EPA 402-R-14-010
                                       www.epa.gov/narel
                                         September 2014
                 Validation of
     Rapid Radiochemical Method for
       Radium-226 in Brick Samples
for Environmental Remediation Following
           Radiological Incidents
            U.S. Environmental Protection Agency

                Office of Air and Radiation
             Office of Radiation and Indoor Air
      National Analytical Radiation Environmental Laboratory
                 Montgomery, AL 36115

          Office of Research and Development National
             Homeland Security Research Center
                  Cincinnati, OH 45268

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
This report was prepared for the National Analytical Radiation Environmental Laboratory of the Office of
Radiation and Indoor Air and the National Homeland Security Research Center of the Office of Research
and  Development,  United  States Environmental Protection  Agency  (EPA).  It  was prepared  by
Environmental Management Support, Inc., of Silver Spring, Maryland, under contract EP-W-13-016, Task
Order 0014,  managed by Dan Askren. This document has been  reviewed in  accordance with  EPA policy
and approved for publication. Note that approval does not signify that the contents necessarily reflect the
views of the Agency. Mention of trade names, products, or services does  not convey EPA approval,
endorsement, or recommendation.

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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


                                      Contents

Acronyms, Abbreviations, Units, and Symbols	iii
Radiometric and General Unit Conversions	v
Acknowledgments	vi
1.    Introduction	7
2.    Radioanalytical Methods	8
3.    Method Validation Process Summary	8
4.    Participating Laboratory	10
5.    Measurement Quality Objectives	10
6.    Method Validation Plan	11
     6.1  Method Uncertainty	11
     6.2  Detection Capability	11
     6.3  Method Bias	12
     6.4  Analyte Concentration Range	14
     6.5  Method Specificity	14
     6.6  Method Ruggedness	14
7.    Techniques Used to Evaluate the Measurement Quality Objectives for the Rapid Methods
     Development Project	15
     7.1  Required Method Uncertainty	15
     7.2  Required Minimum Detectable Concentration	16
8.    Evaluation of Experimental Results	17
     8.1  Summary of the Method	17
     8.2  Required Method Uncertainty	17
     8.3  Required Minimum Detectable Concentration	20
     8.4  Evaluation of the Absolute and Relative Bias	23
     8.5  Method Ruggedness and Specificity	25
9.    Timeline to Complete a Batch of Samples	26
10.  Reported Modifications and Recommendations	26
11.  Summary and Conclusions	27
12.  References	28
Attachment I: Estimated Elapsed Times	29
Attachment II:  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices
     Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses for
     Environmental Remediation Following Radiological Incidents	30
     Appendix: Rapid Technique for Milling and Homogenizing Concrete and
         Brick Samples	51
Attachment III:  Rapid Radiochemical Method for Ra-226 in Building Materials for
     Environmental Remediation Following Radiological Incidents	60
Attachment IV:  Composition of Brick Used for Spiking in this Study	92
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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


                                       Figure

Figure 1 - Yields for Method Based on Measurement of 225Ra	26

                                       Tables

Table 1 - 226Ra Method Validation Test Concentrations and Results	11
Table 2 - Sample Identification and Test Concentration Level for Evaluating the Required
          Minimum Detectable Concentration	12
TableS - MARLAP "Level C" Acceptance Criteria	16
Table 4A - Ra-226 Analytical Results for Required Method Uncertainty Evaluation	19
Table 4B - Experimental Standard Deviation of the Five PT Samples by Test Level	20
Table 5 -Reported 226Ra Concentration Reagent Blank Samples	21
Table 5 A -Concentrations of the Blank Brick Samples Used to Determine the Inherent 226Ra ..21
Table 5B-Reported 226Ra Concentration of Blank Brick Samples	22
Table 6 - Reported Results for Samples Containing 226Ra at the As-Tested MDC Value (1.025
          pCi/g)	23
Table 7-Relative Bias Evaluation of the Rapid 226Ra Brick Method	24
Table 8 - Summary of 225Ra Radiochemical Yield Results for Test and Quality Control Samples
           	25
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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


                     Acronyms, Abbreviations, Units, and Symbols

AAL	analytical action level
ACS	American Chemical Society
APS	analytical protocol specification
Bq	becquerel
CZ/NC	critical net concentration
CSU	combined standard uncertainty
Ci	curie
d	day
DL	discrimination level
dpm	disintegrations per minute
dps	disintegrations per second
DQO	data quality obj ective
DRP	discrete radioactive particle
EPA	U.S. Environmental Protection Agency
FRMAC	Federal Radiological Monitoring and Assessment Center
ft	foot
FWHM	full width at half maximum
g	gram
gal	gallon
G-M	Geiger-Muller [counter or probe]
GEL	General Engineering Laboratories
Gy	gray
h	hour
ICP-AES	inductively coupled plasma - atomic emission spectrometry
ID	identifier/identification number
IND	improvised nuclear device
IUPAC	International Union  of Pure and Applied Chemistry
kg	kilogram (103 gram)
L	liter
Lc	critical level
LCS	laboratory control sample
m	meter
M	molar
MARLAP	Multi-Agency Radiological Laboratory Analytical Protocols Manual
MDA	minimum detectable activity
MDC	minimum detectable concentration
MeV	mega electron volts  (106 electron volts)
mg	milligram (10~3 gram)
min	minute
mL	milliliter (10~3 liter)
mm	millimeter (10~3 meter)
MQO	measurement quality obj ective
MVRM	method validation reference material
uCi	microcurie (1CT6 curie)
um	micrometer (10~6 meter)


September 2014                            iii                                   DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


NAREL	EPA's National Analytical Radiation Environmental  Laboratory, Montgomery,
             AL
NHSRC	EPA's National Homeland Security Research Center, Cincinnati, OH
NIST	National Institute of Standards and Technology
ORD	U.S. EPA Office of Research and Development
ORIA	U.S. EPA Office of Radiation and Indoor Air

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
                        Radiometric and General Unit Conversions
To Convert
years (y)
disintegrations per
second (dps)
Bq
Bq/kilogram (kg)
Bq/cubic meters (m3)
Bq/m3
microcuries per
milliliter ((iCi/mL)
disintegrations per
minute (dpm)
cubic feet (ft3)
gallons (gal)
gray (Gy)
roentgen equivalent:
man (rem)
To
seconds (s)
minutes (min)
hours (h)
days (d)
becquerels (Bq)
picocuries (pCi)
pCi/gram (g)
pCi/L
Bq/L
pCi/L
jiCi
pCi
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
1(T3
109
4.50xlO~7
4.50X10"1
2.83xlO~2
3.78
102
io-2
To Convert
s
min
h
d
Bq
pCi
pCi/g
pCi/L
Bq/L
pCi/L
pCi
m3
L
rad
Sv
To
y
dps
Bq
Bq/kg
Bq/m3
Bq/m3
(iCi/mL
dpm
ft3
gal
Gy
rem
Multiply by
3.17xl(T8
1.90xl(T6
1.14x10^
2.74xl(T3
1
3.70xl(T2
37.0
37.0
IO3
io-9
2.22
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.
September 2014
DRAFT

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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


                                   Acknowledgments

The U.S. Environmental Protection Agency's (EPA's) Office of Radiation and Indoor Air's
(ORIA) National Analytical Radiation Environmental Laboratory (NAREL), in conjunction with
the EPA Office of Research and Development's National Homeland Security Research Center
(NHSRC) developed this method validation report. Dr. John Griggs served as project lead.
Several individuals provided valuable support and input to this document throughout its
development. Special acknowledgment and appreciation are extended to Kathleen M. Hall, of
NHSRC.
We also wish to acknowledge the valuable suggestions provided by the staff of NAREL, who
conducted the method validation studies. Dr. Keith McCroan, of NAREL, provided significant
assistance with the equations used to calculate minimum detectable concentrations and critical
levels. Numerous other individuals, both inside and outside of EPA, provided comments and
criticisms of this  method, and their suggestions contributed greatly to the quality, consistency,
and usefulness of the final method. Environmental Management Support, Inc. provided technical
support.
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


1.  Introduction

Rapid methods need to be developed and validated for processing samples taken in response to a
radiological incident. In order to address this need, EPA initiated a project to develop rapid
methods that can be used to prioritize environmental sample processing as well as provide
quantitative results that meet measurement quality objectives (MQOs) that apply to the
intermediate and recovery phases of an incident.l Similar to the rapid method project initiated in
2007 for radionuclides in water (EPA 2008), this rapid method development project for a brick
matrix addressed four different radionuclides in addition to 226Ra: 241Am, natU, 90Sr, and 239240Pu.
Each of these radionuclides will have separate method validation reports for the brick matrix.
The methodology used for this validation process makes use of 225Ra tracer (validated for water
matrices) and a new process for fusing brick samples. The combination of these two techniques
provides a unique approach for rapid analysis of brick samples.

The method validation plan developed for the rapid methods project follows the guidance in
Method Validation Guide for Qualifying Methods  Used by Radiological Laboratories
Participating in Incident Response Activities (EPA 2009), Validation and Peer Review of U.S.
Environmental Protection Agency Radiochemical Methods of Analysis (2006), and Chapter  6 of
Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP) (EPA 2004).
The method was evaluated according to MARLAP method validation "Level C" (see MARLAP
Sections 6.1 and 6.6.3.5). The method formulated was preliminarily tested at a government
laboratory and refinements to the method were made according to the feedback from the
laboratory and the quality of the generated results. For the method validation process, the
laboratory analyzed several  sets  of blind proficiency test (PT) samples according to
specifications that meet established MQOs and guidance outlined in Radiological Sample
Analysis Guide for Incident Response - Radionuclides in Soil (EPA 2012).

The proposed MQO specification for the required method uncertainty at the analytical action
level (AAL) was based on a 226Ra concentration of approximately 5.0 pCi/g. Performance test
samples were prepared to meet this proposed AAL, and the final tested AAL value was 4.755
pCi/g. This value is the combined 226Ra spike value of the soil plus the inherent 226Ra in the soil
of 1.025  0.027 pCi/g (standard error) as determined from ten blank brick samples. The required
method uncertainty at this AAL was calculated to be 0.62 pCi/g.

This report provides a summary  of the results of the method validation process for a combination
of two methods; Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices
Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses for Environmental
Remediation Following Radiological Incidents (Attachment II) and Rapid Radiochemical
Method for Ra-226 in Building Materials for Environmental Remediation Following
Radiological Incidents (Attachment III). In this document, the combined methods are referred to
as "combined rapid 226Ra - Brick method." The method validation process is applied to the
fusion dissolution of brick using sodium hydroxide and the subsequent separation and
quantitative analysis of 226Ra using alpha spectrometry to detect the 4.60- and 4.78-million
1 ORIA and the Office of Research and Development jointly undertook the rapid methods development projects. The
MQOs were derived from Protective Action Guides determined by ORIA.
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples

                                                99^
electron volt (MeV) alpha particles from the decay of  Ra and the 7.07-MeV alpha particle
from 217At (progeny of 225Ra) that is used as the tracer yield monitor. The laboratory's complete
report, including a case narrative and a compilation of the reported results for this study, can be
obtained by contacting EPA's National Analytical Radiation Environmental Laboratory
(NAREL) (http://www.epa.gov/narel/contactus.html).

2.  Radioanalytical Methods
	                 oo/r                                                    _
The combined rapid   Ra - Brick method was written in a format consistent with EPA guidance
and conventions. The rapid method was formulated to optimize analytical throughput for sample
preparation, chemical processing, and radiation detection.

                                                                        99^
Specifications for sample processing were incorporated into the combined rapid   Ra - Brick
method. These specifications are reflected in the scope and application and in the body of the
methods. The specifications include the use of a radiotracer yield monitor and the required
method uncertainty. Known interferences are addressed in Section 4 of the attached method
(Attachment III). For this validation study, the laboratory used a 1,000-minute counting time for
three test level samples for the method uncertainty evaluation  and an 800-minute counting time
for the required minimum detectable concentration (MDC) samples. A 1-g sample size was
processed by the rapid method for both the method uncertainty and required MDC evaluations. A
summary of the rapid method is presented in Section 8.1 prior to presenting the experimental
results of the method validation analyses.
	                 oo/r                                        99^
The combined rapid   Ra - Brick method used for rapid analysis of  Ra in brick samples is
included in Attachments II and III of this report. Although this final method is a departure from
the originally tested method, the incorporated revisions are significant improvements and do not
change the general methodology. The validation process was performed using this final
combined method in the attachments.

3.  Method Validation Process Summary
	                                             oo/r
The method validation plan for the combined rapid   Ra - Brick method follows the guidance
provided in Method Validation Guide for Qualifying Methods Used by Radiological
Laboratories Participating in Incident Response Activities (EPA 2009), Validation and Peer
Review of U.S. Environmental Protection Agency Radiochemical Methods of Analysis (EPA
2006), and Chapter 6  of MARLAP (2004). This method validation process was conducted under
the generic Quality Assurance Project Plan Validation of Rapid Radiochemical Methods for
Radionuclides Listed in EPA 's Standardized Analytical Methods (SAM) for Use During
Homeland Security Events (EPA 2011). The method was evaluated according to MARLAP
method validation "Level C" (see Section 6.1 and MARLAP Section 6.6.3.5). More specifically,
the method was validated against acceptance criteria for the required method uncertainty (MMR) at
a specified AAL concentration and the required MDC. In addition, analytical results were
evaluated for radiochemical yield (as a characteristic of method ruggedness), and relative bias at
each of the three test-level  radionuclide activities. The absolute bias of the method was evaluated
using the laboratory's reagent blanks because the brick used as the method validation reference
material (MVRM) had native 226Ra that was not removed prior to spiking the MVRM.
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
The method validation process was divided into four phases:

   1.  Phase I
          a. Laboratory familiarization with the methods for brick samples.
          b.  Set-up of the laboratory and acquisition of reagents, standards and preparation of
             in-house PT samples.
          c. Perform preliminary tests of the new fusion method and continue the analysis
             using the dissolved flux from that process with the existing combined rapid 226Ra
             - Brick method, having the brick samples spiked with 226Ra and the 225Ra tracer.
          d. Make changes to improve the method based on consultation with Environmental
             Management Support, Inc. consultants and the results of the preliminary tests.
   2.  Phase II
          a. Conduct blank sample analyses to assess the method's critical level concentration.
          b. Conduct method validation test for required method uncertainty.
   3.  Phase III
          a. Conduct verification of the required MDC
   4.  Phase IV
          a. Report results.
          b. Laboratory writes report to describe the process and narratives on the method.
          c. Review and comment on method.
          d. Environmental Management Support, Inc., writes  method validation report, which
             is reviewed by laboratory.

During Phases I, II, and III, the laboratory processed and evaluated batch quality control samples
according to their laboratory quality manual, including an analytical reagent blank, laboratory
control sample (LCS), and a  sample duplicate.2

The dual objectives of the first (preliminary) phase were to familiarize the laboratory with the
formulated rapid method  and then gain hands-on experience using the rapid method to identify
areas that might require optimization. During this phase, the laboratory processed samples of
blank brick material and blank brick that was spiked in-house with 226Ra activities consistent
                                                                        	        oo/r
with evaluating the required method uncertainty at the AAL and the required MDC (see "  Ra
Method Validation Test Concentrations and Results," Table 1;  see footnote 3 on the next page).
The blank and laboratory  spiked samples used in Phase I were made by the laboratory in order to
assess the original feasibility of the proposed method. Based on information and experience
gained during Phase 1 practice runs, the rapid 226Ra method was optimized without
compromising data collected during the validation process in Phases II and III.

During Phases II and III of the method validation process, the laboratory analyzed PT samples
(consisting of MVRMs) provided by an external, National Institute of Standards and Technology
(NIST)-traceable source manufacturer (Eckert & Ziegler Analytics, Atlanta, GA). The MVRM
was brick prepared and homogenized prior to spiking by Eckert and Ziegler (see Attachment IV).
The laboratory was instructed to analyze specific blind PT samples having concentration  levels
 During the validation study, the laboratory prepared an LCS, substituted PT blanks for their lab blank and used
replicate PT samples for their lab duplicates.


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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


consistent with validation test levels for the required method uncertainty and the required MDC.
The test levels of the PT samples are listed in Tables 1  and 2. Following completion of the
method validation studies, comments from the labs were evaluated and the method revised to
conform to the documented "as-tested" conditions in Phases II and III. Thus, the validation data
presented in this report reflect the combined final method included in the attachments to this
document.

4.  Participating Laboratory

NAREL validated the combined rapid 226Ra - Brick method using NIST-traceable test samples
prepared in a brick medium.

5.  Measurement Quality Objectives

The combined rapid 226Ra - Brick method was developed to meet MQOs for the rapid methods
project. The selected MQOs  included the radionuclide concentration range, the required method
uncertainty at a specified radionuclide concentration (e.g., AAL), and the required MDC. The
required relative method uncertainty (cpMn) for the combined rapid 226Ra method was set at 13%3
at an AAL equal to 4.755 pCi/g, which is approximately the  1 x 1CT5 risk concentration for a 50-
year exposure period for a soil matrix. This brick concentration value is based on guidance found
in Federal Radiological Monitoring and Assessment Center (FRMAC) for soil.4 This particular
value is consistent with the concentration limit for site cleanup activities. This value is about five
times greater than 226Ra concentrations that commonly exist in brick (~ 1 pCi/g).  Specific action
levels for 226Ra in soil are provided in the Radiological Sample Analysis Guide for Incidents of
National Significance - Radionuclides in Soil (draft EPA 2012).  The exact values for  the target
concentrations as tested had  226Ra concentrations that were based on the addition of the inherent
226Ra in the blank brick matrix plus the 226Ra that was spiked in the sample (see Attachment IV
for the chemical composition of the brick matrix). Table 1 summarizes the targeted MQOs for
the method validation process, the calculated known values (which includes the inherent 226Ra in
the blank material) for the samples analyzed, and the average measured values as determined by
this method. The AALs for the four other radionuclides are 241Am (1.570 pCi/g),  239/240pu (1.890
pCi/g), 238U (12.35 pCi/g), and 90Sr (2.440 pCi/g). The PT sample supplier provided test data for
ten 1-gram (g) samples that documents the spread in the spike in the samples as a 1.59% standard
deviation in the distribution of results.
3 Type I and II decision error rates were set at z:_a= 0.01 and z  = 0.05. The required method uncertainty is
calculated using the formula, MMR = (AAL-DL)/[z1_a + z  ] where the analytical action level (AAL) is as noted
above and the discrimination level (DL) is !/2 the AAL.
4 Federal Radiological Monitoring and Assessment Center. Appendix C of the FRMAC Manual (FRMAC 2010) or
calculated using TurboFRMAC 2010 available from Sandia National Laboratory.


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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
            Table 1 - 226Ra Method Validation Test Concentrations and Results

MDC
!/2 x AAL
SO-U1
AAL
SO-U2
3 x AAL
SO-U2
Target
Value,
pCi/g
Inherent
Ra-226
2.5
5.0
15.0
Calculated
Known Value
[i]
1.025 0.027
2.385 0.035
4.755 0.053
15.03 0.23
Average
Measured
Value
1.000
2.427
4.73
15.4
Required
Method
Uncertainty
(MR)
	
0.62
0.62
2.0[2]
Combined
Uncertainty
 0.045
 0.027
0.37
1.1
[1]  The calculated known values listed here are the sum of the spike value added by Eckert & Ziegler Analytics
    plus the measured inherent native 226Ra in the brick of 1.025  0.027 pCi/g. The uncertainties for the spike and
    the standard uncertainty from the blank brick analysis have been calculated in quadrature.
[2]  The value of 2.0 pCi/g is the relative required method uncertainty and represents 13% of 15.03 pCi/g.

6.  Method Validation Plan
	                 oo/r
The combined rapid   Ra - Brick method was evaluated for the six important performance
characteristics for radioanalytical methods specified in Quality Assurance Project Plan
Validation of Rapid Radiochemical Methods for Radionuclides Listed in EPA 's Standardized
Analytical Methods (SAM) for Use During Homeland Security Events (EPA 2011). These
characteristics include method uncertainty, detection capability, bias, analyte activity range,
method ruggedness, and method specificity. A summary of the manner in which these
performance characteristics were evaluated is presented below. The chemical yield of the
method, an important characteristic for method ruggedness, was also evaluated.

6.1  Method Uncertainty
	                                         oo/r
The method uncertainty of the combined rapid   Ra - Brick method was to be evaluated at a
proposed AAL concentration (5.0 pCi/g) specified in the MQOs presented in Table 1. However,
since there was a known inherent 26Ra in the brick of 1.025 pCi/g and the source supplier spiked
at 3.730 pCi/g, the "as tested" AAL was found to be less than the proposed AAL by
approximately 0.24 pCi/g or a final value of 4.755 pCi/g. In accordance with MARLAP method
validation "Level C," this method was a new application and was evaluated at each of three test
concentration levels. The laboratory analyzed five replicate external PT samples containing 226Ra
activities at approximately one-half the AAL, the AAL, and three times the AAL. The method
was evaluated against the required method uncertainty (UMR= 0.62 pCi/g), at and below the "as
tested" AAL, and against the required relative method uncertainty (cpMR= 13% of the known test
value) above the AAL. The test level concentrations analyzed are listed in Table  1.

6.2  Detection Capability

In the statement of work to the laboratory, the detection capability of the combined rapid 226Ra -
Brick method was to be evaluated to meet a MDC of approximately 1.0 pCi/g, which was the
September 2014
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


measured inherent5radium in the blank brick material. The laboratory estimated the counting
time, chemical yield and sample size to meet this 1.0 pCi/g MDC. The final MDC known value
was 1.025 pCi/g as presented in Table 2. In accordance with the guidance provided in Method
Validation Guide for Qualifying Methods Used by Radiological Laboratories Participating in
Incident Response Activities (EPA 2009), the laboratory estimated the critical net concentration
based on the results of seven reagent blank samples. Results from ten replicate MDC brick
samples at the required MDC concentration were to be compared to the critical net
concentrations to determine method detection capability. For this validation study, the laboratory
used a 1000-minute counting time for three test level samples, allowing sufficient time for
ingrowth  of 217At from 225Ra while starting the sample counts the same day as the column
separation, instead of waiting 24 hours before counting as in the concrete validation study (EPA
2014). This approach allowed sufficient ingrowth of tracer counts with an earlier completion of
sample counting. Both the reagent blank samples and the MDC brick test samples were to be
counted for a length of time (800 minutes) to meet the proposed MDC requirement.

