able to effectively support the incident response without additional
preparation and the development of alternate techniques, modified to accommodate their specific
circumstances.
This guide addresses important considerations in the surveillance and control of radioactive
contamination and radiation exposure. It is possible that samples related to a nuclear or
radiological incident may also pose additional risks from other chemical, biological, or physical
hazards. While it is beyond the scope of this document to address such non-radiological hazards,
the laboratory should have procedures in place for the assessment of, and response to, these
additional potential risks.
This guide does not purport to address specific regulatory compliance issues, including the
laboratory's adherence to possession limits and other conditions of its Radioactive Materials
License. In no way does the content of this guide obviate or relieve the laboratory of its
regulatory compliance responsibilities in the areas of employee health, safety, or hazardous and
radioactive materials handling, transportation, or disposal.
This guide is intended to provide planning guidance in preparation for the response to a
radiological or nuclear incident, not replace or supersede existing laboratory safety or quality
plans, such as a Radiation Safety Plan or Laboratory Quality Manual. This guidance may also be
useful in the laboratory's review of the existing Radiation Safety Plan or Laboratory Quality
Manual to ensure the laboratory's readiness to respond to a radiological or nuclear incident.
This guide contains numerous examples of radioactivity and exposure limits and their use in the
control of laboratory contamination and radioanalytical integrity. The values used in the
examples are for illustrative purposes and should not be taken as specific requirements for the
laboratory. This guide cannot address every conceivable situation; each laboratory must develop
its own activity and exposure limits that are appropriate to the particular laboratory environment
and operational goals.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Additional discussion regarding regulatory considerations is provided in the companion
document Guide for Laboratories - Identification, Preparation, and Implementation of Core
Operations for Radiological or Nuclear Incident Response (EPA 2010).
2. PREPARING THE LABORATORY
As in any operation, a radiological laboratory will have routine practices and procedures that
have been established over time to meet the needs of the laboratory, based on the type and
volume of work typically performed. These practices and procedures may not be sufficient or
adequate for the laboratory's participation in the response to a radiological or nuclear incident.
This section describes some key preparations that should be made prior to the acceptance of
samples related to a radiological or nuclear incident.
Any laboratory that handles and analyzes radioactive materials should have areas of the
laboratory designated for specific processes (e.g., sample screening, low-level counting, etc.).
These processes should be segregated by the potential level of radioactivity expected to be
present and the likelihood of the material to cause a laboratory contamination issue.
In laboratories that are accustomed to handling only low-level or environmental samples, the
segregation of these processes is often overlooked because the entire facility is dedicated to
handling samples of the same general activity level. Consequently, the laboratory may be at
significant risk of being rendered unusable by the inadvertent mishandling of high-activity
material if such material is introduced to the laboratory as part of an incident response effort.
Similarly, a laboratory that is accustomed to working with higher levels of radioactivity may be
unprepared for the demands of analyzing very low-activity level samples in the recovery stage of
the event efforts.
When preparing a laboratory to accept unaccustomed activity levels, the receipt, processing,
storage, and disposal of higher levels of radioactive materials should be carefully considered
before allowing work to begin. Likewise, careful consideration should be made of the
laboratory's ability to analyze very low-level materials related to the radiological or nuclear
incident, prior to acceptance of those samples.
Another concern facing many laboratories is that their routine practices may not be directed
toward the handling of very large numbers of samples. Laboratories that typically handle only
small numbers of samples may be unprepared for the high throughput demands of an incident.
The laboratory's preparations, prior to receipt of samples from an incident, should include
consideration of these and other potentially limiting factors.
The laboratory should make advance decisions related to: a) the definition of the different types
of operational areas in the laboratory; b) the establishment of acceptable levels of radiation and
radioactive materials for the different types of areas; c) the specific requirements for PPE in
those areas; d) the configuration of the laboratory, including the layout and the flow of work that
would best minimize contamination risks; and e) the procurement, allocation, placement, and use
of additional physical resources, such as frisking stations, decontamination equipment, and
shielding material. These topics are discussed below, in this section.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
The establishment of protocols for sample handling; movement between areas of the laboratory;
surface and personnel contamination surveillance, prevention, and control; and the appropriate
use of shielding are discussed in Sections 3.0 and 4.0 of this guide.
2.1 Defining Types of Operational Areas and Other Areas Affected by Laboratory
Operations
Prior to an incident, the laboratory should consider carefully defining the various types of
segregated areas in a laboratory that may be used during the incident response and that may
potentially be affected by radioactive contamination and elevated levels of radiation. The
following list of areas is intended as an example for the laboratory's consideration. This list may
not be inclusive of all the area types that an individual laboratory might identify and consider.
2.1.1 Unrestricted Public Areas
Unrestricted Public Areas include areas open to any individual who is not under the operational
control of the laboratory. Some areas, such as roads, sidewalks, parking lots, reception and office
areas, and hallways may be open to members of the general public. Other areas, such as adjacent
businesses, may be secured from members of the general public but are still accessed by
individuals who are not responsible to, or under the direction of, the laboratory. These should all
be considered unrestricted public areas.
The laboratory is responsible for ensuring that radiation doses to the general public from
laboratory operations do not exceed regulatory limits, such as those found in 10 CFR 20 (or
Agreement State regulations). When considering the effects of laboratory operations on radiation
doses to the general public, the laboratory must also ensure that all sources of radiation are
properly accounted for. Wastewater effluents, fume hood exhausts, and radioactive and non-
radioactive waste will need to be carefully monitored.
2.1.2 Buffer Zones
Buffer zones are generally areas outside the operational areas of the laboratory, but still under
control of the laboratory and used to insulate the general public from unnecessary risk. For
example, a building which houses a laboratory operation may be situated on a property, set back
some distance from the boundary of the property. The area between the building itself and the
boundary of the property (sometimes referred to as the "owner controlled area") is not used to
handle or store radioactive materials, but may be used advantageously to keep members of the
general public at a safe distance from sources of radiation within the building.
These buffer zones are not generally at risk of becoming contaminated with radioactive materials
during laboratory operations, but do pose the potential risk of radiation exposure to persons
within the buffer zone. When used in this protective capacity, the buffer zones should be fenced,
or otherwise configured to restrict access, and should be monitored frequently enough to ensure
that changing conditions in the laboratory do not lead to an unacceptable dose to the public.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
In addition to unoccupied buffer zones, the laboratory may wish to establish the traffic areas
immediately outside the receiving area and at the public entrance of the building as buffer zones,
with the acknowledgement that there may be high-volume traffic through those areas,
necessitating frequent exposure monitoring and possibly contamination monitoring.
2.1.3 Operational Areas
CAUTION
Posting Radioactive Materials Areas
Any operational area in
which radioactive
materials are used,
stored, or handled, must
be appropriately posted,
per 10 CFR 20.1902(e)
or other Federal or State
regulation.
RADIOACTIVE
MATERIALS
Of primary concern to this guide are operational
areas (see inset), which are secure areas that are
within the boundaries of the facility and are under
the direct and immediate control of the laboratory.
These areas may be used to handle, process, or
store radioactive materials, or may be administra-
tive areas that are not used for such purposes but
which could inadvertently become contaminated.
These areas are generally within the confines of a
building but could be located outside, as in routes
between buildings or storage areas for samples and
waste.
Operational areas should be further considered according to the levels of radiation, types of work
being performed, the potential for contamination or exposure, and the flow of radioactive
material through the laboratory.
The generalized operational areas of the laboratory are considered below in the order that the
radioactive material flows through the laboratory.
2.1.3.1 Receiving Areas for Incoming Radioactive Materials Packages
A designated Receiving Area for the laboratory should be established for the receipt of
radioactive materials, including samples. The area should facilitate the:
Receipt and inspection of incoming packages, including the determination of radiation
exposure rates from the shipment;
Assessment of the shipper's compliance with pertinent transportation regulations;
Assessment of the integrity of the shipping containers;
Assessment of potential contamination of the container and its contents; and
Routing of the contents of the package to the appropriate area of the laboratory.
The Receiving Area should be set up with consideration that all samples and other radioactive
reagents and supplies will be initially inspected, both visually and with survey instrumentation,
in this area. The continuing integrity of the incoming materials depends upon the correct
assessment of the condition of the material upon receipt, and the prevention of cross-
contamination from one sample or reagent to another. No sample bottle or other primary
container of radioactive material should be opened in the Receiving Area; this should be done in
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
a separate "Screening Area" as described below. The Receiving Area should be solely for the
external assessment of the characteristics of the shipment.
In some cases, the physical constraints of the facility may require that the receiving and
screening process be carried out in the same room. In this case, care should still be taken to
establish separate "areas" for these processes, clearly posted and controlled to prevent the spread
of radiological contamination. Work tables, washable partitions, and laboratory fume hoods may
serve as appropriate means to isolate the different processes.
Receiving Areas for incoming radioactive materials packages should also be sufficiently
separated, or appropriately shielded, from other areas of the laboratory in which radioactive
materials are processed, stored, or analyzed. This will facilitate more accurate surveys of the
incoming packages, and will minimize the potential impact of those incoming packages on
radiation measurements being performed in the laboratory. The area should, at a minimum, be
equipped with the following:
A staging area for incoming materials. Initial exposure rate measurements and removable
surface contamination surveys of the outside of the package may be performed in this
area.
A means for containing and sealing a shipment, sample, or other item that has broken or
been contaminated in shipping or during handling in the laboratory. Containment bins,
large durable trash bags, sealable freezer bags, etc., are useful items to have on hand for
such an incident.
An appropriately configured laboratory fume hood6 or other exhaust ventilation system
for unpacking the shipment. Initial inspection and inventory of the contents, exposure rate
measurements, and removable surface contamination surveys should be performed in the
ventilation hood, to protect the workers from contamination in the event that a sample
container is broken or otherwise compromised in shipment.
A means for containing spilled liquids. This may include a supply of absorbent spill
recovery material, or in the case of larger volumes, a spill containment curb around the
work area. The laboratory should ensure that it has sufficient spill recovery capacity
immediately on hand to adequately contain the volume of sample material in any one
shipment, and that additional supplies are readily available, if needed.
The appropriate equipment and supplies for segregating and decontaminating containers
that have been potentially contaminated by spilled radioactive material. The area should
have ready access to the sample screening area, the High-Level Work Areas, and the
Routine-Level Work Areas, which are described below.
Minimum recommended procedures for receiving radioactive materials, including samples, are
detailed in Section 3.1, Sample Handling Protocols.
6 Guidance for determining appropriate laboratory fume hood specifications and configurations may be found in the
following standards: ANSI/AIHA Z9.5, American National Standards for Laboratory Ventilation; ASHRAE, HVAC
Applications Handbook; NFPA-45, Standard on Fire Protection for Laboratories Using Chemicals; SEFA 1.2,
Laboratory Ventilation.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
2.1.3.2 Screening Areas for Incoming Samples
The Sample Screening Area should be established where the samples are initially opened, initial
sample conditions such as preservation are verified, and an aliquant is potentially removed for
screening analyses. Consequently, the risk of contamination to personnel, laboratory surfaces,
and other samples is potentially high. The area should be designed to facilitate the preparation
and screening of distinct samples or batches/shipments of samples, while minimizing the risk of
contamination to unrelated samples or other areas of the laboratory.
The Sample Screening Area should be a distinct and dedicated area, separate from the sample
Receiving Area whenever possible, but adjacent to and with direct access from the Receiving
Area. The Sample Screening Area should be designed, whenever possible, as a self-contained
preparation and screening analysis laboratory. The area should be equipped with the same
facilities required in other laboratory areas, such as a fume hood, basic laboratory equipment,
screening instrumentation, adequate storage for the immediate access to reagents and supplies,
and adequate utilities, communication systems, and safety and emergency response equipment.
The area should also be equipped with adequate decontamination and survey equipment and
supplies to facilitate the rapid cleanup and release of the work areas for the preparation and
screening of other samples.
As with the Receiving Area, this area should have ready access to both the high- and routine-
level work and storage areas without the need to traverse one to get to the other, if possible.
Minimum recommended procedures for opening sample containers and sub-sampling the
material are detailed in Section 3.1, Sample Handling Protocols.
2.1.3.3 High-Level Work Areas, and 10 CFR 20 "Radiation Areas"
In the following discussion, "High-Level Work Area" is a term defined specifically for this
document and should not be confused with, or used interchangeably with, the terms "Radiation
Area" or "High Radiation Area," which are described in 10 CFR 20.
High-Level Work Areas are
designated areas for processing,
storing, and in some cases analy-
zing samples that present an
elevated risk of sample cross-
contamination, or contamination or
exposure to the employees and the
facility.
In evaluating these risks, the
laboratory should consider both the
activity concentration and the total
amount of activity in the sample.
Elevated activity concentrations
10 CFR 20 Radiation Areas
Activity concentrations or exposure rates in excess of the
upper limit for High-Level Work Areas will likely require the
establishment of a Radiation Area. Radiation Area is a
regulatory term that is used in 10 CFR Part 20.1003 (or
equivalent state regulations) to describe areas "accessible to
individuals, in which radiation levels could result in an
individual receiving a dose equivalent in excess of 0.005 rem
(0.05 mSv) in 1 hour at 30 centimeters from the radiation
source or from any surface that the radiation penetrates."
The establishment of Radiation Areas, and other requirements
of 10 CFR Part 20, include very specific radiation protection
measures, which are outside the scope of this document, but
with which the laboratory should be familiar as a condition of
its radioactive materials license.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
increase the risk of contamination or exposure, but this risk may be somewhat mitigated when
only small amounts of the sample are handled. Conversely, even moderate activity
concentrations may pose an elevated risk of contamination or exposure when the volume of
sample is very large. These concepts are discussed further in Section 2.2, Establishing
Acceptable Levels of Radioactivity and Radiation. In either case, high-activity concentrations in
samples or high levels of activity in sample aliquants may interfere with the laboratory's ability
to meet the measurement quality objectives (MQOs) for the project. The risks associated with
these types of samples may be further increased when the contaminants are potentially volatile,
or are potentially associated with fine or dry particulates that may become airborne during
handling.
The following design items and practices should be carefully considered when establishing a
High-Level Work Area:
Areas designated for the processing or storage of high-activity samples and waste should
be directly accessible from the receiving and screening areas, but should be as remote as
feasible from the lower-level work areas and especially from any analytical
instrumentation that may be affected by either radiation exposure or by inadvertent
laboratory contamination.
The area should be clearly posted as a High-Level Work Area at all entryways and
boundaries between other areas. Access should be restricted to essential personnel only.
High-activity samples should be stored and processed in these areas, without the need to
travel through other parts of the lab, if possible.
Consumable materials and other laboratory supplies and equipment should be unpacked,
to the extent feasible, prior to being moved into the High-Level Work Area. This will
minimize the risk of contamination from the removal of unnecessary packaging and
extraneous material from the High-Level Work Area.
Where the analysis of high-activity
contamination to the routine radia-
tion detection instrumentation, or
where the movement of prepared
samples through other areas of the
laboratory is not desirable, specific
instrumentation may need to be
procured and dedicated for use only
in the High-Level Work Area.
The layout of the area should include
particular consideration for minimi-
zing radiation exposure to personnel.
This may include optimizing the
distance between the accumulated
radioactive materials and the person-
nel work stations, as well as instal-
ling additional shielding materials.
level samples may pose an elevated risk of
Negative Room Air Pressure
Establishing a negative pressure gradient from
higher-level to lower-level areas in the laboratory
will minimize the movement of airborne radio-
activity in the laboratory. Thus, areas with the
highest activities should be maintained at the lowest
pressure level. The pressure should then be succes-
sively increased through the mid- and low-level
areas, and into uncontrolled areas so that the
movement of airborne contamination is always from
low to high. While this may be accomplished with
the existing ventilation system, a qualified industrial
hygienist and health physicist, working with the
laboratory's heating, ventilation, and air condition-
ing (HVAC) contractor, should always be consulted
before making even minor modifications to the
laboratory air handling system.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
If possible, High-Level Work Areas should employ negative air pressure (relative to
adjacent areas) to keep airborne radioactive material inside the room.
Laboratory fume hoods in the High-Level Work Areas may need to be equipped with
high efficiency particulate air (HEPA) filters to reduce the level of radioactive
contaminants in the exhaust air. In addition, the laboratory may need a program for
monitoring the filters, to ensure worker protection and to facilitate proper handling and
disposal.
Personnel working in these areas should be thoroughly trained in the laboratory's
contamination prevention, assessment, and control procedures, and should undergo
routine retraining periodically and when the scope of the activities changes significantly.
If possible, they should participate in practical exercises to supplement the training.
To the extent possible, contamination response procedures for these areas, including
decontamination efforts, should depend first on the personnel working in that area, in
order to minimize unnecessary traffic through that area during the response to a
contamination event.
An integral part of contamination control training for laboratory personnel in these areas
should be to recognize when the nature of a contamination event is outside their expertise
or ability to control and therefore when to seek additional assistance.
The area should be designed to facilitate the support of contamination control procedures
from adjacent areas. Whenever possible, the area should be designed to allow additional
decontamination supplies and equipment to be passed into the laboratory area without
risk of spreading contamination and without constraining the movement of personnel into
or out of the area. The use of pass-through cabinets or material air locks is useful in this
regard and should be employed whenever feasible.
The area will require a more rigorous egress policy than other areas of the lab, with
additional frisking and decontamination resources as described in Section 3.2, Movement
Between Laboratory Areas (Entry/Egress).
Other design considerations for these areas will not differ significantly from other laboratory
areas.
2.1.3.4 Routine-Level Work Areas
Routine-Level Work Areas, as the name implies, are designated for sample radioactivity levels
that fall into the normal scope of work to which the laboratory is routinely accustomed, and for
which the laboratory has historically demonstrated an ability to achieve the applicable MQOs. In
most environmental radiological laboratories, the sample activity levels for these areas will likely
correspond to "normal environmental levels," as defined by the laboratory. These areas should
not require changes in safety and contamination control protocol beyond those already in place in
the laboratory.
11
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Routine-Level Work Areas should be accessible from the sample receiving and/or screening
areas, as well as from the High-Level Work Areas, if possible, following proper egress protocols
from those areas.
The Routine-Level Work Areas should also have ready access to the nuclear measurements
instrumentation that will be used in the analysis of samples prepared in those areas, although the
instrumentation area should be situated as far as practical from the Sample Receiving Area and
High-Level Work Areas.
The laboratory may choose to include A j- ju *u T JU-UIT
J J As discussed above, the sample screening and high-level
work areas may need to be equipped with their own
dedicated instrumentation; uncharacterized sample material
and high-activity level samples should not be analyzed on
instrumentation dedicated to routine- or low-level work.
the instrumentation area as a part of the
Routine-Level Work Areas, in which
case the instrumentation area should
still be maintained as a separate area
with appropriate entry protocols. It is
recommended, however, that the instrumentation area be designated as a Low-Level Work Area,
with the descriptions and considerations shown below.
2.1.3.5 Low-Level Work Areas
In some cases, it may be advantageous to the project for the laboratory to establish Low-Level
Work Areas, which restrict the flow of radioactive materials and general laboratory traffic in
order to achieve MQOs that may be well below those to which the laboratory is accustomed. The
laboratory may also find it useful to designate the instrumentation areas as Low-Level Work
Areas, in order to maintain the integrity of the instrumentation and the laboratory's ability to
meet the project MQOs.
The following design items and practices should be carefully considered when establishing a
Low-Level Work Area:
Areas designated as Low-Level Work Areas should not be directly accessible from the
receiving and screening areas, or from the High-Level Work Areas.
The area should be clearly posted as a Low-Level Work Area, with access restricted to
essential personnel only.
The location and layout of the area should include particular consideration for a)
minimizing general background radiation to the instrumentation from other parts of the
laboratory, particularly from sample storage areas and High-Level Work Areas, which
can elevate the measurement uncertainty and detection capability of radioanalytical
techniques; and b) minimizing transient variations in the background radiation levels,
from the movements of samples and waste through the laboratory, which can result in
significant biases in the net analytical results, especially at low sample activities.
Only those samples that are necessary for the immediate task at hand should be stored in
this area. Upon verification of successful analysis, residual sample volumes and prepared
samples should be promptly removed from the area and transferred to an appropriate
storage location outside the counting/instrumentation room.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
If possible, the area should employ positive air pressure (relative to adjacent areas) to
keep airborne radioactive material outside the room. As mentioned above, a qualified
industrial hygienist and health physicist, working with the laboratory's HVAC
contractor, should always be consulted before making even minor modifications to the
laboratory air handling system.
Other design considerations for these areas will not differ significantly from other laboratory
areas.
2.1.3.6 Administrative and Public Areas
It is also necessary for the laboratory to recognize those administrative areas occupied by non-
radiation workers, and those areas that allow for general public access, which may include areas
not under the direct control of the laboratory.
These areas will not require any special equipment or supplies, but may require periodic
monitoring for contamination of the areas and for exposure levels to the occupants of those areas.
In addition, exiting any of the laboratory areas directly into administrative or public areas will
require appropriate egress protocols.
2.2 Establishing Acceptable Levels of Radioactivity and Radiation
Once the various types of operational areas are identified, the laboratory should establish
acceptable levels of radioactivity and radiation exposure and dose rates that will further define
the areas.
The laboratory should be mindful that the ultimate purpose of establishing limits on the levels of
radioactivity and radiation, and for pursuing a Radiological Controls Program in general, is to
ensure that the laboratory can perform the necessary radioanalytical work while minimizing both
personnel exposure and the radioanalytical effects of laboratory contamination and sample cross-
contamination.
Acceptable levels of radioactivity and radiation in the different areas might be based on the
initial condition of the lab, the type of work routinely performed, and the type of work expected
from the radiological or nuclear incident. These acceptable levels should reflect the laboratory's
assessment as to what maximum activity and radiation levels should be allowed so that the risk
to personnel, project MQOs, and the overall integrity of the laboratory's radioanalytical
processes are not compromised.
The Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP 2004,
Chapter 2) provides guidance for pursuing a "directed planning process," such as the data quality
objective (DQO) process, for setting well-defined objectives and developing reliable sampling
and analysis plans that support decisionmaking processes. This directed planning approach will
be useful in the laboratory's selection of acceptable levels of radioactivity and radiation, and for
establishing laboratory-specific protocols for contamination monitoring that support decision-
making at those levels.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
2.2.1 Action Levels: AAL, Required Method Uncertainty, and ADL
Portions of this guide rely heavily on the use of the terms "analytical action level" (AAL),
"required method uncertainty" (MMR), "required relative method uncertainty" (#>MR), and
"analytical decision level" (ADL) in characterizing the desired levels of performance of
screening and analysis methods and the radioanalytical results for use in decisions regarding the
exceedence of established levels of radioactive contamination and radiation exposure. These
terms may be used to describe the MQOs for the analysis of field samples related to a nuclear or
radiological incident, as well as the analysis of internal samples related to the surveillance of
contamination in the laboratory. Each combination of sample type and analytical method may
have an AAL, Z/MR, #>MR, and ADL specific to the requirements of the pertinent MQOs.
The term "analytical action level" (AAL) is used as a general term denoting a radioactivity or
radiation level at which some action must be taken. In the context of laboratory contamination
control, action is taken by the laboratory to reduce the impact of radiological contamination or
radiation in and around the laboratory. This action may include surface decontamination, sample
segregation, emplacement of shielding, increased monitoring frequency, or other actions
determined by the laboratory. The AALs should correspond to the laboratory's assessment of
risk to the radioanalytical processes or to personnel. In making these assessments, the laboratory
should incorporate what it considers to be acceptable error rates in its decisions as to whether
personnel or analytical processes are impacted to an unacceptable degree. Assessments of
acceptable risk and the corresponding radioactivity and radiation levels, and decisions regarding
acceptable decision error rates, will be specific to individual laboratories and incident response
activities. These assessments should include significant input from qualified technical resources,
such as senior analytical, health and safety, and radiation protection personnel.
The selection, validation, and use of a particular analytical method or screening technique rely on
the ability of that method or technique to provide a result with a specified required method
uncertainty, Z/MR, at the AAL, and a corresponding required relative method uncertainty, ^MR, for
results above the AAL. This condition ensures that the quality of the measurement will be
adequate for making decisions, considering the acceptable decision error rates discussed above.
Whenever the reported activity or exposure rate exceeds a pre-defined level (the ADL), the AAL
can be assumed to have been exceeded and appropriate action is warranted. The derivation and
use of AAL, Z/MR, #>MR, and ADL are discussed in this section and in other companion guides in
this series.
While closely interrelated, it is important to note that the use of AAL (and the associated Z/MR and
MR, and ADL will depend on the laboratory area under consideration
and the analytical processes being performed. This guide offers examples of AALs, Z/MR, and
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
considered as guidance for the laboratory to develop its own action levels and criteria by which
to make contamination and exposure control decisions.