 Table 2 - Sample Identification and Test Concentration Level for Evaluating the Required
                           Minimum Detectable Concentration
Test Sample Designation
1-10
(Brick MDC samples)
RS41-R47
(Reagent blanks)
R41-R47
(Brick2 matrix blanks)
Number of
Samples
Prepared
10
7
7
Nuclide
226Ra
226Ra
226Ra
Calculated Known
Value for MDC
(pCi/g)1
1.025 0.027

1.025 0.027
Mean Measured
Concentration (pCi/g)
1.000 0.045
.0.045 0.015
1.120.13
 [1]  Weighted mean and weighted standard deviation of 10 separate blank brick samples analyzed prior to the
    method validation.
 [2]  Blank brick matrix supplied by Eckert & Ziegler Analytics, Atlanta, Georgia.

 6.3   Method Bias

 Two types of method bias were evaluated, absolute and relative.

 Absolute Bias

 The blank brick material used for this method validation study contained 226Ra (See Attachment
 IV). Therefore, the absolute bias for the method was determined using the reagent method blanks
 that were put through the entire process.

 The results from the seven blank samples for the required MDC evaluation were assessed for
 absolute bias according to the protocol and equation presented in the Method Validation Guide
for Qualifying Methods Used by Radiological Laboratories Participating in Incident Response
 Activities (EPA 2009).  Absolute bias was to be determined as a method performance parameter;
5 The inherent 226Ra content of the brick matrix was estimated by analyzing 10 replicate samples and determining
the weighted mean and weighted standard deviation of the results.
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


however, there was no acceptance limit for bias established for the method in the validation
process.
	                                                        oo/r
The following protocol was used to test the method blanks for  Ra for absolute bias:

1.   Calculate the mean (X) and estimated standard deviation (sx) for "N" (at least seven) blank
    sample net results.

2.   Use the equation below to calculate the |T| value:

                                       T

3.   An absolute bias in the measurement process is indicated if:

                                     T>tl_al2(N-l)                                  (2)

    where 1-0/2 (AM) represents the (1 - a/2)-quantile of the ^-distribution with AM degrees of
    freedom. For seven blanks, an absolute bias is identified at a significance level of 0.05, when
    |T|> 2.447.

Relative Bias

The results from the seven samples for each of the three test levels and the 10 MDC samples
were evaluated for relative bias according to the protocol and equation presented in the Method
Validation Requirements for Qualifying Methods Used by Radioanalytical Laboratories
Participating in Incident Response Activities (EPA 2009). No acceptable relative bias limit was
specified for this method validation process.
	                                                      oo/r
The following protocol was used to test the combined rapid   Ra - Brick method for relative
bias:


1. Calculate the mean (X) and estimated standard deviation (sx) of the replicate results for each
       method validation test level.

2. Use the equation below to calculate the |T| value:

                                            X-K
                                   T=  .                                             (3)
where:
    X is the average measured value
    sx  is the experimental standard deviation of the measured values
    N  is the number of replicates
    K  is the reference value
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


   u(K) is the standard uncertainty of the reference value

A relative bias in the measurement process is indicated if:

                                      \T\>t                                           ,~ x
                                      1 '    l-/2("^f)                                   (3a)

The number of effective degrees of freedom for the T statistic is calculated as follows:


                                                                                      (4)
veff, as calculated by the equation, generally is not an integer so veff should be truncated (rounded
down) to an integer. Then, given the significance level, 0.05, the critical value for "|T|" is defined
to be ?i-o/2(vefi), the (1 - a/2)-quantile of the ^-distribution with veff degrees  of freedom (see
MARLAP Appendix G, Table G.2).

6.4  Analyte Concentration Range
___                  oo/r
The combined rapid   Ra - Brick method was evaluated for the required method uncertainty at
three test level activities. The five replicate PT samples from each test level concentration were
analyzed. The proposed (target) and "as tested" (calculated known) test level activities are
presented in Table 1 . Note that the final test concentration values for the PT samples varied from
                                            996
the proposed test levels because of the inherent   Ra in the blank brick matrix.

6.5  Method Specificity
___                        996                            996
The method is specific for   Ra by collecting and purifying   Ra through a series of column
separations after sample digestion. The brick sample is fused with sodium hydroxide in
zirconium crucibles for -15 minutes at 600 C in a furnace. The fused material is dissolved using
water and transferred to a centrifuge tube. A preconcentration step using a calcium carbonate
precipitation is used to remove all isotopes of Ra from the alkaline matrix. The precipitate is
dissolved in dilute acid and loaded onto cation resin to remove calcium (Ca) ions. After elution
from the cation resin, barium (Ba) ions present in brick are removed using Sr Resin to prevent Ba
interference on alpha peak resolution. This step eliminates concern about  sample size and native
Ba content adversely affecting alpha peak resolution. The sample is then passed through Ln
(lanthanide) Resin to remove actinium-225 (225 Ac) and any residual Ca ions. Ra-226 in the
purified sample is precipitated using barium sulfate microprecipitation in  the presence of
isopropanol  to prepare sources for alpha counting.

6.6  Method Ruggedness

The rapid sodium hydroxide fusion is very rugged and will dissolve refractory particles  present.
The series of column separations removes alpha-emitting interferences and results in very good
alpha peak resolution and spectra free from interferences. The sodium hydroxide fusion has been
used successfully on the U.S. Department of Energy's Mixed Analyte Performance Evaluation


September 2014                             14                                    DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


Program soil samples containing refractory actinides. When brick or soil samples are digested in
an alkaline matrix, iron hydroxide precipitates, resulting in Ra loss in that precipitate. If the
sample were passed through MnC>2 resin, for example, at an alkaline to neutral pH, there would
be loss of Ra in that iron hydroxide precipitate. A MnC>2 precipitation can also collect unwanted
Ca present in the sample. With this approach, any Ra that precipitates with the iron hydroxide
present is also captured in the calcium carbonate precipitate, thus providing significant method
ruggedness. The use of 225Ra as a tracer also provides method ruggedness, providing an
improved measurement of chemical yield versus 133Ba, which may or may not behave identically
to Ra. The use of 133Ba tracer would also preclude use of Sr Resin to remove native Ba in the
brick samples.

7. Techniques Used  to Evaluate the Measurement Quality Objectives for the
   Rapid Methods Development Project

A general  description of  the specifications  and techniques used to evaluate the required  method
uncertainty, required MDC, and bias was presented in Section 6. The detailed method evaluation
process for each MQO, the bias, and the radiochemical yield is presented in this section.

7.1  Required Method  Uncertainty
	                oo/r
The combined rapid   Ra - Brick method was evaluated following the guidance presented  for
"Level C" Method Validation: Adapted, Newly Developed Methods, Including Rapid Methods"
in Method Validation Guide for Qualifying Methods Used by Radiological Laboratories
Participating in Incident Response Activities (EPA 2009) and Chapter 6 of Multi-Agency
Radiological Laboratory Analytical Protocols Manual (EPA 2004).

MARLAP "Level C" method validation requires the laboratory to conduct a method validation
study wherein five replicate samples from each of the three concentration levels are analyzed
according to the method. The concentration test levels analyzed are listed in Table 1. For
validation "Level C," externally prepared PT samples consisting of NIST-traceable 226Ra were
used to spike the MVRM. In order to determine if the proposed method met the rapid methods
development project MQO requirements for the required method uncertainty (MMR = 0.62 pCi/g),
each external PT sample  result was compared with the method uncertainty acceptance criteria
listed in the table below.  The acceptance criteria stated in Table 3 for "Level C" validation
stipulate that, for each test sample analyzed, the measured value had to be within  2.9
(required method uncertainty) for test level activities at or less than the AAL, or  2.9
(required relative method uncertainty) for test level  activities above the AAL.
September 2014                            15                                   DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
                    Table 3 - MARLAP "Level C" Acceptance Criteria
MARLAP
Validation
Level

C


Application

New
Application


Sample
Type111
Method
Validation
Reference
Materials

Acceptance
Criteria [2]
Measured value
within 2.9 UUR or
 2.9 cpMR of
validation value

Number of
Test Levels

3


Number of
Replicates

5

Total Number
of
Analyses

15

[1]  "Method Validation Reference Materials" is not a requirement of MARLAP for these test levels. However, in
    order to assure laboratory independence in the method validation process, a NIST- traceable source
    manufacturer was contracted to produce the testing materials for Phases II and III of the project.
[2]  The measured value must be within 2.9 UMR for test level concentrations at or less than the AAL and within 
    2.9 <0yR for a test level concentration above the AAL. It was assumed that the uncertainty of a test sample
    concentration will be negligible compared to the method uncertainty acceptance criteria and was not
    incorporated in the acceptance criteria.

7.2  Required  Minimum Detectable Concentration

The analytical results reported for the PT  samples having a 226Ra concentration at the tested
MDC of 1.025 + 0.027 pCi/g were evaluated according to Sections 5.5.1 and 5.5.2 of Testing for
the Required MDC in Method Validation Guide for Qualifying Methods Used by Radiological
Laboratories Participating in Incident Response Activities (EPA 2009). NAREL analyzed the
external PT samples in accordance with the proposed rapid method.

Critical Net Concentration
In order to evaluate whether the combined method can meet the required MDC (1.025 pCi/g), the
critical net concentration, as determined from the results of method reagent blanks, must be
calculated. The critical net concentration (CLNC) with a Type I error probability of a = 0.05 was
calculated using the following equation (consistent with MARLAP, Chapter 20, Equation 20.35):
                            CZNC(pCi) = t1 a(n-
'Blanks
                                            (5)
where SBianks is the standard deviation of the n blank-sample net results (corrected for instrument
background) in radionuclide concentration units of pCi/g, and t\-a(n-\) is the (1 - a)-quantile of
the ^-distribution with n-\ degrees of freedom (see MARLAP Table G.2 in Appendix G). For this
method validation study a Type I error rate of 0.05 was chosen.
For seven blank results (six degrees of freedom) and a Type I error probability of 0.05, the
previous equation reduces to:
                                CLNC(pCi/g) =
          ' Blanks
                                            (6)
September 2014
16
                          DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


Verification of Required MDC

Each of the 10 analytical results reported for the PT samples having a concentration at the
required MDC for 226Ra (1.025 pCi/g) was compared to the estimated critical net concentration
for the method.  The following protocol was used to verify a method's capability to meet the
required method MDC for a radionuclide-matrix combination:

I.      Analyze a minimum of seven matrix blank samples for the radionuclide.

II.     From the reagent blank sample net results, calculate the estimated Critical Net
       Concentration, CL^c-

III.     Analyze 10 replicate samples spiked at the required MDC.

IV.     From the results of the 10 replicate samples spiked at the required MDC, determine the
       number (Y) of sample results at or below the estimated CL^c-

V.     If Y < 2, the method evaluated at the required MDC passes the test for the required MDC
       specification.

VI.    If Y > 2, the method evaluated at the required MDC fails the test for the required MDC
       specification.

8.   Evaluation of Experimental Results

Only the experimental results for Phases II and III of the method validation process are reported
and evaluated in this study. Information presented in this section will include results for Sections
6 and 7. The 226Ra analytical results were evaluated for the required method uncertainty, required
MDC, and bias. In addition, the mean radiochemical yield for the method for Phases II and III is
reported to provide the method user the expected mean and range of this method performance
characteristic.

8.1  Summary of the Method

The brick sample is fused with sodium hydroxide in zirconium crucibles for -15 minutes at 600
C in a furnace.  The fused material is dissolved using water and transferred to a centrifuge tube.
The sample is digested using sodium hydroxide fusion and the Ra is preconcentrated from the
alkaline fusion matrix using calcium carbonate precipitation. Calcium ions are effectively
removed using cation exchange separation,  native Ba in the samples is removed using Sr Resin,
and a final removal of 225Ac and Ca ions is performed using Ln Resin. Radium is precipitated
using barium sulfate microprecipitation in the presence of isopropanol for alpha spectrometry
counting.

8.2  Required  Method Uncertainty
	                      oo/r
Table 4A summarizes the  Ra results and the acceptability of each result compared to the
acceptance criteria presented in Section 7.1. Based on the results of the individual analyses
counted for 1,000 minutes, it may be concluded that combined rapid 226Ra - Brick method is
September 2014                            17                                   DRAFT

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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


capable of meeting a required method uncertainty of 0.62 pCi/g at and below the AAL of 4.755
pCi/g, and a relative method uncertainty of 13% above the AAL.
September 2014                            18                                  DRAFT

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                Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
    Table 4A - Ra-226 Analytical Results for Required Method Uncertainty Evaluation
Nuclide: 226Ra

Proposed Method: Rapid Metho
Events
Required Method Validation Le
Matrix: Brick
AAL Tested: 4.755 uC
dfor Ra-226 in Brick for Environmental Restoration Following h
vel: MARLAP "C"
Required Method Uncertainty, u\/n>: 0.62 pC
Acceptance Criteria:
Test Levels 1 and 2: 2.9 x
Test Level 3: 2.9 x
HMR = 1.8
9>MR = 37.
i/g
homeland Security
i/g at and below AAL; 13% of the known value above AAL
pCi/g of quoted known value of sample in test level
7% of quoted known value of sample in test level
Test Level 1
Sample
R01
R02
R03
R04
R05
pCi/g
Known
2.385
csu [1]
(pCi/g)
0.035
pCi/g
Measured
2.45
2.40
2.39
2.44
2.45
CSU pl
(pCi/g)
0.15
0.15
0.15
0.15
0.15
Allowable Range
[31(pCi/g)


0.59-4.2


Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 2
Sample
R06
R07
R08
R09
RIO
pCi/g
Known
4.755
csu [1]
(pCi/g)
0.053
pCi/g
Measured
5.18
4.30
5.00
4.75
4.43
CSUP1
(pCi/g)
0.30
0.24
0.28
0.26
0.24
Allowable Range
[3]
(pCi/g)


3.0-6.5


Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 3
Sample
Rll
R12
R13
R14
R15
pCi/g
Known
15.03
CSU [1]
(pCi/g)


0.23


pCi/g
Measured
15.97
15.78
16.63
14.99
13.77
csu[2]
(pCi/g)
0.77
0.75
0.80
0.70
0.65
Allowable Range [3]
(pCi/g)
9.4-21
Acceptable
Y/N
Y
Y
Y
Y
Y
[1]  Quoted combined standard uncertainty (CSU; one sigma) determined by combining in quadrature the standard
    error of the mean inherent 226Ra in blank brick and the reported uncertainty (coverage factor k= 1) by the
    radioactive source manufacturer.
[2]  Combined standard uncertainty (CSU), coverage factor k=l.
September 2014
19
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples

[3] Because the test level is actually above the proposed action level, the relative required method uncertainty was
   used to calculate the acceptable range.

As a measure of the expected variability of results for a test level, the calculated standard
deviation of the seven measurements of each test level is provided in Table 4B. The standard
deviation of the analytical results for a test level was much smaller than the required method
uncertainty.

    Table 4B - Experimental Standard Deviation of the Five FT Samples by Test Level



Test Level
1
2 (AAL)
3
Mean
Concentration
Measured
(pCi/g)
2.427
4.73
15.4

Standard Deviation of
Measurements
(pCi/g)
0.027
0.37
1.1


Required Method
Uncertainty
0.62
0.62
2.0 [1J
 [1] This figure represents the absolute value of the required method uncertainty, calculated by multiplying the mean
    known value of Test Level 3 by the required relative method uncertainty (13%).

8.3  Required Minimum Detectable Concentration

The rapid 226Ra method was validated for the required MDC using the methods identified in
Attachments II and III and MDC samples counted for 800 minutes.

Tables 5, 5 A, and 6 summarize the 226Ra results and the acceptability of the method's
performance specified in Section 7.2 to meet the tested required MDC of 1.025  0.027 pCi/g.

Table 5 documents that the reported CSUs for the blank reagent sample measurements were
similar in magnitude as the calculated standard deviation of the seven sample results, indicating
that the inputs into the calculation of the CSU were properly estimated.
September 2014
20
DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
                                 226
             Table 5 - Reported   Ra Concentration Reagent Blank Samples
Sample ID [1]
RS41
RS42
RS43
RS44
RS45
RS46
RS47
Mean [3]
Standard Deviation
Critical Net Concentration
(pCi/g)
Concentration (pCi/g)
0.076
0.032
0.035
0.038
0.046
0.047
0.044
0.045
0.015
0.028
CSU [2] (pCi/g)
0.020
0.013
0.015
0.014
0.016
0.016
0.015
0.016


    [1]  These samples were prepared at NAREL in demineralized water.
    [2]  Combined standard uncertainty (CSU), coverage factor k=\.
    [3]  Mean and standard deviation were calculated before rounding.
In order to determine the inherent   Ra in the blank brick material, 10 additional blank brick
samples were processed prior to the method evaluation process and the weighted mean and
weighted standard uncertainty (standard error of the mean) of the 10 results calculated. Table 5 A
provides the results of these measurements.
   Table 5A -Concentrations of the Blank Brick Samples Used to Determine the Inherent
                                          226Ra
Sample ID [1]
1
2
3
4
5
6
7
8
9
10
Weighted Mean
Weighted Standard Deviation
PI
Concentration (pCi/g)
1.17
0.90
0.990
1.063
1.12
0.945
1.11
1.002
0.90
1.167
1.025
0.027
CSU [1] (pCi/g)
0.13
0.11
0.065
0.069
0.13
0.070
0.12
0.069
0.11
0.082


     [1] Combined standard uncertainty (CSU), coverage factor k=l.
     [2] Standard error (k=l).
September 2014
21
DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
In additional to the seven reagent blanks, seven blank brick samples were also processed as part
of the method validation process. These blank brick samples were processed to determine if the
inherent 226Ra concentration in the brick material was consistent in  a separate set of brick
aliquants. Table 5B presents the results for these seven blank samples. The mean and standard
deviation of the reported seven values were 1.12  0.13 pCi/g. As indicated in Table 7, there was
no bias between the results in Table 5 A and 5B.

             Table SB - Reported 226Ra Concentration of Blank Brick Samples
Sample ID [1]
R41
R42
R43
R44
R45
R46
R47
Mean [3]
Standard Deviation
Concentration (pCi/g)
1.153
1.29
0.921
0.964
1.188
1.20
1.117
1.12
0.13
CSU [2] (pCi/g)
0.099
0.12
0.076
0.088
0.097
0.11
0.094
0.097141

    [1]  These samples were prepared at Eckert & Ziegler Analytics and analyzed by NAREL using the
        proposed combined radium method.
    [2]  Combined standard uncertainty (CSU), coverage factor k= 1.
    [3]  Mean and standard deviation were calculated before rounding.
    [4] Mean of reported CSU values.

Critical Net Concentration

The critical net concentration for reagent blanks for the method under evaluation was calculated
using Equation 6 from Section 7.2. Based on the results of the seven analytical blanks (Table 5),
the critical net concentration for the combined method was estimated to be 0.028 pCi/g.
Although there was a bias in the reagent blank sample results (Table 7), the bias would not
significantly affect the estimate of the net critical concentration. The bias may be attributed to
trace 226Ra contamination in the sodium carbonate used (25  mL, 2M sodium carbonate). Based
on limited testing at NAREL, it may be possible to lower 226Ra blank measurements by lowering
the excess carbonate levels to 10-15 mL, 2M sodium carbonate, but this approach was not
formerly validated in this study.

RequiredMDC
                                                     99^                  	
A summary of the reported results for samples containing   Ra at the required MDC (1.025
pCi/g) is presented in Table 6. The mean measured value for 226Ra in the 10 MDC test samples
was calculated as 1.000  0.045  pCi/g (k=\). Based on the analytical results, the combined rapid
226Ra - Brick method is capable of meeting a required MDC of 1.0 pCi/g. As a matter of interest,
the average a priori MDC  reported for the reagent blank, blank brick and MDC samples was of
the order of 0.02 to 0.03 pCi/g for a 800 minute counting time. A much shorter count could be
used to meet a MDC of 1 pCi/g. The count time, however, was designed to allow sufficient
ingrowth of 217At while allowing the count time to begin late in the same day as the column
September 2014
22
DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
separation instead of waiting 24 hours to begin the count. Therefore, decreasing the count time
would have to take the ingrowth of 217At tracer counts into account.
  Table 6 - Reported Results for Samples Containing
                                       (1.025 pCi/g)
                                                     226
            Ra at the As-Tested MDC Value
Sample ID
R30
R31
R32
R33
R34
R35
R36
R37
R38
R39
Mean [2]
Standard Deviation of Results





Concentration
(pCi/g)
0.994
1.099
0.989
0.978
1.052
0.941
0.982
0.963
1.009
0.993
1.000
0.045
C.LNC
Acceptable maximum values <
C.LNC
Number of results > CLNC
Number of results < CLNC

csu [1]
(pCi/g)
0.086
0.090
0.083
0.084
0.091
0.083
0.082
0.081
0.086
0.086






Evaluation
Test Result
< Reagent Blank
rr Pi
^-LNC
N
N
N
N
N
N
N
N
N
N


0.028 pCi/g
2
10
0
Pass
[1]  Combined standard uncertainty (CSU), coverage factor k=\.
[2]  Mean and standard deviation were calculated before rounding.
[3]  Critical net concentration.

8.4  Evaluation of the Absolute and Relative Bias
	   oo/r                                            	
The  Ra results for the seven reagent blank samples (Table 5), seven blank brick samples
(Table 5B), 10 MDC samples (Table 6), and five replicate PT samples on the three test levels
(Table 4A) were evaluated for bias according to the equations presented in Section 6.3. The
results and interpretation of the evaluation are presented below in Table 7.
September 2014
23
DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
                                                          226,
            Table 7 - Relative Bias Evaluation of the Rapid   Ra Brick Method


Type of
Bias

Absolute
Relative
Relative
Relative
Relative
Relative


Test
Level
Method
reagent
blanks
Brick
Blanks
MDC
1
2-AAL
3

Calculated
Known Value
 CSU (k=l)
(pCi/g)[1]

0.0000
1.025 + 0.027
1.025+0.027
2.385+0.035
4.755+0.053
15.03+0.23
Mean of
Measurement
s  Standard
Deviation [2]
(pCi/g)

0.045+0.015
1.12 + 0.13
1.000+0.045
2.427+0.027
4.73+0.37
15.4+1.1


Difference
from
Known

0.045
0.10
-0.025
0.042
-0.025
0.37

Number of
Measurements/D
egrees of
Freedom

7/6
7/10
10/>100
5/>100
5/4
5/5


|T|

8.22
1.65
0.82
1.13
0.14
0.75


tdf

2.45
2.23
1.97
1.97
2.78
2.57


Bias
Yes/N
0

Y
N
N
N
N
N
[1] The stated CSU includes the uncertainty in the   Ra reference standard used to prepare the samples and the
   standard uncertainty of the measurement results for the test samples.
[2] Standard deviation of the measurements.
Only the method reagent blank samples prepared by NAREL using method reagents could be
evaluated for absolute bias since the blank brick had inherent 226Ra as part of its makeup. These
method reagent blank samples were taken through the entire method described in Attachment II
and III. Based on a statistical analysis of the results shown in Table 7, an absolute bias exists for
the reagent blanks. Since the observed sample results of the seven measurements were of the
same magnitude, most likely there was inherent 226Ra in the reagents, notably the Na2CC>3 used in
the pre-concentration of radium from the hydroxide matrix. Limited testing with less sodium
carbonate at NAREL did lower blank activity levels, but the level of sodium carbonate was kept
the same as the concrete validation study for consistency. The magnitude of the 226Ra content in
the reagents, however, is very low and would not affect the method validation evaluation results.
                                               	                                  oo/r
Measurement results for the 10 blank brick samples (Table 5 A) used to estimate the inherent
Ra in the blank brick material had a weighted mean and weighted standard uncertainty of 1.025
+ 0.027 pCi/g.  This inherent concentration of 226Ra was added to the spike values certified by
Eckert & Ziegler Analytics for the MDC and the three method uncertainty test levels. The stated
uncertainty for these calculated known values was determined by summing, in quadrature, the
uncertainty of the spiked value and the standard uncertainty (standard error) in the inherent
mean blank value.
                                                                                  226-
                                                                Ra
The 10 MDC test level samples were also blank brick samples that had a final calculated known
value of 1.025 + 0.027 pCi/g. The mean measured concentration of these MDC samples was
1.000 + 0.045 pCi/g. As determined by the paired Mest described in Section 7, no relative bias
was indicated for the MDC samples. In addition, no relative bias was determined for the sample
results of the three test levels for the method uncertainty evaluation. The relative percent
difference for the mean of the MDC samples and the mean of method uncertainty test level
samples compared to the known values was:
      MDC:
-2.4%
September 2014
                      24
DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
      Test Level 1:  1.8%.
      Test Level 2:  -0.53%.
      Test Level 3:  2.5%.
The small average bias versus reference values at the 3 test levels, as well as the MDC study,
                                                     976
indicates a very robust, reliable rapid method to determine   Ra in brick samples.

8.5  Method Ruggedness and Specificity

The results summarized in Table 8 represent the radiochemical yields for all three test levels, the
reagent and brick blanks, the LCSs, and the MDC samples that were processed in accordance
with the final method identified in Attachments II and III. The observed radiotracer yield results
for the 50 analyses were evaluated and the mean and standard deviation of the distribution were
calculated to be 71.0 + 8.6%.

               Table 8 - Summary of   Ra Radiochemical Yield Results for Test
                               and Quality Control Samples
Number of Samples
Mean Radiochemical Yield
Standard Deviation of Distribution (la)
Median
Minimum Value
5th Percentile
95th Percentile
Maximum Value
50
71.0%
8.6%
70.6%
38.5%
58.7%
86.4%
87.2%
The yields for samples evaluated using this method are shown on Figure 1. The mean yield and
standard deviation of the results were within expected values. The reagent blank samples had the
highest yields (samples 10-17).
September 2014
25
DRAFT

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              Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
%
Y
i
e
1
d
Ra-225 Yield Results
mn n
Qn n
an n
70.0
fin n
RD n
An n
3n n -


* *. * vv* -* ~
***' _ 'vV****
 


0 10 20 30 40 50 60
Sample Number
                Figure 1 - Yields for Method Based on Measurement of  Ra
9.   Timeline to Complete a Batch of Samples

NAREL kept a timeline log on processing a batch of samples and associated internal quality
control samples. The total time to process a batch of samples, including counting of the samples
and data review and analysis, was about 17 hours, excluding a ~ 6 hour wait time to allow
additional ingrowth of21 At. The amount of ingrowth time can be varied depending on the
amount of tracer used and the number of tracer counts desired. NAREL's breakdown of the time
line by method-process step is presented in Attachment I (this information is also presented in
more detail in the method flow chart in Attachment III, Section 17.5).

10.  Reported Modifications and Recommendations
    -^^                   99^
NAREL performed the rapid   Ra method validation and made a minor modification to the
method prior to analyzing samples for Phases II and III of the project. Selected modifications and
recommendations provided by NAREL are listed below.

Modifications  of the Method During Phases II and III:

Rapid Radiochemical Method for Ra-226 in Building Materials for Environmental Remediation
Following Radiological Incidents (Attachment III):

         11.2.8   Transfer each sample solution from Step 11.2.3.12 into the appropriate
                 column at -1-1.5 mL/min.
September 2014
26
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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


                  NOTE: It is important to load samples rapidly enough (1-1.5 mL/min) to avoid any
                  retention of Ra on Ln Resin, but not so fast that Ac-225 breaks through resin and
                  causes erroneously high tracer yields.

11.  Summary and Conclusions

The combined rapid 226Ra - Brick method was successfully validated according to "Method
Validation Requirements for Qualifying Methods Used by Radioanalytical Laboratories
Participating in Incident Response Activities" and Chapter 6 of Multi-Agency Radiological
Laboratory Analytical Protocols Manual (EPA 2004). The method was evaluated using well-
characterized brick analyzed for its macro-constituents by an independent laboratory6 and for its
radiological constituents (Attachment IV) using the combined rapid 226 Ra - Brick method by
NAREL.

The pulverized brick samples were spiked with three 226Ra concentrations consistent with a
concentration range that incorporated the 10~5 exposure risk contaminant level in soil in the
                                    9/11     9^Q    QO                	        	
presence of low-level concentrations of  Am,   Pu,  Sr, and uranium (Table 1). The combined
rapid 226Ra - Brick method met MARLAP Validation Level  "C" requirements for required
method uncertainty of 0.62 pCi/g at and below the AAL, and for the required relative method
uncertainty of 13% above the AAL concentration of 4.755 pCi/g. A 1-g sample aliquant and a
1,000-minute counting time were used for the method uncertainty evaluation.

For a reagent blank matrix containing no 226Ra, the critical net concentration for the method was
estimated to be 0.028 pCi/g for an  800-minute counting time. The mean reported MDC value  for
the reagent blank and MDC test samples was ~ 0.02 - 0.03 pCi/g or 1/40 the theoretical a priori
MDC for blank samples of ~1 pCi/g, indicating the method passed the MDC capability test.

Predicated on the statistical tests provided in the Method Validation Guide for Qualifying
Methods Used by Radiological Laboratories Participating in Incident Response Activities (EPA
2009), the combined  rapid 226Ra - Brick method was found to have an absolute bias for the
reagent blank matrix. The mean and standard  error of the seven reagent blank samples were
                                                             99^
calculated as 0.0455 + 0.0057 pCi/g. It was suspected that inherent  Ra in the Na2CC>3 reagent
used in the pre-concentration of radium from the hydroxide matrix was the cause of the bias. No
relative bias was noted for the measurements performed on the 10 MDC test level samples. The
mean concentration of 1.000 + 0.045 pCi/L for the 10 MDC test samples falls within -0.025
pCi/g of the calculated known value.

No bias was noted for the three test levels for the method validation evaluation samples. The
percent difference of the mean measured value and the known value for the three test levels was
1.8%, -0.53% and 2.5%, respectively. The excellent results at the three test levels demonstrate
that the rapid method for 226Ra in brick samples is both rugged and robust under the conditions
tested.

The chemical interferences that were present in the brick matrix, plus those noted in the Method
Ruggedness section of this report, were tested during this method development.
6 Wyoming Analytical Laboratories, Inc. of Golden, Colorado performed the macro analysis.


September 2014                            27                                   DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples


The observed radiotracer yield results for the 50 analyses was evaluated and the mean and
standard deviation of the distribution were calculated to be 71.0 + 8.6%. Chemical yields that
were lower tended to be reagent blank samples rather than actual brick samples. The brick matrix
components tend to facilitate higher chemical yields, presumably due to more efficient recovery
across the calcium carbonate precipitation step, presumably aided by iron hydroxide precipitation
that also occurs due to Fe in the brick matrix under alkaline conditions

The laboratory provided a minor modification and recommendations to clarify and improve the
rapid 226Ra method. The modifications were applied to the analyses of samples during Phases II
and III of the method validation process. The method is rapid and  the validation study indicates it
can be used with confidence after a radiological incident for the analysis of emergency brick
samples.

12.    References

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

U.S. Environmental Protection Agency (EPA). 2006. Validation and Peer Review of U.S.
    Environmental Protection Agency Radiochemical Methods of Analysis. FEM Document
    Number 2006-01, September 29. Available at: www.epa.gov/fem/agency_methods.htm.

U.S. Environmental Protection Agency (EPA). 2008. Radiological Laboratory Sample Analysis
       Guide for Incidents of National Significance - Radionuclides in Water, Office of Air and
       Radiation, Washington, DC, EPA 402-R-07-007, January 2008. Available at:
       http://nepis.epa.gov/Adobe/PDF/60000LAW.PDF.

U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for Qualifying
    Methods Used by Radiological Laboratories Participating in Incident Response Activities.
    Revision 0. Office of Air and Radiation, Washington, DC. EPA 402-R-09-006, June.
    Available at: www.epa.gov/narel.

U.S. Environmental Protection Agency (EPA). 2011. Quality Assurance Project Plan Validation
    of Rapid Radiochemical Methods For Radionuclides Listed in EPA 's Standardized Analytical
    Methods (SAM) For Use During Homeland Security Events. July, Revision 2. Office of Air
    and Radiation, National Analytical Radiation Environmental Laboratory.

U.S. Environmental Protection Agency (EPA). 2012. Radiological Sample Analysis Guide for
    Incident Response  Radionuclides in Soil. Revision 0. Office of Air and Radiation,
    Washington, DC. EPA 402-R-12-006, September 2012.

U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method for Radium
    226 in Building Materials for Environmental Remediation Following Radiological Incidents,
    Office of Air and Radiation, Washington, DC, EPA 402-R-07-007, April 2014. Unpublished.
September 2014                            28                                   DRAFT

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               Validation of Rapid Radiochemical Method for Ra-226 in Brick Samples
                                       Attachment I:
                                Estimated Elapsed Times
Step
Rapid Fusion
Vacuum Box Setup
Load Sample to cation resin columns
Transfer Ra eluate to 150mL glass beakers
Load sample to Sr Resin cartridge for Ba
removal
Transfer Ra eluate to lOOmL glass beakers
Load sample to Ln Resin cartridges
Microprecipitation
Count sample test source (16.7 hours)**
Elapsed
Time (hours)
3
3.5
5
5.75
6.25
7.5
8
9
13-22
             *These estimates depend on the number of samples which can be processed
             simultaneously. These estimates are based on-15-20 samples.
             ** AJI a priori MDC of0.02 to 0.03 pCi/g can be obtained for a counting time of
             800 minutes. Shorter counting times can be used to obtain MDC values of greater
             magnitudes.
September 2014
29
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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


                                    Attachment II:

Rapid Method for Sodium Hydroxide Fusion of Concrete7 and Brick Matrices Prior
     to Americium, Plutonium, Strontium, Radium, and Uranium Analyses for
           Environmental Remediation Following Radiological Incidents

1.  Scope and Application
   1.1. The method is applicable to the sodium hydroxide fusion of concrete and brick samples,
       prior to the chemical separation procedures described in the following procedures:
        1.1.1.  Rapid Radiochemical Method for Americium-241 in Building Materials for
              Environmental Remediation Following Radiological Incidents (Reference 16.1).
        1.1.2.  Rapid Radiochemical Method for Plutonium-238 and Plutonium-239/240 in
              Building Materials for Environmental Remediation Following Radiological
              Incidents (Reference 16.2).
        1.1.3.  Rapid Radiochemical Method for Radium-226 in Building Materials for
              Environmental Remediation Following Radiological Incidents (Reference 16.3).
        1.1.4.  Rapid Radiochemical Method for Total Radiostrontium (Sr-90) in Building
              Materials for Environmental Remediation Following Radiological Incidents
              (Reference 16.4).
        1.1.5.  Rapid Radiochemical Method for Isotopic Uranium in Building Materials for
              Environmental Remediation Following Radiological Incidents (Reference 16.5).
   1.2. This general method for concrete and brick building material applies to samples
       collected following a radiological or nuclear incident. The concrete and brick samples
       may be received as core samples, pieces of various sizes, dust or particles (wet or dry)
       from scabbling, or powder samples.
   1.3. The fusion method is rapid and rigorous, effectively digesting refractory radionuclide
       particles that  may be present.
   1.4. Concrete or brick samples  should be ground to at least 50-100 mesh size prior to fusion,
       if possible.
   1.5. After a homogeneous,  finely ground sample is obtained, the dissolution of concrete or
       brick matrices by this fusion method is expected to take approximately 1 hour per batch
       of 20 samples. This method assumes the laboratory starts with a representative, finely
       ground, 1-1.5-g aliquant of sample and employs simultaneous heating in multiple
       furnaces. The preconcentration steps to eliminate the alkaline fusion matrix and collect
       the radionuclides are expected to take approximately 1 hour.
   1.6. As this method is a sample digestion and pretreatment technique, to be used prior to
       other separation and analysis methods, the user should refer to those individual methods
 U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method for Plutonium-238 and
   Plutonium-239/240 in Building Materials for Environmental Remediation Following Radiological Incidents,
   Office of Air and Radiation, Washington, DC, EPA 402-R-07-007, April 2014. Unpublished.
September 2014                            30

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


        and any project-specific requirements for the determination of applicable measurement
        quality objectives (MQOs).
    1.7. Application of this method by any laboratory should be validated by the laboratory using
        the protocols provided in Method Validation Guide for Qualifying Methods Used by
        Radioanalytical Laboratories Participating in Incident Response Activities (Reference
        16.6), or the protocols published by a recognized standards organization for method
        validation.
        1.7.1.  In the absence of project-specific guidance, MQOs for concrete or brick samples
               may be based on the Analytical Action Levels (AALs), the Required Method
               Uncertainty (MMR) and the Required Relative Method Uncertainty (cpMn) found in
               the Radiological Laboratory Sample Analysis Guide for Incident Response 
               Radionuclides in Soil (Reference 16.7).

2.  Summary of Method
    2.1. The method is based on the rapid fusion of a representative, finely ground 1-1.5-g
        aliquant using rapid sodium hydroxide fusion at 600 C.
    2.2. Pu, U, and Am are separated from the alkaline matrix using an iron/titanium hydroxide
        precipitation (enhanced with calcium phosphate precipitation) followed by a lanthanum
        fluoride matrix removal step.
    2.3. Sr is separated from the alkaline matrix using a carbonate precipitation, followed by a
        calcium fluoride precipitation to remove silicates.
    2.4. Ra is separated from the alkaline matrix using a carbonate precipitation.

3.  Definitions, Abbreviations and Acronyms
    3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a sample
        of any matrix where a high concentration of radioactive material is present as a tiny
        particle (|im range).
    3.2. Multi-Agency Radiological Analytical Laboratory Protocols  (MARLAP) Manual
        (Reference 16.8).
    3.3. The use of the term concrete or brick throughout this method is not intended to be
        limiting or prescriptive, and the method described herein refers to all concrete or
        masonry-related materials. In cases where the distinction is important, the specific issues
        related to a particular sample type will be discussed.

4.  Interferences and Limitations

    NOTE: Large amounts of extraneous debris (pebbles larger than Vi", non-soil related debris) are not
    generally considered to be part of a concrete or brick matrix. When consistent with data quality
    objectives (DQOs), materials should be removed from the sample prior to drying. It is recommended this
    step be verified with Incident Command before discarding any materials.
September 2014

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
   4.1.  Concrete or brick samples with larger particle size may require a longer fusion time
        during Step 11.1.8.
   4.2.  As much information regarding the elemental composition of the sample should be
        obtained as possible. For example some concrete or brick may have native
        concentrations of uranium, radium, thorium, strontium or barium, all of which may have
        an effect on the chemical  separations used following the fusion of the sample. In some
        cases (e.g., radium or strontium analysis), elemental analysis of the digest prior to
        chemical separations may be necessary to determine native concentrations of carrier
        elements present in the sample.
        NOTE: In those samples where native constituents are present that could interfere with the
                                                     90C
        determination of the chemical yield (e.g., strontium for  Sr analysis) or with the creation of a
                                . 226T
        sample test source (e.g., Ba for  Ra analysis by alpha spectrometry), it may be necessary to
        determine the concentration of these native constituents in advance of chemical separation (using a
        separate aliquant of fused material) and make appropriate adjustments to the yield calculations or
        amount of carrier added.

   4.3. Matrix blanks for these matrices may not be practical to obtain. Efforts should be made
        to obtain independent, analyte-free materials that have similar composition as the
        samples to be analyzed. These blanks will serve as process monitors for the fusion, and
        as potential monitors for cross contamination during batch processing.
   4.4. Uncontaminated  concrete or brick material may be acceptable blank material for Pu,
        Am, and Sr analyses, but these materials will typically contain background levels of U
        and Ra isotopes.
        4.4.1.  If analyte-free blank material is not available and an empty crucible is used to
              generate a reagent blank sample, it is recommended that 100-125 milligram (mg)
              calcium (Ca) per gram of samples be added as calcium nitrate to the empty
              crucible as blank simulant. This step facilitates Sr/Ra carbonate precipitations
              from the alkaline fusion matrix.
        4.4.2.  Tracer yields may be slightly lower for reagent blank matrices, since the concrete
              and brick matrix components typically enhance recoveries across the
              precipitation steps.
   4.5. Samples with elevated activity or samples that require multiple analyses from a single
        concrete or brick sample may need to be split after dissolution. In these cases the initial
        digestate and the split fractions should be carefully measured to ensure that the sample
        aliquant for analysis is accurately determined.
        4.5.1.  Tracer or carrier amounts (added for yield determination) may be increased
              where the split allows for the normal added amount to be present in the
              subsequent aliquant. For very high activity samples, the addition of the tracer or
              carrier may need to be postponed until following the split, in which case special
              care must be taken to ensure that the process is quantitative until isotopic
              exchange with the yield monitor is achieved. This deviation from the method
              should be thoroughly documented and reported in the case narrative.
        4.5.2.  When this method is employed and the entire volume of fused sample is
              processed in the subsequent chemical separation method, the original sample size
September 2014                             32

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


              and units are used in all calculations, with the final results reported in the units
              requested by the project manager.
        4.5.3.  In cases where the sample digestate is split prior to analysis, the fractional
              aliquant of the sample is used to determine the sample size. The calculation of
              the appropriate sample size used for analysis is described in Section 12, below.
   4.6.  In the preparation of blank samples, laboratory control samples (LCSs) and duplicates,
        care should be taken to create these quality control samples as early in the process as
        possible, and to follow the same tracer/carrier additions, digestion process, and sample
        splitting used for the field samples. In the case of this method, quality control samples
        should be initiated at the point samples are aliquanted into crucibles for the fusion.
   4.7.  Although this method is applicable to a variety of subsequent chemical separation
        procedures, it is not appropriate where the analysis of volatile constituents such as iodine
        or polonium is required. The user of this method  must ensure that analysis is not
        required for any radionuclide that may be volatile under these sample preparation
        conditions, prior to performing this procedure.
   4.8.  Zirconium crucibles used in the fusion process may be reused.
        4.8.1.  It is very important that the laboratory have a process for cleaning and residual
              contamination assessment of the reused zirconium crucibles. The crucibles
              should be cleaned very well using soap and water, followed by warm nitric acid
              and then water. Blank measurements should be monitored to ensure effective
              cleaning.
        4.8.2.  Segregation of crucibles used for low and high activity samples is recommended
              to minimize the risk of cross-contamination while maximizing the efficient use
              of crucibles.
   4.9.  Centrifuge speed of 3500 rpm is prescribed but lower rpm speeds (>2500 rpm) may be
        used if 3500 rpm is not available.
   4.10. Titanium chloride (TiCb) reductant is used during the co-precipitation step with iron
        hydroxide for actinides to ensure tracer equilibrium and reduce uranium from U+6 to
        U+4 to enhance chemical yields. This method adds 5 mL 10 percent by mass (wt%)
        TiCb along with the Fe. Adding up to 10 mL of 10 wt% TiCb may increase uranium
        chemical yields, but this will need to be validated by the laboratory.
        	             oo/r                                      r)r)f\
   4.11. Trace levels of   Ra may be present in Na2CC>3 used in the   Ra pre-concentration step
        used in this method. Adding less 2M Na2CC>3 (<25 mL used in this method) may reduce
        226Ra reagent blank levels, while still effectively pre-concentrating 226Ra from the
        fusion matrix. This will need to be validated by  the laboratory.
   4.12. La is used to pre-concentrate actinides along with LaF3 in this method to eliminate
        matrix interferences, including silica, which can cause column flow problems. La
        follows Am in subsequent column separations and must be removed. Less La (2 mg)
        was used for brick samples to minimize the chance of La interference  on alpha
        spectrometry peaks. While this may also be effective for concrete samples, this will
        have to be validated by the laboratory.
September 2014                            33

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses

5.  Safety
    5.1.  General
        5.1.1.   Refer to your laboratory safety manual for concerns of contamination control,
               personal exposure monitoring and radiation dose monitoring.
        5.1.2.   Refer to your laboratory's chemical hygiene plan (or equivalent) for general
               safety rules regarding chemicals in the workplace.
    5.2.  Radiological
        5.2.1.   Discrete Radioactive Particles (DRPs or "hot particles")
               5.2.1.1. Hot particles will be small, on the order of 1 millimeter (mm) or less.
                      DRPs are typically not evenly distributed in the media and their
                      radiation emissions are not uniform in all directions (anisotropic).
               5.2.1.2. Concrete/brick media should be individually surveyed using a thickness
                      of the solid sample that is appropriate for detection of the radionuclide
                      decay particles.
                      NOTE: The information regarding DRPs should accompany the samples during
                      processing as well as be described in the case narrative that accompanies the
                      sample results.
    5.3.  Procedure-Specific Non-Radiological Hazards:
        5.3.1.   The sodium hydroxide fusion is performed in a furnace at 600 C. The operator
               should exercise extreme care when using the furnace and when handling the hot
               crucibles. Long tongs are recommended. Thermal protection gloves are also
               recommended when performing this part of the procedure. The fusion furnace
               should be used in a ventilated area (hood, trunk exhaust, etc.).
        5.3.2.   Particular attention should be paid to the use of hydrofluoric acid (HF). HF is an
               extremely  dangerous chemical used in the preparation of some of the reagents
               and in the microprecipitation procedure. Appropriate personal protective
               equipment (PPE) must be used in  strict accordance with the laboratory safety
               program specification.
6.  Equipment and Supplies
    6.1.   Adjustable temperature laboratory hotplates.
    6.2.   Balance, top loading or analytical, readout display of at least  0.01 g.
    6.3.   Beakers, 100 mL, 150 mL capacity.
    6.4.   Centrifuge able to accommodate 225 mL tubes.
    6.5.   Centrifuge tubes, plastic, 50 mL and 225 mL capacity.
    6.6.   Crucibles, 250 mL, zirconium, with lids.
    6.7.   100  uL, 200 uL, 500 uL, and 1 mL pipets or equivalent and appropriate plastic tips.
    6.8.   1-10 mL electronic/manual pipet(s).
    6.9.   Drill with masonry bit (H-inch carbide bit recommended).