It should be understood that the terms AAL, WMR, ^MR, and ADL are also applicable to the MQOs
assigned to the laboratory analysis of field samples from incident response activities. In fact, the
AALs, WMR, #>MR, and ADLs that apply to the laboratory contamination control measurements
might be derived from the AALs, WMR, #>MR, and ADLs that apply to the analysis of field samples.
Where it becomes necessary in this document to distinguish field sample MQOs from
contamination control MQOs, the parentheticals (S) and (C) will be added as needed for clarity:
AAL(,S) = Analytical action level for field sample analyses
UMR(S) = Required method uncertainty at or below the AAL(,S) for field sample
analyses
Ms.(C) = Required relative method uncertainty above the AAL(Q for contamination
control analyses
ADL(C) = Analytical decision level for contamination control analyses
Other guides in this series (see Preface) provide additional discussion and examples for deriving
and applying these values in a variety of scenarios using both external, incident-derived DQOs
and internal, laboratory-specified DQOs.
The following sections, 2.2.2 through 2.2.4, provide an example of the process and associated
calculations that a hypothetical laboratory might follow to derive AAL(C), MMR(C), and finally
ADL(C) for swipe sample measurements.
Additional examples describing the determination of AAL(C), MMR(C), and ADL(C) values for
sample screening activity, and exposure rate monitoring are provided in Appendix J,
Establishing MQOs for Sample Screening Measurements, and Appendix K, Establishing
MQOs for Sample Exposure Rates.
2.2.2 Establishing Analytical Action Levels for Contamination Control AAL(C)
Consider an example scenario in which the laboratory wants to establish limits for removable
alpha-emitting radioactive contamination on surfaces in a particular laboratory area. In this case,
MQOs for contamination control measurements, i.e., AAL(C), MMR(C), and ADL(C), will be
directly related to the required MQOs for incident response sample analyses, AAL(,S), UMR($),
and ADL(S).
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
In this example scenario:
The laboratory area is used for the preparation of samples that are required to meet MQOs
that apply to the majority of sample analyses performed by the laboratory. Consequently, this
area is considered a "Routine-Level Work Area."
The most stringent MQO states that the required method uncertainty, Uy^fS) (i.e., the
combined standard uncertainty (CSU) estimated by the laboratory) is not to exceed 1.5 pCi/g
at the specified AAL(,S), which is 10 pCi/g.
Sample activity measurements below 10 pCi/g are also limited to the required method
uncertainty, u^S), of 1.5 pCi/g and measurements above 10 pCi/g are limited to a required
relative method uncertainty,
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
The AAL(C), expressed in activity units of pCi, is therefore 1.5 pCi alpha activity.7
Following this assessment, the laboratory technical personnel are consulted, the sample
preparation process is reviewed, and potential sources and mechanisms of contamination are
identified. Based on the available information, and perhaps based in large part on the technical
judgment of the staff, it is estimated that surficial contamination from approximately 10 cm2 of
laboratory workbench surfaces could potentially enter the analytical process and result in
radioanalytical contamination. This estimate may come from empirical task assessments or from
general observations of how much a technician inadvertently touches the benchtop, etc. Again,
note that the values in this example are for illustrative purposes only. Each laboratory will need
to assess its own processes and situations on a case-by-case basis. In all cases, however, the
potential contamination should be limited to a level that does not significantly impact the
required sample analysis method uncertainty,
Limiting potential contamination from laboratory workbench surfaces to 1.5 pCi (as determined
above) per 10 cm surface area gives a maximum allowable contamination level of
1.5 pCi / 10 cm2 = 0.15 pCi/cm2.
A removable surface contamination swipe, covering a standard area of 100 cm2, should therefore
have no more than:
99 o
0.15 pCi/cm x 100 cm =15 pCi alpha activity per swipe sample.
The AAL/Q, therefore, is 15 pCi of alpha activity per swipe sample, expressed in terms of
activity units per swipe sample.
In this example, the laboratory estimates that limiting the potential contribution from sources of
laboratory contamination to 1.5 pCi would effectively limit the CSU in the reported sample
results to:
Modifying the Plan
Any modifications to the area type definitions,
acceptable activity levels, laboratory layout, or
usage of a given area should be accompanied by
a thorough review to ensure that the protection of
health, safety, and the environment, and the
Because the maximum allowable removable prevent10n of laboratory and sample contamma-
the required method uncertainty (WMR) of 1.5
pCi/g at the 10 pCi/g AAL, and
the required relative method uncertainty
(
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
determination of the required method uncertainty, MMR(C), and analytical decision level, ADL(C),
in the laboratory's contamination control measurements are discussed later in this section.
The laboratory may then consider similar scenarios for the various processes and work areas, and
generate a list of AAL(C) values beyond which the levels of radioactivity or radiation will be
considered too high, which will be the laboratory's indication that some response, or corrective
action, is warranted. These AAL(C) values should guide the development of analytical methods
to be used for making contamination and exposure control decisions in the different work areas.9
These values should be periodically reviewed and may need to be occasionally modified. If
possible, a focal review and any necessary adjustments should be made after reviewing the
available information about a radiological or nuclear incident and the MQOs for the project, and
before receiving samples from the incident.
The laboratory, at a minimum, should establish those levels of radioactivity and radiation that
define High-Level Work Areas. The laboratory should distinguish those areas from "routine"
work areas that represent the type of work to which the laboratory is accustomed and that are
already governed by the laboratory's existing Radiation Protection Program or Radiation Safety
Manual. It is recommended, however, that a more thorough classification of potential activity
and exposure levels be considered. An example of the scope of classifications and activity levels
segregating the different area types is shown in Table 1, Laboratory AALs for Contamination
and Exposure Control: An Example of Maximum Sample Activity, Exposure and Dose Rate, and
Radioactive Contamination by Area Type.
9
Note that the values shown in Table 1 include the AAL of 33 dpm per 100 cm swipe for
removable surface alpha contamination, as determined in the example above.
While the classifications and values shown in Table 1 may be based in part on practical
experience in a variety of radiological laboratories, they should be considered only as examples
and are intended simply to provide conceptual guidance for the laboratory to establish its own
criteria. Each individual laboratory should evaluate the requirements of a specific project and the
type of work typically performed at that laboratory and in the various work areas, and assign area
types and activity levels that are appropriate to the project at hand.
Table 1 describes example AALs for three general aspects of radiological laboratory operations.
Analytical action levels for radioactive contamination, sample activity concentrations, and
exposure and dose rates are provided for each area type, such as "High-Level," "Routine-Level,"
etc. Sample activity and contamination AALs are further classified by alpha, beta, and gamma
activity levels. In some cases, a distinction is made between lower- and higher-energy beta
activity because the required limits of detection and necessary instrumentation may differ
significantly for low-energy beta-emitters, such as 3H and 14C.
9 When assessing appropriate AAL(Q values for radioanalytical contamination control, the laboratory should
consider the impact that different types of contamination have on the various processes that are affected. For
example, alpha spectrometry analyses may be significantly affected by very small amounts of alpha-emitting
contaminants. Alternately, pure beta-emitting contaminants, such as Sr-90, may have little radioanalytical impact on
that analysis. The type of radiation and the impact on the desired MQOs should be carefully considered.
18
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Table 1 - Laboratory AALs for Contamination and Exposure Control: An Example of
Maximum Sample Activity, Exposure and Dose Rate, and Radioactive Contamination by
Area Type
Maximum Removable Contamination (netdpm/100 cm2)
alpha
beta/gamma
beta<150keV
Maximum Fixed Contamination (net dpm/100 cm2)
alpha
beta/gamma
Maximum Screening Activity Concentrations per Matrix
Solids (pCi/g)
alpha
beta>150keV
beta<150keV
gamma
Liquids (pCi/L)
alpha
beta>150keV
beta<150keV
gamma
Air Filters (pCi/filter)
alpha
beta>150keV
beta<150keV
gamma
Alternate Total Activity per Aliquant (pCi)
alpha
beta>150keV
beta<150keV
gamma
Maximum Sample Exposure Rate (|jR/h at surface of container)
Maximum Area Ambient Exposure Rate (pR/h)
Maximum Estimated Dose Rate, TEDE (mrem/h) per 10 CFR 20*
AREA DEFINITIONS
Public
Access
Admin.
&
Buffer
Low
Level
Routine
Level
High
Level
CONTAMINATION LIMITS
<5
<20
<25
<20
<100
<5
<20
<25
<20
<100
5
20
50
20
100
33
350
350
175
850
200
2,000
2,000
350
2,000
SAMPLE ACTIVITY LIMITS
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
na
4
8
20
8
40
75
400
70
4
8
20
8
500
1,000
2,500
1,000
100
200
500
200
100
200
1,000
200
100
200
500
200
5,000
10,000
25,000
10,000
1 E+04
2E+04
5 E+04
2 E+04
1 E+04
2 E+04
1 E+05
2 E+04
1 E+04
2 E+04
5 E+04
2 E+04
1 E+07
2E+07
5 E+07
2 E+07
EXPOSURE AND DOSE RATE LIMITS
2xbkg
0.01
2xbkg
0.01
100
2xbkg
0.50
5,000
500
2.50
100,000
1,000
5.0
* 10 CFR 20 limits the maximum dose rate to the public and to workers. 0.01 mrem/h is the value that is
approximately equivalent to the annual public limit 100 mrem/y; 2.5 mrem/h is the value that is equivalent to the
5,000 mrem annual dose limit to radiation workers working 2,000 hours per year; 5 mrem/h is the maximum dose
rate allowed before establishing a "Radiation Area"; the value of 0.50 mrem/h for Low-Level Work Areas has no
regulatory basis, but rather may reflect the laboratory's desire to further limit the radiation in that area.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
2.2.3 Limiting the Method Uncertainty,
In the example scenario provided above, the laboratory has determined the actual levels of
radioactive contamination or radiation exposure that should trigger responsive action in the
laboratory to mitigate the effects of such levels of contamination or exposure. The laboratory
must then select a method for sampling and analyzing the parameter of interest, which in this
case is removable surface contamination by alpha-emitting radionuclides.
If the laboratory had a method that would definitively measure that parameter with absolute
precision, it would be a simple matter of comparing the measurement results directly to the
AALs derived above. Of course, this is not the case for any analytical method, and the
uncertainty of the method must be taken into account when comparing the measurement result to
the established AALs.
In order to make effective decisions regarding the presence or absence of radioactivity or
radiation at a specified level, a careful assessment should be made of the maximum uncertainty
that should be tolerated in the sampling and analysis method. The companion document, A
Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological or
Nuclear Incident (EPA 2011), provides a detailed example for calculating the required method
uncertainty in a swipe sampling and analysis scenario. Other guides in this series, including
Radiological Laboratory Sample Analysis Guide for Incidents of National Significance -
Radionuclides in Air (EPA 2009a), Radiological Laboratory Sample Screening Analysis Guide
for Incidents of National Significance (EPA 2009b), and Guide for Laboratories - Identification,
Preparation, and Implementation of Core Operations for Radiological or Nuclear Incident
Response (EPA 2010), provide additional examples that are pertinent to other situations that
might be encountered.
In general, the required method uncertainty, MMR, at activity levels equal to the AAL is calculated
as:
AAL-DL
Where
AAL = analytical action level
DL = discrimination level10
zi-a and z\-p are the 1- a and I-/? quantiles of the standard normal distribution function,
where a and ft are the respective probabilities of making a Type I or Type II error.
In the example scenario, the analytical action level for alpha activity in removable surface
contamination swipes, AAL(C), 1
Other AALs are shown in Table 1.
r\
contamination swipes, AAL(C), has been established as 33 dpm per 100 cm swipe sample.
The DL is the point where it is important to be able to distinguish the expected measurement
result from the AAL. When one expects the instrument response to a sample to be at the
10 Careful distinction should be made between the discrimination level (DL) and the analytical decision level (ADL).
These terms have quite different meanings and are not to be used interchangeably.
20
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
background response rate for that instrument, then the DL might be zero. If one expects an
instrument response near the AAL, however, the DL might be closer to the AAL. In the example
scenario, the AAL(C) for removable alpha activity in Routine-Level Work Areas (33 dpm per
swipe) is expected to be distinguishable from the AAL(C) for Low-Level Work Areas, so the DL
is set to 5 dpm per swipe.n
The z-factor of 1.645 is selected from a standard table of cumulative normal distributions,
corresponding to a and/? probabilities of 0.05.
Under these conditions, the required method uncertainty for the contamination control analysis,
at the AAL will be:
_. AAL-DL 33-5
UMR (Q = = , ,.,. , ... = 8.5 dpm per swipe
zi-a+zi-/3 1.645 + 1.645
It is now incumbent upon the laboratory to identify sampling and analysis conditions that satisfy
the required method uncertainty. This may be as simple as adjusting swipe sample count times
on an instrument or as involved as developing entirely new sampling or analysis protocols to
control the overall result uncertainty. Once these sampling and analysis conditions are identified,
they should be recorded and actively associated with the specific AAL, preferably in the form of
a laboratory's SOP. If the laboratory ultimately cannot satisfy the required method uncertainty, a
careful assessment should be made by experienced technical personnel of the impact on the
analysis of field samples and the risk of failing to meet those MQOs in the event of laboratory
contamination. The Incident Commander, as well as the laboratory's management and quality
assurance personnel, should be immediately notified of any potential failure to meet incident
MQOs.
Required method uncertainties should then be determined for each AAL, and the appropriate
sampling and analytical protocols documented, once again based on laboratory-specific
conditions.
2.2.4 Determining the Analytical Decision Level
After determining the required method uncertainty (MMR) for the contamination analysis, the
laboratory can then determine the ADL, which is the calculated radioanalytical value that is to be
1 9
used in making decisions as to whether the AAL is likely to have been exceeded.
11 In general, the DL for a given scenario may be selected as the AAL for that category in the next lower activity
level area, with DL=0 for low-level work areas and administrative areas. DLs should be evaluated by each
laboratory for each AAL on a case-by-case basis.
12 Specific application of UMR to the AAL, to determine the appropriate ADL, will depend on which decision error
the laboratory would consider to be worse; deciding that the sample activity is below the AAL when it is not, or
deciding that the sample activity is above the AAL when it is not. A detailed discussion addressing both situations is
provided in Section 4 of the companion document, A Performance-Based Approach to the Use of Swipe Samples in
Response to a Radiological or Nuclear Incident (EPA 2011).
21
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
In the example scenario introduced above, the laboratory establishes an ADL that is below the
AAL to minimize the risk of incorrectly deciding that the true swipe alpha activity is below the
AAL, when it is actually above the AAL. Consequently, the ADL(C) would be calculated as:
ADL(C) = AAL(C) - z,_a x UMR (Q
= 33 - (1 .645 x 8.5) = 19 dpm per swipe
ADLs should then be calculated for each AAL in Table 1 and its corresponding WMR. It may be
convenient for laboratory personnel to list the AAL, WMR, ADL, and the sampling and analytical
conditions (i.e., pertinent SOPs) required to achieve these MQOs, for each area type that might
be encountered. The example values provided in Table 1 have been reduced to the values
pertinent to the Routine-Level Work Area, and supporting information for each parameter has
been added.
Selected ADL values are presented below in Table 2. The laboratory may find it useful to
include similar information in the training of personnel working in this area, and to post this
information in the Routine-Level Work Areas so that it is readily available when needed.
Additional examples describing the determination of AAL(C), MMR(C), and ADL(C) values for
sample screening activity, and exposure rate monitoring are provided in Appendix J,
Establishing MQOs for Sample Screening Measurements, and Appendix K, Establishing
MQOs for Sample Exposure Rates.
2.2.5 Establishing Appropriate Corrective Action when the ADL(C) is Exceeded
When the ADL(C) is exceeded for any given measurement, the laboratory should respond
quickly and decisively in order to prevent the uncontrolled spread of contamination and to
maintain the integrity of its radioanalytical processes. The laboratory should have formalized
procedures describing the appropriate response and corrective action to be taken for each type of
exceedence.
At a minimum, the corrective action should include the return of the laboratory environment to
its previous condition, and the performance of follow-up measurements to verify the
effectiveness of the laboratory's response.
To continue the example presented above, if a removable contamination survey is performed in a
Routine-Level Work Area, and the survey result for gross alpha activity exceeds the ADL(C) of
19 dpm per swipe, some corrective action must be taken. The laboratory's corrective action plan
may require:
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Table 2 - Laboratory ADLs for Contamination and Exposure Control: An Example of
Routine-Level Work Area MQOs
Maximum Removable Contamination (netdpm/100 cm2)
alpha
beta/gamma
beta<150keV
Maximum Fixed Contamination (net dpm/100 cm2)
alpha
beta/gamma
Maximum Screening Activity Concentrations per Matrix
Solids (pCi/g)
alpha
beta>150keV
beta<150keV
gamma
Liquids (pCi/L)
alpha
beta>150keV
beta<150keV
gamma
Air Filters (pCi/filter)
alpha
beta>150keV
beta<150keV
gamma
Alternate Total Activity per Aliquant (pCi)
alpha
beta>150keV
beta<150keV
gamma
Maximum Sample Exposure Rate (pR/h at surface of container)
Maximum Area Ambient Exposure Rate (pR/h)
Maximum Estimated Dose Rate, TEDE (mrem/h)
MQOs for ROUTINE-LEVEL WORK AREAS
AAL
UMR[1]
Sampling
SOPH
Analysis
SOP
ADL
CONTAMINATION LIMITS
33
350
350
175
850
8.5
100
91
47
230
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
19
190
200
98
480
SAMPLE ACTIVITY LIMITS
100
200
500
200
100
200
1,000
200
100
200
500
200
5,000
10,000
25,000
10,000
29
58
150
58
18
40
180
40
29
58
150
58
1,400
2,700
6,800
2,700
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
52
100
260
100
70
140
700
140
52
100
260
100
2,800
5,500
14,000
5,500
EXPOSURE AND DOSE RATE LIMITS
5,000
500
2.50
1,500
150
0.6
SOP#
SOP#
SOP#
SOP#
SOP#
SOP#
2,600
260
1.5
[1] The calculation of MMR in this table assumes a z-factor of 1.645, related to a and /? probabilities of 0.05.
[2] The Laboratory Sampling and Analysis SOPs have been omitted, as actual method parameters are not used
to generate these specific example values. In an actual DQO summary, these columns would be completed
with the laboratory method references that correspond to the stated MQOs.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
notification to the area supervisor or Radiation Safety Officer (RSO);
surface decontamination, following established protocols;13
follow-up survey to verify that the removable surface contamination is now below the
ADL(C); and
filing of a brief incident report to the area supervisor or RSO documenting the incident,
the corrective action taken, the results of the follow-up measurements, and the necessary
approval to resume work.
The laboratory's response to area exposure rate ADL(C) excursions may be to move nearby
samples to remote storage. Sample activity concentration ADL(C) excursions might be addressed
by processing the sample material in a higher-activity area or by sub-sampling to limit the total
amount of activity being handled, which is discussed in more detail below. The laboratory should
develop individual requirements for immediate response, corrective action, and the resumption
of work, for each contamination control measurement in each area type.
2.3 Additional Comments Regarding Radioactivity and Exposure Limits
Limits on sample activity concentrations are intended to allow the use of sample screening data
to segregate radioactive samples to a particular part of the laboratory for processing. In some
laboratories, however, it may not be possible to have both a "High-Level" and "Routine-Level"
facility for every process. For that reason, Alternate Total Activity limits are provided to allow
for the segregation of a small representative sample aliquant (portion of a high-activity sample)
in the higher-activity level area. That reduced aliquant may then be brought into a lower-activity
level area for further processing.
EXAMPLE 1: The screening analysis results from a 500-g solid sample indicates beta activity of
approximately 5,000 pCi/g, for beta-emitters with emission energies >150 keV. While the
laboratory has facilities for the gross handling and digestion of high-activity samples, there
are no separate facilities for chemical separation or counting. What is the largest sample
aliquant allowed for processing in the Routine-Level Work Areas?
In this case, the sample exceeds the 100 pCi/g activity concentration ADL for this category
of beta activity. A small representative aliquant may be processed in the Routine-Level
Work Area, provided that the total beta activity does not exceed the 5,500 pCi total sample
activity ADL, as determined by the screening results. Consequently, 1.1 g of material may
be segregated in the High-Level Work Area and brought into the Routine-Level Work Area
for further processing: (5,500 pCi limit) / (5,000 pCi/g sample activity) = 1.1 gram sample
limit.
EXAMPLE 2: In the same scenario, how much sample material may then be transferred into the
instrumentation laboratory for analysis, if that area is considered a Low-Level Work Area
and the corresponding ADL for total beta activity per sample is 500 pCi?
13 See Appendix I, Decontamination of Laboratory Surfaces and Equipment, for a general example of a
decontamination protocol.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
The representative 1.1-g sample aliquant that was brought into the Routine-Level Work
Area for processing should be further reduced to the equivalent of no more than a 0.1-g
aliquant, prior to being brought into the instrumentation lab: (500 pCi limit) / (5,000 pCi/g
sample activity) = 0.1 gram sample limit.
Additional discussion regarding the handling and sub-sampling of higher-activity samples is
given in Section 3.1, Sample Handling Protocols.
The limits on exposure and dose rates in Table 2 are intended to allow the laboratory to specify
protective measures for the employees based on the type of area, and to control the impact of
radiation on the analytical instrumentation in the various areas. Similarly, contamination limits
allow the laboratory to control the potential impact of laboratory operations on the ability of the
laboratory to achieve certain MQOs, as well as allowing the laboratory to further target
protective measures to specific work areas.
Note that the values given in Table 2, and in the examples above, are provided for guidance only
and are intended to illustrate possible limits that may be used for controlling radioactivity and
radiation levels in the various parts of the laboratory. These values will need to be adjusted based
on specific laboratory operations. For example, in areas performing gross a/P analyses, the AAL
and corresponding ADL values may be considerably higher than those that might be acceptable
for areas in which alpha spectrometry analyses are performed. These decisions must be carefully
considered on a case-by-case basis.
When establishing operational limits to the measured radioactivity and radiation levels in the
different parts of the laboratory, a significant concern will be the potential effect of that
radioactivity and radiation on the laboratory's ability to perform sample measurements that meet
the MQOs that have been established for the radiological or nuclear incident response. For
example, a laboratory might limit sample activity concentrations in an area based on an
estimation of the level of cross-contamination among samples that is likely for some particular
process, such as soil grinding or the vigorous boiling of water samples. The laboratory may wish
to limit the radioactivity associated with such potential cross-contamination to an amount that
will not have a significant impact on the incident response decisionmaking process.
In a similar example, the laboratory may wish to limit the fluctuations in nearby counting
instrumentation by estimating the exposure rate that would be required from a batch of samples
transiting the laboratory, to cause such a response in the instrument. This maximum allowable
exposure rate might be distributed among several samples to determine a maximum allowable
exposure rate, per sample.
In each example, the AAL established by the laboratory is the level of radioactivity or radiation
that is expected to negatively impact laboratory operations. As this true sample value cannot be
measured with absolute precision, the uncertainty of the measurement method (MMR) as well as an
acceptable level of decision error rate, are also considered when determining an ADL, which is
the measurement value beyond which it is understood that the AAL is likely to have been
exceeded.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
2.4 Determining Appropriate Levels of Personal Protective Equipment
Once the acceptable levels of radioactive materials and radiation are established for the various
areas, the laboratory must designate required PPE that is appropriate for the activity levels,
chemical hazards, and the type of work being performed.
It is not possible, within the scope of this document, to determine appropriate levels of PPE for
the unique situations encountered in each laboratory. As with the designated activity
concentrations, and contamination and exposure levels shown in Table 1, this document provides
only examples for the laboratory to consider in its determination of appropriate levels of PPE.
These examples are shown in Table 3, Suggested PPE for Operational Areas.
Table 3 - Sugc
Long sleeves, pants.
Closed, flat work shoes.
Safety Glasses
Lab Coat
Disposable Gloves
Head Covering
Disposable Lab Coat/Smock
Disposable Shoe Covers (Booties)
Disposable Cuffs
Disposable Gloves (2nd Layer)
Disposable Coveralls
Respiratory Protection (see note)
ested PPE for O
Work Area
Definitions
"55
1 -3 SJ
3 s 3
I 1 l.
_J C£ ±
XXX
XXX
XXX
X X
XXX
1 *
1 x
X
1 *
1 x
X
perational Areas
Important Note: Example requirements for
respiratory protective equipment have been
intentionally omitted from Table 3, as the selection,
training, and use of respiratory protective
equipment are complex and well outside the scope
of this guide. These matters should be carefully
considered by the laboratory's health and safety
professionals, in light of the type of samples,
activity levels, methodologies, and engineering
controls to be used, and should be thoroughly
documented in the laboratory's Radiation
Protection and Respiratory Protection Programs.
Qualified health physicists and industrial hygienists
should be consulted prior to designating the use of
this equipment.
It is important to note, however, that most standard laboratory PPE does not provide adequate
protection from external exposures to gamma or high-energy beta activity. PPE is primarily
designated as protection against chemical hazards, heat/cold and other physical hazards, and as a
mechanism for controlling worker and laboratory contamination. Protection against ionizing
radiation is discussed further in Section 4.0, Exposure Control and Radiation Shielding.