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


   6.10.  Hot water bath or dry bath equivalent.
   6.11.  Ice bath.
   6.12.  Muffle furnace capable of reaching at least 600 C.
   6.13.  Tongs for handling crucibles (small and long tongs).
   6.14.  Tweezers or forceps.
   6.15.  Sample size reduction equipment (ball mill, paint shaker, etc.) and screens. The
          necessary equipment will be based on a laboratory's specific method for the process of
          producing a uniformly ground sample from which to procure an aliquant.
          NOTE: See appendix for a method for ball-milling and homogenization of concrete or brick
   6.16.  Vortex stirrer.

7. Reagents and Standards
   NOTES:
   Unless otherwise indicated, all references to water should be understood to mean Type I reagent water
   (ASTM D1193; Reference 16.9).
   All reagents are American Chemical Society (ACS)-grade or equivalent unless otherwise specified.
   7.1.   Type I  reagent water as defined in ASTM Standard Dl 193 (Reference 16.9).
   7.2.   Aluminum nitrate (A1(NO3)3' 9H2O)
          7.2.1.  Aluminum nitrate solution (2M): Add 750 g of aluminum nitrate (A1(NO3)3'
                 9H2O) to -700 mL of water and dilute to 1 L with water. Low-levels of
                 uranium are typically present  in A1(NC>3)3 solution.
                 NOTE: Aluminum nitrate reagent typically contains trace levels of uranium
                 concentration. To achieve the lowest possible blanks for isotopic uranium measurements,
                 some labs have removed the trace uranium by passing ~250 mL of the 2M aluminum
                 nitrate reagent through ~7 mL TRU Resin or UTEVA Resin (Eichrom Technologies),
                 but this will have to be tested and validated by the laboratory.

   7.3.   Ammonium hydrogen phosphate (3.2M): Dissolve  106 g of (NH/^HPC^ in 200 mL of
          water, heat on low to medium heat on a hot plate to dissolve and dilute to 250 mL with
          water.
   7.4.   Boric Acid, H3BO3.
   7.5.   Calcium nitrate (1.25M): Dissolve 147 g of calcium nitrate tetrahydrate
          (Ca(NO3)2'4H2O) in 300 mL of water and dilute to 500 mL with water.
   7.6.   Iron carrier (50 mg/mL): Dissolve 181 g of ferric nitrate (Fe(NC>3)3  9H2O) in 300 mL
          water and dilute to 500 mL with water.
   7.7.   Hydrochloric acid (12M): Concentrated HC1, available commercially.
          7.6.1.  Hydrochloric acid (0.01M): Add 0.83 mL of concentrated HC1 to 800 mL of
                 water and dilute with water to 1  L.
          7.6.2.  Hydrochloric acid (1.5M): Add  125 mL of concentrated HC1 to 800 mL of
                 water and dilute with water to 1  L.
September 2014                             35

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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


   7.8.   Hydrofluoric acid (28M): Concentrated HF, available commercially.
   7.9.   Lanthanum carrier (1.0 mg La3+/mL): Add  1.56 g lanthanum (III) nitrate hexahydrate
         [La(NO3) 3 . 6H2O] in 300 mL water, diluted to 500 mL with water.
   7.10. Nitric acid (16M): Concentrated HNOs, available commercially.
         7.10.1. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water and
                dilute to 1 L with water.
         7.10.2. Nitric acid-boric acid solution (3M-0.25M): Add 15.4 g of boric acid and 190
                mL of concentrated HNOs to 500 mL of water, heat to dissolve, and dilute to 1
                liter with water.
         7.10.3. Nitric acid (7M): Add 443 mL of concentrated HNO3 to 400 mL of water and
                dilute to 1 L with water.
         7.10.4. Nitric acid (8M): Add 506 mL of concentrated HNO3 to 400 mL of water and
                dilute to 1 L with water.
   7.11. Sodium carbonate (2M): Dissolve 212 g anhydrous Na2CC>3 in 800 mL of water, then
         dilute to 1 L with water.
   7.12. Sodium hydroxide pellets.
   7.13. Titanium (III) chloride solution (TiCl3), 10  wt% solution in 20-30 wt% hydrochloric
         acid.
   7.14. Radioactive tracers/carriers (used as yield monitors) and spiking solutions. A
         radiotracer is a radioactive isotope of the analyte that is added to the sample to
         measure any losses of the analyte. A carrier is a stable isotope form of a radionuclide
         (usually the analyte) added to increase the total amount of that element so that a
         measureable mass of the element is present. A carrier can be used to determine the
         yield of the chemical process and/or to carry the analyte or radiotracer through the
         chemical process. Refer to the chemical separation method(s) to be employed upon
         completion of this dissolution technique. Tracers/carriers that are used to monitor
         radiochemical/chemical yield should be added at the beginning of this procedure. This
         timing allows for monitoring and correction of chemical losses in the combined
         digestion process, as well as in the chemical separation method. Carriers used to
         prepare sample test sources but not used for chemical yield determination (e.g., cerium
         added for microprecipitation of plutonium or uranium), should be added where
         indicated.

8. Sample Collection, Preservation, and Storage
   Not  Applicable.

9. Quality Control
   9.1.   Where the subsequent chemical separation technique requires the addition of carriers
         and  radioactive tracers for chemical yield determinations, these are to be added prior to
         beginning the fusion procedure, unless there is good technical justification for doing
         otherwise.
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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


   9.2.   Batch quality control results shall be evaluated and meet applicable analytical protocol
         specifications (APS) prior to release of unqualified data. In the absence of project-
         defined APS or a project-specific quality assurance project plan (QAPP), the quality
         control sample acceptance criteria defined in the laboratory's Quality Manual and
         procedures shall be used to determine acceptable performance for this method.
         9.2.1. An exception to this approach may need to be taken for samples of
                exceptionally high activity where human safety may be involved.
   9.3.   Quality control  samples are generally specified in the laboratory's Quality Manual or
         in a project's APS. At the very minimum the following are suggested:
         9.3.1. A laboratory control sample (LCS), which consists solely of the reagents used
                in this procedure and a known quantity of radionuclide spiking solution, shall
                be run with each batch of samples.  The concentration of the LCS should be at
                or near the action  level or level of interest for the project
         9.3.2. One reagent blank shall be run with each batch of samples. The blank should
                consist solely of the reagents used in this procedure (including tracer or carrier
                from the analytical method  added prior to the fusion process).
         9.3.3. A sample duplicate that is equal in  size to the original aliquant should be
                analyzed with each batch of samples. This approach provides assurance that
                the laboratory's sample size reduction and sub-sampling processes are
                reproducible.

10. Calibration and Standardization
   10.1. Refer to the individual chemical  separation and  analysis methods for calibration and
         standardization  protocols.

11. Procedure
   11.1. Fusion
         11.1.1.  In accordance with the DQOs and sample processing requirements stated in
                  the project plan  documents, remove extraneous materials from the concrete
                  or brick sample  using a clean forceps or tweezers.
         11.1.2.  Weigh out a representative, finely ground 1-g aliquant of sample into a
                  labeled crucible (1.5-g aliquants for 90Sr analysis).
                  NOTES:
                  It is anticipated that concrete or brick powder sample material will be dry enough to
                  aliquant without a preliminary drying step. In the event samples are received that
                  contain moisture, the samples may be dried in a drying oven at 105 C prior to taking
                  the aliquant.
                  For Sr  and Ra analyses, a reagent blank of 100-150 mg calcium per gram of sample
                  (prepared by evaporating 2.5 mL of 1.25M calcium nitrate, Ca(NO3)2, for radium and 3
                  mL of 1.25M Ca(NO3)2 for strontium) should be added to the crucible as a blank
                  simulant to ensure the blank behaves like the concrete or brick samples during the
                  precipitation steps.
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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


         11.1.3.   Add the proper amount of tracer or carrier appropriate for the method being
                  used and the number of aliquants needed.
         11.1.4.   Place crucibles on a hot plate and heat to dryness on medium heat.
                  NOTE: Heat on medium heat to dry quickly but not so high as to cause splattering.
         11.1.5.   Remove crucibles from hot plate and allow to cool.
         11.1.6.   Add the following amounts of sodium hydroxide based on the aliquant
                  size/analysis required.
                   1 g for Pu, Am, U:            15 g NaOH
                   l.SgforSr:                  15 g NaOH
                   IgforRa:                   10 g NaOH
         11.1.7.   Place the crucibles with lids in the 600 C furnace using tongs.
         11.1.8.   Fuse samples in the crucibles for-15 minutes.
                  NOTE: Longer times may be needed for larger particles.
         11.1.9.   Remove hot crucibles from furnace very carefully using tongs, andtransfer to
                  hood.
         11.1.10.  Add -25-50 mL of water to each crucible -8 to 10 minutes (or longer) after
                  removing crucibles from furnace, and heat on hotplate to loosen/dissolve
                  solids.
         11.1.11.  If necessary for dissolution, add more water, and warm as needed on a
                  hotplate.
         11.1.12.  Proceed to Section 11.2 for the actinide preconcentration procedure, 11.3 or
                  11.4 for Sr preconcentration, or 11.5 for Ra preconcentration steps.
   11.2. Preconcentration of Actinides (Pu, U, or Am) from Hydroxide Matrix
         11.2.1.   Pipet 2.5 mL of iron carrier (50 mg/mL) into a labeled 225-mL centrifuge
                  tube for each sample.
         11.2.2.   Add La carrier to each 225-mL tube as follows:
                     Concrete: 5 mL of 1 mg La/mL for Pu, Am, U
                     Brick: 5  mL of 1 mg La/mL for Pu, and U; 2 mL 1 mg La/mL for Am

         11.2.3.   Transfer each fused sample to a labeled 225 mL centrifuge tube, rinse
                  crucibles well with water, and transfer rinses to each tube.
         11.2.4.   Dilute each sample to approximately 180 mL with water.
         11.2.5.   Cool the 225 mL centrifuge tubes in an ice bath to approximately room
                  temperature as needed.
         11.2.6.   Pipet 1.25M Ca(NO3) 2 and 3.2M (NH4)2HPO4 into each tube as follows:
                  Pu, Am:   2 mL 1.25M Ca(NO3) 2 and 3 mL 3.2M (NH4)2HPO4
                  U:        3 mL 1.25M Ca(NO3)2 and 5 mL 3.2M (NH4)2HPO4
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          11.2.7.  Cap tubes and mix well.
          11.2.8.  Pipet 5 mL of 10 wt% TiCb into each tube, and cap and mix immediately.
          11.2.9.  Cool the 225 mL centrifuge tubes in an ice bath for -10 minutes.
          11.2.10. Centrifuge tubes for 6 minutes at 3500 rpm.
          11.2.11. Pour off the supernate, and discard to waste.
          11.2.12. Add 1.5M HC1 to each tube to redissolve each sample in a total volume of
                  -60 mL.
          11.2.13. Cap and shake each tube to dissolve solids as well as possible.
                  NOTE: There will typically be undissolved solids, which is acceptable.
          11.2.14. Dilute each tube to  -170 mL with 0.01M HC1. Cap and mix.
          11.2.15. Pipet 1 mL of 1.0 mg La/mL into each tube.
          11.2.16. Pipet 3 mL of 10 wt% TiCb into each tube. Cap and mix.
          11.2.17. Add 22 mL  of concentrated HF into each tube. Cap and mix well.
          11.2.18. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
          11.2.19. Centrifuge for -10 minutes at 3000 rpm or more, as needed.
          11.2.20. Pour off supernate,  and discard to waste.
          11.2.21. Pipet 5 mL of 3M HNCh - 0.25M boric acid into each tube.
          11.2.22. Cap, mix and transfer contents of the tube into a labeled 50 mL centrifuge
                  tube.
          11.2.23. Pipet 6 mL of 7M HNOs and 7  mL of 2M aluminum nitrate into each tube,
                  cap and mix (shake or use a vortex stirrer), and transfer rinse to 50-mL
                  centrifuge tube.
          11.2.24. Pipet 3 ml of 3M HNO3 directly into the 50 mL centrifuge tube.
          11.2.25. Warm each 50 mL centrifuge tube in a hot water bath for a few minutes,
                  swirling to dissolve.
          11.2.26. Remove each 50 mL centrifuge tube from the water bath and allow to cool to
                  room temperature
          11.2.27. Centrifuge the 50 ml tubes at 3500 rpm for 5 minutes to remove any traces of
                  solids (may  not be visible prior to centrifuging), and transfer solutions to
                  labeled beakers or tubes for further processing. Discard any solids.
          11.2.28. Proceed directly to  any of those methods listed in Sections 1.1.1, 1.1.2, or
                  1.1.5(forPu, U, or  Am).
                            on
    11.3.  Preconcentration of  Sr from Hydroxide Matrix (Concrete)
          NOTE: The preconcentration steps for 90Sr in this section can also be applied to brick samples, but
          this will have to be validated by the laboratory. See Section 11.4 for steps validated for 90Sr in
          brick samples.
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         11.3.1.   Transfer each fused sample to a 225-mL centrifuge tube, rinse crucibles well
                  with water, and transfer rinses to each tube.
         11.3.2.   Dilute to approximately 150 mL with water.
         11.3.3.   Add 15-mL concentrated HC1 to each tube.
         11.3.4.   Cap and mix solution in each tube.
         11.3.5.   Pipet 1-mL of 1.25M Ca(NO3)2into each tube.
         11.3.6.   Add 2-mL of 50-mg/mL iron carrier into each tube.
         11.3.7.   Add 25-mL of 2MNa2CO3to each tube.
         11.3.8.   Cap tubes and mix well.
         11.3.9.   Cool the 225-mL centrifuge tubes in  an ice bath for -10 minutes.
         11.3.10.  Centrifuge tubes for 5 minutes at 3500 rpm.
         11.3.11.  Pour off the supernate, and discard to waste.
         11.3.12.  Add 1.5MHC1 to each tube to redissolve each sample in a total volume of
                  -50 mL.
         11.3.13.  Cap and shake each tube to dissolve solids as well as possible.
         11.3.14.  Dilute each tube to -170 mL  with 0.01M HC1. Cap and mix.
         11.3.15.  Add 22 mL of concentrated HF into each tube. Cap and mix well.
         11.3.16.  Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
         11.3.17.  Centrifuge for-6 minutes at 3500 rpm.
         11.3.18.  Pour off supernate, and discard to waste.
         11.3.19.  Pipet 5 mL of concentrated HNO3and 5 mL of 3M HNO3 - 0.25M boric acid
                  into each 225 mL tube to dissolve precipitate.
         11.3.20.  Cap and mix well. Transfer contents  of the tube into a labeled 50-mL
                  centrifuge tube.
         11.3.21.  Pipet 5 mL of 3M HNOs and  5 mL of 2M aluminum nitrate into each tube,
                  cap tube and mix.
         11.3.22.  Transfer rinse solutions to labeled 50-mL centrifuge tubes and mix well
                  (shake or use vortex stirrer).
         11.3.23.  Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
                  of solids.
         11.3.24.  Transfer solutions to labeled beakers or new 50 mL tubes for further
                  processing.
         11.3.25.  If solids remain, add 5 mL 3M HNO3 to each tube, cap, and mix well,
                  centrifuge for 5 minutes and add the supernate to the sample solution.
                  Discard any residual solids.
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          11.3.26. If solids remain in the original 50 mL tubes (step 11.3.23), add 5 mL of 3M
                  HNO3 to each tube containing solids, cap, and mix well, Centrifuge for 5
                  minutes and add the supernate to the sample solution from step 11.3.24.
                  Discard any remaining solids.
   11.4.  Preconcentrati011 of 90Sr from Hydroxide Matrix (Brick)
          NOTE: The preconcentration steps for 90Sr in this section, using calcium phosphate instead of
          calcium carbonate,  can also be applied to concrete samples but this will have to be validated by the
          laboratory. see Section 11.3 for steps validated for 90Sr in concrete samples.
          11.4.1.  Transfer each fused sample to a labeled 225-mL centrifuge tube, rinse
                  crucibles well with water, and transfer rinses to each tube.
          11.4.2.  Dilute to approximately 150 mL with water.
          11.4.3.  Pipet2mL 1.25M Ca(NO3) 2 into each tube.
          11.4.4.  Add 1 mL  50-mg/mL iron carrier into each tube.
          11.4.5.  Add 5 mL  3.2M (ML^HPCMo each tube.
          11.4.6.  Cap tubes and mix well.
          11.4.7.  Centrifuge tubes for 5 minutes at 3500 rpm.
          11.4.8.  Pour off the supernate and discard to waste.
          11.4.9.  Add 1.5M  HC1 to each tube to redissolve each sample in a total volume of
                  -60 mL.
          11.4.10. Cap and shake each tube to dissolve solids as well  as possible.
          11.4.11. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
          11.4.12. Add 22 mL of concentrated HF into each tube. Cap and  mix well.
          11.4.13. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
          11.4.14. Centrifuge for-6 minutes at 3500 rpm.
          11.4.15. Pour off supernate and discard to waste.
          11.4.16. Pipet 5  mL of concentrated HNO3 and 5 mL of 3M HNO3 - 0.25M boric acid
                  into each 225 mL tube to dissolve precipitate.
          11.4.17. Cap and mix well. Transfer contents of the tube into a labeled 50-mL
                  centrifuge tube.
          11.4.18. Pipet 5  mL of 3M HNOs and  5 mL of 2M aluminum nitrate into each tube,
                  cap tube and mix.
          11.4.19. Transfer rinse solutions to labeled 50 mL centrifuge tubes and mix well
                  (shake or use vortex stirrer).
          11.4.20. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
                  of solids.
          11.4.21. Transfer solutions to labeled beakers or new 50 mL tubes for further
                  processing.
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          11.4.22. If solids remain in the original 50 mL tubes (step 11.4.20), add 5 mL of 3M HNO3
                  to each tube containing solids, cap, and mix well, Centrifuge for 5 minutes and add
                  the supernate to the sample solution from step 11.4.21. Discard any remaining
                  solids.
          11.4.23. Set aside for 90Sr analysis using Rapid Radiochemical Method for Total
                  Radiostrontium (Sr-90) In Building Materials for Environmental
                  Remediation Following Radiological Incidents (Reference 16.4).
    11.5.  Preconcentration of 226Ra from Hydroxide Matrix
          11.5.1.  Transfer each sample to a labeled 225 mL centrifuge tube, rinse crucibles
                  well with water, and transfer rinses to each tube.
          11.5.2.  Dilute to approximately 150 mL with water.
          11.5.3.  Add 10 mL of concentrated HC1 to each tube.
          11.5.4.  Cap and mix each tube well.
          11.5.5.  Pipet 0.5 mL of 1.25M Ca(NO3)2into each tube.
          11.5.6.  Add 25 mL of 2M Na2CO3 to each tube.
          11.5.7.  Cap tubes and mix.
          11.5.8.  Cool the 225-mL centrifuge tubes in an ice bath for -5-10 minutes.
          11.5.9.  Centrifuge tubes for 6 minutes at 3500 rpm.
          11.5.10. Pour off the supernate, and discard to waste.
          11.5.11. Pipet 10 mL 1.5M HC1 into each tube to dissolve precipitate. Cap and mix.
          11.5.12. Transfer sample solution to a labeled 50-mL centrifuge tube.
          11.5.13. Pipet lOmL 1.5MHC1 into each 225-mL tube to rinse. Cap and rinse well.
          11.5.14. Transfer rinse solution to  50 mL-tube and mix well.
                 NOTE: Typically the HC1 added to dissolve the carbonate precipitate is sufficient to
                 acidify the sample. If the precipitate was unusually large and milky suspended solids
                 remain, indicating additional acid is needed, the pH can be checked to verify it is pH 1
                 or less. To acidify the pH <1,1 or 2 mL of concentrated hydrochloric acid may be added
                 to acidify the solution further and get it to clear. Undissolved solids may be more likely
                 to occur with brick samples. Tubes may be warmed in a water bath to help dissolve
                 samples.
          11.5.15. If solids remain in the original 225 mL tubes, add 5 mL of 1.5MHC1 to each
                  tube containing solids, cap, and mix well. Centrifuge for 5 minutes and add
                  the supernate to the sample solution from step 11.5.14. Discard any
                  remaining solids.
          11.5.16. Set aside for 226Ra analysis using Rapid Radiochemical Method for Radium-
                  226 in Building Materials for Environmental Remediation Following
                  Radiological Incidents (Reference 16.3).