2.5 Laboratory Layout and Process Flow
A key element of laboratory contamination control is the specific and dedicated use of different
areas in the laboratory, with proper consideration to how the activity levels in the various areas
are related and how materials and staff will move from one area to another.
The laboratory should be configured, whenever possible, to reflect the logical flow of operations
and to minimize the impact of potential contamination events. Dedicated work spaces can
26
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
minimize the risk that contamination in one area will impact other processes. The laboratory
should also establish contingency plans for handling out-of-control events, such as sample spills
or broken containers.
In existing facilities, work areas might be reassigned or rearranged to facilitate a more efficient
and controlled environment. In designing new facilities, careful attention should be paid to the
physical layout of the laboratory and the anticipated flow of work through the different areas. In
some cases, separate facilities may be constructed for handling high-level vs. low-level samples.
In combined facilities, it is advantageous to have the low-level processes as remote as feasible
from high-level processes. Related processes should be situated close to one another to minimize
traffic through the work areas, and the flow of work through the laboratory should be smooth,
logical, and efficient. These factors will help minimize incidental contamination issues and help
contain the contamination when it does occur. Appendix A, Planning Considerations for
Laboratory Layout and Process Flow., provides a more detailed discussion of the various
considerations for separating high-level and low-level sample processing areas in a single
laboratory facility. The examples are intended to be illustrative and may be applicable to a wide
variety of laboratory configurations.
Additional information about laboratory configuration, process flow, and other critical elements
in the preparation of a laboratory for response to a radiological or nuclear incident is provided in
the Guide for Laboratories - Identification, Preparation, and Implementation of Core
Operations for Radiological or Nuclear Incident Response (EPA 2010).
2.6 Additional Planning Considerations
In addition to defining operational areas in the laboratory, establishing acceptable levels of
radioactivity and radiation for those areas, determining appropriate levels of PPE, and
considering the layout and process flow in the laboratory, several other important planning
considerations are briefly introduced below.
2.6.1 Controlled Entry/Egress Points
When planning the various work areas in the laboratory, consideration should be made for
existing traffic paths and entryways, as these may be limitations to the intended layout of the
work areas.
Each distinct area type, examples of which are provided in Section 2.1, should have limited and
controlled access and egress points. Further, the points of entry should be distinct and distant
from the points of egress, whenever possible.
2.6.2 Step-Off Pads
The strategic placement and liberal use of adhesive step-off pads or mats will significantly
decrease the risk of laboratory contamination resulting from the migration of radioactive
materials from foot traffic. Step-off pads should be changed frequently to maintain their
effectiveness and should be surveyed prior to removal and disposal so that potential
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
contamination issues may be identified and corrected. The proper use of step-off pads is
discussed in Appendix F, Egress Into a Lower-Activity Area.
2.6.3 PPE Donning/Doffing Areas
Sufficient space should be allotted at the area entry points for the storage of, and access to, the
PPE that is required in that area. Consideration may also need to be given to space for benches,
tables, or other ancillary furniture that will facilitate easy and efficient donning of the required
PPE.
The efficient removal (doffing) of PPE, in a manner that helps prevent laboratory contamination,
should be facilitated by the placement of PPE doffing stations at the controlled egress points.
Doffing areas should include step-off pads, frisking stations, and used PPE and waste
receptacles, as well as ready access to personnel decontamination equipment and a phone or
intercom to summon assistance, if needed.
2.6.4 Frisking Stations
Frisking stations are locations that provide ready access to hand-held survey equipment. The
survey equipment to be used at these stations may be incident-specific. Geiger-Miiller probes,
exposure rate meters, etc., should be selected with consideration of the radionuclide and type of
radiation encountered in the specific incident as well as the detection sensitivity of the instrument
and the ability to meet the operational objectives established by the laboratory. Frisking stations
should be planned for strategic areas throughout the facility, including egress points and
laboratory areas where sample containers, work surfaces, or personnel should be frequently
monitored for contamination.
The layout and location of a frisking station should facilitate the task it is intended to
accomplish:
Frisking stations should be located so as to intercept the movement of potentially
contaminated materials or personnel through the lab. It is necessary to place frisking
stations at the controlled egress points from an area of higher activity to an area of lower
activity, so that personnel and materials can safely move to the lower-activity area. It may
also be desirable to place additional frisking stations within a work area to monitor the
movement of radioactivity within the lab.
Except for the necessary frisking stations at controlled egress points, locating a frisking
station in a high traffic area such as a hallway may increase the risk of contamination to
passing personnel and equipment since potentially contaminated materials are
deliberately brought to the frisking station for survey. Having a frisking station in a high
traffic area may also discourage a thorough survey if the traffic impedes or interferes with
the surveying process. Whenever possible, if a frisking station is to be located in a high
traffic area, it may be advisable to create a small alcove for that purpose, or to allow
sufficient room for traffic to keep well clear of the frisking process.
Frisking stations should be equipped with a table or other surface for placing materials to
be surveyed. The table should be covered with plastic-lined, absorbent, disposable
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
laboratory paper, which should be changed frequently. The surface should be divided into
two areas, one for staging "incoming" materials to be surveyed and the other for "clean"
materials that have been successfully surveyed. If any item is determined to be
contaminated, the item and the "incoming" area should be decontaminated and the
laboratory paper replaced. Consequently, frisking stations should be designed with ready
access to decontamination equipment and supplies, a receptacle for potentially
contaminated waste, and ready access to a phone or intercom system to summon
assistance, if needed.
Frisking stations at controlled egress points should be equipped with hand-held survey
probes necessary for surveying clothing, materials, and other surfaces. In addition,
stationary hand-and-foot monitors may expedite traffic through the area.
2.6.5 Personnel Decontamination Stations
Personnel decontamination stations need not be elaborate or take up significant space beyond a
normal laboratory configuration. A typical decontamination station should be equipped with a
sink for routine hand-washing as well as a shower or drench hose with eyewash station. The
laboratory should ensure that the decontamination area is adequately supplied with:
Hand soap and a chelating detergent;
Disposable sponges, scrub brushes (such as fingernail brushes), and paper towels;
Temporary clothing, such as paper coveralls and booties, in the event that the employee's
clothing must be removed;
A temporary modesty screen, to encourage the disposal of potentially contaminated
clothing prior to leaving the area; and
Receptacles for potentially contaminated clothing and supplies.
The laboratory's Radiation Protection Program should provide additional detailed guidance on
personnel decontamination that is tailored to the specific facilities and to the radioactive
materials and processes in use. These laboratory-specific details are outside the scope of this
document.
2.6.6 Spill Response/Surface Decontamination Equipment
As with personnel decontamination stations, laboratory spill response and surface
decontamination preparedness need not be overly burdensome to the laboratory. Many needed
supplies and equipment will already be on hand for response to chemical spills and
decontamination.
Supplies to address minor decontamination events, such as sample bottles or laboratory bench
surfaces, should be kept in the individual laboratory area and should include:
A chelating detergent in a spray or squeeze bottle;
Disposable wipes;
Paper towels;
A supply of secondary containment bags or bins; and
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Access to a receptacle for potentially contaminated waste.
Equipment and supplies for larger events involving the response to radioactive materials spills
and surface decontamination should be readily available at strategic locations throughout the
laboratory. The primary equipment and supplies will be preferably located on a cart, so that the
materials can be easily brought to the location of the spill/contamination. The cart and its
contents should be clearly marked for use only in spill or contamination response, to prevent
their use in normal housekeeping tasks. The cart and its contents should be frequently inspected,
preferably using a check-off/sign-off document to ensure that adequate supplies are readily
available when needed.
2.6.7 Contamination Follow-Up Protocol
Following a sample spill or other contamination event, it will be necessary to verify that the
affected surfaces, materials, and equipment have been properly decontaminated before they are
approved for use in the laboratory. The laboratory should have established guidelines for re-
surveying potentially contaminated surfaces, etc., documenting the results of those follow-up
surveys, and in some cases obtaining the approval of the RSO or other safety staff before
resuming normal operations.
2.6.8 Additional Shielding Material
The laboratory should establish fixed radiation shielding in those areas where protection from
elevated exposure to beta and gamma radiation is needed. These areas may include the sample
and waste storage areas for high radioactivity materials, selected work stations in the high-level
and routine areas, and the radiation measurement instrumentation area.
In addition to fixed shielding, the laboratory should keep on hand a variety of temporary and
portable shielding devices that will accommodate activity sources that were not anticipated in the
initial planning or the laboratory layout. These devices may include:
Lead bricks or sheets;
Lead pigs or other containers for transporting samples; and
Polycarbonate or acrylic sheets, to be used for beta shielding.
In planning for the laboratory to respond to a radiological or nuclear incident, the availability,
location, and transportation of these additional shielding materials within the laboratory should
be considered. A more thorough discussion of shielding requirements is found in Section 4,
Exposure Control and Radiation Shielding.
2.6.9 Glove Boxes
In some cases, high-activity samples and samples that present a high risk of airborne
contamination should be processed in a glove box. Whether it is a permanent structure or a
temporary glove box located inside a fume hood, the laboratory should ensure that it is large
enough for the intended purpose and properly equipped with all required sample handling and
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decontamination equipment, and that the personnel are adequately trained in the transfer of
material into and out of the box, and the associated surveillance and decontamination practices.
If the laboratory intends to install a glove box, qualified engineering and health physics
professionals should be consulted. The engineering and safety requirements related to the
selection and use of glove boxes are complex and beyond the scope of this guide.
2.7 Changing the Work Area Designation During an Incident Response
The modification of a work area's designation with respect to activity levels, particularly the
change from a higher-level work area to a lower-level work area (e.g., the conversion of a High-
Level Work Area to a Routine-Level Work Area) should generally be discouraged during an
incident response due to the potential for allowing unobserved contamination to remain in the
newly designated lower-level work area. Nonetheless, it is recognized that some modification of
the laboratory's processes may be necessary under certain circumstances.
Prior to allowing an area's designation to be changed from a higher-level work area to a lower-
level work area, a detailed plan should be created by the laboratory that addresses:
which areas will be affected;
how the flow of work through the laboratory will be affected;
which equipment and surfaces in the area under consideration will remain and which will
be removed;
what decontamination protocols will be used on both the remaining equipment and
surfaces, and those to be removed;
which contamination control ADL(C)s will be applicable to the new area (i.e., what the
area-type designation of the new area shall be);
the number and type of surveys that will be necessary to change the area-type
designation; and
the requirements for documentation and approval prior to allowing the work area to be
placed into service under the lower-level designation.
Similarly, the conversion of a lower-level work area to a higher-level designation should require
a plan that addresses the same considerations described above, except that decontamination and
surveillance prior to changing the area-type designation are not necessary in that case.
Any plan for converting laboratory areas should include consideration that materials and
equipment being moved through the laboratory in preparation for the conversion are likely to be
moved through other lower-level work areas, for which lower contamination and exposure limits
apply. Consideration should also be made for the ultimate re-use or disposal of equipment or
materials being removed from higher-level work areas, and for the ultimate return of a newly-
designated higher-level work area to its former lower-level status. Finally, the frequent or
repetitive change of area-types should not be allowed as a routine practice and should not be
considered a reasonable substitute for having sufficient laboratory space and infrastructure to
properly respond to a radiological or nuclear incident.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
3. RADIOACTIVE CONTAMINATION CONTROL
After preparing the physical laboratory to respond to a radiological or nuclear incident, as
described in Section 2.0, the laboratory should consider establishing operational protocols that
provide task-specific instruction to personnel for controlling radioactive contamination and
radiation exposure.
The protocols in the associated appendices are provided as generalized templates only, and are not
intended to prescribe specific requirements for the laboratory. Some of the example protocols provide
great detail simply to illustrate the benefit of a careful and systematic approach to sample handling.
Each laboratory will need to make its own decisions regarding the need for specific protocols, and the
content of those protocols it decides to implement in order to accommodate the unique layout and
established procedures in the laboratory.
These protocols should address the areas of concern related to the handling and control of
elevated levels of radioactivity in samples, waste, and other laboratory materials and the
processing of the large numbers of samples that may be expected during the response to a
radiological or nuclear incident. These areas of concern include:
The appropriate handling of radioactive samples, including the initial receipt of samples,
the proper handling of opened sample material, the isolation of small amounts of material
for further processing, and modified procedures for chemical separations.
The establishment of dedicated equipment for high-activity samples and the use of
detector QC measurements to control and monitor low-level radioanalytical
contamination.
The proper movement of materials and personnel through the laboratory to prevent the
migration of radioactive contamination.
The systematic monitoring and removal of radioactive contamination.
Brief discussions regarding these specific topics are presented below. Example protocols are
presented in the associated appendices.
In establishing protocols for the control of radioactive material, the laboratory may find it useful
to require that additional personnel are readily available to support the primary employee by
providing supplies, recording data, and performing other tasks as needed. This may help to
minimize the number of collateral tasks being performed by the person handling the samples and
other potentially contaminated materials, thereby minimizing the likelihood of laboratory
contamination.
In addition, the establishment of specific protocols will generally require the measurement of
radiation and a comparison of the measurement results to the analytical decision level, as
discussed in Section 2.2. The laboratory should be familiar with the concepts related to MQOs,
ADLs, AALs, etc. Familiarity with the companion guides14 in this series and MARLAP (2004)
14 See Preface.
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Appendix C, Measurement Quality Objectives for Method Uncertainty and Detection and
Quantification Capability., will significantly aid in the understanding and application of these
concepts.
3.1 Sample Handling Protocols
The laboratory should develop protocols for receiving and screening potentially radioactive
materials. Elevated activity samples should be segregated from low-level samples as soon as they
are identified, ideally at the point where they are shipped from the field and before they reach the
laboratory. The laboratory should communicate with the field personnel, where possible, and
make arrangements for segregated shipments, whenever possible. Advance notification from
field personnel regarding the expected delivery of samples, including the number, field screening
information, and a copy of the chain of custody, may assist the laboratory in its preparations for
sample receipt. Samples should be screened as part of the sample receipt process and separated
into low-level and high-level streams, as early as practicable, but prior to their release to the
laboratory for analysis. Field screening results may be considered in the laboratory's initial
receipt of the samples but should not replace laboratory screening protocols. In some cases,
extremely elevated activity levels may necessitate that a sample be rejected for receipt by the
laboratory, or routed to another location for additional processing or sub-sampling prior to
acceptance by the laboratory. Guidance on sample screening, including examples, can be found
in the companion document, Radiological Laboratory Sample Screening Analysis Guide for
Incidents of National Significance (EPA 2009b).
The laboratory should develop protocols for opening, transferring, sub-sampling, and aliquanting
sample material. These protocols should incorporate screening data proactively to ensure
appropriate handling of elevated activity samples, including the isolation of small sample
fractions for processing in lower-activity areas, if necessary.
Sample preparation practices should be reviewed to ensure that they minimize the risk of
laboratory contamination and sample cross-contamination, and incorporate contamination
monitoring and control techniques, where possible. The analytical procedures should ensure that
the risk of detector contamination is minimized, and that such contamination is rapidly identified
and corrected, when it does occur.
3.1.1 Initial Receipt of Radioactive Materials
Upon receipt of sample material or radioactive sources, it is extremely important that an external
dose rate measurement and a survey of the removable surface contamination from the shipping
package be performed. These surveys may be required by federal and applicable state regulations
for certain radioactive materials packages, but they are strongly recommended for the receipt of
all shipments that could potentially contain radioactive materials. In addition, the contents of the
package should be surveyed for removable surface contamination prior to distribution in the
laboratory. Finally, the inside of the package and any packing material may need to be surveyed
prior to disposal, where the survey of the contents indicates potential contamination.
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The laboratory should consider establishing a specific protocol that would be appropriate for the
general receipt of radiological material, with activity and exposure limits that reliably ensure
identification of materials that may compromise the laboratory's established contamination and
exposure limits. An example of a sample receipt protocol is provided in Appendix B, Initial
Receipt of Radioactive Materials. In addition to the limits selected by the laboratory, the
laboratory should be familiar with the requirements of 10 CFR 20, 10 CFR 71, 49 CFR 173, and
other applicable regulations regarding the transportation, receipt, and handling of radioactive
materials packages.
It is recommended that the laboratory develop a standardized form, to be completed with each
shipment, which guides the technician through the various steps of receiving a package. The
form should document the measurements performed and include or reference appropriate action
levels, and instructions for responding to measurements above the action levels. An example of
this type of form is shown in Figure 8, Example of Radioactive Materials Shipments Initial
Survey Results, in Appendix B.
3.1.2 Opening, Transferring, and Aliquanting Sample Material
The opening of the sample container and the removal of sample material present a significant
risk of laboratory contamination, particularly when handling dusty or friable samples, or when
the samples contain discrete radioactive particles (DRPs), also referred to as "hot particles,"
which may become electrostatically charged and therefore difficult to control. Upon receipt in
the laboratory, the sample container may need to be opened and sample material removed for
screening analysis to determine gross activity levels. Decisions regarding the appropriate storage
areas and work locations for the sample should be based on those screening measurements.
The laboratory might consider a protocol that addresses the staging and opening of the sample
containers, the removal of sample material, and the transfer of that material to an appropriate
container for further processing. Issues such as the dedicated use of work areas for specific tasks,
the screening of sample containers, the proper disposal of waste materials, and the ultimate
destination for the removed sample material should be addressed.
An example protocol for this phase of sample handling is provided in Appendix C, Opening,
Transferring, and Aliquanting Sample Material. As in all the examples provided in this guide,
suggestions are offered for the laboratory's consideration, but the laboratory will need to make
its own decisions about the establishment and content of specific protocols.
The example provided in Appendix C is somewhat simplified and is very specific to the transfer
and aliquanting of soil material. It is intended to illustrate particular points regarding the flow of
work, the organization of the work area, suggested practices to control dust and to minimize
laboratory contamination, and surveillance practices to identify contamination events if they
occur. Other laboratory procedures and steps should be examined in the light of these points to
control contamination.
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3.1.3 Isolating Reduced Fractions for Transfer to Lower-Level Work Areas
As discussed in Section 2.2., the laboratory will benefit from designating specific areas for the
handling of sample materials with pre-set activity ranges. Nonetheless, it is recognized that not
all laboratories will be able to establish redundant facilities in multiple areas for all tasks. Where
laboratory facilities are limited, it may be helpful in some cases to isolate a small, representative
aliquant of a highly radioactive sample to be brought into the lower-level work areas for
processing. This may be done in a small High-Level Work Area in the laboratory, or may even
be done in a remote facility, separate from the analytical laboratory.
If the desired target aliquant is large enough that it can be taken directly from the bulk sample
and an accurate measurement of a representative subsample may be reasonably expected, the
laboratory might allow the procedures described in Appendix C to be followed. If the desired
target aliquant is very small, a reliable measurement of the aliquant size may be difficult or the
homogeneity of the aliquant may not be assured. In such cases, a larger intermediate aliquant
may need to be taken, digested, or diluted, and a fraction of the final digestate/solution then
taken that is equivalent to the target aliquant. In these cases, the accuracy of any dilutions
performed will be improved and the uncertainty of the final concentration minimized if the initial
sample amount and the digestate solution taken for analysis are measured gravimetrically. An
example protocol is briefly described in Appendix D, Isolating Reduced Fractions for Transfer
to Lower-Level Areas, and is carried out in the laboratory fume hood configuration described in
Appendix C.
In this relatively simple manner, a larger subsample of the original material may be further
divided into much smaller representative aliquants that may contain micrograms or microliters,
or less, of the original sample. The reduced aliquant with the associated reduced activity level
may then be brought into lower-level work areas for processing.
3.1.4 Sample Preparation and Chemical Separation Processes
Where possible, the laboratory's sample preparation and chemical separation procedures should be
flexible enough to allow the laboratory to accommodate both pre-established incident response MQOs
and incident-specific MQOs. The laboratory's procedures should incorporate the collection, review,
and communication of screening data proactively to ensure the appropriate handling and aliquanting of
elevated activity samples. Laboratories with pre-established digestion and dilution protocols that use
screening results as "trigger" points will save time during sample preparation. At the same time, this
process ensures that the total activity handled during sample processing is decreased and that the
subsequent decontamination of labware, equipment, and detectors is minimized.
If a sample must be processed to separate and purify radionuclide(s) of interest, measures should
be taken to detect and minimize cross-contamination. While specific measures taken should
reflect the needs and vulnerabilities of each operation, examples of typical measures could
include:
Minimizing the levels of activity, based on screening results, that may be handled in any area
or specific operation;
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Grinding solid samples using equipment such as paint shakers or ball mills, which minimize
the release of particulates into the air;
Maximizing the use of disposable labware for high-level work, and segregating labware and
equipment for low-level work from that for high-level work;
Providing dedicated facilities for cleaning low- and high-activity labware and equipment;
Making provisions to test the effectiveness of cleaning/decontamination, such as analyzing
rinse waters or performing equipment blanks;
Establishing a system to identify equipment used and the sequence in which samples were
prepared to facilitate corrective action whenever unexpected high activity is identified later
in the process;
Using plastic-backed, bench/hood absorbent paper liners in preparation areas;
Pre-treating fume hoods or other surfaces with a strippable coating, which proactively
enables effective decontamination;15 and
Identifying housekeeping expectations and responsibilities and setting a schedule for keeping
work areas clean.
3.1.5 Instrumentation and Radioanalytical Controls
The purpose of radioanalytical contamination control is to protect the quality of the results and to
ensure that the required radiochemistry MQOs are met. The levels of contamination that
significantly affect the quality of the data are generally much lower than those needed to protect
the health of laboratory personnel. Effective radioanalytical contamination control will, by
default, minimize personnel contamination and simplify decontamination efforts, both of which
have significant impacts on the sample throughput and laboratory staff morale.
The starting point for effective radioanalytical contamination control is good laboratory
practices. However, good laboratory practices which may be sufficient for routine operations
may not be sufficient when high-level activity samples are processed. Contamination control
measures, initiated during the receipt and processing of the samples, should be continued during
the analytical process to maintain the integrity of the laboratory.
Such measures should be proactive, and the initiation of corrective actions should take place
before contamination becomes a detrimental factor to laboratory processes and jeopardizes the
reliability of the data. Implemented measures should reflect the needs and vulnerabilities of each
operation. Examples of measures to protect the integrity of the counting instrumentation and the
resulting measurements include:
Logging sample IDs in the order of preparation for non-disposable equipment (e.g., grinders,
glassware, etc.) to facilitate investigation of potential cross-contamination;
Protecting gamma-ray detectors by bagging samples, detectors, or both;
15 Additional information on the use and efficacy of strippable coatings may be found in Section 3.2 of the
companion document, A Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological
or Nuclear Incident (EPA 2011).
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Swipe-testing certain sealed sample test sources, such as bagged gamma test sources or liquid
scintillation vials, prior to their transfer to the nuclear instrumentation room, to verify the
lack of removable surface contamination;
Screening sample test sources to identify excessively high-activity samples prior to
introduction into detectors;
Designating detectors for low and high-activity samples;
Designating detectors for specific analytes, especially those analytes that are susceptible to
interference from the residual effects of other analyses performed in the same detectors (e.g.,
americium and plutonium results by alpha spectrometry may be biased by the residual effects
of short-lived uranium and thorium progeny contamination on the detector);
Establishing AALs, MQOs, and ADLs for investigation and corrective action (e.g., sample
count rate or final sample activity exceeds pre-established criteria);
Removing high-activity samples from gas proportional counters and alpha spectrometers as
soon as the count is finished;
Checking detector background after exposure to high-activity samples, after first defining
"high activity" as it pertains to levels that may cause radioanalytical concerns;
Periodically performing removable surface contamination surveys on gamma detectors to
QO 9^Q
assess contamination from non-gamma-emitting radionuclides (e.g., Sr, Pu) on sample
containers and other laboratory surfaces; and
Increasing emphasis on tracking and trending of detector background count rates and method
blank results.
In some cases, the laboratory may perform periodic cleaning of certain detector components,
such as alpha or gamma spectrometer detectors. The laboratory should establish acceptable
protocols for the periodic maintenance of detector systems. In addition, the laboratory should
ensure that appropriate quality control checks are performed prior to cleaning and maintenance,
to support the data acquired prior to any potential changes to the detector system, as well as
ensuring that new background calibrations are performed after cleaning but prior to resuming
sample analyses.
3.2 Movement Between Laboratory Areas (Entry/Egress)
After the laboratory defines and delineates the various types of work areas, as described in
Section 2.1, it is recommended that protocols be established for movement between the areas.
These protocols should be designed to minimize the risk of contamination to personnel, samples,
supplies, and equipment, and to facilitate the isolation and removal of such contamination, if it
occurs.
Entrance and egress points should be well defined and, whenever possible, separate. It is
recognized, however, that separate entrance and egress points are not always possible in all
laboratory settings, and that a single entryway or doorway will often need to serve both purposes.