12. Data Analysis and Calculations
    12.1.  Equations for determination of final result, combined standard uncertainty, and
          radiochemical yield (if required) are found in the corresponding chemical separation
          and analysis methods, with the project manager providing the units.
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    12.2.  In cases where samples have elevated activity, smaller initial sample aliquants may be
          taken from the original sample. Alternately, smaller aliquant volumes may be taken
          from the final  sample volume containing the dissolved precipitate (digestate).
          Aliquants should be removed carefully and accurately from this final sample volume.
          NOTE: Small aliquants taken from the final sample digestate for Sr and Ra analysis may be used
          in the respective analytical procedures as is. Smaller aliquants for actinide analysis should be
          diluted to a 15 mL total volume with 3M HNO3 so that load solution acidity is maintained when
          valence adjustment reagents are added.

          For a single split, the effective size of sample is calculated:


                                        w  =w  2_     (-i\
                                          a     s T^l      \ '
                                                   s
          Where:
              Ws  = original sample size, in the units designated by the project manager (e.g.,
                      1 g, etc.)
              Ds  =  mass or volume of the entire final digestate, (e.g., 20 mL, etc.).
              Da  =  mass or volume of the aliquant of digestate used for the individual
                      analyses, (e.g., 5.0 mL, etc.). Note that the values for Da must be in the
                      same units used in Ds.
              Wa =  sample aliquant size, used for analysis, in the units designated by the
                      project manager (e.g.,  kg, g, etc.).
          NOTE: For higher activity samples, additional dilution may be needed. In such cases, Equation 1
          should be modified to reflect the number of splits and dilutions performed. It is also important to
          measure the masses or volumes, used for aliquanting or dilution, to enough significant figures so
          that their uncertainties have an insignificant impact on the final uncertainty budget. In cases
          where the sample will not be split prior to analysis, the sample aliquant size is simply equal to the
          original sample  size, in the same units requested by the project manager.

13. Method Performance
    13.1.  Report method validation results.
    13.2.  The method performance data for the analysis of concrete and brick by this dissolution
          method may be found in  the attached appendices.
    13.3.  Expected turnaround time per sample
          13.3.1.  For a representative, finely ground 1 -g aliquant of sample,  the fusion should
                  add approximately 2 hours per batch to the time specified in the individual
                  chemical separation methods.
          13.3.2.  The preconcentration steps should add approximately 2 to 2.5 hours per
                  batch.
                  NOTE: Processing times for the subsequent chemical separation methods are given in
                  those methods for batch preparations.

14. Pollution Prevention
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   This method inherently produces no significant pollutants. The sample and fusion reagents
   are retained in the final product and are carried into the ensuing chemical separation
   techniques, which marginally increases the salt content of the effluent waste. It is noted that
   if the sampled particulates include radionuclides that may be volatile under the fusion
   conditions, these constituents will be exhausted through the fume hood system.

15. Waste Management
   15.1. Refer to the appropriate chemical separation methods for waste disposal information.

16. References
   Cited References
   16.1. U.S. Environmental Protection Agency (EPA). 2013. Rapid Radiochemical Method
         for Americium-241 in Building Materials for Environmental Remediation Following
         Radiological Incidents. Revision 0, EPA 402-R14-007. Office of Air and Radiation,
         Washington, DC. Available at: www.epa.gov/narel.
   16.2. U.S. Environmental Protection Agency (EPA). 2013. Rapid Radiochemical Method
         for Pu-238 and Pu-239/240 in Building Materials for Environmental Remediation
         Following Radiological Incidents. Revision 0, EPA 402-R14-006. Office of Air and
         Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.3. U.S. Environmental Protection Agency (EPA). 2013. Rapid Radiochemical Method
         for Radium-226 in Building Materials for Environmental Remediation Following
         Radiological Incidents. Revision 0, EPA 402-R14-002. Office of Air and Radiation,
         Washington, DC. Available at: www.epa.gov/narel.
   16.4. U.S. Environmental Protection Agency (EPA). 2013. Rapid Radiochemical Method
         for Total Radiostrontium (Sr-90) in Building Materials for Environmental
         Remediation Following Radiological Incidents. Revision 0, EPA 402-R14-001. Office
         of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.5. U.S. Environmental Protection Agency (EPA). 2013. Rapid Radiochemical Method
         for Isotopic Uranium in Building Materials for Environmental Remediation Following
         Radiological Incidents. Revision 0, EPA 402-R14-005. Office of Air and Radiation,
         Washington, DC. Available at: www.epa.gov/narel.
   16.6. U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for
         Qualifying Methods  Used by Radiological Laboratories Participating in Incident
         Response Activities. Revision 0. Office of Air and Radiation, Washington, DC. EPA
         402-R-09-006, June. Available at: www.epa.gov/narel.
   16.7. U.S. Environmental Protection Agency (EPA). 2012. Radiological Laboratory Sample
         Analysis Guide for Incident Response  Radionuclides in Soil. Revision 0. Office of
         Air and Radiation, Washington, DC. EPA 402-R-12-006, September 2012. Available
         at: www.epa.gov/narel.
   16.8. MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
         2004. Volumes  1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576, NTIS
         PB2004-105421, July. Available at: www.epa.gov/radiation/marlap.


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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses


   16.9.  ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of Standards
         11.01, current version, ASTM International, West Conshohocken, PA.
   Other References
   16.10. Maxwell, S., Culligan, B. and Noyes, G. 2010. Rapid method for actinides in
         emergency soil samples, RadiochimicaActa. 98(12): 793-800.
   16.11. Maxwell, S., Culligan, B., Kelsey-Wall, A. and Shaw, P. 2011. "Rapid Radiochemical
         Method for Actinides in Emergency Concrete and Brick Samples," Analytica Chimica
         Acta. 701(1): 112-8.
   16.12. U.S. Environmental Protection Agency (EPA). 2010. Rapid Radiochemical Methods
        for Selected Radionuclides in Water for Environmental Restoration Following
         Homeland Security Events, Office of Air and Radiation. EPA 402-R-10-001, February.
         Revision 0.1 of rapid methods issued October 2011. Available at: www.epa.gov/narel/.
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17. Tables, Diagrams, and Flow Charts

    17.1.  Fusion Flow Chart

            Timeline for Rapid  Fusion and Preparation of Building
               Materials Samples for Precipitation and Analysis
           Rapid Fusion (Steps 11.1 - 11.9)
           1.  Add concrete or brick sample to 250 mL Zr crucible.
           2.  Add appropriate tracers/carriers.
           3.  Dry on hot plate.
           4.  Add 10-15 g NaOH pellets to crucible.
           5.  Heat -15 min. at 600 C.
           6.  Remove from furnace and allow to cool.
                                   V
           Prepare for precipitations (Step 11.1.10)
           1.  Add waterto crucibles to dissolve fused sample as
              much as possible and transferto centrifuge tubes.
           2.  Warm on hotplate to dissolve/loosen solids.
           3.  Transfer to 225 mL centrifuge tube.
           4.  Rinse crucibles well with water and transferto tubes.
           5.  Fusion solution is ready foractinide orRa/Sr
              precipitations.
                                 Elapsed Time
                                 45 minutes
                                                                                11/2 hours
                                           Continued on Appropriate
                                               Procedure Chart
I
Actinide
Precipitation
Procedure


X
/
Carbonate (concrete)
or Phosphate (brick)/
Fluoride
Precipitations for Sr
Procedure

\
/
Carbonate
Precipitation for Ra
Procedure

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    17.2.  Actinide Precipitation Flow Chart

                       Actinide Precipitation Procedure
       Actinide
     Precipitation
      Procedure
           Continued from 17.1 Fusion  Flow Chart
           1.   Add Fe and La to each tube.
           2.   Dilute to 180 ml_ with water.
           3.   Cool to room temperature in ice bath.
           4.   Add Ca and (NH4)2HPO4 to each tube. Cap and mix.
           5.   Add TiCI3 to each tube. Cap and mix.
           6.   Cool in ice bath foMO min.
           7.   Centrifuge for6 min and pour off supernate.
           8.   Redissolve in 1.5M HCI.
           9.   Dilute to 170 mLwith 0.01M HCI.
           10.  Add La, TiCI3, and HF and cool in ice bath for 10 min.
           11.  Centrifugefor 10 min and pour off supernate.
           12.  Redissolve in 5mL 3M HNO3-0.25M H3BO3 + 6 mL
               HNO3 +7 mL 2M AI(NO3)3 + 3 mL 3M HNO3, warming
               to dissolve in 50 mL centrifuge tubes.
           13.  Centrifuge to remove any trace solids.
           14.  Transfer sample solutions to newtubes or beakers
               and discard any traces of solids.
           15.  Allow sample solutions to cool to room temperature.
           16.  Analyze sample solutions forspecific actinides using
               rapid methods forspecific actinides in building
               materials.
                                  Elapsed Time
                                 3 hours
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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
    17.3.  Strontium Precipitation Flow Chart
       Strontium Precipitation Procedure (Concrete)
                        CaCO3 / CaF2
                      Precipitation for Sr
                         in Concrete
                          Procedure
                       Elapsed Time
      Continued from 17.1 Fusion Flowchart
      1.  Dilute to 150 ml with water.
      2.  Add 15 ml of concentrated HCL to each tube.
      3.  Add 1 ml 1.25M Ca (NO3)2, 100 mg Fe and 25 ml
         2M Na2CO3 to each tube.
      4.  Cool 10 min in ice bath.
      5.  Centrifuge for 5 min. and pour off supernate.
      6.  Add 1.5M HCI to each tube to redissolve each
         sample.
      7.  Dilute each tube to-170 ml with 0.01 M HCI.
      8.  Add 22 ml concentrated HF and cool in ice bath for
         10 min.
      9.  Centrifuge for 6 min and pour off supernate.
      10. Redissolve in 5 ml 3M HNO3-0.25M H3BO3 + 5mL
         concentrated HNO3 +5 ml 2M AI(NO3)3 + 5 ml 3M
         HNO3.
      11. Cap and mix using shaking orvortex stirrer.
      12. Centrifuge for 5 min and discard trace solids.
      13. Analyze sample solutions for 90Sr using 90Sr method
         for building materials.
                         21/2 hours
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  Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
         Strontium Precipitation Procedure (Brick)
                       Ca3(PO4)2 / CaF2
                     Precipitation for Sr
                      in Brick Procedure
      Continued from 17.1 Fusion Flowchart
      1.  Dilute to 150 ml with water.
      2.  Add 2 ml 1.25M Ca(NO3)2, 50 mg Fe, and 5 ml
         3.2M (NH4)2HPO4 to each tube.
      3.  Centrifuge for 5 min and pour off supernate.
      4.  Redissolve in -60 ml_1.5M HCL
      5.  Dilute to 170 ml with 0.01M  HCI.
      6.  Add 22 ml Concentrated HF and wait 10 min.
      7.  Centrifuge for 6 min and pour off supernate.
      8.  Redissolve in 5 ml 3M HNO3-0.25M H3BO3 + 5 ml
         concentrated HNO3 +5 ml 2M AI(NO3)3 + 5 ml 3M
         HNO3.
      9.  Cap and mix using vortex stirrer.
      10. Centrifuge for 5 min and discard trace solids.
      11. Analyze sample solutions for 90Sr using 90Sr method
         for building materials.
                           Elapsed Time
                          21/2 hours
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    17.4.  Radium Precipitation Flow Chart
      Carbonate Precipitation for Radium Procedure
                                        Carbonate
                                      Precipitation for
                                     Radium Procedure
  Continued from 17.1 Fusion Flowchart
  1.  Dilute to 150 ml with water.
  2.  Add 10 ml concentrated HCI to each tube.
  3.  Add 0.5 ml 1.25M Ca(NO3)2 and 25 ml 2M Na2CO3
     to each tube.
  4.  Cool ~10 min in ice bath.
  5.  Centrifuge for 6 min and pour off supernate.
  6.  RedissolveinIO ml 1.5M HCL.
  7.  Transfer to 50 ml centrifuge tubes.
  8.  Rinse 225-mL tube with 10-mL 1.5M HCL and
     transfer to  50-mLtube.
  9.  Cap and mix by shaking or using vortex stirrer.
  10. Centrifuge for 5 min and discard trace solids.
  11. Analyze sample solutions for 226Ra using 226Ra
     method for building materials.
                          Elapsed Time
                          3 hours
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                                       Appendix:

       Rapid Technique for Milling and Homogenizing Concrete and Brick Samples

Al.   Scope and Application
      ALL  Concrete or brick samples may be received as powder, core samples or other size
            pieces or chunks. The goal is to obtain representative sample aliquants from
            homogeneous amounts of sample.
      A1.2.  The ball mill method describes one approach for the rapid,  gross preparation of
            concrete or brick samples to yield representative 1-2-g aliquant for radiochemical
            analysis of non-volatile radionuclides. The method addresses steps for splitting,
            drying, and milling of 50-2,000 g concrete or brick samples. The concrete or brick
            sample must be reduced to pieces or fragments less than -25 mm in diameter prior
            to using the  ball mill. This can be done with a hydraulic press or mallet.
      Al .3.  The method is designed to be used as a preparatory step for the attached methods
            for fusion of concrete or brick  for 241Am, 2J9/240Pu, U, *Sr,  and 226Ra. It may also
            be applied to other matrices whose physical form is amenable to pulverization in
            the ball mill.
      Al .4.  If the levels of activity in the sample are low enough to permit safe radiological
            operations, up to 2 kg of concrete or brick can be processed.
      Al .5.  For smaller  amounts of concrete or brick samples,  a drill with masonry bit can be
            used in a lab hood inside a plastic bag to collect the powder that results.
A2.   Summary of Methods
      A2.1.  This method uses only disposable equipment to contact the sample, minimizing the
            risk of contamination and cross-contamination and eliminating concerns about
            adequate cleaning of equipment.
      A2.2.  Extraneous material, such as rocks or debris, may be removed  prior to processing
            the sample unless the project requires that they be  processed as part of the sample.
             NOTE: The sample mass is generally used for measuring the size of solid samples. The initial
             process of acquiring a representative aliquant uses the volume of the sample, as the total
             sample size is generally based on a certain volume of concrete or brick (e.g., 500 mL).

      A2.3.  The entire sample as received (after reducing fragment size to  less than -25 mm
            diameter) is split by coning and quartering until 75-150 mL of concrete or brick are
            available for subsequent processing. If less than 450 mL of concrete or brick is
            received, the entire sample is processed.
      A2.4.  The concrete or brick is transferred to a paint can or equivalent. Percent solids are
            determined, if required, by drying in a drying oven. A mallet and plastic bag or
            hydraulic press may be needed to break up larger pieces.
      A2.5.  Grinding media (stainless  steel or ceramic balls or rods) are added, and the sample
            is milled to produce a finely-ground, well-homogenized, powder with predominant
            particle size less than 250 micrometers (um).
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            NOTE: A mortar and pestle may also be used as needed to grind the sample further.

      A2.6.  If the sample may contain discreet radioactive particles (DRPs), particles larger
            than a nominal size of 150 um are screened for radioactivity, and further milled, or
            processed with another appropriate method to ensure that they will be chemically
            available for subsequent processing.
      A2.7.  The resulting milled sample is stored in, and aliquanted directly from, the container
            used for pulverization.
      A2.8.  The drill bit method involves drilling into the sample using a drill bit. The
            operation is performed inside  a disposable plastic bag in a hood so that the drilled
            out sample is caught within the plastic bag (this approach also minimizes the spread
            of contamination).  A drill bit such as a H-inch carbide bit is recommended. The
            holes should be drilled in such a way as to obtain representative powdered samples.
            The drill bit should be cleaned between uses on different samples using soap and
            water.
A3.   Definitions, Abbreviations, and Acronyms
      A3.1.  Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
            sample of any matrix where a high concentration of radioactive material is
            contained in a tiny particle (um range).
      A3.2.  Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
            (Reference A16.3).
      A3.3.  ASTM C999 Standard Practice for Soil Sample Preparation for the Determination
            of Radionuclides (Reference A16.4).
A4.   Interferences
      A4.1.  Radi ol ogi cal Interference s
            A4.1.1.  Coning and quartering provides a mechanism for rapidly decreasing the
                    overall size of the sample that must be processed while optimizing the
                    representativeness of the subsampling process. By decreasing the time and
                    effort needed to prepare the sample for subsequent processing, sample
                    throughput can be  significantly improved. Openly handling large amounts
                    of highly contaminated materials, however, even within the containment
                    provided by a fume hood, may pose an unacceptable risk of inhalation of
                    airborne contamination and exposure to laboratory personnel from
                    radioactive or other hazardous materials. Similarly, it may unacceptably
                    increase the risk of contamination of the laboratory.
            A4.1.2.  In such cases, the coning and quartering process may be eliminated in lieu
                    of processing the entire sample. The time needed to dry the sample will
                    increase significantly, and the container size and the number and size of
                    grinding media used  will need to be adjusted to optimize the milling
                    process. See ASTM C999 for an approach for homogenization and milling
                    of larger soil samples.
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            A4.1.3.  The precise particle size of the milled sample is not critical to subsequent
                    processes. However, milling the sample to smaller particle sizes, and
                    thorough mixing, both facilitate representative sub-sampling by
                    minimizing the amount of sample that is not pulverized to fine mesh and
                    must be discarded. Additionally, subsequent fusion and digestion
                    processes are more effective when performed on more finely milled
                    samples.
            A4.1.4.  This method assumes that radioactivity in the sample is primarily adsorbed
                    onto the surface of particles, as opposed to being present as a hot particle
                    (see discussion of DRPs below). Thus, nearly all of the activity in a
                    sample will be associated with sample fines. By visually  comparing the
                    sample to a qualitative standard of 50-100 mesh size particles, it is
                    possible to rapidly determine whether the sample is fine enough to
                    facilitate the subsequent fusion or digestion. This method assumes that
                    when greater than 95% of the sample is as fine or finer than the 50-100
                    mesh sample,  bias imparted from losses of larger particles will be
                    minimal.
            A4.1.5.  If the sample was collected near the epicenter of a radiological dispersal
                    device (RDD) or improvised nuclear device (IND) explosion, it may
                    contain millimeter- to micrometer-sized particles of contaminant referred
                    to as "discrete radioactive particles" or DRPs. DRPs may consist of small
                    pieces of the original radioactive source and thus may have very high
                    specific activity. They may also consist of chemically intractable material
                    and present special challenges in the analytical process. Even when the
                    size is reduced to less than 50-100 mesh, these particles may resist fusion
                    or digestion of the solids into ionic form that can be subjected to chemical
                    separations.
            A4.1.6.  When DRPs may be present, this method isolates larger particles by
                    passing the sample through a disposable 50-mesh screen  after which they
                    can be reliably checked for radioactivity. DRPs may reliably be identified
                    by their very high specific activity, which is readily detectable, since they
                    show high count rates using hand-held survey equipment such as a thin-
                    window Geiger-Muller (G-M) probe.
            A4.1.7.  When present, DRPs may be further milled and then recombined with the
                    original sample. Alternatively, the particles, or the entire sample may need
                    to be processed using a different method capable of completely
                    solubilizing the contaminants such that the radionuclides they contain are
                    available for subsequent chemical separation.
A5.   Safety
      A5.1.  General
            A5.1.1.  Refer to your safety manual for concerns of contamination control,
                    personal exposure monitoring, and radiation dose monitoring.
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            A5.1.2.  Refer to your laboratory's chemical hygiene plan (or equivalent) for
                     general safety rules regarding chemicals in the workplace.
      A5.2.  Radiological
            A5.2.1.  Refer to your radiation safety manual for direction on working with
                     known or suspected radioactive materials.
            A5.2.2.  This method has the potential to generate airborne radioactive
                     contamination. The process should be carefully evaluated to ensure that
                     airborne contamination is maintained at acceptable levels. This should
                     take into account the activity level, and physical and chemical form of
                     contaminants possibly present, as well as other engineering and
                     administrative controls available.
            A5.2.3.  Hot Particles (DRPs)
                     A5.2.3.1.   Hot particles will usually be small, on the order of 1 mm or
                                 less. Typically, DRPs are not evenly distributed in the
                                 media, and their radiation emissions are not uniform in all
                                 directions (anisotropic). Filtration using a 0.45 urn or
                                 smaller filter may be needed following subsequent fusion to
                                 identify the presence of smaller DRPs.
                     A5.2.3.2.   Care should be taken to provide  suitable containment for
                                 filter media used in the pretreatment of samples that may
                                 have DRPs, because the particles become highly statically
                                 charged as they dry out and will  "jump" to other surfaces
                                 potentially creating contamination-control issues.
      A5.3.  Method-Specific Non-Radiological Hazards
            A5.3.1.  This method employs a mechanical  shaker and should be evaluated for
                     personnel hazards associated with the high kinetic energy associated with
                     the milling process.
            A5.3.2.  This method employs a mechanical  shaker and involves vigorous agitation
                     of steel or ceramic balls inside steel cans. The process should be evaluated
                     to determine whether hearing protection is needed to protect the hearing of
                     personnel present in the area in which the apparatus is operated.
A6.   Equipment and supplies
      A6.1.  Balance, top-loading, range to accommodate sample size encountered, readability
            to 1%.
      A6.2.  Drying oven, at 110  10 C.
      A6.3.  Steel paint cans and lids (pint, quart, 2-quart,  1-gallon, as needed).
      A6.4.  Steel or ceramic grinding balls or rods for ball milling, -15-25 mm diameter. The
            size and  number of grinding media used should be optimized to suit the types of
            concrete or brick, the size of the can, and the volume of sample processed.
      A6.5.  Disposable wire cloth - nominal 48  mesh size (-300 um).