When moving between areas of different activity levels, precautions should be taken to protect
both the workers and the materials from contamination. In specifying these precautions, the
laboratory should ensure that the employees are well trained in the protocols and that those
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protocols are thorough, but not unnecessarily burdensome. Overly burdensome guidelines,
whose purpose is not immediately obvious, may be circumvented or ignored by the staff.
When providing training for entry and egress protocols, the following points should be
emphasized:
Individuals should be mindful that entry into an area of higher radioactivity will
necessitate the eventual exiting from that area, with the associated egress protocols, and
that entry is always easier and faster than egress.
Any movement from an area of higher radioactivity to an area of lower radioactivity
entails the risk of contamination to the personnel, samples, supplies, and equipment in the
lower-activity area. Consequently, any transition should be carefully considered and
planned to minimize the number of trips and the unnecessary movement of materials into
(and out of) an area.
No material should be removed from a higher-activity area to a lower-activity area unless
it has been surveyed and determined to meet the entrance criteria for the lower-activity
area and decontaminated, if necessary.
Where possible, additional equipment should be procured in order to minimize the need
to move equipment between different types of areas, especially where the risk of
contamination to the equipment or the area is high.
As there is no effective decontamination for sample material, any sample material
processed in a higher level area may need to be screened or sub-sampled in order to allow
its entry into a lower-activity area. This is time consuming and should be avoided
whenever possible. Sample materials transiting an area should remain properly sealed.
Having noted the preceding points, the laboratory may wish to develop specific protocols to
guide personnel in their entry to and egress from specific areas in the laboratory.
3.2.1 Entry Into a Higher-Activity Area
When entering a higher-activity area from a lower-activity area, as when moving from the
instrumentation laboratory to sample preparation lab, the primary concern should be the
protection of the employee and the materials being moved from the potential sources of
contamination in the higher-activity areas. There is little concern that the materials or supplies
entering the higher levels area will contaminate that area because they begin in the lower level
areas, and it is assumed that the materials have met the criteria for those areas. Consequently,
entering a higher level area from a lower level area need not entail contamination surveillance,
such as screening or frisking practices, or decontamination protocols.
It may be helpful for the laboratory to ensure that the entry area, immediately outside the higher-
activity area access point, is equipped with the following items:
Lockers, cubbies, bins, or other containers for storing personal items that are not to be
transported into the area;
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An ample supply of PPE items required for entry. This may include a selection of gloves,
shoe covers, disposable coveralls, etc.; and
A table or other surface for staging materials.
When entering the higher level area, the materials being moved into that area should be carefully
considered. The number of trips back and forth should be minimized and no unnecessary items,
such as redundant supplies or unneeded packing materials, should be taken into the area as these
items present an unnecessary contamination risk.
Appendix E, Entry Into a Higher-Activity Area, provides an example of the type of protocol a
laboratory may establish for transiting from a lower-activity area to a higher-activity area. Each
laboratory should specify the entry protocol for each area, which will depend greatly on how the
area types are defined, what activity levels are specified, and what type of PPE is required.
3.2.2 Egress Into a Lower-Activity Area
When leaving a higher-activity area, the primary concerns should be the containment of any
radioactive materials being moved, and the assessment and control of contamination on the
employee and the materials being moved. The goal is to prevent the migration of any potential
contamination into the lower-activity area, which would expose lower level sample materials,
laboratory facilities, and unprotected employees to the contamination source.
The protocols for egress from a higher-activity area will necessarily be more complex than the
entry protocols. It may be useful to ensure that additional personnel are available to assist the
egress process, including decontamination activities, if needed. An example protocol for moving
personnel and materials from a higher level area to a lower level area is provided in Appendix F,
Egress Into a Lower-Activity Area. As with other example protocols, this is based on a
hypothetical laboratory operation, under very specific operating conditions, and is intended only
as an example on which a laboratory might choose to base its own protocols.
The egress area should have provisions for contamination surveillance, removal of PPE, and the
effective decontamination of items that are identified as contaminated. An example layout for an
egress area is shown in Figure 11 of Appendix F.
3.3 Laboratory Contamination Monitoring and Control
In order to detect, control, and prevent the spread of radioactive contamination in the laboratory,
a fully functional Radiological Controls Program should be implemented. This program must
address low levels of radiological contamination that also present radioanalytical problems for
the laboratory.
In some cases, the spread of cross-contamination as low as 0.25-1 pCi for beta/gamma-emitting
nuclides and 0.1 pCi for alpha-emitting nuclides could lead to the reporting of erroneous results
for low-level environmental samples and allow low levels of contamination to escape outside of
the radiologically controlled area.
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A laboratory's established radiological monitoring program should provide for adequate
monitoring during normal operations and should include additional provisions for monitoring
when handling samples that contain concentrations of radioactive contaminants well above those
normally processed. These additional provisions could include increasing the frequency of
surveys as a function of the activity level and number of samples processed, and expanding the
areas of concern to include:
Hallways, sample receipt area (inside and outside), and even administration areas;
Inaccessible areas, such as laboratory hoods (including ductwork, fans, and exhaust stacks),
floor drains, sink drains, and traps;
Hood filters, and hood scrubber waste water; and
Building external locations, such as the roof, loading and receiving docks, and the nearest
sanitary or storm drains into which building liquid discharges are directed.
Surveys can be performed using portable survey meters, taking swipe samples, or taking grab
samples, if appropriate. Additional information regarding contamination and dose can be
obtained from ambient air monitoring of sample receipt and high-activity sample processing
areas and from samples of mop water and step-off pads.
It is important to establish baseline activity values for these measurements under current
laboratory conditions. Because some of these surveys may not be performed during routine
operations of the laboratory, it may be necessary to develop and implement documented
procedures to identify critical areas, and approaches to performing non-routine surveys. This also
means that data should be collected for all sample locations, so that a baseline and an action level
are established for each type of measurement and location. Any data collected during the
incident response period should be evaluated against this baseline, assessed quickly, and
followed with appropriate response, such as additional surveys or cleanup to minimize exposure,
protect the integrity of samples and radioanalytical measurements, and prevent laboratory
contamination or releases of radioactive materials to the environment.
Radiological monitoring of designated areas should take place at specified frequencies,16 with
specified sampling and measurement techniques, using pre-determined MQOs. Examples of
these important components of a radiological monitoring program are provided in Appendix G,
Active Radiological Monitoring Program for Contamination Control. Specific procedures for
surveillance and decontamination of laboratory surfaces, equipment, and personnel are discussed
in the following sections.
16 Guidance on strategies for establishing survey frequencies was issued by the U.S. Nuclear Regulatory
Commission (NRC, 1999: NUREG 1556, vol. 11), but each laboratory should develop its own program. The
approach should also keep in mind that the NUREG document is focused primarily on human health concerns,
although much lower levels of radioactive contamination may be of concern in radioanalytical facilities where
measurements of low-level radioactivity are being performed.
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3.3.1 Surveillance of Laboratory Surfaces and Equipment
Surveillance of laboratory surfaces and equipment should employ both hand-held survey
equipment and laboratory swipes. Section 2.2 and Appendix G discuss the need to establish
acceptable levels of fixed and removable contamination17 and associated survey MQOs in the
various area types prior to accepting samples from a radiological or nuclear incident. Note that in
the transfer of materials from a higher-activity area to a lower-activity area, the contamination
limits must satisfy the requirements of the lower activity before the materials leave the higher-
activity area.
3.3.1.1 Fixed Contamination Surveys
Fixed contamination surveys, using hand-held
survey instruments, should be required on all
potentially affected surfaces that present a risk
of exposing laboratory workers to radiation
above the limits specified in the area
descriptions or causing elevated or unstable
background levels that may adversely affect
instrumentation. Laboratory surfaces should
be surveyed periodically and after any
necessary decontamination efforts. All
materials, such as laboratory equipment,
paperwork, samples, etc., that are being
moved from a high-activity level area to a
lower-activity level area should also be
surveyed. In some instances, it may be useful
to survey sample test sources that have been prepared in a high-activity level area, prior to
transferring those samples to a lower-activity level area.
The laboratory should ensure that the hand-held survey instrument selected for use is appropriate
to the type of radiation expected in the samples from the incident. If the type of potential
contamination is uncertain or if the samples from the incident involve multiple types of radiation,
the surface may need to be surveyed repeatedly using the different instrument types. When
possible, survey equipment should be calibrated with the radionuclide of interest or an
appropriate conversion factor should be determined. Additional guidance on the calibration and
use of hand-held survey equipment is provided in Radiological Laboratory Sample Screening
Analysis Guide for Incidents of National Significance (EPA 2009).
While the laboratory will have established procedures for the calibration and use of hand-held
survey equipment, the actual implementation of these procedures can be highly technique-
"Fixing" Contamination In Place
The use of paints, epoxies, and other coatings to
affix contamination to a surface permanently or
semi-permanently may be a viable option for alpha
and low-energy beta contamination in cases where
the fixed-in-place radionuclides pose no external
dose risk to personnel. These techniques can be
especially useful when the contaminated surface is
difficult to clean (e.g., porous concrete, wood, etc.)
but replacement costs are prohibitive. Careful
records must be kept to
decommissioning activities
fixed contamination areas
identified in the laboratory.
assist any eventual
in the facility, and
should be clearly
17 For purposes of this document, "fixed" contamination refers to the portion of contamination that remains attached
to a surface after reasonable attempts to clean or decontaminate that surface. Contamination that is fixed to the
surface is usually of concern only as a source of external exposure unless it becomes loose and is redistributed.
"Removable" contamination is transferable by contact, inhalation, or ingestion. The amount of removable
contamination usually is determined by obtaining swipe samples (EPA 2011).
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dependent, and the instrument results can vary significantly from one user to another. The
response of any hand-held survey instrument, particularly those measuring alpha and beta
radiation, to a radioactive source is dependent on the orientation and distance of the probe to the
surface being measured, which may be different for each person unless steps are taken to ensure
uniformity in the use of these instruments. Instrument check sources, therefore, should be
measured by each technician daily or prior to use. The frequent measurement of check sources
and the comparison of the results to established acceptance criteria by each individual technician
performing the surveys may help to ensure consistency in the use of the instruments.
3.3.1.2 Removable Surface Contamination (Swipe) Surveys
The collection and analysis of swipes is intended to identify removable surface contamination. In
general, a swipe survey is performed by selecting an appropriate swiping material, such as a
paper or glass fiber filter. The swipe may be used dry or may be wetted with an appropriate
agent, and is then drawn across a pre-determined area of the potentially contaminated surface.
The swipe is then analyzed with an appropriately calibrated instrument, such as a gas
proportional counter, liquid scintillation counter, or gamma spectrometer. Results are usually
reported in activity units per swipe or per unit area swiped.
Swipes specifically designed for radiological surveys are commercially available, in a variety of
materials, with or without adhesive backing for planchet mounting, and soluble in liquid
scintillation cocktail, if desired.
The laboratory should develop and validate procedures for performing swipe surveys that are
specifically suited to the surfaces and the type of radiological material in use. Those procedures
should be specifically designed to meet the MQOs of the survey, which are in turn based on the
type of area being surveyed and the activity levels employed there. Those procedures should be
sufficiently clear and straightforward to ensure that appropriately trained personnel responsible
for performing a survey for radioactive contamination can properly select and use the survey
equipment and other necessary instrumentation.
Additional information and suggestions for the implementation of radiological surveys, including
example forms for recording survey data, are included in Appendix H, Surveillance of
Laboratory Surfaces and Equipment.
Due to the wide variety of survey equipment, swipe materials, and swipe analysis techniques,
this guide does not address the use of specific equipment or the performance of specific
analytical practices. Where specific techniques are discussed in Appendix H, they are provided
only as examples and should be carefully reviewed by the laboratory technical management staff
to determine applicability to the specific laboratory conditions.
Detailed guidance for performing swipe surveys is provided in the companion document A
Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological or
Nuclear Incident (EPA 2011) and in the Multi-Agency Radiation Survey and Assessment of
Materials and Equipment Manual (MARSAME 2009).
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3.3.2 Decontamination of Laboratory Surfaces and Equipment
Decontamination procedures for surfaces in the laboratory will generally be limited to non-
porous surfaces that can be readily cleaned with conventional methods. It is therefore important
that the laboratory restrict the use of absorbent or porous materials, such as fabric or unfinished
wood, to those absolutely necessary to the laboratory operations. Absorbent or porous surfaces
are difficult, and frequently impossible, to decontaminate to acceptable levels after a
contamination incident. These items must then be disposed of as radioactive waste, which may
be difficult and expensive. If such items or surfaces must be used, they should be coated to the
extent possible with a non-absorbent covering. For example, if a wood pallet is needed to bring
new equipment into the hot zone, the pallet may be covered with Tyvek to reduce the risk of
contaminating the pallet.
Appendix I, Decontamination of Laboratory Surfaces and Equipment., is an example protocol
intended to provide guidance for the decontamination of laboratory surfaces. In developing its
own protocols, the laboratory will consider the types of surfaces, work areas, etc., that may be
unique to that facility.
3.4 Personnel Contamination Monitoring and Control
Personnel contamination monitoring and control are critical to the control of radioanalytical
contamination in the laboratory, and should be a significant component of the existing radiation
protection program. The three major components of personnel contamination control are
prevention, monitoring for personnel contamination, and the effective decontamination of
personnel should contamination occur. Depending on the existing contamination control
practices in place in the laboratory, some of the measures listed below might already be in place,
while others should be planned prior to, and implemented during, incident response activities. In
any case, all routine practices and any additional personnel contamination control practices that
might be put into effect during incident response situations should be accompanied by detailed
and clearly written SOPs. The laboratory staff should be trained in these procedures, and the
training should be documented.
3.4.1 Personnel Contamination Prevention
The spread of very low-level radioanalytical contamination as a result of staff activities can
occur easily and is difficult to detect. Very often, practices that have no serious consequences in
a laboratory used for the analysis of stable metals or environmental organic contaminants may
significantly impact the quality of radioanalytical data. For example, uncontrolled movement of
personnel or materials from one area to another may result in spread of contamination and, even
in very low amounts, may increase the instrument background and adversely affect detection
limits. It may be advisable to consider limiting staff to specific functions and work areas. To
continue the example, analysts working with open sample containers who are thus potentially
exposed to radioanalytical contamination should be precluded from entering the instrumentation
area, where the sample test sources are counted and where maintaining low background is most
critical.
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Some of the additional recommended practices listed below are not intuitive, and others are
simply "good laboratory practices," but all need to be considered when planning for incident
response activities involving samples with increased levels of radioactivity:
Single use of disposable gloves when handling samples;
Removal and disposal of gloves when moving from a hood area to a laboratory bench
area;
Frisking of laboratory coats prior to and after use;
Frequent change of laboratory coats (and subsequent laundering or disposal depending
upon the laboratory situation);
Proper use of laboratory coats (i.e., keeping them buttoned and with sleeves rolled down
and used only when not compromised);
Careful placement of contaminated materials into disposal containers (as opposed to
dropping them in or overfilling) to avoid spread of contamination through release of
particulates into the air;
Removal of gloves and frisking of hands before touching non-contaminated items (e.g.,
telephones, computers, cabinets, drawers, doorknobs, reference texts, etc.);
Review of personal hygiene and taking appropriate protective measures, such as tying
back or covering loose hair with disposable caps, removing threadbare or compromised
garments, removing loose jewelry, wearing appropriate footwear, and covering wounds
securely; and
Identifying the procedures and having equipment in place for a rapid decontamination of
personnel, clothing, and other items.
3.4.2 Personnel Contamination Surveillance
Contamination survey procedures for personnel are identical to those used for fixed
contamination surveys of laboratory surfaces, described above. Additional procedural guidance
is recommended, however, to ensure that the individual surveying him/herself does not
inadvertently contaminate the survey equipment.
Radiological surveys of laboratory personnel should be conducted after handling radiological
material, before leaving the work area. In addition, surveys of the hands, arms, or other pertinent
areas may be performed frequently during the handling of radiological material to detect and
prevent the spread of contamination during the process. Frequent personnel surveys may also
help maintain control of radiological material within a small work area such as a fume hood,
where the integrity of low-activity zones within the hood itself may be important for
radioanalytical contamination control.
While the laboratory will develop its own personnel surveillance protocols, those found in
Appendix F, Egress Into a Lower-Activity Area, may be helpful.
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Specific requirements for personnel contamination monitoring depend on the level of activity
expected and the potential for radiation exposure during handling. These requirements should be
considered for every staff member and every visitor and must be identified in the RPP. In
incident response situations accompanied by the potential of increased exposure, additional
considerations might include:
Implementation or increased frequency of monitoring of external exposure using
thermoluminescence dosimeters (TLDs) and finger rings, including potential use of real
time dosimetry when working with significantly elevated levels of radiation.
Implementation or increased frequency of monitoring of internal exposure using
techniques such as in-vivo and in-vitro bioassay and air sampling. An arrangement with
an outside laboratory specializing in in-vivo and in-vitro radiobioassay analyses may be
necessary, unless in-house capability is available.
Increased frequency of exposure reporting. In addition to more timely warnings of
increased worker exposure, this may have the added benefit of providing frequent
reminders to workers that work habits impact exposure control.
Additional personnel contamination surveillance information can be found in the U.S. DOE
Radiological Control Manual (DOE, 1994).
3.4.3 Personnel Decontamination
Any instance of personnel contamination should be reported immediately to the laboratory's
Radiation Safety Officer, or other qualified response personnel identified by the laboratory. In
general, personnel decontamination efforts consist of removing the contaminated article of PPE
or personal clothing, as appropriate. In cases where the employee is found to be directly
contaminated, the decontamination procedure may be similar to that used for chemical
decontamination of personnel. A discussion of typical equipment and supplies for personnel
decontamination stations is provided in Section 2.5.
The procedure should consider whether movement to another area or decontamination in place is
most appropriate. In some situations, the employee's movements through the work areas should
be restricted to prevent the spread of contamination through the laboratory, unless there is urgent
need to move the employee to another location, such as a chemical shower. In other cases,
moving the employee to a contained decontamination area may be the most effective way to
protect the laboratory and other personnel and to facilitate decontamination of the affected
individual(s).
The laboratory should develop protocols for personnel decontamination that address the specific
sample materials, reagents, and radionuclides involved in the incident response. The combined
issues of radiological and chemical exposures, and medical treatment and surveillance are
beyond the scope of this guide. A qualified health physicist, industrial hygienist, and
occupational medical professional, as appropriate, should be involved in the development of
personnel decontamination protocols.
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Hospital and Emergency Medical Treatment
In the event that radiologically contaminated personnel require urgent medical attention, emergency
response and hospital workers will need to treat and transport those contaminated personnel. The
laboratory should coordinate, in advance, with hospital and emergency room personnel to ensure that
those facilities are willing and prepared to receive and treat contaminated personnel. In some cases,
the laboratory may need to provide decontamination and surveillance support at the hospital.
4. EXPOSURE CONTROL AND RADIATION SHIELDING
ALARA
TIME, DISTANCE, SHIELDING
The information in this section assumes a basic
understanding of the physical properties of alpha, beta,
and gamma radiation. Federal regulations18 require that
laboratory personnel receive sufficiently detailed
training in these and related issues, prior to being
allowed to work in a radiologically controlled area,
such as the laboratory areas described in this guide.
Nonetheless, a complete and detailed discussion of the
subject of radiation protection and dose reduction is
complex and well beyond the scope of this guide, and
should be referred to a qualified health physicist,
particularly in cases where elevated activity levels are
encountered and a measurable radiation dose may be
received by laboratory personnel.
4.1 ALARA Principles
In all cases, a worker's exposure to radiation and radioactive materials should be kept As Low
As Reasonably Achievable (ALARA). Any shielding techniques employed by the laboratory
should be considered in this broader context of ALARA, which should take into account
practices that maximize the distance between the source of radiation and the worker or equipment
affected, and that minimize the amount of time spent in proximity to the source of radiation.
These time and distance factors should be considered and optimized prior to making decisions
about shielding requirements.
4.2 General Shielding Information
Despite the detailed level of training that a laboratory worker may receive prior to handling
radioactive materials, the subject of shielding radioactive sources to prevent exposure to
personnel is conceptually complex due to the various interactions between the primary radiation
and the material through which it travels. This often results in additional, secondary sources of
radiation that should also be considered. Consequently, the laboratory should be initially content
with a simplified first-order approximation of the shielding requirements, and then be prepared to
make minor adjustments based on actual survey measurements performed during the initial
10 CFR 20 and 29 USC 654,(b)(l), § 5(a)(l).
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
phases of the project. This empirical approach will expedite the initial setup of the laboratory and
facilitate improved responsiveness to changing laboratory conditions.
In the selection of shielding materials, the laboratory should ensure that all shielding material is
of sturdy construction and impervious to penetration by the radiological sample material, and
that the outer surfaces are able to be easily decontaminated. Fabric, paper, cardboard, and similar
materials, though capable of providing adequate shielding from alpha and beta radiation, should
not be used because they cannot be effectively decontaminated.
The effectiveness of any shielding measures will be determined primarily by performing area
surveys with hand-held survey meters. The employees must be adequately trained in the use of
hand-held survey meters and the interpretation of the results.
When considering shielding requirements in the laboratory, the source and type of radiation
should be carefully considered. Improperly shielded beta activity can actually increase the risk of
exposure to the workers and the laboratory equipment, and unnecessary gamma shielding can be
expensive and unwieldy. A thorough knowledge of the details of the radiological or nuclear
incident and continuous vigilance in the performance of laboratory radiation surveys will help in
the selection and use of shielding that is appropriate to the project.
In determining appropriate shielding requirements for different types of radiation, two relatively
simple concepts are typically employed. The first is that of the "range" of particle radiation,
which is the average distance that a particle will travel through a specific type of shielding. The
range of an emitted particle is dependent on the type of particle, its emission energy, and the
material used to construct the shielding. Most alpha particles, for example, have a limited range
of less than 10 centimeters in air. The second concept is the "half-value layer," which will be
applied to gamma radiation. Simply stated, the half-value layer is the thickness of a given
material that will reduce the intensity of the gamma radiation to one-half of its original value.
These values are entirely dependent on the gamma emission energy and the type of shielding
employed. For example, if 137Cs is the source term radionuclide in a radiological or nuclear
incident, the intensity of the resulting 662 keV gamma emissions from the sample material will
be reduced to one-half of its original value by using a 6.3-mm thick layer of lead shielding. The
half-value layer and other analogous measures, such as the 1/10* value layer, are commonly
used to decide the thickness of shielding material needed to provide adequate protection.
An additional consideration in the design and implementation of radiation shielding is the
occupancy of the personnel, or the amount of time that an individual spends in close proximity to
the radiation source. Areas with a low occupancy, such as waste storage areas, may require less
shielding than areas in which a worker spends the majority of his/her time, although these low
occupancy areas still require appropriate posting and dose rate monitoring.
The examples provided below are intended to illustrate possible solutions to shielding
requirements in the laboratory. Every actual laboratory situation, however, is likely to be unique
and will require solutions that are tailored to those specific laboratory conditions.
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4.2.1 Alpha Shielding
Shielding against alpha radiation is not a concern in a radiological laboratory. The range of any
alpha particle through a solid material, such as a glass or polypropylene sample container, will be
much less than the thickness of the container. For stored materials, the sample, waste, or source
container provides adequate shielding against alpha radiation. For in-process materials, where
the primary health concern is the inhalation or ingestion of alpha-emitting radionuclides, worker
protection is ensured by the use of appropriate engineering controls such as the laboratory fume
hood as well as PPE. Nearby instrumentation is unaffected because the instrument housing
effectively blocks all alpha radiation.
4.2.2 Beta Shielding
Beta shielding should address two primary concerns: protection against the effects of the beta
particle itself and protection from the bremsstrahlung (photon) radiation that is produced when
the velocity of a beta particle is changed suddenly, as when thin sheets of metal are used for
shielding. Whenever possible, primary beta shielding should minimize the production of
bremsstrahlung radiation by employing material of a low atomic number (Z), such as
polycarbonate, instead of high-Z material such as lead. Even in low-Z material, however, the
production of bremsstrahlung radiation may be high enough to require secondary shielding. In
these cases, a high-Z secondary shielding material, such as lead, is placed between the primary
shielding and the area to be shielded. When handling and storing beta-emitting radionuclides,
careful surveillance of both the beta and gamma field near the material is required, even when
the radionuclide is known to be only a beta-emitter, with no associated gamma emissions, such
as 90Sr/Y.
The storage conditions should be considered when determining the need for shielding beta-
emitting materials. Most beta particles will have a range of less than 100 cm in air, and a much
smaller range of less than 1-2 cm in solid materials. The laboratory should have on hand an
adequate supply of conveniently sized 0.25-0.5-cm thick plastic panels, to be used for additional
beta shielding, as needed.
If the storage conditions are such that
The beta-emitting material is stored in durable glass or plastic containers;
Sufficient distance is maintained between the radiological material and the laboratory
personnel and equipment; and
The employee presence in the storage area is minimal
it may be preferable to avoid the use of additional shielding material in very close proximity to
the samples. This may reduce the production of bremsstrahlung radiation and avoid the need for
additional shielding material.
Beta shielding for work in progress should consist of a low-Z material, such as polycarbonate
sheets or an enclosure such as a glove box. The material should be clear to allow the sample to
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be seen during handling and should be configured to allow necessary access of the hands while
protecting the rest of the worker's body, particularly the face and any other exposed parts. In
some cases, when shielding high energy beta sources results in the production of excessive
bremsstrahlung radiation, an additional layer of leaded glass may provide sufficient protection
while maintaining visibility and access to the sample.
Shielding the hands of the individual handling the sample material, although often neglected, can
be readily achieved with a second layer of durable gloves, such as butyl rubber.
Radiation detection instrumentation rarely requires additional beta shielding for the same reason
that alpha shielding is not required. For most beta particle measuring instrumentation used in the
laboratory, the detector's housing generally reduces or eliminates external beta radiation.
The need for beta shielding in any given situation will be difficult to predict, due to the self-
absorption by the samples and their containers, and should be determined by empirical
measurement of the beta radiation in the area. In addition, gamma radiation measurements
should be performed regularly, after the beta sources and shielding are in place, to determine the
need for additional shielding of the resulting bremsstrahlung radiation.
4.3 Gamma Shielding of Storage Areas
Gamma radiation is, by far, the most likely type of radiation that will require additional shielding
measures due primarily to the penetrating nature of gamma photons. Gamma shielding, which
necessarily consists of massive material such as lead bricks and panels, is not always easily
moved and may be in limited supply in the laboratory.
Prior to accepting samples from a radiological or nuclear incident, the laboratory should make an
initial estimate of the amount of shielding that is likely to be required. This estimate should
account for the volume of space to be shielded; the placement, number, and activity levels of the
sample material; and the projected waste streams. The laboratory may want to enlist the
assistance of a qualified health physicist to perform this estimate.
Due to the expense and the difficulty in moving some shielding materials, some generalized
considerations for designing gamma shielding for storage areas are discussed below.
4.3.1 Use of Buffer Zones and Other Unoccupied Spaces
Figure 1 shows an example of sample and waste storage areas in a laboratory diagram excerpted
from Appendix A, Planning Considerations for Laboratory Layout and Process Flow. The large
arrows represent the exposure gradient that might be expected, based on the amount of shielding
provided, with the darker areas representing areas of high gamma exposure and the lighter areas
representing lower levels. Notice that the less shielding provided, the more distance is required
for the gamma field to be reduced to lower levels.
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PORTABLE
SHEILDING
Waste
Accumulation
Area
Sample
Storage
Area ^
INCOMING TRAFFIC AREA
Rad waste receptacle
Frisker
' i = Gamma Shielding
A= Example of shielding that
allows continued access
Exposure
Gradient
Figure 1 - Example of Shielding Considerations in Sample and Waste Storage Areas
4.3.2 Consideration of the Occupancy of Affected Areas
Inside the building, the laboratory may consider the occupancy factor expected in adjacent areas.
In the example shown in Figure 1, it is assumed that the sample staging area is a transitional
holding area for samples that are about to be processed, and that the time the workers spend in
this area is minimal. Consequently, shielding requirements for this area may be reduced. These
areas, however, still require appropriate posting and dose rate monitoring.
Similarly, shielding inside the storage areas has been kept to a minimum in this example, on the
assumption that the time any worker spends inside the actual storage areas is limited. In some
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
instances, however, this may not be the case. For example, if the laboratory employs a sample
custodian whose primary responsibilities are to manage the samples inside the storage areas,
additional shielding may be required inside the storage area to protect the worker during the
considerable time spent inside that area.
Unlike the unoccupied buffer zones or areas with low occupancy, the sample receiving area may
be continually occupied and must be adequately shielded from the radiation in the adjacent room.
The effect of occupancy may be considered arithmetically. First, assign an occupancy factor that
is equal to the fraction of time that the area in question is occupied. In the above example of the
sample staging area, the area is occupied only 20 percent of the time, which is equal to
occupancy factor of 0.20. Next, determine the acceptable level of exposure in that area by
dividing the usual acceptable exposure level by the occupancy factor. The application of any
occupancy factor less than 1.0 to allow exceptions to the acceptable exposure levels in any area
should be reviewed and approved by the laboratory's RSO or health physicist.
4.3.3 Strategic Placement of Gamma Shielding Materials
After considering buffer zones and pertinent occupancy factors, shielding should be placed as
needed to prevent exceeding the maximum exposure levels stated in the laboratory's area
definitions. The placement of shielding should also optimize the stability of the background
levels in nearby instrumentation.
In some cases, it may be more convenient to place the shielding outside the area. Figure 1 shows
additional shielding material added immediately outside the Sample Storage Area, in the
hallway.
In some cases, the cost to the laboratory for permanent shielding materials may be reduced, and
the laboratory's ability to respond to changing conditions within the facility may be increased, by
the judicious use of portable shielding, such as the panel shown in Figure 1 between the Sample
Staging Area and the Gross Preparation and Aliquanting area. Such portable shielding may be
used to address a sudden influx of samples in the Staging Area during an incident response.
Caution should be used in this approach, however, because the placement of shielding further
from the source of radiation allows for less overall protected work area due to the reduced
shielding angle. Reliance on reduced occupancy factors in the unshielded areas should be
controlled to minimize worker exposure. In addition, portable shielding may be secured or
controlled in a manner similar to an electrical "Lock Out/Tag Out" program to prevent
unintended worker exposure by movement of the shielding by unauthorized personnel.
Figure 1 also shows a particular situation in which the entryway to the Sample Storage Area
must be shielded to protect the workers immediately outside, while still allowing access to the
area. In this example, the shielding inside the door (labeled "A") is stationary and personnel walk
around it to access the sample storage area. This is just one example of a technique that might be
employed for shielding traffic lanes.
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4.3.4 Consideration of Multi-Level Facilities
Not shown in Figure 1 is consideration of multi-level facilities that house radiological
laboratories. It should be understood that radiation extends in three dimensions and that in such
facilities, it may be necessary to evaluate areas on adjacent levels and to potentially shield the
work areas above and below the sources of radiation exposure.
4.4 Gamma Shielding of In-Process Materials
When radioactive materials are handled directly by the employees performing radioanalytical
processes on the materials, additional shielding and other precautionary measures may need to be
taken, since the sample material is now in very close proximity to the employees and may be
open to the environment. In addition, changes in background associated with the movement of
elevated levels of radioactivity in the laboratory may compromise measurements performed
within the changing radiation field. Appropriate shielding may help minimize changes in the
background.
Sensitive instrumentation is readily shielded in the same manner and with the same materials as
storage areas. Lead bricks or panels placed strategically between the source of radiation and the
instrumentation are simple and effective shielding solutions.
Shielding the employees who must handle the radioactive material is not always as
straightforward. Small amounts of highly radioactive material (in an appropriate sample
container) may be placed inside a lead pig, to be opened only as needed to remove small
aliquants. Larger quantities of material should be staged inside small lead enclosures until
needed, then minimally handled to perform the necessary laboratory functions.
When providing gamma shielding for samples undergoing laboratory procedures, particular care
should be taken to evaluate potential exposures in all directions. These considerations are often
overlooked in laboratories that are unaccustomed to higher levels of radioactivity. Figure 2
demonstrates the need to evaluate gamma
shielding in three dimensions. The
worker should be adequately protected
from "gamma shine." This includes
direct irradiation by the sample material,
as well as scattered gamma photons and
induced X-rays from the surrounding
materials.
In some situations, workers may be
shielded effectively from gamma
radiation emitted from a relatively
localized source by placing the shielding
in close proximity to the source, as
shown in Figure 3a. This configuration maximizes the shielded work area with a minimum
amount of shielding.
Figure 2 - Three-Dimensional Shielding
Considerations
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In situations involving sources that are distributed over a larger area and where limited shielding
is available, it may be preferable to shield the worker from gamma radiation in the same manner
that instrumentation is shielded. That is, the shield is placed in close proximity to the work
station in such a way that it protects only the specific worker or area, rather than shielding a
larger work area, which might require significantly more shielding material. This alternate
shielding configuration is shown in Figure 3b. This configuration may conserve shielding
material in some situations and may provide additional flexibility and responsiveness to the
laboratory in its efforts to respond to a radiological incident. This configuration may also have
the added benefit of potentially reducing exposure due to scattered gamma photons, which can
increase the shielding requirements.
Caution is needed in this approach, since it assumes a low occupancy factor for the unshielded
parts of the work area. As with such consideration in storage areas, discussed above,
incorporating low occupancy factors in the determination of shielding requirements should be
approved by the laboratory's Radiation Safety Officer or Health Physicist.
3a.
Figure 3 - Alternate Shielding Configurations
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5. SUMMARY
A laboratory preparing to support the response to a radiological or nuclear incident will
anticipate a dramatic increase in the number of samples received, the range of activity levels in
those samples, and the associated analytical and human health risks of radiological laboratory
contamination and increased radiation.
To minimize those risks, the laboratory should consider taking a number of tangible preliminary
steps that may help prevent, identify, and control potential contamination and exposure
challenges when the samples arrive at the laboratory.
The laboratory should plan and prepare for the arrival of the incident samples and the
associated analytical work by deciding what type of work will be performed in the
different laboratory areas and what operational constraints will apply to that work. These
decisions should take into consideration the physical layout of the laboratory facilities,
the expected flow of work through the facility, the levels of radioactivity and radiation
that can be expected to be safely and properly handled in each area, and the resources that
will be required to maintain those operations.
The laboratory should establish operational protocols for the new and different
procedures and situations that are likely to be encountered and provide training for
personnel who will be affected by the change in laboratory operations. These protocols
will necessarily be tailored to each individual laboratory and will depend greatly on the
specific circumstances of each laboratory.
These preliminary steps can be taken by any laboratory, regardless of size, resources,
organizational affiliation, or type of work currently performed. If these preliminary steps are
properly addressed, it simply remains to execute the established protocols and remain vigilant
against laboratory contamination and exposure problems. By carefully considering the measures
recommended in this guide, the laboratory will be better able to participate in the incident
response, preserve the ongoing analytical integrity of the laboratory, and resume normal
operations after the event.
The intention of this guide is not to prescribe specific practices for the laboratory to follow, but
to provide pertinent topics for the laboratory to consider in its own efforts to preserve and
enhance its analytical capabilities, to preserve the health and well-being of its personnel, and to
assist in a significant national effort to protect the public health.
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6. REFERENCES
U.S. Department of Energy (DOE). 1994. Radiological Control Manual. DOE/EH-0256T. April.
Available at http://www.hss.energy.gov/publications/rcm/rcm.html.
U.S. Environmental Protection Agency (EPA). 2008. Radiological Laboratory Sample Analysis
Guide for Incidents of National Significance - Radionuclides in Water. Revision 0. Office of
Air and Radiation, Washington, DC. EPA 402-R-07-007, January. Available at:
www.epa.gov/narel/incident_guides.html.
U.S. Environmental Protection Agency (EPA). 2009a. Radiological Laboratory Sample Analysis
Guide for Incidents of National Significance - Radionuclides in Air. Revision 0. Office of
Air and Radiation, Washington, DC. EPA 402-R-09-007, June. Available at:
www.epa.gov/narel/incident guides.html.
U.S. Environmental Protection Agency (EPA). 2009b. Radiological Laboratory Sample
Screening Analysis Guide for Incidents of National Significance. Revision 0. Office of Air
and Radiation, Washington, DC. EPA 402-R-09-008, June. Available at:
www.epa.gov/narel/incident guides.html.
U.S. Environmental Protection Agency (EPA). 2010. Guide for Laboratories - Identification,
Preparation, and Implementation of Core Operations for Radiological or Nuclear Incident
Response. Revision 0. Office of Air and Radiation, Washington, DC. EPA 402-R-10-002,
June. Available at: www.epa.gov/narel/incident_guides.html.
U.S. Environmental Protection Agency (EPA). 2011. 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 and www.epa.gov/narel/incident guides.html.
U.S. Environmental Protection Agency (EPA). 2012. Uses of Field and Laboratory
Measurements During a Radiological or Nuclear Incident. Revision 0. Office of Air and
Radiation, Washington, DC. EPA 402-R-12-007, August. Available at:
www.epa.gov/narel/incident_guides.html.
Multi-Agency Radiological Laboratory Analytical Protocols [Manual] (MARLAP). 2004. Vols.
I (EPA 402-B-04-001A), II (EPA 402-B-04-001), and III (EPA 402-B-04-001C), July.
Available at: www.epa.gov/radiation/marlap/manual.html.
U.S. Nuclear Regulatory Commission (NRC). 1999. Consolidated Guidance About Materials
Licenses: Program-Specific Guidance About Licenses of Broad Scope. Washington, DC.
NUREG-1556, Volume 11, April. Available at: www.nrc.gov/reading-rm/doc-collections/
nuregs/staff/sr 155 6/v 11 /.
55
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX A: PLANNING CONSIDERATIONS FOR LABORATORY LAYOUT AND
PROCESS FLOW
Once the acceptable activity levels and required PPE for the various types of work areas have
been defined by the laboratory, as discussed in Section 2, the physical areas in the laboratory
corresponding to the area types should be delineated. A plan view or map of the facility may be a
useful planning tool, as shown in the following example.
The proposed layout of the laboratory should take into consideration the flow of work and the
paths that various radioactive materials will take through the laboratory. The physical constraints
of the building and the likely need to establish controlled entrance and egress points to specific
areas should also be considered.
Figure 4 depicts a simplified example for a suggested layout of laboratory and administrative
areas in a laboratory operation. Discussion of the flow of work through these areas follows the
diagram. It is important to note that every laboratory has a different physical design, performs
different types of analytical work, and uses different systems to perform the necessary work.
Each laboratory must evaluate its own operation and determine the best work area layout and
work flow for its facility.
UNRESTRICTED PUBLIC ACCESS
LO
LO
LU
U
U
y
i
CD
=>
CL
Q
y
DC
te
LU
UNOCCUPIED/RESTRICTED BUFFER ZONE
UNOCCUPIED/RESTRICTED BUFFER ZONE
m
on
n
m
O
-Q
C
DO
^
n
>
n
n
m
on
on
UNRESTRICTED PUBLIC ACCESS
>=> =
PROCESS FLOW FOR RAD MATERIALS OR PERSONNEL
I = BUILDING PERIMETER
= PROPERTY BOUNDARY
Figure 4 - Conceptual Layout of the Laboratory and Associated Areas
56
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Incoming Traffic Buffer Zone
Samples entering the laboratory generally arrive via courier or public delivery service and are
brought to the designated sample receiving area through the incoming traffic buffer zone. The
laboratory should recognize that this zone may become contaminated and should be surveyed
periodically.
Outgoing packages should be screened prior to release, and processed in a segregated staging
area, to minimize the risk of contamination from incoming packages. Ideally, the shipment of
material out of the facility should occur from a location other than that used for receiving
samples.
Receiving Area for Incoming Radioactive Materials Packages
Incoming radioactive materials packages are delivered directly to the designated sample
receiving area. No other area of the laboratory should be used to accept delivery of potentially
radioactive materials. Instead, such deliveries should be redirected to the appropriate receiving
area. Incoming packages will contain a variety of samples, with potentially unknown physical
and chemical characteristics, and a broad range of radioactivity concentrations from very low to
very high levels. It may be useful for the laboratory to employ high-level gamma monitors in the
sample receiving area, which may automatically sound an alarm when pre-set gamma exposure
levels are exceeded, thereby providing the laboratory with an early warning of high gamma
activity samples.
The physical flow of samples within the receiving area should be organized logically so that
initial processes, such as acceptance of delivery, collection of external swipes, and exposure
measurements, are performed nearer to the delivery entrance than later processes. Packages
should then be moved into subsequent processing areas, such as a fume hood designated for
unpacking, to physically separate the different receiving steps as much as possible. The
laboratory's processes should be designed to create a linear, one-way path for material through
the various areas. In the event of a contamination issue, this will help the laboratory to isolate the
potentially contaminated work surfaces and equipment. Figure 5, Process Flow in the Sample
Receiving Area, shows a generalized view of one possibility for the one-way flow of radioactive
materials through the area.
In the sample receiving areas and all subsequent areas, the laboratory should consider identifying
specific decontamination areas (labeled "Decon Area" in Figure 5) for sequestering and isolating
material identified as potentially contaminated. These areas should be separate from those used
for the regular flow of samples, i.e., in no case should material identified as contaminated be
returned to the process flow where it could potentially contaminate otherwise uncompromised
material, until the contamination issue has been addressed. Additional information regarding
radiological decontamination is provided in Appendix I, Decontamination of Laboratory
Surfaces and Equipment.
Necessary materials and supplies for the work being performed in an area should be situated
close at hand, but preferably out of the direct flow of sample traffic. After being properly
57
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
screened for external exposure rates19 and removable surface contamination,20 the unopened
contents of the radioactive materials packages should be routed directly to the sample screening
lab. Consequently, the receiving area should have direct access to the Sample Screening Area
whenever possible. This will minimize the risk of contamination associated with moving
uncharacterized samples through the laboratory.
Certain equipment and supplies may need to be routed directly between the receiving area and
the various work areas, and it may be both unnecessary and undesirable to move these materials
through the Sample Screening Area. It may, therefore, also be desirable to enable ready access to
the routine laboratory areas from the receiving area. Clear protocols should be established that
define the acceptable movement of materials, supplies, and samples.
^
Sample Receiving and
Additional Supplies
fD
I Incoming Materials
^Yr*
Fn^
To Screening
Package
Inspection &
Survey
Staging
Area for
Unpacking
Fume Hood
o
Decon
Area
COOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO^
p>
Rad waste receptacle
Frisker
I Step-off Pad
Figure 5 - Process Flow in the Sample Receiving Area
Screening Areas for Incoming Samples
As with the Sample Receiving Areas, Screening Areas for Incoming Samples will process a
variety of sample types, with a wide range of activity concentrations. Whenever possible, it may
19 See Radiological Laboratory Sample Screening Analysis Guide for Incidents of National Significance (EPA 402-
R-09-008, June 2009)
20 See A Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological or Nuclear
Incident (EPA 2011)
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
be useful for the laboratory to consider establishing separate screening areas, or separate
workstations within a single area, for samples of known or expected activity ranges. For
example, samples that exceed preset decision levels for external exposure readings or for which
reliable field screening data indicate elevated activity may be processed for screening in one area
while samples that fall below those decision levels, or samples that are not expected to contain
elevated activity levels, may be processed in another. This may reduce the risk of sample cross-
contamination.
In any case, the screening areas should be set up to accommodate the flow of work, moving the
samples from the receiving area entrance in a linear path toward the exit to sample storage and
processing areas whenever possible. Figure 6a shows a generalized view of the one-way flow of
radioactive materials through this area. In this view, the incoming samples are initially processed
near the entrance and then moved to the instrumentation areas, which are close to the exits.
Reagents and supplies that must remain clean and uncontaminated are stored close at hand but
out of the flow of the samples.
In some laboratory areas, there may be either a single entrance to the room or other conditions
that prevent the linear flow of materials through the laboratory area. In these cases, the path into
and out of a work area may be through the same doorway or aisle-way. In these situations, the
flow of work might be organized with the preliminary steps closer to the entrance and the later
steps, such as screening measurements, further inside the room. During a contamination event,
which is most likely to occur in the earlier handling steps, this configuration may minimize the
spread of contamination to the analytical areas by restricting traffic to the necessary cleanup
areas near the door. Again, the consumable supplies, etc., should be stored out of the flow of the
samples but still readily available. In this type of situation, the layout shown in Figure 6a is still
applicable with the separate exits to the High Level and Routine areas removed, as shown in
Figure 6b, so that entrance to and egress from the area is through Sample Receiving.
Reagents &
Supplies
Decon. Area
Reagents &
Supplies
To Routine
Area
To High
Activity Area
l|
o
Sample Prep&
Fume Hood
00
o
OJ
cc.
E
o
0 t
Sample Prep&
Fume Hood
Rad waste receptacle
Frisker
]Step-off Pad |
Figure 6a - Process Flow in the Screening Areas
59
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Reagents &
Supplies
Decon.Area
Reagents &
Supplies
Sample Prep&
Fume Hood
Sample Prep &
Fume Hood
Rad waste receptacle
Frisker
I Step-off Pad]
Figure 6b - Process Flow in the Screening Area with a Single Entryway
Other Laboratory and Storage Areas
As in the Sample Receiving and Screening Areas, the flow of radioactive materials through the
general laboratory areas, including the High-Level, Routine, and Low-Level Areas, should
follow a path that closely matches the flow of work.
Figure 7 demonstrates one possible layout for a typical laboratory area. For clarity, Figure 7
shows only the Routine-Level Work Areas in the example laboratory. Work flow may be routed
into other types of laboratory areas, such as the High-Level and Low-Level work areas, and the
following suggestions are generally applicable to all types of laboratory areas:
Storage of large numbers of samples or samples with elevated activity should be located near
the entrance of the area, furthest away from instrumentation or personnel activities. This
configuration will minimize exposure to the workers and provide lower and more stable
background radiation levels for the instruments.
Areas for the initial gross preparation (such as drying, grinding, filtering, etc.) and
aliquanting of the sample material are established next.
In some cases, it may be helpful to then establish an area for the digestion of solid materials.
After this point, the sample material will be in a liquid form, which is generally easier to
contain and handle, may be further sub-sampled, and is much less likely to cause a laboratory
contamination issue. Undigested solid materials, other than those in a sealed container that
will remain unopened (such as for gamma spectrometry), should not be brought further into
the laboratory than this point.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Samples are then moved further along the preparation process and, consequently, further into
the laboratory areas. The final steps of chemical purification and preparation of the sample to
be presented to the instrumentation area are performed in closer proximity to the
instrumentation area than the previous steps.
Ancillary areas for storage of (non-radioactive) supplies and equipment should be
strategically located between potential sources of radiation and the instrumentation and
administrative areas, in order to provide an additional buffer zone and to separate people as
much as possible from the High-Level Work Areas.
./v
A
INSTRUMENT
& LOW LEVEL
--x
"X
Plating, -^-i
Planchetting,
etc.
Chemical
Separations
Sample
Digestions
t
Gross Prep
and
Aliquanting
Sample
Staging
Area
- -
Waste
/
f
_X x
* Plating, N
Planchetting,
etc.
__
DeconArea
<^
<
^j
A
1
" %
i Computer &
1 DeskAreas,
1 Ir. etc.
Storage for .III
Reagents, [Tl
Supplies, LLJI I
Other i ^ ^ ^ ^
Consumables (, Rad
1
1 Standards
I DeconArea
1 &
\l Chemical | Sub- Sample
Separations Staging Area
O 1 ^ 1
? >
SCREENING
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s
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M
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)
Sample
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r
\J
N
RECEIVING
HIGH LEVEL
1 Rad waste receptacle
) PPE Donning Station
' Frisker | [Step-off Pad
<$ PPE Doffing Station
Figure 7 - Process Flow in the Routine Work Areas
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Administrative and Public Areas
Personnel exiting the laboratory areas should carefully follow the laboratory's exit protocols. An
example of laboratory egress protocols is given in Appendix F: Egress Into a Lower-Activity
Area. There should be absolutely no flow of sample material or potentially contaminated
equipment or materials from the laboratory into the administrative or public areas.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX B: INITIAL RECEIPT OF RADIOACTIVE MATERIALS
The following is a suggestion for a protocol that might be used for the general receipt of
radiological material. Appropriate PPE is required for all steps.
EQUIPMENT AND MATERIALS
Exposure rate meter
Removable surface contamination swipes
Spill kit
Secondary containment bins
Plastic-backed laboratory bench paper
Laboratory trays and carts for staging samples and supplies
Radioactive Materials Shipment Initial Survey Results form
PROCEDURE
1. Immediately upon receipt, inspect the package for visible signs of damage or leakage of the
contents. DO NOT OPEN THE PACKAGE until preliminary administrative, visual, and
radiological checks have been completed (Steps 1.1 through 3).
1.1. If the package appears to be undamaged and intact, place it in the staging area for
incoming radioactive materials and proceed to Step 2.
1.2. If the package appears to be damaged or leaking, immediately contain the package in a
durable plastic bag, secondary containment bin, or other suitable containment material to
prevent the spread of radioactive material. If it is possible to move the contained package
into a fume hood without risking the spread of radioactive material, do so, then
immediately contact the RSO and wait for further instructions.
1.3. Take a preliminary measurement of the package exposure rate, in uR/h, near the package
surface. If the measurement of the package dose rate exceeds 2,600 uR/h,21 shield
personnel, notify the RSO, and wait for further instructions.
2. Initiate a Radioactive Materials Shipment Incoming Survey Results form, completing the
first section and noting the date and time of receipt of the shipment. See Figure 8, Example of
Radioactive Materials Shipments Initial Survey Results.