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      A6.6.   Disposable sieves, U.S. Series No. 50 (300 um or 48 mesh) and U.S. Series No.
             100 (150 urn or 100 mesh).
      A6.7.   Red Devil 5400 mechanical paint shaker or equivalent.
      A6.8.   Disposable scoop, scraper, tongue depressor or equivalent.
A7.   Reagents and Standards
      No reagents needed.

A8.   Sample Collection, Preservation and Storage
      A8.1.   Samples should be collected in appropriately sized plastic, metal  or glass
             containers.
      A8.2.   No sample preservation is required. If samples are to be held for an extended period
             of time, refrigeration may help minimize bacterial growth in the sample.
      A8.3.   Default sample collection protocols generally provide solid sample volumes
             equivalent to approximately 500 mL of sample. Such samples will require two
             splits to obtain a -100 mL sample.
A9.   Quality Control
      A9.1.   Batch quality control results shall be evaluated and meet applicable Analytical
             Protocol Specifications (APS) prior to release of unqualified data. In the absence of
             project-defined APS or a project-specific quality assurance project plan (QAPP),
             the quality control sample acceptance criteria defined in the laboratory quality
             manual and procedures shall be used to determine acceptable performance for this
             method.
      A9.2.   Quality control samples should be initiated as early in the process as possible.
             Since the risk of cross-contamination using this process is relatively low, initiating
             blanks and laboratory control  samples at the start of the chemical separation
             process is acceptable. If sufficient sample is available, a duplicate sample should be
             prepared from the two discarded quarters of the final split of the coning and
             quartering procedure.
A10.   Procedure
       NOTE: This method ensures that only disposable equipment comes in contact with sample materials
       to greatly minimize the risk of sample cross-contamination and concerns about adequate cleaning of
       equipment. Under certain circumstances (disposable sieves are not available, for example), careful,
       thorough cleaning of the sieves with water and the ethanol may be an option.

       A10.1. If necessary, reduce the concrete or brick particle diameter to less than -25 mm
              using a hydraulic press, mallet, or alternate equipment capable or reducing the
              fragment size.
       A10.2. Estimate the total volume of sample, as received.
              NOTE: If the sample is dry, the risk of resuspension and inhalation of the solids may be
              determined to be unacceptable. In such cases, the entire sample may be  processed in a larger
              can. The drying and milling time will be increased, and more grinding media will be
              required to obtain a satisfactory result.
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              NOTE: The next step uses absorbent paper in the reverse fashion for the normal use of this
              type of paper; it allows for a smooth division of the sample and control of contamination.

             Al 0.2.1.   Spread a large piece of plastic backed absorbent paper, plastic side up
                        in a hood.
             A10.2.2.   If the sample volume is less than 450 mL, there is no benefit to coning
                        and quartering.8
                        A10.2.2.1.   Carefully pour the sample onto the paper.
                        Al0.2.2.2.   Remove extraneous material, such as rocks or debris,
                                    unless the project requires that such material be processed
                                    as part of the sample. Continue with Step A10.2.5.
             A10.2.3.   If the sample volume is greater than -450 mL,  carefully pour the entire
                        sample into a cone onto the paper.
                        Remove extraneous material, such as rocks or debris unless the project
                        requires that such material be processed as part of the sample.

             A10.2.4.   If levels of gross activity in the sample permit, the sample is split at
                        least twice using the coning and quartering steps  that follow.
                        NOTE: Unused quarters are considered representative of the original  sample and
                        may be reserved for additional testing. The process should be carried out
                        expediently to minimize loss of volatile components in the sample, especially if
                        volatile components or percent solids are to be determined.

                        A10.2.4.1.   Spread the material into a flat circular cake of soil using a
                                    tongue depressor or other suitable disposable implement.
                                    Divide the cake radially and return two opposing quarters
                                    to the original  sample container.
                        Al0.2.4.2.   Reshape the  remaining two quarters into a smaller cone,
                                    and repeat Step A10.2.2.1 until the total volume of the
                                    remaining material is approximately 100-150 mL.
                                    NOTE: Tare the can and lid together. Do not apply an adhesive
                                    label. Rather,  label the can with permanent marker since the can
                                    will be placed  in a drying oven. The lid should be labeled
                                    separately since it will be removed from the can during drying.

             A10.2.5.   Transfer the coned and quartered sample to a tared, labeled 1-pint paint
                        can. If the total volume was less than -450 mL, transfer the entire
                        sample to a tared, labeled 1-quart paint can.
                        NOTE: Constant mass may be determined by removing the container from the
                        oven and weighing repeatedly until the mass remains constant with within 1% of
                        the starting mass of the sample. This determination may also be achieved
 International Union of Pure and Applied Chemistry (IUPAC). 1997. Compendium 1675 of Chemical Terminology,
2nd ed. (the "Gold Book"). Compiled by A. D. (Reference A16.1).


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                        operationally by observing the time needed to ensure that 99% of the samples
                        will obtain constant mass.

       A10.3. Place the can (without lid) in an oven at 110  10 C and dry the concrete or brick
              to constant mass.
              NOTE: Concrete or brick samples may be dry enough such that heating prior to
              homogenizing the sample is not required.

       A10.4. Weigh the combined mass of the can, sample, and lid. If the percent solids are
              required see Section A12.1 calculations. Remove can from oven and allow to
              cool.
       A10.5. Add five 1.5 cm stainless steel or ceramic balls or rods to the can. Replace the lid
              and seal well.
       A10.6. Shake the can and contents for 5 minutes, or longer, as needed to produce a
              finely-milled, well-homogenized, sample.
              NOTE: Although the precise particle size of the milled sample is not critical, complete
              pulverization and fine particle size facilitates representative sub-sampling and subsequent
              fusion or digestion processes. A qualitative standard can be prepared by passing quartz sand
              or other milled material through a 50-mesh and then a 100-mesh screen. The portion of the
              sample retained in the 100  mesh screen can be used as a qualitative visual standard to
              determine if samples have been adequately pulverized.

       A10.7. Visually compare the resulting milled sample to a qualitative 50-100  mesh
              pulverized sample (-150-300 um or 50-100 mesh using the Tyler screen scale).
              The process is complete once 95% of the sample (or greater) is as fine, or finer,
              than the qualitative standard. If, by visual estimation, more than -5%  of total
              volume of the particles in the sample appear to be larger than the particle size in
              the standard, return the sample to the shaker and continue milling until the process
              is complete.
       A10.8. Following milling, a small fraction of residual larger particles may remain in the
              sample.
              A10.8.1.  If the sample  was collected close to the epicenter of an RDD or IND
                        explosion, it may also contain particles of contaminant referred to as
                        "discrete radioactive particles" or DRPs. In such a case, the larger
                        particles should be isolated by passing through a disposable 48 mesh
                        screen and checked for radioactivity. DRPs are readily identified by
                        their very high specific activity which is detectable using hand-held
                        survey equipment such as  a thin-window G-M probe held within an
                        inch  of the particles.
                        A10.8.1.1.   If radioactivity is clearly detected, the sieved material is
                                    returned to the can and ball milled until the desired mesh
                                    is obtained. In some cases, these materials may be
                                    resistant to further pulverization and may need to be
                                    processed according to a method specially designed to
                                    address highly intractable solids.
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                       A10.8.1.2.   If the presence of DRPs is of no concern, the larger
                                   particles need not be included in subsequent subsamples
                                   taken for analysis. It may be possible to easily avoid
                                   including them during aliquanting with a disposable
                                   scoop. If not, however, they should be removed by sieving
                                   through a nominal 50 mesh screen (disposable) prior to
                                   further subsampling for subsequent analyses.
       A10.9. Sample fines may be stored in,  and aliquanted directly from, the container used
              for drying and pulverization.
Al 1.   Calibration and Standardization
       Al 1.1. Balances used shall be calibrated using National Institute of Standards and
              Technology (NIST)-traceable weights according to the process defined by the
              laboratory's quality manual.
A12.   Data Analysis and Calculations
       A12.1. The percent solids (dry-to-as-received mass ratio) for each sample is calculated
              from data obtained during the preparation of the sample as follows:
                            M  -M
                  n / o  1*1      dry     tare   -i f\f\
                  % Solids =	x inn

          Where:
              Mdry   = mass of dry sample + labeled can + lid (g)
              Mtare   = tare mass of labeled can + lid (g)
              Mas rec  = mass of sample as received + labeled can + lid (g)

       A12.2. If requested,  convert the equivalent mass of sample, as received, to dry mass. Dry
              mass is calculated from a measurement of the total  as received mass of the sample
              received as follows:

                   _.   _    ,    .   ,      -.         % Solids
                   Dry Sample Equivalent = Mtotal.asrec x	
              Where:
                      Mtotai-as rec. = total mass of sample, as received (g)

       A12.3. Results Reporting
              A12.3.1.  The result for percent solids and the approximate total mass of sample
                       as received should generally be reported for each result.
Al3.   Method Performance
       A13.1. Results of method validation performance are to be archived and available for
              reporting purposes.
       A13.2. Expected turnaround time is about 3 hours for an individual sample and about 4
              hours per batch.
A14.   Pollution Prevention.
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       Not applicable

A15.   Waste Management
       Al5.1. All radioactive and other regulated wastes shall be handled according to
             prevailing regulations.
A16.   References
       A16.1. International Union of Pure and Applied Chemistry (IUPAC). 1997. Compendium
             of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D.
             McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford. XML
             on-line corrected version: http://goldbook.iupac.org/C01265.html. (2006) created
             by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. Last update: 2010-
             12-22.

       A16.2. ALS Laboratories, Fort Collins, SOP 736.
       A16.3. MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
             2004. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,
             NTIS PB2004-105421, July. Available at: www.epa.gov/radiation/marlap.
       A16.4. ASTM C 999-05, "Standard Practice for Soil Sample Preparation for the
             Determination of Radionuclides," Volume 12.01, ASTM, 2005.
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                   Rapid Radiochemical Method for Radium-226 in Building Materials
                                    Attachment III:

 Rapid Radiochemical Method for Ra-226 in Building Materials for Environmental
                   Remediation Following Radiological Incidents

1.  Scope and Application
   1.1.    The method will be applicable to samples where contamination is either from known
          or unknown origins.
   1.2.    This method uses rapid radiochemical separations techniques for the isotopic
          determination of 226Ra in building materials samples, such as concrete and brick,
          following a nuclear or radiological incident.
          	                       oo/r
   1.3.    The method is specific for   Ra. It uses 50WX8 cation resin to separate radium from
          concrete or brick matrix constituents, followed by additional separation steps using Sr
          Resin and Ln Resin to remove interferences.
   1.4.    The method is capable of satisfying a required method uncertainty for 226Ra of 0.62
          pCi/g at an  analytical action level (AAL) of 4.76 pCi/g, a required relative method
          uncertainty (cpMn) of 13% above the AAL and a MDC of 1.0 pCi/g. To attain the
          required method uncertainty at the AAL, a sample aliquant of approximately 1 g and
          count time of 8 hours (or longer) are recommended. Application of the method must
          be validated by the laboratory using the protocols provided in Method Validation
          Guide for Qualifying Methods Used by Radiological Laboratories Participating in
          Incident Response Activities (EPA 2009, Reference 16.1). The sample turnaround
          time and throughput may vary based on additional project MQOs, the time for
          analysis of the sample test source, and initial sample weight/volume.
          	        oo/r
   1.5.    The rapid  Ra method was initially validated for concrete building materials
          following the guidance presented for "Level E Method Validation: Adapted or Newly
          Developed Methods, Including Rapid Methods" in Method Validation Guide for
          Qualifying Methods Used by Radiological Laboratories Participating in Incident
          Response Activities (EPA 2009, Reference 16.1) and Chapter 6 of Multi-Agency
          Radiological Laboratory Analytical Protocols Manual (EPA 2004, Reference 16.2).
          Subsequent building material matrices were validated at Level C ("Similar
          Matrix/New Application").
   1.6.    Other solid samples such as soil can be digested using the rapid sodium hydroxide
          fusion procedure as an alternative to other digestion techniques, but the laboratory
          will have to validate this procedure.

2.  Summary of Method
   2.1.    A known quantity of 225Ra is used as the yield tracer in this analysis. The sample is
          fused using procedure, Rapid Method for Sodium Hydroxide Fusion of Concrete and
          Brick Matrices Prior to Americium, Plutonium,  Strontium, Radium,  and Uranium
          Analyses  (Reference 16.3),  and then the radium isotopes are removed from the fusion
          matrix using a carbonate  precipitation step. The sample is acidified and loaded onto
          50WX8 cation resin to remove sample interferences such as calcium. The radium is
          eluted from the cation resin with 8M nitric acid. After evaporation of the eluate, the
          sample is dissolved and passed through  Sr Resin to remove Ba. This solution is
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
          evaporated to dryness, redissolved in 0.02M HC1 and passed through Ln Resin to
          remove interferences such as residual calcium and to remove the initial 225Ac present.
          The radium (including 226Ra) is prepared for counting by microprecipitation with
          BaSO4.
   2.2.   Low-level measurements are performed by alpha spectrometry. The activity measured
          in the 226Ra region of interest is corrected for chemical yield based on the observed
          activity of the alpha peak at 7.07 MeV (217At, the third progeny of 225Ra). See Table
          17.1 for a list of alpha particle energies of the radionuclides that potentially may be
          seen in the alpha spectra.

3.  Definitions, Abbreviations and Acronyms
   3.1.   Analytical Protocol Specifications (APS). The output of a directed planning process
          that contains the project's analytical data needs and requirements in an organized,
          concise form.
   3.2.   Analytical Action Level (AAL). The term "analytical action level" is used to denote
          the value of a quantity that will  cause the decisionmaker to choose one of the
          alternative actions.
   3.3.   Discrete Radioactive Particles (DRPs or Hot Particles). Particulate matter in a sample
          of any matrix where a high concentration of radioactive material is contained in a tiny
          particle (micron range).
   3.4.   Multi-Agency Radiological Analytical Laboratory Protocols Manual (MARLAP)
          provides guidance for the planning, implementation, and assessment phases of those
          projects that require the laboratory analysis  of radionuclides (Reference 16.2).
   3.5.   Measurement Quality Objective (MQO). The analytical data requirements of the data
          quality objectives that are project- or program-specific and can be quantitative or
          qualitative. These analytical  data requirements serve as measurement performance
          criteria or objectives of the analytical process.
   3.6.   Radiological Dispersal Device (RDD), i.e., a "dirty bomb." This device is an
          unconventional weapon constructed to distribute radioactive material(s) into  the
          environment either by incorporating them into a conventional bomb or by using
          sprays, canisters, or manual dispersal.
   3.7.   Required Method Uncertainty (Z/MR). The required method uncertainty is a target value
          for the individual measurement  uncertainties and is an  estimate of uncertainty (of
          measurement) before the sample is actually  measured.  The required method
          uncertainty as an absolute value is applicable at or below an AAL.
   3.8.   Relative Required Method Uncertainty ((pMn)- The relative required method
          uncertainty is the Z/MR divided by the AAL and is typically expressed as a percentage.
          It is applicable above the AAL.
   3.9.   Sample Test Source. This is  the final form of the sample that is used for nuclear
          counting. This form is usually specific for the nuclear counting technique in the
          method, such as a solid deposited on a filter for alpha spectrometry analysis.

4.  Interferences
   4.1.   Radiological


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                    Rapid Radiochemical Method for Radium-226 in Building Materials
          4.1.1.    Unless other radium isotopes are present in concentrations greater than
                   approximately three times the 226Ra activity concentration, interference from
                   other radium alphas will be resolved when using alpha spectrometry.
                   Method performance may be compromised if samples contain high levels of
                   radium isotopes due to ingrowth of interfering decay progeny, but this
                   interference will depend on the actual spectral resolution.
          4.1.2.    Radionuclides with overlapping alpha energies such as 229Th, 234U, and
                   237Np will interfere if they are not removed effectively. The method removes
                   these radionuclides.
          4.1.3.    Decay progeny from the 225Ra tracer will continue to ingrow as more time
                   elapses between the separation of radium and the count of the  sample.
                   Delaying the count significantly longer than a day may introduce a possible
                   positive bias in results near the detection threshold. When MQOs require
                   measurements close to detection levels, and coordinating sample processing
                   and counting schedules is not conducive to counting the sample within -36
                   hours of the separation of radium, the impact of tracer progeny tailing into
                   the 226Ra may be minimized by reducing the activity of the 22 Ra tracer that
                   is added to the sample. This approach will aid in improving the signal-to-
                   noise ratio for the 2 6Ra peak by minimizing the amount  of tailing from
                   higher energy alphas of the 225Ra progeny.
          4.1.4.    There is also a possibility that the higher energy peaks associated with the
                   225Ra progeny may result in energy-attenuated counts that show up in the
                   lower energy 226Ra alpha spectra region, so reducing the  225Ra tracer while
                   still achieving enough 217At counts to minimize tracer uncertainty may be
                   optimal.
                              	             ooc
                   4.1.4.1.     The amount of   Ra added to the samples may be decreased, and
                              the time for ingrowth between separation and counting increased,
                              to ensure that sufficient 225 Ac, 221Fr, and 217At are present for
                              yield corrections at the point of the count. Although this detracts
                              from the rapidity of the method, it does not detract significantly
                              from the potential for high throughput.
          4.1.5.    A purified 225Ra tracer solution may be used when performing this method
                   (See Appendix).
                   4.1.5.1.     When using a purified source of 225Ra, the beginning of decay
                              for 225Ra is the activity reference date established during
                              standardization of the 225Ra  solution.
                                         f\f\ c                     99O	
          4.1.6.    It is also possible to use   Ra in equilibrium with  Th for convenience,
                                                               1 	                 99O	
                   which may be added to each sample as  a tracer. This allows use of   Th
                   without purification and therefore is a simpler approach.  This approach
                   requires complete decontamination of a relatively high activity of 229Th in
1 The single-laboratory validation for this method was performed successfully by adding 225Ra in secular equilibrium
with 229Th tracer. See Appendix of this method for a method for separating (and standardizing) 225Ra tracer from
229Th solution.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                   the later steps in the method, since the spectral region of interest (ROI) for
                   229Th slightly overlaps that of 226Ra.
          4.1.7.    229Th is removed during the cation exchange step (retained), and the 225Ra
                   is unsupported from this point on in the method (retained on the cation
                   resin). If the time delay between the cation exchange step and the Ln Resin
                   separation of 229Th is 6 hours or less the error associated with the 225Ra
                   reference value is < 1.2% due to 225Ra decay. A correction for this decay can
                   also be made by recording the  cation exchange elution time, and decaying
                   225Ra from this point until the Ln Resin separation time to eliminate this
                   relatively small bias.
                   	                                     OOP	
          4.1.8.    The method provides effective removal of   Th. Inadequate
                   decontamination of 229Th may lead to high bias in the 226Ra result especially
                   when the levels of 226Ra in the sample are below 1 pCi/g. The spectral
                   region above 226Ra corresponding to 229Th should be monitored routinely to
                   identify samples where 22 Th interference may impact compliance with
                   project MQOs. If problematic  levels of 229Th are identified in spectra,
                   measures must be taken to address the interference. These might include:
                                       99S        99O	
                   4.1.8.1.    Separating   Ra from   Th prior to its use as a tracer.
                   4.1.8.2.    Increasing the sample aliquant size without changing the amount
                             of tracer added will increase the analyte signal and reduce the
                             relative  impact of the interference to levels that may be amenable
                             with project MQOs.
                             	                     OOP	
                   4.1.8.3.    The absolute amount of   Th added to the samples may be
                             decreased, as long as the time for ingrowth between separation
                             and counting is increased to ensure that sufficient 217At is present
                             for yield corrections at the point of the count. Although this
                             approach detracts from the rapidity of the method, it allows more
                             flexibility in the timing of the count and does not detract from
                             the potential for high throughput.
                   4.1.8.4.    The samples may be counted as early as about 8 hours after
                             separation time with an 8-hour count time if-100 pCi 229Th is
                             added, but separation times and counting time midpoints must be
                             recorded carefully and precisely.
                                             99S                     99O	
          4.1.9.    When a solution containing   Ra in equilibrium with   Th is used as a
                   tracer, thorium is removed during the processing of the sample. The
                   equilibrium between the 225Ra and 229Th is essentially maintained until the
                   cation exchange elution step is performed. At this point, the 225Ra activity in
                   the eluate is unsupported and begins to decay. 225Ac is removed during the
                   Ln Resin separation.
          4.1.10.   Ascorbic acid is added to the sample load solution to reduce Fe3+ present to
                   Fe2+, which has less retention on cation resin than Fe 3+.
          4.1.11.   Trace levels of 226Ra may be present in Na2COs used in the 226Ra pre-
                   concentration step of the fusion method. Adding less 2M Na2COs (<25 mL
                   used in this method) may reduce 226Ra reagent blank levels, while still
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                   effectively pre-concentrating   Ra from the fusion matrix. This will need to
                   be validated by the laboratory.
   4.2.    Non-radiological
          4.2.1.    The amount of inherent stable (non-radioactive) barium in the sample that
                   may be carried through the processes prior to microprecipitation should not
                   significantly exceed the amount of the barium carrier (50 ug), which is
                   added for microprecipitation. Microprecipitates on the sample test source
                   greater than 50 jig Ba may severely degrade the resolution of alpha spectra.
                   4.2.1.1.    In this procedure, barium is removed using Sr Resin and alpha
                             peak resolution is typically very good. It is important for the total
                             volume of 3M HNCb passed through Sr Resin to be kept
                             relatively small per procedure to remove Ba effectively. It is
                             likely that Sr Resin can be washed and reused to reduce resin
                             costs, but this will have to be validated by the laboratory.
                   4.2.1.2.    The removal of Ba allows larger aliquant sizes of concrete, brick
                             or soil to be analyzed that could not typically be tolerated in
                             methods that do not remove Ba, allowing shorter count times and
                             lower minimum detectable activity (MDA) levels.
          4.2.2.    Ca can also cause alpha peak resolution problems and needs to be
                   effectively removed. Most of the Ca ions are removed using the initial
                   cation exchange separation. A small amount is removed during the final Ln
                   Resin purification step.
          4.2.3.    A smaller sample size may need to be selected when these interferences
                   cannot be removed adequately.
          4.2.4.    After initial separations using cation resin and Sr Resin, the sample eluent
                   solution is evaporated to dryness. This heating to dryness just prior to
                   redissolution in very dilute HC1 must be performed at very low heat
                   (removed from hot plate just prior to going to dryness) to avoid formation of
                   any oxides that may not dissolve well in the very dilute HCL just prior to
                   loading on Ln Resin. This is important to maximize chemical yields.
          4.2.5.    It may be possible to skip the HC1/H2O2 evaporation step after evaporating
                   the 3M HNOs to reduce sample preparation time, but this would have to be
                   validated by the laboratory.
          4.2.6.    The Ln Resin step provides a final purification for the Ra-225 tracer.  If the
                   flow rate is too fast (>1.5 drops/second)  and Ac-225 is present prior to the
                   final separation time breaks through the resin, a high bias in the tracer yield
                   will occur.