3. Perform external surveys of the package.
3.1. Measure the instrument background response and record that value on the survey results
form. Be sure to perform this initial measurement in an area that is well removed from
potential sources of radiation exposure, in order to obtain an accurate background
reading.
3.2. Measure the exposure rate, in uR/h, at a distance of 30 cm from the surface of the
package and record the value on the survey results form.
21 Referring to the example in Section 2.2., Table 2, 2,600 uR/h is the ADL for exposure rate measurements in
Routine-Level work areas. The ADL described the measurement result that should trigger a decision that the 5,000
uR/h AAL may have been exceeded and that additional steps should be taken, such as those described in Step 1.3,
above.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
3.3. Measure the exposure rate, in uR/h, at the external surfaces of the package and record
the highest measured value on the survey results form.
3.4. Perform a swipe survey of 300 cm2 of the outside surface of the package. Count the
swipe on the appropriate instrumentation and record the alpha and beta activity values on
the survey results form.
3.5. Record the date and time that the surveys were completed on the results form.
3.6. If any of the ADLs23 shown on the form are exceeded, initiate the appropriate corrective
action, as described on the survey results form. If all results are below the prescribed
ADLs, proceed to the Step 4.
Note that the ADLs shown on the form in Figure 8 are taken from Table 2, in Section 2.2., and
are derived from the example AALs for contamination and exposure control in Routine-Level
Work Areas.
22 While the characterization of the exposure rate at a distance of 30 cm from the surface of the package is consistent
with the requirements of 10 CFR 20 for the establishment of a Radiation Area, the laboratory may select other
internal requirements that address the specific needs and operational conditions of the work area.
23 As in other places in this guide and the various companion documents, these ADLs describe the measurement
result that should trigger a decision in the laboratory to take additional steps. In this example, the hypothetical
laboratory ADLs correspond to AALs that are based on federal regulations, such as 40 CFR 173.421 and 173.403.
64
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
XYZ Laboratories, Inc.
RADIOACTIVE MATERIALS SHIPMENTS
INITIAL SURVEY RESULTS
Shipper: Client:
CoC ID:
Delivery Date & Time:
Nuclide(s):
Other Info:
Instrument Backgroun
Project:
Cooler ID:
CH (check if unknown)
Exposure Rate uR/h
Exposure Rate @ 30 cm from package surface
ADL*= 1,OOOuR/h uR/h
If ADL is exceeded
Max. Exposure Rate (g
ADL =
If ADL is exceeded
report to Radiation Safety Officer.
I package surface
2,600 uR/h uR/h
report to HazMat Shippng Officer and Radiation Safety Officer
External Removable Contamination Survey alpha dpm/swipe
beta dpm/swipe
Perform 300 cm2 swipe on outside of package.
ADL = 1.1 dpm/cm2 (330 dpm total) alpha
1 1 dpm/cm2 (3300 dpm total) beta
If Action Level is exceeded, report to HazMat Shippng Officer and Radiation Safety Officer.
External Survey Completion Date & Time:
Removable Contamination Survey of Contents
Item*
1
2
3
4
5
6
7
8
9
10
11
12
ADL =
If ADL is exceeded
Approved By:
Date:
Description alpha dpm/swipe beta dpm/swipe
Perform 100 cm2 swipe on inner container of source.
0.1 dpm/cm2 (10 dpm total) alpha, per Lab Radiation Protection Plan.
1 dpm/cm2 (100 dpm total) beta, per Lab Radiation Protection Plan.
secure the package and the receipt area and report to Radiation Safety Officer.
*ADL =Analytical Decision Level
Figure 8 - Example of Radioactive Materials Shipments Initial Survey Results
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
4. Unpack the shipping container.
4.1. Prepare a clean laboratory fume
hood by lining the bottom with
plastic-backed absorbent labora-
tory paper. The fume hood,
similar to most work areas for
radiological materials, will have
a "hot" zone on one side, a
"warm" zone in the middle, and
a "cool" zone on the other side.
In the example shown in Figure
9, the "hot" zone is to the left
and the "cool" zone is to the right.
In this section and elsewhere in this guide, certain
techniques may suggest the use of one hand (or one side
of a work surface) over the other. This preference is
generally arbitrary, or in some cases indicated by the
"handed-ness" of the person performing the task. The
primary purpose of such techniques is to maintain a
"clean" hand (or work area), considering the other to be
"potentially contaminated." In all cases, the specific
configuration should be determined by the most effective
contamination-control practices, which may include
consideration of individuals involved.
FUME HOOD
O
o
o
I Sample
| Package
T r
I Workspace
Sample
Bottles in
Contain-
ment Bins
O
o
Figure 9 -Work Flow Inside Fume Hood; Unpacking Samples
4.2. On the right side of the hood, preferably on a laboratory tray, lay out enough swipes to
survey each sample container expected in the shipment and enough supplies to mount
and label each swipe.
4.3. Move the shipping container to the far left side of the fume hood.
4.4. Carefully open the container. Treat all packing material, enclosed paper work, and any
other contents as potentially contaminated until verified to be below the release limits
designated in the RPP. Before removing the contents, inspect the inside of the container
for signs of spilled material or other damage to the contents. If a sample container has
broken, or sample material has spilled inside the shipping container, immediately close
the shipping container, notify the RSO, and wait for further instructions.
4.5. If the samples appear intact, carefully remove them one at a time, swipe them, and place
them in a secondary containment bin. Other control checks, such as sample temperature,
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
are not described here but may be incorporated into individual laboratory procedures, as
necessary.
4.5.1. Remove the sample from the shipping container with the left hand. This hand
will be used only to handle the individual sample containers, if possible.
4.5.2. Take a new swipe in the right hand (it may be useful to have another person hand
the swipes over, in such a way as to avoid transferring contamination to the
helper), swipe the sample container, and place the swipe on a pre-labeled
planchet.
4.5.3. Place the sample container in a secondary containment bin or other suitable
laboratory storage container.
4.5.4. As each sample container is placed in the secondary containment bin, record the
field ID and other appropriate information on a laboratory chain-of-custody or
other suitable form. The laboratory's internal ID labels may be affixed to the
samples at this time, if necessary.
4.5.5. Cover the containment bin and move it, along with the shipping container, to a
suitable holding area until the swipes are analyzed.
4.6. Survey the shipping container, enclosed documentation, packing material, hood liner,
hood surfaces, and personnel, following the prescribed ADLs for the area, as shown in
the example in Section 2.2., Table 2.
4.7. Count the swipes. The instrument and count parameters should be carefully chosen to
address the laboratory's predetermined contamination limits. Record the results and
transfer the samples to the designated storage area.
4.7.1. If the results of the removable surface contamination surveys of the sample
containers are below the established limits, the samples may be transferred to the
appropriate sample storage area. The shipping container and packing materials
may be disposed in the sanitary trash or returned to service if the project allows.
4.7.2. If any of the results of the removable surface-contamination surveys are above the
AAL, the samples, packing material, and shipping container must be returned to
the fume hood or other appropriate location, and decontaminated. Following
decontamination, return to Step 4.5 and re-survey the containers to verify that the
decontamination was successful. If decontamination is not feasible, the RSO
should be notified and the material disposed according to the laboratory's
Radioactive Waste Management Plan.
4.8. Review and approval of the survey results should be performed by qualified personnel.
If any AALs are exceeded, the RSO should review and approve of the decontamination
process and the final survey results.
4.9. Upon completion of the survey, the survey results form should be included with the
sample chain of custody and other laboratory documentation of the sample receipt.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX C: OPENING, TRANSFERRING, AND ALIQUANTING SAMPLE
MATERIAL
This protocol is generally applicable for the opening of sample containers and the removal of
either the entire sample or a fraction of the sample, from the perspective of minimizing the risk
of laboratory contamination. This may be applicable to samples arriving in the screening area as
well as samples being processed in the radiochemistry laboratory areas.
In this example protocol, samples are staged outside the hood, waiting for processing. Single
samples are brought into the hood, opened, and an aliquant removed. If further processing is to
immediately follow in the hood, as may be the case in the screening lab, the sample aliquants are
staged inside the hood for further processing. If sample aliquants are to be returned to the storage
area for processing at a later time, the aliquant is sealed in an appropriate container, the outside
of the container is cleaned, and both fractions of the sample (the original and the new aliquant)
are returned to storage. A generalized view of the work area for this procedure is shown in
Figure 10.
This appendix also provides an example in which multiple aliquants are removed simultaneously
in anticipation of multiple analyses being performed on the sample. In this example, one aliquant
is removed for a primary analysis and the other "reserve" aliquant is held for contingent analysis.
Careful planning will determine the number and size of the sample aliquants that may ultimately
be needed, including any additional aliquants required for further screening or for reserve/
contingent analyses. In some cases, this approach may minimize handling and the associated risk
of laboratory contamination, and may also optimize sample throughput. While the example uses
a soil sample, analogous procedures could be used for other types of samples. The laboratory
may also consider that, while the process of aliquanting a sample and preparing the aliquant for
screening may be amenable to a single laboratory hood space, it may still be advisable to break
up the process into stages (e.g., aliquanting all samples, then digesting all sample aliquants, then
planchetting all samples), rather than trying to perform the complete cycle on each sample in
turn. This approach may facilitate the rapid handling of large numbers of samples and minimize
the amount of equipment and supplies in the work area at one time, thereby reducing the risk of
accidents and other potential contamination issues. These are all issues for the individual
laboratory to decide.
1. Prepare a clean laboratory fume hood for the sample handling process by lining the bottom
with an underlayment of plastic-backed, absorbent laboratory paper and assembling the
necessary equipment, which will be dependent on the type of samples and the sub-sampling
technique.
2. Establish a staging area for samples to be processed outside of the hood, but in close
proximity to the "hot" side of the hood. Establish another staging area outside the hood, but
in close proximity to the "cool" side of the hood, for necessary supplies.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
FUME HOOD
Staging
Area for
Samples
Staging
Area for
Supplies
Figure 10 - Opening, Transferring, and Aliquanting Sample Material
3. Determine what supplies will be needed for processing each sample and assemble those
supplies in the hood, as needed. The use of disposable or single-use laboratory supplies is
strongly encouraged to minimize the risk of cross-contamination. Examples of supplies
needed to aliquant a soil sample would be:
Single sheet of plastic-backed laboratory bench paper (approximately 45cm x 45cm),
spread out on the center work area;
Disposable spatulas;
Disposable vessels, with lids, or other suitable, sealable containers, pre-weighed (with
lid) and labeled;
Containment bin or tray for processed samples;
Spray bottle of decon solution;
Paper towels or disposable wipes;24 and
Survey meters to periodically monitor hands, sample containers, work areas, and
swipes during the process.
4. Bring one sealed sample container from the staging area outside the hood into the "hot" area
of the hood. Only one sample should be processed at a time.
5. Open the sample container, remove the aliquant(s), then close the sample container and the
new aliquant container.
5.1. Open the sample container carefully, holding the sample container in one hand and
removing the lid with the other.
24 The distinction is made here between "wipes," which are used for cleaning purposes and which may be surveyed
prior to disposal as an indication of contamination, and "swipes," which are used solely to measure removable
surface contamination.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
5.2. Keep the sample container in the one hand and put the lid down, top side down, to the
left side of the bench paper square.
5.3. Survey the gloved right hand and the inside of the container lid and for indications of
unexpected levels of activity, or levels that would require segregation of the sample in
the high activity work areas.
5.4. Place two pre-weighed, labeled disposable vessels on the bench paper, one designated
for the primary analysis and the other designated as a "reserve" aliquant.
5.5. Using a disposable spatula and working over the bench paper, carefully transfer the
desired representative aliquants from the sample container to the aliquant vessels.
Minimize the agitation of the sample or any aggressive motions that may cause dust,
splashing, or other loss of the sample material to the work area.
Although removal of "representative" aliquants of the sample is important, and effort to
homogenize the sample should be taken prior to removing an aliquant, aggressive
agitation of open material increases the risk of laboratory contamination. The
requirements for sample homogenization and representative sub-sampling should be
clearly stated in the project DQOs and should be reflected in the laboratory's sample
handling and contamination control protocols.
5.6. Place the spatula in the waste receptacle inside the hood.
5.7. Replace the cover on the original sample container and put the sample down in the
hood. Survey gloved hands before proceeding.
5.8. Carefully seal the aliquant vessels. Place the sample aliquant designated for screening
in the aliquant staging area inside the hood, designated for further processing.
5.9. Place the sample aliquant to be reserved for future testing on the other side of the hood,
with the original sample. This aliquant will be returned to storage with the original
sample container.
6. Clean the containers with a damp disposable wipe before moving them.
6.1. Pick up sample/aliquant containers in one hand only.
6.2. Use the other (clean) hand to spray containers and wipe them clean.
6.3. After cleaning, place the damp wipe on the bench paper square, to be surveyed in the
next step, grasp the container with a clean wipe and move it to the staging location. The
staging location may be outside the hood, for samples to be returned to storage, or inside
the hood, for samples to be further processed.
6.4. Survey the gloved hands and the wipes to determine removable surface contamination
levels on the sample container.
6.5. Where multiple containers are provided for a sample, repeat for each container.
7. Dispose of consumables and prepare the work area for another sample.
7.1. Gather any potentially contaminated consumables and other waste (spatulas, etc.) onto
the bench paper square, fold the waste up into the paper, and place the bundle of
contained waste into the designated waste receptacle inside the hood.
7.2. Replace gloves.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
7.3. Replace the bench paper square and consumable supplies and proceed with the next
sample, from Step 3.
Continue sample processing.
8.1. The original sample container and the reserve aliquant are sealed and cleaned and may
be returned to the appropriate sample storage area. The reserve aliquant may be taken,
en route, to a balance station to obtain a gross container weight for use in the anticipated
analysis.
8.2. Likewise, the aliquant designated for the screening analysis may also be weighed. The
sample preparation process can then proceed, according to the laboratory's SOP.
After appropriate aliquants have been removed from all samples, and the samples have been
removed from the hood, the plastic-backed bench paper should be removed, and the hood
should be cleaned and surveyed in preparation for processing other samples.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX D: ISOLATING REDUCED FRACTIONS FOR TRANSFER TO LOWER-
LEVEL AREAS
This protocol provides a strategy for isolating a very small, yet representative amount of high-
activity sample material when it is necessary to bring that material into a lower-activity-level
work area for processing or analysis. This is particularly applicable to laboratories without
separate low-level and high-level facilities for all processes.
The laboratory should first recognize the inherent challenges in obtaining representative
subsamples from any field sample, particularly from solid matrices such as soil, debris, or
particulate air filters. The project DQOs and the laboratory's sample handling protocols should
clearly address the requirements and specific techniques for sample homogenization and
representative sub-sampling, including minimum allowable aliquant sizes that may be considered
representative and acceptable practices and equipment for measuring sample aliquants. In
addition to these established protocols, unusual or difficult samples or samples that might be
expected to be heterogeneous should be evaluated by qualified laboratory personnel to determine
the limitations of direct sub-sampling techniques.
The examples provided here are not intended to give specific guidance on the aliquant sizes to be
used or the acceptable techniques for sample homogenization, but are simply intended to
illustrate a possible technique for reducing a representative aliquant to a manageable size, with
particular emphasis on controlling radioactive contamination in the laboratory. The actual
aliquant sizes used by the laboratory will be determined by the sample screening results, the
analytical method to be performed, the analytical requirements for homogeneity and sub-
sampling, and the laboratory's specific contamination control practices.
Once the laboratory's protocols for sample homogenization and representative sub-sampling are
addressed, an "intermediate" aliquant is taken from the sample material and the aliquant size is
measured. Liquid samples may be initially measured volumetrically, if volumetric reporting units
are required. Solid samples may be weighed, then digested to facilitate further sub-sampling.
Gravimetric dilutions of all samples are then performed, in series if necessary, to minimize
laboratory contamination and to allow accurate measurement of very small aliquants.
The selection of equipment for volumetric and gravimetric measurements should reflect the
incident response analytical requirements; the uncertainty of the measurement should be
controlled at a level that is consistent with the project MQOs and should be reflected in the
combined standard uncertainty that is reported with the analytical results. In the following
procedure, the inclusion of specific equipment, such as volumetric pipettes and analytical
balances, is for illustrative purposes only.
1. Before proceeding, estimated target aliquants should be determined based on the sample
screening results and the ultimate "target activity" that should be isolated. The target activity
is the amount of activity that is desired for subsequent procedures. These values are based on
the established limits for sample activity, determined in Section 2.2., Establishing Acceptable
Levels of Radioactivity and Radiation.
2. Remove an "intermediate" aliquant, s, by the same technique described in Appendix C,
Opening, Transferring, and Aliquanting Sample Material, and place the aliquant in a pre-
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
weighed, labeled vessel, such as a specimen cup, beaker, crucible, etc., that can be tightly
covered or sealed to appropriately contain the sample. The type of vessel used will depend on
the sample material, the target radionuclides for which the sample is to be analyzed, and the
digestion or dilution technique used.
2.1 For liquids that are to be analyzed on a volumetric basis (results reported as activity per
volume of sample), remove the intermediate aliquant with a calibrated pipette and record
the volume, v, of the aliquant.
2.2. For filters and swipes, record the fraction,/ of the sample taken, such as 0.5 filter or
0.25 filter. It is preferable, whenever possible and without compromising the requested
analyses, to digest the entire filter, in which case the intermediate aliquant sample size is
1.0 filter. Where the filter is physically cut or split, a preliminary survey may provide
early indication of inhomogeneity or "hot particle" activity.
2.3. For solids that are to be analyzed on a gravimetric basis (results reported as activity per
mass of sample):
2.3.1. Seal the samples to allow transport outside the hood.
2.3.2. Where indicated by the sample screening results or other laboratory
contamination control protocols, perform a removable surface contamination
swipe survey on the container prior to removing it from the fume hood.25 This
step should be performed for all samples, where necessary, whenever the sample
container is removed from the fume hood.
2.3.3. Transport the samples to the weighing station, record the gross mass of the sample
and the container, and determine and record the net mass, m, of the intermediate
aliquant.
2.3.4. Return the sealed samples to the fume hood.
2.4. Perform the required digestion or dilution of the sample material. Quantitatively transfer
each solution to a new pre-weighed container. Seal the containers and transport them to
the weighing station to determine the net total mass, mt, of the solution. Return the
samples to the fume hood.
2.5. Before proceeding, it may be desirable to perform another screening measurement on the
sample solution to confirm the appropriate aliquant size for analysis.26
2.6. With a disposable transfer pipette, remove an approximate aliquant that is representative
of the final target aliquant and transfer it to another pre-weighed, labeled container.
2.7. Seal the sample containers to allow transport outside the hood.
2.8. Weigh the container with the final aliquant for analysis and determine the net weight,
ma, of the final target aliquant of the solution.
2.9. The final sample aliquant, a, is calculated as
25 See Appendix H, Surveillance of Laboratory Surfaces and Equipment, and Section 2.2., Establishing Acceptable
Levels of Radioactivity and Radiation.
26 See Radiological Laboratory Sample Screening Analysis Guide for Incidents of National Significance (EPA
2009b).
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
mt
where s = the intermediate sample size, v,f, or m, depending on the sample type, from
Step 2.1, 2.2, or 2.3, above.
2.10. Where very small aliquant sizes are required, additional serial dilutions may be
necessary. These may be performed by repeating steps 2.6 through 2.9, above. In this
tn
case, the final dilution factor, ^ in the previous step, is replaced with
m
mt\
where ^- is the dilution factor for each serial dilution performed.
mt,
In this relatively simple manner, an aliquant that is equivalent to very small amounts of the
original sample (e.g., jig, jiL, etc.) may be sequestered from the bulk sample. The reduced
aliquant, and the reduced activity level that results, may be brought into lower-level work areas
for processing.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX E: ENTRY INTO A HIGHER-ACTIVITY AREA
1. Plan all work in advance to help minimize the movement of materials and the number of trips
into and out of the room. In many cases, pre-job planning meetings will help to ensure the
involvement of all affected personnel and facilitate planning for various contingencies.
2. Evaluate the materials being moved into the higher level areas and remove all non-essential
items.
2.1 Personal items, such as jewelry, watches, etc., should be removed. These items may be
difficult to decontaminate and may need to be discarded if a significant contamination
event occurs.
2.2. Common items (such as pens, notepads, etc.) should be available in the destination area
and should not be transported back and forth between the areas.
2.3. The movement of paperwork or other documentation from higher-activity areas should
be minimized, as these items are difficult and time consuming to assess for
contamination. The use of fax machines and document scanning technology and the
electronic management of information may significantly reduce the risk of laboratory
contamination.
2.4. Extraneous packaging materials that will simply be discarded should not be moved into
the higher-activity area. Otherwise, these materials must be surveyed, and potentially
decontaminated or classified as radioactive waste, prior to removal. This presents an
additional burden to personnel and additional contamination risk to the laboratory.
3. Secure/seal materials, if appropriate.
3.1 Some materials, such as necessary documents, exposure meters, and samples that are
only transiting the area en route to another processing area, should be effectively sealed
against contamination in a locking plastic bag or other container.
4. Remove PPE designated for use only in the lower-level area. For example, a laboratory coat
designated for use in the "routine-level" areas should not be worn in the "high-level" areas.
5. Don the required PPE. The laboratory SOP should provide the explicit list and the order in
which it must be donned. For example:
Scrubs;
Head cover;
Nitrile gloves;
Tyvek coveralls;
Shoe covers; and
Second pair of Nitrile gloves.
6. Gather any materials being brought into the area and enter.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX F: EGRESS INTO A LOWER-ACTIVITY AREA
The following egress protocol is provided only as an example. Each laboratory must specify the
egress protocol for each area, which will depend greatly on how the area types are defined, what
activity levels are specified, and what type of PPE is required.
In this protocol, the egress area consists of two step-off pads, with a buffer zone between them.
The first, or "primary," step-off pad is used for the removal of PPE that was worn in the higher-
activity level area. Once that PPE is removed, the worker moves to the buffer zone and proceeds
to don any PPE necessary to enter the lower-activity level area. The worker then surveys the
materials being transferred to the lower-activity level area and enters that area after using the
"secondary" step-off pad as an additional precaution against the migration of radioactive
contamination through the laboratory.
Disposable PPE and other consumable supplies that exceed the pre-determined survey limits for
a given area are placed in the "Rad Waste Container" for disposal as radioactive contaminated
waste. Otherwise, the item is placed in the "Potentially Contaminated Waste Container" for
further characterization prior to final disposal.27
In this protocol, the egress area is equipped with the following items:
A primary step-off pad;
A table or other appropriate surface for staging materials;
Adequate decontamination supplies;
A frisking station with the appropriate survey instrument for the types of radiation being
processed in the area28; the survey meter probe should be positioned face-up and
ready to perform an initial survey of the worker's gloved hand, without the need to
handle the probe before the initial survey is complete;
A receptacle for positively contaminated PPE;
A receptacle for potentially contaminated PPE;
A supply of any PPE that is required to enter the lower-activity area;
Ready access to a phone, intercom, or other means of summoning assistance, if needed;
Ready access to a personnel decontamination station; and
A secondary step-off pad.
27 The laboratory should have a detailed Waste Management Plan, or similar document, that clearly identifies the
accumulation, characterization, and ultimate disposal of laboratory waste.
28 Stationary hand and foot monitors are useful for monitoring personnel contamination, and they may facilitate the
rapid movement of personnel through controlled egress points. They are not, however, a complete replacement for
hand-held survey equipment, which is useful for surveying clothing and other items.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Materials
to be
surveyed.
Primary
Step-off
Pad.
Surveyed
aterials.
Secondary
Step-off
Pad.
o
o"
>
^
QJ
1 = Rad Waste Container
2 = Potentially Contaminated Waste Container
Figure 11 - Example Layout of the Egress Area
Stage the items to be removed from the higher level work area.
All items to be moved into the lower-activity area should be initially placed on a table, or
other suitable staging area, adjacent to the frisking station. Any tools or equipment that are
potentially contaminated should be thoroughly cleaned and surveyed/swiped before being
placed in the staging area.
Step on to the primary step-off pad.
Enter the egress area by stepping onto the primary step-off pad. While standing on the
primary step-off pad, remove the PPE as described below, starting at the head and working
down to the feet.
Disposable PPE and other consumable supplies that exceed pre-determined survey limits are placed in
the "Rad Waste Container." Otherwise, the item is placed in the "Potentially Contaminated Waste
Container." All laboratory waste and related materials should be characterized and disposed of
according to the laboratory's Radiation Protection Program and Waste Management Protocols.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
At each step, the item to be removed is surveyed prior to removal and is placed in the
appropriate waste receptacle. Particular attention should be paid to the areas that are prone to
contamination, such as the front and cuffs of the laboratory coat or coveralls, and the bottom
of the shoes and shoe coverings.
3. Survey and remove outer gloves.
When removing outer gloves, the exposed side of the outer layer is considered "dirty" and
the inner glove is considered "clean." Contact of a clean surface should be made only by
another clean surface.
3.1 As discussed above, the survey meter probe should be positioned face-up, ready to allow
the worker to perform an initial survey of the gloved hands without picking up the probe.
Survey both gloved hands.
3.2. Grasp the outside of one glove, near the wrist, using the other gloved hand.
3.3. Peel the glove away from the hand, turning it inside out as it is removed.
3.4. While holding the removed glove with the remaining "dirty" gloved hand, insert the
"clean" tip of one finger underneath the edge of the remaining "dirty" glove at the wrist
opening.
3.5. Peel the second outer glove off, turning it inside out as it is removed.
3.6. Keep holding the first glove until the second glove envelopes the first and both are
contained in a single package, with both gloves inside out, one inside the other.
3.7. Place the gloves into the appropriate waste receptacle.
3.8. Survey the inner gloves before proceeding to ensure that they have not been
contaminated and that the survey probe may now be handled without becoming
contaminated.
4. Survey and remove disposable coveralls.
4.1 After surveying the coveralls, push the hood back off the head, taking care not to allow
contact between the gloved hand and the face or head.
4.2. Unzip the coveralls.
4.3. Peel the coveralls away from the body, starting at the top and turning them inside out as
they are removed. During this step, minimize contact between the gloved hands and the
outside of the suit, and do not allow the outside of the suit to contact the inner layer of
protective clothing (e.g., scrubs).
4.4. With the coveralls rolled inside out, place them in the appropriate waste receptacle.
5. Survey and remove shoe covers.
5.1 After surveying the bottom of each shoe cover, place the survey probe on the table, face
up.
5.2. Grasp the outside of the shoe cover, at the back, above the heel, with one gloved hand.
5.3. With the other gloved hand, grasp the outside of the same shoe cover, on the top side,
near the toe.
5.4. Slide the shoe cover off the shoe and step the exposed shoe down on the floor past the
primary step-off pad, not back onto the primary step-off pad.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
5.5. Place the shoe cover into the appropriate waste receptacle.
5.6. Survey the gloved hands before proceeding.
5.7. Remove and discard the second shoe cover in the same manner, stepping completely off
the primary step-off pad when the second shoe cover is removed.
6. Don a laboratory coat or other required PPE indicated for the area being entered.
7. Survey the materials being removed from the area. Decontaminate, if necessary. Place items
that pass the survey acceptance criteria into the staging area for survey materials. Instructions
for performing the surveys and decontamination are provided in Appendix I,
Decontamination of Laboratory Surfaces and Equipment.
8. Survey the gloved hands, bottom of shoes, the laboratory coat, pant legs, and any other
exposed surfaces of the employees clothing.
9. Put the survey probe down, face up. The instrument should be ready to perform a new survey
without being handled.
10. Remove inner gloves using the same procedure described in Step 3, survey the hands, and
don a new pair of gloves, if required for the new area or for subsequent work.
11. Collect surveyed items and proceed into the lower level area, using the secondary step-off
pad on the way.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
APPENDIX G: ACTIVE RADIOLOGICAL MONITORING PROGRAM FOR
CONTAMINATION CONTROL
In order to detect and prevent the spread of radioactive contamination from a higher-level sample
processing area to lower-level sample processing and administrative areas, a fully functional
radiological monitoring program for the laboratory facilities should be implemented. In some
cases, the spread of contamination with activity as low as 0.25-1 pCi for beta/gamma-emitting
nuclides and 0.1 pCi for alpha-emitting nuclides29 could lead to cross-contamination of samples
and the reporting of erroneous results for low-level environmental samples. Detecting
contamination at these low levels cannot be accomplished with typical health physics
contamination control program applications. A survey meter may be useful for the detection of
higher levels of contamination in the high-level processing and sample storage areas, and as a
"go/no-go" measurement when moving materials from the high-level areas to the routine-level
areas, for example. Other more sensitive techniques will be required to detect lower levels of
contamination that may cause radioanalytical problems for the laboratory.
The first element that should be considered is the development of a contamination control plan,
followed by a contamination control implementation program. The following elements should be
considered in developing a plan:
Personnel responsible for developing and implementing the program;
Suggested changes to the laboratory layout;
Laboratory/building areas to monitor;
Methods and frequency of monitoring;
Action levels and corresponding analytical decision levels30 for each type of
contamination and monitored area; and
Documentation.
Personnel Responsible for Developing and Implementing the Program
Generally, key radiochemistry, quality assurance, and radiation protection personnel have
different concerns and perspectives and should therefore all be involved in the development and
implementation of the contamination control plan. Certain work functions needed for the
implementation of the program (swipes, surveys, sample analysis, floor mopping, etc.) can be
carried out by technicians, analytical staff, and other appropriately trained support personnel.
29 These values are examples only, based on experience in specific laboratory settings with specific MQOs. Each
laboratory should determine its own AAL(Q, MMR(O, and ADL(Q values, based on the individual laboratory
environment and the project MQOs being addressed. See section 2.2, Establishing Acceptable Levels of
Radioactivity and Radiation, for more detail.
30 See Appendix VI in Radiological Laboratory Sample Analysis Guide for Incidents of National Significance -
Radionuclides in Water (EPA 2008), "Establishing DQOs and MQOs for Incident Response Analysis."
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Suggested Changes to the Laboratory Layout for Radiological or Nuclear Incident
Response Operations
Appendix A of this guide, Planning Considerations for Laboratory Layout and Process Flow,
provides general guidance for establishing the physical layout of the laboratory, with
consideration for the type of work being done and the levels of radioactivity being handled.
Appendix A shows only a simplified, conceptual layout of laboratory areas to be considered for
general planning purposes.
In this appendix, a different, more detailed example of a laboratory configuration is considered,
in which a variety of analytical functions may be performed, both radiological and non-
radiological. In this case, activities related to a radiological or nuclear incident response may
require the laboratory to make temporary changes to specific radiochemistry, sample receiving,
and storage areas to accommodate the potential influx of higher-activity samples.
Figures 12 and 13 provide specific examples of how laboratory and facility contamination and
radiation monitoring controls might change from normal operation to the incident response
situation. The suggested changes should be considered only as examples, and a laboratory may
have to come up with its own solutions to specific problems. For example, if it is not feasible to
install an additional hood (see hood #3 in Figure 13b) in the sample prep area, perhaps a portable
fume hood can be purchased and reserved for handling of high-activity samples.
Figure 12a describes a hypothetical environmental laboratory, with the radiochemistry laboratory
and the nuclear instrumentation area (the counting room) expanded in Figure 12b. Figure 13
represents the same laboratory modified for radiological or nuclear incident response. Figure 13a
includes modifications to the whole laboratory, such as the creation of High-Level Work Areas,
additional area monitoring thermoluminescent dosimeters (AMTLDs) in areas normally not
monitored for exposure to radiation, and creation of long-term radioactive sample and
radioactive waste storage in a remote area of the facility. Figure 13b represents the expanded
view of the radiochemistry laboratory and the nuclear instrumentation area modified for incident
response. Table 4 summarizes the major changes suggested for this hypothetical laboratory when
a radiological or nuclear incident response is taking place and the rationale for each. Once again,
these modifications are provided only as examples. They may be examined and subsequently
included in the laboratory contamination control plan only after careful consideration of the
laboratory's individual needs.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
D)
W
OrganicAnalysis
Laboratory
r^
Staff Off ices
F
VJ
1
Radiochemistry
Laboratory
V/
Receiving
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Storeroom
Supplies
V
Nuclear
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7
a
InorganicAnalysis
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c
i
~r\
0
!
+
c
(
Q
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^
k^
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il
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n
0
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Reception
n
~J Main
^Entrance
Staff and Visitor Parking
Staff&
Handicap
Entrance
Figure 12a - Hypothetical Environmental Laboratory Operating Under Normal Conditions
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Radiochemistry Laboratory (Expanded View)
£
CO
"o_
E
co
CO
0)
c?
I"
o
CO
o
o
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o
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Radioactive Materials Area
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n
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[7
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Sample Staging
(Shielded)
IK,, 1 I HPGe Gamma | / ^ \
Na v o * * / sT \
1 v 1 1 Spectrometry 1 11
\ / ^^ ^^ -f
\ a
x °
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Figure 12b - Hypothetical Environmental Laboratory Operating Under Normal Conditions
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
en
.9 .*
0. 0
0.0
OrganicAnalysis
Laboratory
Staff Off ices
Microbiology
Laboratory
-No Access: Emergency Only
A
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/I'
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n I Rad. Sample 1^
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r^fu^^ ^ ^ %^
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/Handicap
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.."Controlled Area Authorized
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Area Monito ring TLD
Radioactive waste receptacle
Frisker (survey meter)
Step-off pad (required)
Restricted access area
Routine-Level Work Area
High-level Work Area
Figure 13a - Hypothetical Environmental Laboratory Operating Under Incident-Response
Conditions
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Radiochemistry Laboratory (Expanded View)
0)
1
E
ro
OT
O Hood #3
fcr
m
Hood #1
....
**«
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© *
l^adN
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encyOnly
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r
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.*^ Radioactive Materials Area *^^**»» I
si
~ OT
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6 I
T
\^
.^^ Radioactive Wa;
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1
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Sample Staging
(Shielded)
f HPGe Gamma |
I Spectrometry I
^^ ^^
(w}
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. * analyzer are moved from the Nuclear f ^v
t~f) Instrumentation Roomtothe facility's V"J)
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Figure 13b - Hypothetical Environmental Laboratory Operating Under Incident-
Response Conditions: Radiochemistry Laboratory Expanded View
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Table 4 - Summary of Major Changes Suggested for Radiological or Nuclear Incident
Response Operations
Programmatic
Issue
Change from Normal Operation
Rationale
Controlled access
areas
Access to laboratory areas is limited to
authorized personnel only.
The laboratory limits access to work areas to
only those persons possessing appropriate,
documented training. This will prevent
exposure of members of the general public to
radioactivity and help ensure use of safe work
practices in the laboratory and, thereby,
protection of workers.
Isolated
preparation area
for radiological
screening upon
receipt
Gross o/p and gross y screening has been
instituted for all incident-related samples
that might contain elevated levels of
radioactivity. A fully functional prepara-
tion area (including a hood and all other
necessary equipment, safety equipment,
waste containers, step-off pad, etc.) has
been set up adjacent to receipt area.
Expanded screening beyond the DOT
radiological screens routinely performed
supports the contamination control program and
permits prioritization of sample analysis
according to different activity levels. Isolating
the handling of elevated activity samples from
routine low-level work minimizes the risk of
cross-contamination.
Isolated
instrumentation
area for rad
screening upon
receipt
Nal-y detector and liquid scintillation
counters (LSCs) have been transferred
from the routine counting area to an ante-
room in the receipt area to identify and
segregate samples with the elevated
activity.
The size of the facility and limited amount of
instrumentation prevent identifying a more
remote area for sample counting. However, rad
screening in a separate area minimizes impact
of radioactive samples on low-level counting
operations. The laboratory also should institute
measures to minimize impact of transient
sources of radiation on counting.
Isolated radioactive
sample preparation
area
A discrete area has been designated for
preparing, splitting and screening, and
aliquanting samples prior to release to
radiochemistry laboratory for chemical
separations and source preparation.
Although use of separate areas for handling rad
and non-rad samples would be most ideal, due
to the small size of the laboratory and limited
instrumentation, contamination will be
controlled by preparing aliquants of limited
known gross activity prior to release to the
radiochemistry laboratory.
Designated zones
for radioactive
sample handling
within the
radiochemistry
area
The laboratory has designated two zones
in its radiochemistry laboratory for
processing samples containing different
activity levels.
Complete segregation is preferable, but facility
size precludes multiple areas for chemical
separations of samples containing different
activity levels. Screened aliquants of limited
known gross activity will be prepared and
released to the appropriate zone of the
radiochemistry laboratory for processing to
minimize the risk of cross-contamination.
Step-off pads
Added step-off pads at egress points in
areas handling rad samples.
To control personnel contamination and limit
the spread of contamination through the
laboratory.
Survey meters
Survey meters have been located where
significant quantities of radioactive
materials are in use.
Survey meters, while limited in their sensitivity,
may permit real-time detection of activity and
radioactive contamination before it spreads and
compromises health and safety or data quality.
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
Programmatic
Issue
Radioactive waste
receptacles
Dosimetry
AMTLDs
AMTLDs
Remote storage of
radioactive samples
Remote storage of
radioactive waste
Change from Normal Operation
Receptacles have been added where
incident-related processes will produce rad
waste (or potential rad waste, including
step-off pads). This is only a temporary
waste receptacle and should be emptied
daily to a more remote waste storage
location.
Laboratory has instituted use of personnel
dosimetry (e.g., TLDs andbioassay).
Installed AMTLDs wherever significant
activity is stored or in use.
Installed AMTLDs in areas accessible to
public.
Storage of samples is limited to in-
progress samples. Remote, secure,
climate-controlled sample storage and
archiving areas are established (e.g.,
parking lot).
Storage of radioactive waste in work areas
is limited and radioactive waste is moved
to remote storage area on a frequent basis
(e.g., daily or weekly) to prevent
accumulation of significant amounts of
material.
Rationale
To capture incident-related wastes per prior
evaluation of incident-related procedures.
Personal dosimetry provides measurements of
exposure to workers and allows exposures to be
kept as low as reasonably achievable. Where
high levels of activity are handled, more
frequent or even real-time dosimetry may be
required.
To measure highest potential external dose to
workers.
To measure highest potential external dose to
public.
Personnel exposures will be minimized, the risk
of contamination reduced, and impact on
instrument backgrounds minimized by
maintaining only in-process samples in sample
storage, laboratory processing, and
instrumentation areas.
Personnel exposures will be minimized, the risk
of contamination reduced, and impact on
instrument backgrounds minimized by
maintaining only in-process waste in sample
storage, laboratory processing, and
instrumentation areas.
Areas to Monitor During a Radiological Event
Areas in a laboratory where radioactive materials are used, stored, or transported should be
subjected to the most frequent monitoring. The laboratory should carefully consider the physical
configuration of the work areas, the flow of work through those areas, and the level of
radioactivity being handled in those areas when deciding what areas should be surveyed and with
what frequency. Generally, the more activity in use, the more frequent monitoring is required.
Areas where radioactive materials are used in an open or uncontained form generally are
associated with the highest likelihood of contamination and would require the highest frequency
of monitoring. Office areas, lunch areas, and the like are much less likely to be contaminated
(generally by transport of contamination from another area) and thus would generally be
monitored with the least frequency.
The following laboratory areas are examples of areas that are typically considered for
monitoring:
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Sample receiving areas
The monitoring program for sample receiving areas should be sure to consider any area
or surface that is used to process uncharacterized samples, including shipping containers,
as well as any surfaces that receiving personnel may come into contact with during
sample receipt operations. Other surfaces that may not have direct contact, but may
become indirectly contaminated, such as air foils or sink drains, should be carefully and
critically evaluated to determine a level of monitoring and control that is appropriate to
the specific conditions in that area.
An abbreviated example of the types of items and surfaces to be considered includes:
o Incoming samples;
o Shipping containers and packing materials;
o Bench tops;
o Hood surfaces;
o Floors and loading docks;
o Keyboards, phones, and other office equipment; and
o Light switches and doorknobs.
In this, and in the following examples, the list is provided only to illustrate the types of
items and surfaces to be considered. These examples should in no way be considered to
be prescriptive or complete. Each laboratory must evaluate its own activities, procedures,
and levels of radioactive materials to determine the appropriate items and surfaces,
monitoring frequency, action levels, and other content of a radiological monitoring
program that is specific to the area being evaluated.
Sample preparation areas
This area should include the same types of surfaces and work areas discussed above for
the sample receiving areas, but would also incorporate items that are specific to the
handling and preparation of open sample material, with consideration of the activity
levels, sample matrices, and types of tasks being performed. This includes areas such as
the Sample Screening Areas, High-, Routine-, and Low-Level Work Areas. Additional
items to consider may include:
o Labware;
o Sample and waste storage areas, shelves, etc.;
o Egress area equipment;
o Step-off pads;
o Instrument control panels; and
o Sinks, floor drains, and traps.
Nuclear instrumentation rooms, whether they are in High-, Routine-, or Low-Level Work
Areas, should also incorporate the ongoing evaluation of analytical equipment, as well as
those surfaces and areas listed above that might be applicable:
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o Detectors, instrument housing surfaces, shields; and
o Desiccators or other sample storage cabinets.
In addition, the laboratory may wish to incorporate into the Radiological Monitoring Program a
real-time evaluation of instrument performance checks and QC control charts, as an indication of
emerging low-level laboratory contamination issues.
General and administrative areas
Although perhaps less frequently, these areas should be evaluated periodically to ensure
that laboratory contamination is contained and controlled, and has not migrated out of the
designated radiological areas. These evaluations may include areas and surfaces such as:
o Hallways and floors;
o Administrative areas - desks, doorknobs, telephones/switchboards, keyboards;
o Break room and restroom fixtures;
o Sinks, traps, and floor drains; and
o Door handles at the building exits.
While the frequency for these monitoring activities may be less than for the general laboratory
areas, the MQOs for the survey measurements should be carefully considered and should be
appropriate for the lower levels of acceptable exposure to non-radiological workers and to the
general public.
Monitoring Method and Frequency of Monitoring
Once the laboratory has determined what changes may be appropriate to the layout of the
laboratory and which areas and items require increased contamination surveillance, the
laboratory should then determine which contamination monitoring techniques will be appropriate
and how frequently they should be performed.
Ambient exposure and dose rate measurements, fixed and removable contamination surveys, and
the analysis of process by-products such as mop water or HVAC air filters all provide
information about the various laboratory activities and the specific contamination risks
associated with different areas. In all cases, the contamination surveillance measurements should
support the laboratory's ability to make decisions regarding the potential for radioanalytical
contamination that interferes with the MQOs of the incident response.
An example of target areas to be monitored, techniques used, and minimum frequency
recommended is summarized in Table 5.31 Additional information on the contamination
31 For all of these measurements, baseline values representing normal routine operations should be established
before any incident-related samples are received. General guidance is provided in NUREG 1556, vol. 11, but each
laboratory should develop its own program. The approach should also keep in mind that the NUREG document is
focused primarily on human health concerns, although much lower levels of radioactive contamination may be of
concern in radioanalytical facilities where measurements of low-level radioactivity are being performed.
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monitoring of laboratory surfaces and equipment is provided in Appendix H, Surveillance of
Laboratory Surfaces and Equipment.
Table 5 - Target Areas, Techniques, and Frequency of Radiological Monitoring
Laboratory Area
Sample Receipt
High-Level Screening
and Processing Areas
Routine-Level
Processing Areas
Long-Term Sample or
Waste Storage - High-
Level
Nuclear Instrumentation
Room - High-Level
Nuclear Instrumentation
Room - Routine-Level
Hallways
Administrative
Sinks, Traps, and Floor
Drains
External Radiation
Monitoring
Item Monitored
Samples received
Bench top
Floor
Bench tops, doorknobs
Hoods
Floor
Labware (non-disposable)
Sample and waste storage
areas, shelves, etc.
Entry area
Egress area
Sticky pads
Bench tops, doorknobs
Hoods
Floor
Labware
Sample and waste storage
areas, shelves, etc.
Shelves
Floor
Detectors, instruments,
shields
Bench and work areas
Computer keyboards
Floor
Detectors, instruments,
shields
Bench and work areas
Computer keyboards
Floor
Floors
Desks, doorknobs
Sink surfaces, drain
elbows, beneath sinks
One TLD in areas of high-
level samples
Type of Monitoring
Survey meter, swipe
Survey meter, swipe
Mop water, swipes
Survey meter, swipe
Survey meter, swipe
Mop water
Rinse water
Survey meter, swipe
Sticky pad
Survey meter - hand
and foot monitoring
Gamma spectrometer
Survey meter, swipe
Survey meter, swipe
Mop water
Rinse water
Survey meter, swipe
Survey meter, swipe
Mop water
Swipes
Swipes
Swipes
Mop water
Swipes
Swipes
Swipes
Mop water
Mop water
Swipes
Swipes and "on-
contact" dose rate
measurements
Environmental TLDs
Frequency I1]
Upon receipt
Weekly
Every two weeks
composite
Daily
Daily
Daily
Weekly
composite
Weekly
Weekly
Upon leaving
area
Weekly
Every two weeks
Every two weeks
Every two weeks
Weekly
composite
Every two weeks
Weekly
Weekly
Weekly
Weekly
Weekly
Weekly
Weekly
Every two weeks
Every two weeks
Every two weeks
Every two weeks
Monthly
Monthly
Monthly
[1] Monitoring frequencies during
effectiveness of the laboratory'
the first several days of an incident response may need to be increased until the
s contamination control measures can be assessed.
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Investigation and Action Levels for Each Monitored Area
Within the contamination control plan and program, action levels should be specified which,
when exceeded, require some type of intervention.
For certain analytical methods, such as gamma spectrometry or gas proportional
counting, in which the total number of radiation events is integrated over a measurable
counting period, each action level should have an associated ADL based on the
probability of committing Type I and II errors.32 When the contamination measurement
result is above the ADL, it is assumed that the action level has been exceeded.
Alternately, for survey techniques such as exposure rate meters or Geiger-Miiller (G-M)
probes that simply provide an instantaneous dose- or count-rate, an "investigation level"
should be established, which would trigger further action when exceeded. This further
action may include additional swipe surveys or other definitive analytical techniques. In
some cases, these investigation and action levels may correlate to the level of
radioactivity typically encountered in the laboratory under routine conditions. In this
case, a change in laboratory radioactivity levels can be determined only if an accurate
baseline measurement has been previously performed for the specific method being
evaluated.
Table 6 provides examples of the types of investigation and action levels that might be
considered for the laboratory. These will necessarily vary by the type of area and the specific
operations performed in that area.
Table 6 - Example Contamination Investigation and Action Levels
Instrument
Survey meters (e.g.,
exposure rate meters, G-
M probes, etc.)
Gross alpha / beta - GPC
Gamma Spectrometry
Item
Bench tops, instrument
surfaces
Swipes
Swipes, mats
Mop and rinse water
Investigation Levels (for survey
meters) and Action Levels (for
instrumentation)
3 times ambient background33
1 pCi beta
0.1 pCi alpha
15 pCi gross gamma
(ref. 137Cs)
The type of actions triggered by exceeding investigation levels or ADLs may vary from
increased monitoring to process stoppage and decontamination of the area to acceptable levels.
The investigation and action levels will vary according to laboratory area. A certain amount of
contamination that may be tolerable in the high-level sample processing area would not be
permissible in the low-level nuclear instrumentation area. The results of the monitoring activities
32 See Appendix VI in Radiological Laboratory Sample Analysis Guide for Incidents of National Significance -
Radionuclides in Water for the determination of an ADL as a function of Type I and Type II decision errors.
33 See the companion documents, Guide for Laboratories - Identification, Preparation, and Implementation of Core
Operations for Radiological or Nuclear Incident Response (EPA 2010) and Radiological Laboratory Sample
Screening Analysis Guide for Incidents of National Significance (EPA 2009b) for additional discussion regarding
considerations in the appropriate determination of instrument background count rates.
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in Table 5 should be compared on a periodic (e.g., weekly) basis to the established investigation
and action levels to determine whether an action is needed, and to identify trends that might
indicate a developing problem. Action items from the contamination control program should be
entered into the laboratory's corrective action program, indicating the date, cause of the action,
action to be taken, person responsible for implementation of the action, and the due date for
completion of the corrective action.
Documentation
A summary of the results of the contamination control program should be incorporated, as a
separate section, into the laboratory's quality assurance program reports and documentation. In
addition, the results of the contamination control program should be discussed at quality
assurance and safety program staff meetings.
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APPENDIX H: SURVEILLANCE OF LABORATORY SURFACES AND EQUIPMENT
1. Fixed Contamination Surveys
1.1 Fixed contamination surveys should be performed:
On any object or material being transferred from a higher-activity area to a lower-
activity area.
On any surface that has been potentially contaminated by the handling of radioactive
material.
On the hands, feet, and outer garments of any employee exiting a radiological
processing area. This includes any employee moving from a higher-activity area to a
lower-activity area.
1.2. Survey instrument readings should be recorded in a logbook or on a standardized form to
ensure a record of the survey activities, and to allow for supervisory/management review
of the survey results. An example form is shown in Figures 14 and 15, which may also
be used to record swipe surveys discussed in Section 2 of this appendix. When
developing such a form, it is useful for the laboratory to include a map of the facility or
area to aid in the survey description. The map should be sufficiently detailed to allow the
survey technicians to indicate specific items, such as bench tops and fume hoods.
1.3. Measure and record the instrument background reading.
Where survey results and/or action levels are referenced to a background level, an
appropriate measurement of the instrument background readings must be taken prior
to measuring the surfaces.