5.  Safety
   5.1.    General
          5.1.1.    Refer to your safety manual for concerns of contamination control, personal
                   exposure monitoring and radiation dose monitoring.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
          5.1.2.    Refer to your laboratory's chemical hygiene plan for general chemical
                   safety rules.
   5.2.   Radiological
          5.2.1.    Hot Particles (DRPs)
                   5.2.1.1.    Hot particles, also termed "discrete radioactive particles"
                             (DRPs), will be small, on the order of 1 mm or less. Typically,
                             DRPs are not evenly distributed in the media and their radiation
                             emissions are not uniform in all directions (anisotropic).
          5.2.2.    For samples with detectable activity concentrations of these radionuclides,
                   labware should be used only once due to the potential for cross
                   contamination.
   5.3.   Procedure-Specific Non-Radiological Hazards:
          5.3.1.    Solutions of 30% H2O2 can rapidly oxidize organic materials and generate
                   significant heat. Do not mix large quantities of peroxide solution with
                   solutions of organic solvents as the potential for explosion and conflagration
                   exists.

6.  Equipment and supplies
   6.1.   Alpha spectrometer calibrated for use over the range of ~3.5-7.5 MeV.
   6.2.   Cartridge reservoirs, 10 or 20 mL syringe style with locking device, or reservoir
          columns (empty luer tip, CC-10-M) plus 12 mL reservoirs (CC-06-M), Image
          Molding, Denver, CO, or equivalent.
   6.3.   Centrifuge tubes, polypropylene, 50 mL, disposable or equivalent.
   6.4.   Chromatography columns, polypropylene, disposable:
          6.4.1.    1.5 cm inner diameter x 15 cm or equivalent (Environmental Express,
                   Mount Pleasant, SC).
          6.4.2.    Additional frits for 1.5 cm inner diameter  x  15 cm  columns (Environmental
                   Express, Mount Pleasant, SC).
   6.5.   Filter funnels.
   6.6.   Filter manifold apparatus with 25 mm-diameter polysulfone. A single-use
          (disposable) filter funnel/filter combination may be used, to  avoid cross-
          contamination.
   6.7.   100 uL, 200 uL, 500 uL and 1 mL pipets or equivalent and appropriate plastic tips.
   6.8.   1-10 mL electronic pipet or manual equivalent.
   6.9.   Glass beaker, 50 mL and 150 mL capacity.
   6.10.  Heat lamp.
   6.11.  Hotplate.
   6.12.  Graduated  cylinders, 500 mL and 1000 mL.
   6.13.  25 mm polypropylene filter, 0.1 um pore size, or equivalent.
   6.14.  pH paper.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
   6.15.  Stainless steel planchets or other adhesive sample mounts (Environmental Express,
          Inc. P/N R2200) able to hold the 25 mm filter.
   6.16.  Tips, white inner, Eichrom part number AC-1000-IT, or PFA 5/32" x i/4" heavy-wall
          tubing connectors, natural, Ref P/N 00070EE, cut to 1 inch, Cole Farmer, or
          equivalent
   6.17.  Tips, yellow outer, Eichrom part number AC-1000-OT, or equivalent.
   6.18.  Tweezers.
   6.19.  Vacuum box, such as Eichrom part number AC-24-BOX, or equivalent.
   6.20.  Vacuum pump or laboratory vacuum system.
   6.21.  Vortex mixer.
   6.22.  Heat lamp.

7.  Reagents and  Standards
   NOTES:
   All reagents are American Chemical Society (ACS) reagent grade or equivalent unless otherwise
   specified.
   Unless otherwise indicated, all references to water should be understood to mean Type I reagent water
   (ASTM D1193, Reference 16.4). For microprecipitation, all solutions used in microprecipitation should
   be prepared with water filtered through a 0.45 um (or smaller) filter.
   7.1.    Type I reagent water as defined in ASTM Standard Dl 193 (Reference 16.4).
   7.2.    Ammonium sulfate, solid (NH4)2SO4.
   7.3.    Barium carrier (1000 |ig/mL as Ba2+). May be purchased as an inductively coupled
          plasma - atomic emission spectrometry (ICP-AES) standard and diluted, or prepared
          by dissolving 0.90 g reagent grade barium chloride, dihydrate (BaCl2'2H2O) in water
          and diluting to 500 mL with water.
   7.4.    Calcium nitrate (1.25M): Dissolve 147 g of calcium nitrate tetrahydrate
          (Ca(NO3)2-4H2O) in 300 mL of water and dilute to 500 mL with water.
   7.5.    Cation resin, 50WX8, 200-400 um mesh size (available from Eichrom Technologies,
          Lisle, IL).
   7.6.    Ethanol, reagent (C2HsOH): Available commercially (or mix 95 mL 100% ethanol
          and 5 mL water).
   7.7.    Hydrochloric acid (12M):  Concentrated HC1, available commercially.
          7.7.1.    Hydrochloric acid (3.0M): Add 250 mL of concentrated HC1 to 600 mL of
                   water and dilute to 1.0 L with water Hydrochloric acid (1.5M): Add 125 mL
                   of concentrated HC1 to  800 mL of water and dilute to 1.0 L with water.
          7.7.2.    Hydrochloric acid (1.5M): Add 125 mL of concentrated HC1 to 800 mL of
                   water and dilute to 1.0 L with water.
          7.7.3.    Hydrochloric acid (1M): Add 83 mL of concentrated HC1 to 800 mL of
                   water and dilute to 1.0 L with water.
          7.7.4.    Hydrochloric acid (0.1M): Add 8.3 mL of concentrated HC1 to 950 mL of
                   water and dilute to 1.0 L with water.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
          7.7.5.    Hydrochloric acid (0.02M): Add 1.66 mL of concentrated HC1 to 950 mL of
                   water and dilute to 1.0 L with water
   7.8.    Hydrogen peroxide, H2O2 (30 % weight/weight): Available commercially.
   7.9.    Isopropanol, 2-propanol, (CsHyOH): Available commercially.
          7.9.1.    Isopropanol (2-propanol), 20% (volume/volume) in water: Mix 20 mL of
                   isopropanol with 80 mL of water.
   7.10.  Ln Resin cartridges, 2 mL, small particle size (50-100 |j,m), in appropriately sized
          column pre-packed cartridges.
   7.11.  Methanol (CH3OH): Available commercially
   7.12.  Nitric acid (16M): Concentrated HNOs, available commercially.
   7.13.  Ra-225 tracer in 1M HC1 solution in a concentration amenable to accurate addition of
          about 180 dpm per sample (generally about 150-600 dpm/mL).
                                                                99Q,  99S
          7.13.1.   Ra-225 may be purified and standardized using a   Th/  Ra generator as
                   described in the Appendix of this method.
          7.13.2.   Th-229 (-70-100 pCi) containing an equilibrium concentration of 225Ra has
                   been successfully used without prior separation of the 225Ra.
          7.13.3.   The tracer activity added and the sample count time should be sufficient to
                   obtain a combined standard uncertainty of less than 5% for the chemical
                   yield measurement.
   7.14.  Sr Resin cartridges, 2 mL, small particle size (50-100 |j,m), in appropriately sized
          column pre-packed cartridges.
   7.15.  Yttrium carrier (10 mg/mL as Y3+) for use in Appendix Step A4.2: May be purchased
          as an inductively coupled plasma - atomic emission spectrometry standard and
          diluted, or prepared by dissolving 4.3 g of yttrium nitrate hexahydrate (Y(NC>3)3  6
          H2O) in water and diluting to 100 mL in water.

8.  Sample Collection, Preservation, and Storage
   Not Applicable.

9.  Quality Control
   9.1.    Batch quality control results shall be evaluated and meet applicable Analytical
          Protocol  Specifications (APS) prior to release of unqualified data. In the absence of
          project-defined APS or a project-specific quality assurance project plan (QAPP), the
          quality control sample acceptance criteria defined in the laboratory quality manual
          and procedures shall be used to determine acceptable performance for this method.
          9.1.1.    A laboratory control sample (LCS) shall be run with each batch of samples.
                   The concentration of the LCS should be at or near the AAL or a level of
                   interest for the project.
          9.1.2.    One method blank shall be run with each batch of samples. The laboratory
                   blank should consist of an acceptable simulant or empty crucible blank
                   processed through the fusion procedure. If an empty crucible is used to
                   generate a reagent blank sample, it is recommended that 150 mg Ca be
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                   added as calcium nitrate to the empty crucible as blank simulant. This
                   addition facilitates Ra carbonate precipitations from the alkaline fusion
                   matrix.
          9.1.3.    One laboratory duplicate shall be run with each batch of samples. The
                   laboratory duplicate is prepared by removing an aliquant from the original
                   sample container.
          9.1.4.    A matrix spike sample may be included as a batch quality control sample if
                   there is concern that matrix interferences, such as the presence of elemental
                   barium in the sample, may compromise chemical yield measurements, or
                   overall data quality.
   9.2.   Sample-specific quality control measures
          9.2.1.    Limits and evaluation criteria shall be established to  monitor each alpha
                   spectrum to ensure that spectral resolution and peak separation is adequate
                                                      99Q   99S
                   to provide quantitative results. When   Th/  Ra solution is added directly
                   to the sample, the presence of detectable counts between -5.0 MeV and the
                   upper boundary established for the 226Ra ROI generally indicates the
                   presence of 229Th in the sample, and in the 226Ra ROI. If the presence of
                   99Q,                                99^
                     Th is noted and the concentration of   Ra is determined to be an order of
                   magnitude below the AAL or the detection threshold of the method, take
                   corrective actions to ensure that MQOs have not been compromised (e.g.,
                   clean-up 225Ra tracer before adding, or re-process affected samples and
                   associated quality control samples. See interferences sections Steps 4.1.4 -
                   4.1.5 for discussion).

10. Calibration and Standardization
   10.1.  Set up, operate, calibrate and perform quality control for alpha spectrometry units in
          accordance with the laboratory's quality manual and standard  operating procedures
          and consistent with ASTM  Standard Practice D7282, Sections 7-13, 18, and 24
          (Reference 16.5).
          NOTE: The calibrated energy range for the alpha spectrometer for this method should be from
          -3.5 to 7.5 MeV.
            99S                                99O	
   10.2.  If  Ra is separated and purified from   Th for use as a tracer, the activity reference
          date established during standardization of the tracer is used as the 225Ra activity
          reference date (see the appendix of this method).
   10.3.  When using 229Th containing an equilibrium concentration of 225Ra, the time of most
          recent separation/purification of the 229Th standard solution must be known in order
                                                             99Q,        99S
          to determine the extent of secular equilibrium between   Th and its   Ra progeny.
          Verify the date of purification by examining the Certificate of Analysis, or other
          applicable documentation, for the standard.
   10.4.  When using 229Th containing an equilibrium concentration of 225Ra, 225Ra is separated
          from its 229Th parent in the  solution during the cation exchange elution step. This is
          the beginning of 225Ra decay and the date and time used for decay correction of the
          tracer. This time must be known and recorded precisely.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                                              OOP	
          10.4.1.   If the purification date of the   Th is not documented, at least 100 days must
                   have elapsed between separation and use to ensure that 229Th, and its
                   progeny 225Ra are in full secular equilibrium (i.e., >99%. See Table 17.3).

11. Procedure
   11.1.  Initial Sample Preparation for Radium
          11.1.1.   Ra isotopes are preconcentrated from building material samples using
                   procedure Rapid Method for Sodium Hydroxide Fusion of Concrete and
                   Brick Matrices Prior to Americium, Plutonium, Strontium, Radium, and
                   Uranium Analyses (Reference 16.3), which fuses the samples using rapid
                   NaOH fusion followed by carbonate precipitation to preconcentrate Ra
                   isotopes from the hydroxide matrix.
          11.1.2.   The carbonate precipitate is dissolved in an HC1 solution and additional
                   separation steps to purify the radium isotopes are performed using this
                   procedure.
          11.1.3.   A smaller volume of the total load solution may be taken and analyzed as
                   needed for very high activity samples, with appropriate dilution factor
                   calculations applied.
          11.1.4.   This separation can be used with other solid sample matrices dissolved in
                   O.lMto 1.5MHC1.
   11.2.  Initial Matrix Removal Using 50WX8 Cation Resin
          11.2.1.   Prepare sample solution
                   11.2.1.1.   Add 3 mL of 1.5M ascorbic acid to each sample solution to
                             reduce any Fe present to Fe 2+. Mix and wait ~3  minutes.
          11.2.2.   Set up vacuum box
                   NOTE: More than one vacuum box may be used to increase throughput as needed.
                   11.2.2.1.   For each sample solution, place the empty large columns (15 cm
                             columns or equivalent) on the vacuum box.
                   11.2.2.2.   Add a water slurry (or weigh out the solid resin) of cation resin
                             50WX8 (200-400 mesh) into each column equivalent to 5 g of
                             resin.
                   11.2.2.3.   Turn the vacuum on and ensure proper fitting of the lid.
                             IMPORTANT: The unused openings on the vacuum box should be
                             sealed. Yellow caps (included with the vacuum box) can be used to plug
                             unused white tips to achieve a good seal during the separation.
                             Alternately, plastic tape can be used to seal the unused lid holes as well.
                   11.2.2.4.   After the water has passed through, place a frit down on top of
                             the resin bed.
                   11.2.2.5.   Add additional water (-10-15  mL) to rinse the resin and  remove
                             fine resin particles.
                   11.2.2.6.   Add 10 mL of 1M HC1 to the column to precondition the resin.
                   11.2.2.7'.   Press frit down tightly on resin bed.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                             NOTE: It is important to control flow rates such that they are not too fast.
                             Gravity flow (no vacuum) may be adequate, although a small amount of
                             vacuum may be needed to get the flow started.
                   11.2.2.8.  Adjust the vacuum (or use no vacuum) to achieve a flow-rate of
                             ~1 mL/min (roughly ~1 drop/sec).
                   11.2.2.9.  Discard column rinses.
                   11.2.2.10. Load sample solution slowly to each column at ~1 mL/min.
                             NOTE: It is likely that the ~1 mL/min flow rate can be achieved with no
                             vacuum at all. The frit should be pressed down tightly to prevent too fast
                             a flow rate.
                   11.2.2.11. Add 5mL of 1.5M HC1 to rinse each sample solution tube and
                             add to column at -1-2 mL/min. Discard eluate.
                   11.2.2.12. Press frit down on resin bed.
                   11.2.2.13. Add 30 mL of 3M HC1 to each column at -1-2 mL/min. Discard
                             rinse.
                             NOTE: The flow rate should not be too fast to ensure effective removal of
                             Ca and other interferences.
                   11.2.2.14. Press frit down tightly on resin bed.
                   11.2.2.15. Place clean 50 mL centrifuge tubes beneath the columns to catch
                             the eluate.
                   11.2.2.16. Press frit down tightly on resin bed.
                   11.2.2.17. Add 25 mL of 8M HNCb to each column to elute Ra at
                             -1 mL/min. Record the date and time as the date and time of
                             separation of 225Ra and thorium to  account for the decay of
                             unsupported 225Ra.
                             NOTE: Date and time need only be recorded if the 225Ra was in
                             equilibrium with 229Th tracer.
                   11.2.2.18. Transfer the eluate solution to 150-mL glass beakers. Rinse tubes
                             with -3 mL of 8M HNCb and add to beaker.
                   11.2.2.19. Add 2 mL of 30 wt% H2O2 to each beaker and evaporate on
                             medium heat to dryness on a hotplate being very careful not to
                             bake material  into the beaker. Samples should be taken off
                             hotplate prior to going dry and allowed to go to dryness as the
                             beaker cools.
                   11.2.2.20. Add 5  mL of 3M HNOs to redissolve each sample, warming
                             slightly on hotplate as needed.
                             NOTE: Barium in the sample can interfere with the 226Ra alpha peak
                             resolution. Sr Resin is used to remove Ba in the sample. The volume of
                             3M HNO3 must be kept small to remove Ba effectively.
          11.2.3.   Sr Resin Separation of Barium
                   11.2.3.1.  Place a 2-mL Sr Resin cartridge on the vacuum box.
                   11.2.3.2.  Condition each Sr Resin cartridge with 5 mL of 3M HNCb at 1
                             mL/min. Discard rinse.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                   11.2.3.3.   Ensure that clean, labeled plastic tubes are placed in the tube
                             rack under each cartridge.
                   11.2.3.4.   Transfer each sample solution from Step 11.2.2.20 into the
                             appropriate Sr Resin cartridge at a flow rate of ~1 mL/min or
                             less.
                   11.2.3.5.   Add 3 mL of 3M HNO3 to each beaker (from Step 11.2.2.20) as
                             a rinse and transfer each solution into the appropriate column at
                             ~1 mL/min.
                   11.2.3.6.   Add 3 mL of 3M HNCb into each reservoir as a column rinse
                             (flow rate -1-2 mL/min).
                   11.2.3.7.   Turn off vacuum. Discard Sr Resin.
                   11.2.3.8.   Remove tubes and transfer sample solution to 100-mL glass
                             beakers.
                   11.2.3.9.   Add 2 mL of 30 wt% H2O2 and evaporate solutions on medium
                             heat to dryness on a hot plate being very careful not to bake
                             material into the beaker. Samples should be taken off the hotplate
                             prior to going dry and allowed to go to dryness as the beaker
                             cools
                             NOTE: The method has been performed in some labs without the
                             following evaporation step with HC1 and H2O2 to save time but the
                             laboratory will have validate this.
                   11.2.3.10. Add 2 mL of 1M-HC1 and 2 mL of 30% H2O2 and evaporate
                             solutions carefully to dryness on low heat and evaporate
                             solutions on medium heat to dryness on a hot plate being very
                             careful not to bake material into the beaker. Samples should be
                             taken off the hotplate prior to going dry and allowed to go to
                             dryness as the beaker cools.
                             NOTE: Heating to dryness on very low heat and allowing to dry just after
                             coming off the hotplate with low heat is very important to prevent oxide
                             formation, which can be difficult to redissolve in low acid and cause
                             lower yields.
                   11.2.3.11. Add 2 mL of 0.1M HC1 to each beaker, warming on a hotplate to
                             dissolve.
                   11.2.3.12. Add 8 mL water and swirl to mix. Warm to ensure sample is
                             dissolved.
          11.2.4.   Final Purification Using Ln Resin.
          11.2.5.   Place a 2 mL Ln Resin cartridge on the vacuum box.
          11.2.6.   Add 5 mL of 0.02M HC1 into each column to precondition resin at ~1
                   mL/min. Discard rinse.
          11.2.7.   Ensure that clean, labeled plastic tubes are in the tube rack below each
                   cartridge.
          11.2.8.   Transfer each sample solution from Step 11.2.3.12 into the appropriate
                   column at -1-1.5 mL/min.
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                     Rapid Radiochemical Method for Radium-226 in Building Materials
                   NOTE: It is important to load sample rapidly enough (1-1.5 mL/min) to avoid any
                   retention of Ra on Ln Resin.
           11.2.9.  Add 5 mL of 0.02M HC1 to each beaker (from Step 11.2.3.12) as a rinse and
                   transfer each solution into the appropriate reservoir at -1-2 mL/min).
           11.2.10. Add 5 mL of 0.02M HC1 into each column to rinse at -1-2 mL/min.
           11.2.11. Record the date and time of the last rinse (Step 11.3.6) as the date and time
                   of separation of radium from progeny. This time is also the beginning of
                   ingrowth of 225Ac (and 221Fr and 217At).
                   NOTE: If purified 225Ra tracer is added to the sample (see the appendix), the 225Ra
                   activity was unsupported before the tracer solution was added to the sample. The
                   activity reference date and time established during standardization of the 225Ra tracer
                   is used as the reference date for the 225Ra solution.
                   NOTE: If 225Ra at some degree of secular equilibrium with 229Th is added as tracer in
                   the initial step, the activity of 225Ra is dependent upon the total amount of time
                   between the last 229Th purification and cation exchange elution step (Step 11.2.2.17).
                   The decay of 225Ra starts at the 229Th removal step and is decayed to the Ln Resin
                   separation time, where 225Ac is removed, to determine the reference activity of the
                   225Ra tracer at that point.
           11.2.12. Remove tubes from vacuum box and add 3 mL concentrated HC1 to each
                   tube.  Cap and mix.
           11.2.13. Discard Ln Resin.
    11.3.   Barium sulfate micro-precipitation of 226Ra
           11.3.1.  Add -3.0 g of (NH4)2SO4 to the purified sample solution. Mix well using a
                   vortex stirrer to completely dissolve the salt.
           11.3.2.  Add 50 jig of Ba carrier (50 jiL of 1000 jig Ba/mL) into each tube. Cap and
                   mix well with vortex stirrer.
           11.3.3.  Add 5.0 mL of isopropanol and mix well using a vortex  stirrer.
           11.3.4.  Place each tube in an ice bath filled with cold tap water for at least 15
                   minutes, periodically stirring on vortex stirrer (before placing in ice,
                   midway, and after icing).
           11.3.5.  Pre-wet a 0.1-micron filter using methanol or ethanol. Filter the suspension
                   through the filter using vacuum. The precipitate will not be visually
                   apparent.
           11.3.6.  Rinse the sample container with 3 mL of 20% isopropanol solution.
           11.3.7.  Rinse the filter apparatus with about 2 mL of methanol or ethanol to
                   facilitate drying. Turn off vacuum and discard rinses.
           11.3.8.  Mount the filter on a labeled adhesive mounting disk (or equivalent)
                   ensuring that the filter is not wrinkled and is centered on mounting disk.
           11.3.9.  Place the filter under a heat lamp for -5 minutes or more until  it is
                   completely dry.
                                                                 917
           11.3.10. Store the filter for -24 hours to allow sufficient   At (third progeny of
                   225Ra) to ingrow into the sample test source allowing a measurement
                   uncertainty for the 217At of < -5 %.
September 2014                              72

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                     Rapid Radiochemical Method for Radium-226 in Building Materials
           11.3.11. Count by alpha spectrometry. The count times should be adjusted to meet
                    the uncertainties and detection capabilities identified in Step 1.4.