Activity measurements (e.g., dpm, pCi, Bq, etc.) are, by definition, net results and
should always be appropriately background corrected, which requires a
representative measurement of the instrument background readings for the particular
measurement geometry.
For general measurements of surfaces of a variable or unpredictable composition,
the background readings for instruments measuring alpha and beta activity can be
made by simply removing the survey probe to an acceptable distance from possible
sources of contamination.
When the surfaces being measured are consistent or predictable, such as when
measuring swipe samples or direct measurements of walls or floors, the background
measurement should be made against an appropriate control surface, such as a clean
swipe or a similarly constructed wall or floor outside the work area.
When measuring the background readings for gamma activity, including exposure
and dose rate meters, great care should be taken to ensure that the background
reading is performed well away from potential sources of gamma activity, which can
travel significant distances in the laboratory.
The technicians should be aware of their proximity to radioactive materials storage
areas, waste collection areas, and any other potential sources of gamma activity. In
some cases, the background reading may have to be taken in advance, in another
area of the laboratory, to ensure that the determination of net instrument response is
accurate.
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XYZ Laboratories, Inc.
RADIOACTIVE CONTAMINATION SURVEY REPORT
Date and Time:
Technician:
Instrument ID:
Calibration Date:
Check all that apply:
Routine scheduled surveillance Hand-held survey meter
Response to spill or other incident. Swipe samples
If response to spill or other incident, the RSO has been notified.
Other notes and comments:
Action Levels (specific
If Action Level is e>
to area and type of survey - see Radiation Protection Plan):
Circle Type of Radiation/Reading and
Action Level Units Measurement Units
Alpha uR/h cpm
Beta mrem/h dpm
Gamma Other:
ceeded, report to Radiation Safety Officer.
Survey Results: Indicate location on back of form, if necessary.
Item*
0
1
2
3
4
5
6
7
8
9
10
11
12
Approved By:
Date:
gross net (circle one)
Description Survey Result Units
Background Measurement (Gross Only)
Type of
Radiation
Figure 14 - Example Survey Report Form, Front
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ADMINISTRATIVE & OFFICES
Men
Women
BreakArea
Plating,
Planchetting,
etc.
Chemical
Separations
Sample
Digestions
Gross Prep
and
Aliquanting
Sample
Staging
Area
Waste
Accumulation
Area
INSTRUMENT
& LOW LEVEL
o
o
o
Storage for
Reagents,
Supplies,
Other
Consumables
Plating,
Planchetting,
etc.
(Final
Presentation
to Instrument)
Chemical
Separations
Decon Area
Sample
Storage
Area
Plating,
Planchetting,
etc.
SCREENING
L _
RECEIVING
Computer &
DeskAreas,
etc.
Rad
Standards
Storage
Decon Area
I Sub-Sample
| Staging Area
HIGH LEVEL
Chemical
Separations
Sample
Digestions
__1 1
GrossPrepand Aliquanting
Dashed lines denote work area boundaries and partitions
Solid linesdenote walls
Figure 15 - Example Survey Report Form, Back
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1.4. Measurements are made of the potentially affected surfaces. The probe of the survey
instrument should be moved across the surface to be surveyed slowly (2-3 inches per
second is a customary scan rate) and deliberately to enable detection of discreet areas of
contamination. Typically, hand-held probes may be held approximately one inch from
the surface and moved approximately 2-3 inches per second. In the event that "hot
particles" are suspected, slower scan rates are advisable, as the scanning instrument
response may otherwise be too slow to react. Great care should be taken to protect the
hand-held survey equipment from contamination by the items being surveyed.
When performing the survey, it is not unusual for the instrument reading to fluctuate
somewhat while traversing the areas to be measured. It is acceptable to simply record
the highest observed reading. If the survey indicates unacceptable contamination levels
on a specific part of the surface, a detailed note should be made accordingly.
1.5. Action levels for surveys should be based on the type of area and the acceptable levels of
contamination, as discussed in Section 2.2. Any surface measurement that results in a
survey reading above the associated action levels should be confirmed. Portable items
should be sequestered until decontamination procedures are completed. Access and use
of contaminated laboratory surfaces should be prevented until decontamination is
completed.
1.6. Note that the success of any decontamination activities must be confirmed with a new
survey prior to releasing the surface or object for use in the laboratory.
2. Removable Surface Contamination (Swipes) Surveys34
2.1 Surveys should be required on all potentially affected surfaces that present a risk of
transferring contamination to laboratory workers, equipment, or other samples.
2.1.1 Sample containers should be surveyed before moving the containers from a
high-activity level area to a lower activity level area.
2.1.2 Laboratory equipment that is being moved from a high-activity level area to a
lower-activity level area should be surveyed.
2.1.3 Laboratory surfaces, such as hood interiors, bench tops, floors, etc., should
receive regular, periodic surveys. In addition, these surfaces should be surveyed
following operations with significantly elevated levels of radioactivity, or after a
spill or other release of radiological material, to ensure that the decontamination
efforts are successful.
2.2 Swipe survey protocols, in addition to ensuring accurate results, should be developed to
facilitate the sampling and rapid analysis of large numbers of swipes. Analysis of the
swipes by direct reading instrumentation, without the need for significant preparation or
handling, and the use of instrumentation with an automatic sample changer, should be
considered whenever possible.
2.3 The swipe material should be rugged enough to remove surficial contamination from the
surface of the object being surveyed, without significantly damaging the swipe or
leaving swipe material behind on the surface.
34 Additional detailed information regarding the removable contamination surveys may be found in the companion
document, A Performance-Based Approach to the Use of Swipe Samples in Response to a Radiological or Nuclear
Incident (EPA 2011).
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2.4 The decision to wet the swipe, and the selection of a wetting agent, should take into
consideration the chemical form of the potential contamination and the degree to which
the solution may be compatible with the analytical process.
2.5 As with the use of hand-held survey equipment, the collection of swipe samples may be
greatly affected by the technique of the individual collecting the samples. If possible, the
number of individuals who collect swipes should be limited to ensure consistency in the
final results.
2.6 The survey activities and results should be recorded on a standardized form, such as the
one shown in Figure 14, to ensure complete documentation and to facilitate adequate
supervisory review of the information.
2.7 The area to be swiped should be as consistent as possible. In some cases, it may be
helpful to include a diagram of the standard swipe area, on the form used to record the
survey activities, as a reminder to the survey technician.
2.8 When collecting the swipe samples on larger surfaces, or objects on which the potential
contamination is not expected to be consistent or homogeneous over the entire surface,
multiple swipes may need to be taken to ensure that the final results provide accurate
information about the level of contamination on the object.
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APPENDIX I: DECONTAMINATION OF LABORATORY SURFACES AND
EQUIPMENT
This example is intended to provide guidance for the decontamination of laboratory surfaces. If
the contamination is the result of a spill or other release of radiological materials, this guidance is
applicable after the general containment and removal of debris and gross materials from the spill.
This is a generalized protocol, provided for example purposes only. The user should evaluate
each situation and determine whether these or other measures will be more appropriate and
effective.
1. Selection of Decontamination Equipment and Materials
A ready supply of decontamination equipment and materials should be maintained and kept
close at hand in the work areas. These items are separate from, and in addition to, spill
response equipment and supplies. Decontamination supplies should be selected based on the
surfaces to be cleaned and the type of radiological material being handled in the laboratory,
but should include at a minimum:
Disposable towels or absorbent wipes;
Disposable scrubbing brushes;
Spray bottles containing the appropriate decon solution; and
Sealable plastic bags or other means of containing and disposing of used decontamination
supplies.
Selection of the appropriate decontamination solution should consider the type of
radiological material being handled in the laboratory. Most household cleaning solutions,
such as window cleaner or multi-surface cleaners, will be quite effective in removing a wide
variety of surficial contamination. The laboratory may also consider commercially available
radiological decontamination solutions that contain chelating agents, which are useful in the
removal of radionuclides present in ionic form.
2. Decontamination Procedures
Decontamination procedures for laboratory surfaces are much like any other general cleaning
task in the laboratory. Specific care should be taken, however, to deliberately contain and
remove the contamination without spreading the radiological material to uncontaminated
areas. The laboratory's specific decontamination procedures must address the specific
surfaces, type of radiological materials, levels of radioactivity present, potential exposure
concerns, waste disposal practices, and release criteria. The following steps are intended only
as an example:
2.1. Identify the area to be decontaminated. Previous surveys should have adequately defined
the affected areas and identified the boundaries of the contamination.
2.2. Stage the decontamination supplies and disposal container within reach of the
contaminated area, on top of a disposable piece of laboratory bench paper.
2.3. Spray the contaminated surface with the appropriate decontamination solution.
2.4. With a disposable towel or wipe, start at the outer edge of the contaminated area.
Maintain a definite boundary between the cleaned and contaminated areas.
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2.5. Avoid spreading contamination into the areas already cleaned by working in one
direction and frequently disposing of and replacing the cleaning towels.
2.6. Any potentially contaminated supplies should be immediately transferred to a sealable
plastic bag, or other container, for disposal.
2.7. After the initial decontamination procedure, repeat from the beginning to ensure
adequate removal of the contamination.
2.8. Finally, dispose of all potentially contaminated supplies, including the laboratory bench
paper, and place the waste material in the proper waste collection container.
To minimize the risk of further contamination to the facility, the removal of potentially
contaminated materials and decontamination supplies from the affected area should take place
only after the contamination event has been contained, the materials have been properly secured
and surveyed, and not under the "crisis" or "emergency" conditions that may have been created
by the contamination incident, if possible.
3. Re-Survey of the Contaminated Surfaces
After completing the decontamination process, the objects or surfaces must not be released
for general use until a new survey has been performed to confirm that the decontamination
procedure was successful.
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APPENDIX J: ESTABLISHING MQOS FOR SAMPLE SCREENING
MEASUREMENTS
Section 2.2 of this guide contains an example in which a hypothetical laboratory establishes
contamination control MQOs by determining AAL(C), MMR(C), and ADL(C) values for alpha-
emitting radioactive contamination measurements in Routine-Level Work Areas in the
laboratory. These contamination control MQOs were based on the AAL(S), MMR(S), and ADL(,S)
MQOs that the laboratory is required to meet for sample analyses. This appendix provides an
additional example that illustrates how a laboratory might develop similar MQOs for sample
screening measurements35 when those screening results are used to segregate samples into
different types of work areas, depending on the sample activity levels.
As in Section 2.2, incident response MQOs will be distinguished from the laboratory's internal
screening MQOs by the use of the parentheticals (S) for sample and (C) for potential cross-
contamination from co-processed samples.
1. Determine AAL(C)
Consider an example scenario in which the laboratory wants to establish limits for beta
activity in a Low-Level Work Area. As with the previous example, in Section 2.2, MQOs for
sample screening results, which may be used as the basis of segregating samples by activity
concentration levels, will be directly related to the MQOs for incident response sample
analysis.
Developing MQOs for sample screening measurements in this scenario is very similar to the
development of MQOs for removable surface contamination surveys, as discussed in Section
2.2. In both cases, the potential activity from a source of contamination contributes to the
uncertainty of the field sample measurement, and the estimate of the maximum tolerable
level of contamination is the basis for the Analytical Action Level of the contamination
control or sample screening measurement, i.e., AAL(C).
In this example scenario:
The laboratory area is used for the preparation of samples that are required to meet
MQOs that cannot generally be supported by the "Routine-Level Work Area"
contamination surveillance limits described in Table 2. In this scenario, the laboratory
has established a "Low-Level Work Area" for the preparation of these samples.
The incident response MQO for 90Sr analysis in water samples states that the required
method uncertainty, WMR(<$) is not to exceed 0.15 pCi/L at the specified AAL(,S),
which is 1.5 pCi/L.
Sample activity measurements below 1.5 pCi/L are also limited to the required
method uncertainty, WMR(<$), of 0.15 pCi/L, and measurements above 1.5 pCi/L are
limited to a relative required method uncertainty, (f>us.(S), of 10% of the measured
activity.
35 Additional detailed information regarding sample screening MQOs, sample processing for screening purposes,
instrument calibration considerations, and other key recommendations is provided in the companion guide
Radiological Laboratory Sample Screening Analysis Guide for Incidents of National Significance (EPA 402-R-09-
008, June 2009).
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The current analytical method in use in the laboratory employs a sample aliquant of
0.5 liter and has the capability to produce a CSU of 0.13 pCi/L (8.7%) at an activity
concentration of 1.5 pCi/L, before potential sources of sample cross-contamination
are considered.
The laboratory, therefore, has a method that currently limits the CSU to 0.13 pCi/L at the
prescribed AAL(,S) of 1.5 pCi/L and wishes to determine what maximum level of potential
sample cross-contamination would increase the method uncertainty, Uy^fS), to 0.15 pCi/L.
The required method uncertainty for field sample analyses, UMR(S), may be estimated by the
laboratory by the following equation:
"MR 0?) =
or
+AAL(C)2
Solving for AAL(C) shows that the maximum tolerable level of potential 90Sr sample cross-
contamination, AAL(C), would be equal to 0.075 pCi/L in the field sample analysis.
on
Since each sample analysis employs an aliquant of 0.5 L, the maximum tolerable level of Sr
cross-contamination in each 0.5 L sample aliquant is:
0.075 pCi/L x 0.5 L = 0.0375 pCi.
The AAL(C), expressed in activity units of pCi, is therefore 0.0375 pCi beta activity from
90Sr.
Following this assessment, the laboratory technical personnel are consulted, the sample
preparation process is reviewed, and potential sources and mechanisms of sample cross-
contamination are identified. The volume of sample that may be aerosolized due to vigorous
boiling, or whether a technician inadvertently grasps the inside lip of a beaker during sample
preparation might be considered. Based on the available information, and perhaps based in
large part on the technical judgment of the staff, it is estimated that the 90Sr analysis of a field
sample could potentially receive up to 0.5 mL as cross-contamination from other samples
being processed concurrently.
Note that the values in this example are for illustrative purposes
only. Each laboratory will need to assess its own processes and
situations on a case-by-case basis. In all cases, however, the
potential sample cross-contamination should be limited to a level
that does not significantly impact the required sample analysis
method uncertainty, UMR(S).
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Limiting the potential activity from sample cross-contamination to 0.0375 pCi (as determined
above) per 0.5 mL of sample volume gives the maximum allowable 90Sr activity
concentration for samples being prepared in that Low-Level Work Area:
0.0375 pCi / 0.5 mL = 0.075 pCi/mL
= 75 pCi/L
The AAL^Q, therefore, is 75 pCi/L. For screening analyses it is generally faster, more
convenient, and analytically conservative to measure gross beta activity, rather than actual
90Sr activity. The AAL(C), therefore, is 75 pCi gross beta activity per liter of sample. This
value is shown in Table 1 of this guide, under "Maximum Screening Activity Concentrations
per Matrix", for "beta > 150 keV" in liquids.
2. Limiting the Screening Method Uncertainty,
As discussed in Section 2.2.3, the required method uncertainty, MMR(C), is calculated as:
AAL-DL
Zl-a ~*~ Zl-$
Where
AAL = analytical action level
DL = discrimination level
zi-a and zi-p are the Ia and 1-0 quantiles of the standard normal distribution function,
where a and 0 are the respective probabilities of making a Type I or Type II error.
In this example scenario, the AAL(C), has been established as 75 pCi/L. The DL is selected
as zero because the screening results for samples being processed in a Low-Level Work Area
should be distinguishable from uncontaminated, e.g., zero activity, measurements. The values
for zi-a and zi-p are both set to 1.645, corresponding to 5% Type I and Type II error rates.
Under these conditions, the required method uncertainty for gross beta screening analyses,
WMR(Q, at the AAL will be:
_, AAL-DL 75-0
UMR ((-) = = = 23 pCi/L
z\-a+z\-p 1.645 + 1.645
The laboratory, therefore, must identify analysis conditions for sample gross beta screening
that satisfy the required method uncertainty of 23 pCi/L.
3. Determining ADL(C)
The ADL(C) is the screening result that is used to determine whether or not the actual gross
beta activity in a sample is likely to exceed the AAL(C), determined above. The ADL(C) is
calculated as:
ADL(C) = AAL(Q - z,_a x UMR (Q
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= 75 - (1.645x23) = 37 pCi/L
4. Summary
In this example scenario, the laboratory determined the AAL(C) for gross beta activity in
samples being processed in the Low-Level Work Area. The AAL(C) was determined by the
MQOs associated with the field sample analyses being performed, and the laboratory's
estimate of tolerable levels of sample cross-contamination that would be unlikely to
significantly impact the field sample MQOs.
Once the AAL(C) was determined, the laboratory then established constraints on the
uncertainty, MMR(C), of the screening method to be employed, then used those values to
determine what screening measurement result, ADL(C), would cause the laboratory to decide
that the AAL(C) was likely to have been exceeded, given the screening method uncertainty
and the laboratory's tolerance for errors.
After determining the ADL(C) for gross beta sample screening analyses, the laboratory
should calculate ADL(C) values for other contamination control measurements that will be
necessary for that area, as shown in the example for Routine-Level Work Areas in Table 2.
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APPENDIX K: ESTABLISHING MQOS FOR SAMPLE EXPOSURE RATES
Section 2.2 of this guide contains an example in which a hypothetical laboratory establishes
contamination control MQOs by determining AAL(C), MMR(C), and ADL(C) values for alpha-
emitting radioactive contamination measurements in Routine-Level Work Areas in the
laboratory. These contamination control MQOs were based on the AAL(,S), MMR(S), and ADL(,S)
MQOs that the laboratory is required to meet for sample analyses. This appendix provides an
additional example that illustrates how a laboratory might develop analogous MQOs for
exposure rate measurements when those results are used to segregate samples into different types
of work areas.
It should be carefully noted that there are significant differences between analytical methods
for which the total number of radiation events is integrated over a measurable counting
period (e.g., gamma spectrometry, gas proportional counting, etc.), and methods that simply
provide an instantaneous dose- or count-rate (e.g., G-M probes, exposure rate meters, etc.).
One primary difference is the statistical basis for decisionmaking based on the probability of
committing Type I and Type II errors, which is readily employed in the former type of
measurements, and only roughly approximated in the latter.
In this example scenario, MQOs for exposure rate measurements are developed in a manner
that is analogous to the development of MQOs for integrated activity measurements. These
MQOs may be useful to the laboratory in making decisions regarding the segregation of
samples in order to minimize the impact of excessive or transient exposure on the analytical
process. The laboratory is cautioned, however, against extending the concepts presented in
this example to other applications, such as the measurement of sample radioactivity levels or
the reliance on such measurements to support decisionmaking at a proposed statistical
confidence interval.
A detailed discussion of the applicability and limitations of hand-held survey equipment is
provided in the companion document Uses of Field and Laboratory Measurements During a
Radiological or Nuclear Incident (EPA 2012).
As in Section 2.2, incident response MQOs will be distinguished from the laboratory's internal
exposure rate MQOs by the use of the parentheticals (S) and (C) for potential cross-
contamination from co-processed samples.
1. Determine AAL(C)
Consider an example scenario in which the laboratory wants to establish exposure rate limits
for individual samples in a Routine-Level Work Area. As with the previous example, in
Appendix J, MQOs for sample exposure rates, which may be used as the basis for
segregating samples to different work areas, should be related to the laboratory's ability to
achieve the required MQOs for incident response sample analysis.
Developing MQOs for exposure rate measurements in this scenario is similar to the
development of MQOs for removable surface contamination surveys, as discussed in Section
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2.2, with some notable differences. In both cases, the potential contribution from a source of
radioactive contamination or radiation exposure contributes to the uncertainty of the field
sample measurement, and the estimate of the maximum tolerable level of that contribution, is
the basis for the Analytical Action Level of the contamination control or exposure rate
measurement, i.e., AAL(C). In this example, however, the estimate of the impact on the field
sample MQOs is based on the transient effect of gamma radiation on the laboratory
instrumentation, and the measurement uncertainty is empirically derived, rather than being
calculated as a CSU.
In this example scenario:
The laboratory area is classified as a Routine-Level Work Area and is used for the
preparation and analysis of samples that are required to meet MQOs that apply to the
majority of sample analyses performed by the laboratory.
The incident response MQO for 137Cs analysis in air filters states that the required
method uncertainty, WMR(<$) is not to exceed 5 pCi/filter at the specified AAL(,S),
which is 40 pCi/filter.
Sample activity measurements below 40 pCi/filter are also limited to the required
method uncertainty, MMR(S), of 5 pCi/filter and measurements above 40 pCi/filter are
limited to a relative required method uncertainty,
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Guide for Radiological Laboratories for the Control of Radioactive Contamination and Radiation Exposure
As previously discussed, the required method uncertainty for field sample analyses,
may be estimated by the laboratory by the following equation:36
"MR 0?) =
1MR<
or
f
,
Solving for AAL(C) shows that the maximum tolerable potential bias to the 137Cs results,
AAL(C), which is treated as an additional uncertainty factor in the field sample analysis,
would be equal to 3.6 pCi/filter in the field sample analysis.
Converting this AAL(C) from an activity level to an external sample exposure rate,
^
.7.2x10-
//R-f h
The AAL(C) for sample exposure rate measurements in this particular work area is therefore
5,000 uR/h. This value is shown in Table 1 of this guide, under "Maximum Sample Exposure
Rate (uR/h at surface of container)".
2. Limiting the Survey Method Uncertainty,
As discussed in Section 2.2.3, the required method uncertainty, MMR(C), is calculated as:
AAL-DL
zi-a + zi-p
Where
AAL = analytical action level
DL = discrimination level
zi-a and zi-p are the 1-a and 1-0 quantiles of the standard normal distribution function,
where a and P are the respective probabilities of making a Type I or Type II error.
In this example scenario, the AAL(C), has been established as 5,000 uR/h. The DL is
selected as 100 uR/h, which is the AAL(C) for the Low-Level Work Areas. The values for
zi-a and zi-p are both set to 1.645, corresponding to 5% Type I and Type II error rates.
36 This equation, and others in this example scenario, make certain assumptions about the results of the empirical
study performed by the laboratory, most notably, that the effects of external exposure on the analytical system are
independent, normally distributed contributions to the uncertainty in the reported results of the field samples. This
may be a simplification of the actual laboratory conditions, and other statistical treatments of the derivation of
AAL(Q may be more appropriate in some cases. Additional information regarding the estimation of uncertainty in
various measurement systems, including the treatment of non-normal distributions, is provided in MARLAP (2004),
Chapter 19.
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Under these scenario conditions, the required method uncertainty for exposure rate
measurements, MMR(C), at the AAL will be:
,~ AAL-DL 5000-100 , Aon
«^(Q = = ,, .,. =1489 uR/h
zl_a + z^_p 1.645 +1.645
= 1.5 x 103 uR/h
The laboratory, therefore, must identify measurement conditions for exposure rate
monitoring that satisfy the required method uncertainty of 1,500 uR/h at the AAL(C) of
5,000 uR/h.
It should be noted that the "method uncertainty" in this scenario, and for other hand-held
survey instrument measurements, cannot be determined by calculating a CSU, as is done
routinely with other laboratory instrumentation that integrates the total number of radiation
events over a measurable counting period. In the case of instantaneous readout survey
instruments, the laboratory may make estimates of the uncertainty of the measurement
process by performing empirical studies that incorporate the various contributions to
variability in a measured result. For example, multiple measurements of a source might be
made under different conditions, by various technicians, and the relative standard deviation
of those measurements might be used as an estimate of the "method uncertainty."
Measurements should be taken at the AAL(C) of 5,000 uR/h.
3. Determining ADL(C)
The ADL(C) is the screening result that is used to determine whether or not the actual sample
exposure rate is likely to exceed the AAL(C), determined above. The ADL(C) is calculated
as:
ADL(C) = AAL(C) - Zl_a x UMR (Q
= 5000-(1.645x1489) = 2550 uR/h
= 2.6xl03 uR/h
4. Summary
In this example scenario, the laboratory determined the AAL(C) for sample exposure rates in
samples being processed in the Routine-Level Work Area. The AAL(C) was determined by
the MQOs associated with the field sample analyses being performed and the laboratory's
estimate of tolerable levels of instrument interference that would be unlikely to significantly
impact the field sample MQOs.
Once the AAL(C) was determined, the laboratory then established constraints on the
uncertainty, MMR(C), of the survey method to be employed, and then used those values to
determine what survey measurement result, ADL(C), would cause the laboratory to decide
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that the AAL(C) was likely to have been exceeded, given the screening method uncertainty
and the laboratory's tolerance for errors.
This example scenario makes assumptions about the laboratory's radioanalytical systems and
the direct impact of sample exposure rates on the analytical process. In some cases, the
laboratory may use exposure rate measurements for other purposes, such as a rapid and easy
technique for identifying high-activity samples transiting the laboratory, which may increase
the risk of laboratory contamination. Each laboratory should develop its own survey
measurement protocols based on the anticipated risks and concerns that may be unique to that
laboratory and ensure that the development of AAL, uncertainty, and ADL values
appropriately address those unique laboratory conditions.
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