12. Data Analysis and Calculations
    12.1.   The final sample test source (filter mounted on a planchet) will likely need to have
                                                            99 S        991917
           approximate ingrowth period of 18 to 24 hours for   Ac (and   Fr and   At) to meet
           Analytical Protocol Specifications for chemical yield with a counting time of 4 to 8
           hours. At-217 (third progeny of 225Ra) has a single, distinct alpha peak with a centroid
           at 7.067 MeV and is used for determining the yield.
    12.2.   The following equation can be used to calculate the radiochemical yield:

                                       RY =  Rt~Rb
                                             sxAtx!t                                     ^
           Where:
               RY       =    Fractional radiochemical yield based on 225Ra (from ingrown 217At
                             at 7.07 MeV)
                                                         917
               R\       =    Total count rate beneath the   At peak at 7.07 MeV, cpm
               Rb       =    Background count rate for the same region, cpm
               e         =    Efficiency for the alpha spectrometer
               /t        =    Fractional abundance for the 7.07 MeV alpha peak counted (=
                             0.9999)

           NOTE: If 225Ra is separated from 229Th for use as a purified tracer, the 225Ra activity is
           unsupported and begins to decay at time of prior separation from 229Th. The reference date and
           time established when the tracer is standardized is used for decay correction of the 225Ra activity.
           If 229Th solution (with 225Ra in full secular equilibrium) is added to the sample, the 225Ra activity
           is equal to the 229Th activity added and only begins to decay at the point of separation of 225Ra
           from 229Th during the sample preconcentration steps (cation exchange elution step).
                                         917
               A\       =    Activity of   At at midpoint of the count (the target value that
                             should be achieved for 100% yield), in dpm
                             =  3.0408(/t)(^225Ra)
              ^225Ra    =    Activity in dpm of 225Ra tracer added to the sample decay
                             corrected to the date and time of radium separation in Step 11.3.6.2
2 Unsupported 225Ra: When separated 225Ra tracer is added to the sample, its initial activity, ^sRa-mitmi, must be
corrected for decay from the reference date established during standardization of the tracer to the point of separation
of 225Ra and 225Ac as follows:
        A    -(A         Y^~v< 1
        ^225Ra   y^^Ra-initial A^   /
where: k\ = decay constant for 225Ra (0.04652 d~:); and 4= time elapsed between the activity reference date for the
225Ra tracer solution added to the sample and the separation of 225Ra and 225Ac in Step 11.3.6 (days).

229Th/225Ra added in equilibrium: When 229Th containing ingrown 225Ra is added directly to the sample, the
amount of 225Ra ingrown since purification of the 229Th solution up until 229Th removal point during the method is
calculated as:
        ^fl=UJ-^M)
where: ^4229ih = Activity of the 229Th standard on the date of the separation of Th and Ra (cation exchange elution
step); A! = decay constant for 225Ra (0.04652 d~:); and d, = time  elapsed between the purification of 229Th solution

September 2014                               73

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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                                                     ooc                   917
              d        =    Elapsed ingrowth time for   Ac [and the progeny   At], in days
                            from the date and time of Ra separation to the midpoint of the
                            sample count
              AI        =    0.04652 d"1 (decay constant for 225Ra - half-life = 14.9 days)
              X2        =    0.06931 d"1 (decay constant for 225Ac) - half-life = 10.0 days)
              /t        =    Fractional abundance for the 7.07 MeV alpha peak counted (=
                            0.9999)
              3.0408   =   ^-2/1-^2 + A) [a good approximation as the half lives of 221Fr and
                            917                                                 99S
                              At are short enough so that secular equilibrium with   Ac is
                            ensured]
    12.3.   The activity concentration  of an analyte and its combined standard uncertainty are
           calculated using the following equations:
                               AC  =	^   na	
                                      WaxRntxDaxIax2.22
           and
                                                                                        (3)

          where:
              ACn      =  activity concentration of the analyte at time of count, (pCi/g)
              At        =  activity of 217At at midpoint of the count (the target value that
                            should be achieved for 100% yield), in dpm (see Step 12.2 for
                            detailed calculation)
              RDa       =  net count rate of the analyte in the defined region of interest (ROI),
                            in counts per minute (Note that the peaks at 4.784 and 4.602 MeV
                            are generally included in the ROI for 226Ra)
              Rnt        =  net count rate of the tracer in the defined ROI, in counts per minute
              Wa.        =  weight of the sample aliquant (g)
              D&        =  correction factor for decay of the analyte from the time of sample
                            collection (or other reference time) to the midpoint of the counting
                            period, if required
                                                       996
              /a         =  probability of a emission for   Ra (The combined peaks at 4.78
                            and 4.602 MeV are generally included in the ROI with an
                            abundance of LOO.)3
              uc(ACa)   =  combined standard uncertainty of the activity concentration of the
                            analyte (pCi/L)
              u(At)      =  standard uncertainty of the activity of the tracer added to the
                            sample (dpm)
                            standard uncertainty of the volume of sample aliquant (g)
added to the sample and the separation of 225Ra and 229Th (days). The 225Ra is then corrected for decay to the 225Ac
removal separation time (Step 1 1.3.6) using the first equation above.
3 If the individual peak at 4.78 MeV used, and completely resolved from the 4.602 MeV peak, the abundance would
be 0.9445.
September 20 14                             74

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                      Rapid Radiochemical Method for Radium-226 in Building Materials
               wC^na)     =   standard uncertainty of the net count rate of the analyte in counts
                              per minute
               w(Rnt)     =   standard uncertainty of the net count rate of the tracer in counts per
                              minute
           NOTE: The uncertainties of the decay-correction factors and of the probability of decay factors
           are assumed to be negligible.
           NOTE: The equation for the combined standard uncertainty (z/c(^4Ca)) calculation is arranged to
           eliminate the possibility of dividing by zero if Ra = 0.
           NOTE: The standard uncertainty of the activity of the tracer added to the sample must reflect
           that associated with the activity of the standard reference material and any other significant
           sources of uncertainty such as those introduced during the preparation of the tracer solution
           (e.g., weighing or dilution factors) and during the process of adding the tracer to the sample.
           12.3.1.    The net count rate of an analyte or tracer and its standard uncertainty can be
                     calculated using the following equations:

                                               r    r
                                         n   _ ^x    *-bx
                                                '.    
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
0.4 x
              - 1  + 0.677 x  1 +
^ ]+ 1.645 xfoflf6+0.4)x^
 b J         \              b
                                                           x  1 +  -
                                                             \    i
D
                                   tsxWaxRtxDax!a
                   MDC =
                                                                                      (7)
            where:
                    =   background count rate for the analyte in the defined ROI, in counts
                         per minute
   12.4.  Results Reporting

          12.4. 1 .   The following data should be reported for each result: weight of sample
                   used; yield of tracer and its uncertainty; and full width at half maximum
                   (FWHM) of each peak used in the analysis.
          12.4.2.   The following conventions should be used for each result:
                   12.4.2. 1 .   Result in scientific notation  combined standard uncertainty.

13. Method Performance
   13.1.  Results of method validation performance are to be archived and available for
          reporting purposes.
   13.2.  Expected sample preparation time for a batch of 15 samples is ~9 hours. Total
          processing time is dependent on actual wait time for 217At ingrowth (-16-24 hours)
          and count times (~6 hours).
14. Pollution Prevention
   14.1.  The use of 50WX8 cation resin, Sr Resin and Ln Resin reduces the amount of
          solvents that would otherwise be needed to co-precipitate and purify the final sample
          test source.

15. Waste Management
   15.1.  Nitric acid and hydrochloric acid wastes should be neutralized before disposal and
          then disposed of in accordance with applicable regulations.
   15.2.  All final precipitated materials contain tracer and should be dealt with as radioactive
          waste and disposed of in accordance with the restrictions provided in the facility's
          NRC license.
   15.3.  It may be advisable to rinse the cation resin columns with water to remove strong
          nitric acid prior to resin disposal.
September 20 14
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                   Rapid Radiochemical Method for Radium-226 in Building Materials
16. References
    Cited References
    16.1.  U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for
          Radiological Laboratories Participating in Incident Response Activities. Revision 0.
          Office of Air and Radiation, Washington, DC. EPA 402-R-09-006, June. Available
          at: www.epa.gov/narel.
   16.2.   Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP).
          2004. EPA 402-B-04-001A, July. Volume I, Chapters 6, 7, 20, Glossary; Volume II
          and Volume III, Appendix G. Available at: www.epa.gov/radiation/marlap.
   16.3.   U.S. Environmental Protection Agency (EPA). 2014. Rapid Method for Sodium
          Hydroxide Fusion of Concrete and Brick Matrices Prior to Americium, Plutonium,
          Strontium, Radium, and Uranium Analyses. Revision 0, EPA 402-R-14-004. Office
          of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.4.   ASTM Dl 193, "Standard Specification for Reagent Water," ASTM Book of
          Standards 11.02, current version, ASTM International, West Conshohocken, PA.
   16.5.   ASTM D7282 "Standard Practice for Set-up, Calibration, and Quality Control of
          Instruments Used for Radioactivity Measurements," ASTM Book of Standards 11.02,
          current version, ASTM International, West Conshohocken, PA.
   16.6.   U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
          for Americium-241 in Building Materials for Environmental Remediation Following
          Radiological Incidents. Revision 0, EPA 402-R-14-007. Office of Air and Radiation,
          Washington, DC. Available at: www.epa.gov/narel.
    Other References
   16.1.   U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
          for Pu-238 and Pu-239/240 in Building Materials for Environmental Remediation
          Following Radiological Incidents. Revision 0, EPA 402-R-14-006. Office of Air and
          Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.8.   U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
          for Radium-226 in Building Materials for Environmental Remediation Following
          Radiological Incidents. Revision 0, EPA 402-R-14-002. Office of Air and Radiation,
          Washington, DC. Available at: www.epa.gov/narel.
   16.9.   U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
          for Total Radiostrontium (Sr-90) in Building Materials for Environmental
          Remediation Following Radiological Incidents. Revision 0, EPA 402-R-14-001.
          Office of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.10.  U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
          for Isotopic Uranium in Building Materials for Environmental Remediation
          Following Radiological Incidents. Revision 0, EPA 402-R-14-005. Office of Air and
          Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.11.  Koornneef,  J.M., Stracke, A, Aciego, S., Renbi, O. and Bourdon, B. 2010. "A new
                       	                                            9'lzl    9^0,  9^ 1
          method for U-Th-Pa-Ra separation  and accurate measurement of  U- Th-  Pa-
          99^
            Ra disequilibria in volcanic rocks by MC-ICPMS." Chemical Geology, Vol. 277,
          Issue 1-2, October, 30-41.


September 2014                           77

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                    Rapid Radiochemical Method for Radium-226 in Building Materials
    16.12. Maxwell, S. and Culligan, B. 2012. "Rapid Determination of Ra-226 in
          Environmental Samples," J. Radioanalytical and Nuclear Chemistry, online first
          article, February.
September 2014                             78

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                     Rapid Radiochemical Method for Radium-226 in Building Materials
17. Tables, Diagrams, and Flow Charts
    17.1.   Tables
            Table 17.1 - Alpha Particle Energies and Abundances of Importance
Energy
(MeV)
4.601
4.784
4.798
4.815
4.838
4.845
4.901
4.968
4.979
5.053
5.434
5.449
5.489
5.540
5.580
5.607
5.609
5.637
5.682
5.685
5.716
5.724
5.732
5.732
5.747
Abundance
(%)
5.6
94.5
1.5
9.3
5.0
56.2
10.2
6.0
3.2
6.6
2.2
5.1
99.9
9.0
1.2
25.2
1.1
4.4
1.3
94.9
51.6
3.1
8.0
1.3
9.0
Nuclide
Ra-226
Ra-226
Th -229
Th -229
Th -229
Th -229
Th -229
Th -229
Th -229
Th -229
Ra-223
Ra-224
Rn-222
Ra-223
Ac -225
Ra-223
Ac -225
Ac -225
Ac -225
Ra-224
Ra-223
Ac -225
Ac -225
Ac -225
Ra-223
Energy
(MeV)
5.791
5.793
5.830
5.869
6.002
6.051
6.090
6.126
6.243
6.278
6.288
6.341
6.425
6.553
6.623
6.778
6.819
^?^^
7.386
7.450
7.687
8.376
8.525
11.660

Abundance
(%)
8.6
18.1
50.7
1.9
100.0
25.1
9.8
15.1
1.3
16.2
99.9
83.4
7.5
12.9
83.5
100.0
79.4
^&^
100.0
98.9
100.0
100.0
2.1
96.8

Nuclide
Ac -225
Ac -225
Ac -225
Bi-213
Po-218
Bi-212
Bi-212
Fr-221
Fr-221
Bi-211
Rn-220
Fr-221
Rn-219
Rn-219
Bi-211
Po-216
Rn-219
^^S^
Po-215
Po-211
Po-214
Po -213
Po-212
Po -212




- Analyte

^^^



- 217At (3rd progeny of 225Ra tracer)


- 229Th (Check ROI for indications of inadequate clean-up)


         Includes only alpha particles emissions with abundance > 1% from radionuclides commonly present in
         the sample test source.
      Reference: NUDAT 2.4, Radiation Decay National Nuclear Data Center, Brookhaven National Laboratory;
      Available at: www.nndc.bnl.gov/nudat2/indx dec.jsp: Queried: November 11, 2007.
September 2014
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                   Rapid Radiochemical Method for Radium-226 in Building Materials
   17.2.   Ingrowth curves and Ingrowth factors
         1000
       E
       Q.
      TJ
                        Ac-225 In-Growth in Ra-225
                      200
    400     600

    Time, Hours
               800
              1000
                          Ra-225 In-Growth in Th-229
                                                                 Th-229, dpm

                                                                 -Ra-225, dpm
                   20
40
 60

Days
80
100
120
September 2014
               80

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                      Rapid Radiochemical Method for Radium-226 in Building Materials
                        Table 17.2 - Ingrowth Factors for 217At in 225Ra
Time elapsed between
separation of Ra and
midpoint of count
in hours
Ingrowth Factor*
Time elapsed between
separation of Ra and
midpoint of count
in hours
Ingrowth Factor*

1

0.002881

72

0.1748

2

0.005748

96

0.2200

3

0.008602

120

0.2596

4

0.01144

144

0.2940

5

0.01427

192

0.3494

6

0.01708

240

0.3893

24

0.06542

360

0.4383

48

0.1235

480

0.4391
 'ingrowth Factor represents the fraction of  Ac activity at the midpoint of the sample count relative to the   Ra
 activity present at the date/time ofRa separation.  These ingrowth factors may be closely approximated (within a
fraction of a percent) using the expression for At in Step 12.2.

                        Table 17.3 - Ingrowth Factors for 225Ra in 229Th
Time elapsed between
purification of the 229Th
standard and date of Ra
separation
in days
Ingrowth Factor*
Time elapsed between
purification of the 229Th
standard and date of Ra
separation
in days
Ingrowth Factor*
1

0.04545
50

0.9023
5

0.2075
55

0.9226
10

0.3720
60

0.9387
12

0.4278
70

0.9615
15

0.5023
80

0.9758
20

0.6056
90

0.9848
25

0.6875
100

0.9905
27

0.7152
130

0.9976
30

0.7523
160

0.9994
40

0.8445
200

0.9999
 Ingrowth Factor represents the fraction   Ra activity/  Th activity at the time ofRa separation.
                                                                      225,
                        Table 17.4 Decay Factors for Unsupported   Ra
Time elapsed
between separation
of229Thand225Ra
in days
Decay Factor*
Time elapsed
between separation
of229Thand225Ra
in days
Decay Factor*
1

0.9545
50

0.09769
5

0.7925
55

0.07741
10

0.6280
60

0.06135
12

0.5722
70

0.03853
15

0.4977
80

0.02420
20

0.3944
90

0.01519
25

0.3125
100

0.00954
27

0.2848
130

0.00236
30

0.2477
160

0.00059
40

0.1555
200

0.00009
 Decay Factor represents the fraction   Ra activity remaining as calculated using the equation in Footnote 2.
 September 2014
81

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                   Rapid Radiochemical Method for Radium-226 in Building Materials
   17.3.   Example Alpha Spectrum from a Processed Sample
                  3162
           Energy (keV)
   17.4.   Decay Schemes for Analyte and Tracer
                 a
                164 |
     22.2 y
                            226Ra Decay Scheme
                                    Secular equilibrium is
                                    established between 22BRa
                                    and 222Rn in about 18 days.
1 h
3.1 min
  Q
      27min

          P
                                           1,600y
                                           a
                                                                  3.8 d
                                                                  a
It takes about 4 hours for secular
equilibrium to be established
between 222Rn and 214Po after
fresh 222Rn is separated.
September 2014
            83

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                   Rapid Radiochemical Method for Radium-226 in Building Materials
                 225Ra (Including Parent) Decay Scheme
    45.6 min
                           4.8 min
                     a
                                          a
                                          10.0 d
            a
                                                        P
                                       7.3x103a
                                                       14.9d
                                                  a
Secular Equilibrium between
229Thand225Rais achieved
after about 70 days.
         The short half-lives of 221Fr and 217At allow the
32ms    217^* activityto be calculated from 225Ac activity
         based on secular equilibrium with 225Ac.
September 2014
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                      Rapid Radiochemical Method for Radium-226 in Building Materials
    17.5.   Flowchart
                  Separation Scheme and Timeline for Determination of
                          Ra-226in Building Materials Samples
                                         (Parti)
  Discard load and
  rinse solutions
  (Step 11.2.2.13)
  Discard Sr resin
  (Step 11.2.3.7)
                          Rapid Fusion (See Separate Procedure)
                          1.   Add 225Ra tracer and fuse with NaOH.
                          2.   Ca carbonate precipitation.
                          3.   Dissolve in of 20 ml_ 1.5M HCL (column load solution).
                         Vacuum Box Setup (Step 11.2.2)
                         1.   Prepare cation column using 5 g of 50WX8 200-400
                             mesh resin on vacuum box.
                         2.   Condition column with 10 mL 1M HCI @ 1 mL/min.
                          Load sample to cation resin columns (Step 11.2.2.10)
                          1.  Load sample @ 1 mL/min.
                          2.  Beaker/tube rinse:  5 mL 1.5M HCI @ 1-2 mL/min.
                          3.  Column rinse: 30 mL 3M  HCI @ 1-2 mL/min.
                          4.  Elute Ra with 25 mL 8M HNO3 @ 1 mL/min.
                         Transfer Ra eluate to 150 mL glass beakers
                         (Step 11.2.2.19)
                         1.   Add 2 mL 30 wt% H2O2 to each column.
                         2.   Evaporate eluate to dryness on a hotplate.
                         3.   Dissolve in 5 mL 3M HMOs, warming slightly on
                             hotplate.
                          Load sample to Sr Resin cartridge for Ba removal
                          (Step 11.2.3.4)
                          1. Load sample @ 1  mL/min.
                          2. Beaker rinse: 3 mL 3M HNO3 @ 1 mL/min.
                          3. Column rinse: 3 mL 3M  HNO3 @ 1-2 mL/min.
                          4. Collect load  and rinse solution containing Ra.
                                   Elapsed Time
                                                                                    3 hours
                                                                                    31/2 hours
                                    5 hours
                                    53/4 hours
                                                                                    61/4 hours
                                                                        Continue to Part II
September 2014
85

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                       Rapid Radiochemical Method for Radium-226 in Building Materials
  Discard Ln resin
  (Step 11.2.13)
  Discard filtrates
  and rinses
  (Step 11.3.7)
                        Separation Scheme and Timeline for Determination of
                                 Ra-226in Building Materials Samples
                                                (Part II)
                                    Elapsed Time
                                             Continued from
                                              Fig. 17.5, Part I
                                                    v
                            Transfer Ra eluate to 100 mL glass beakers
                            (Steps 11.2.3.8- 11.2.3.12)
                            1.  Add 2 mL 30 wt% H2O2 to each.
                            2.  Evaporate to dryness on a hotplate with high heat.
                            3.  Add 2 mL of 1M HCI and 2 mL 30 wt% H2O2 to each
                               and evaporate to dryness on a hotplate.
                            4.  Dissolve in 2 mL 0.1 M  HCI, warming.
                            5.  Add 8 mL water to each,  swirl and warm.
                                                    v
                           Load sample to Ln Resin cartridge (Step 11.2.5)
                           1.   Condition Ln Resin with 5 mL 0.02M HCI  @1mL/min.
                           2.   Load sample @ 1-2 mL/min or less.
                           3.   Beaker rinse: 5 mL 0.02M HCI @ 1-2 mL/min.
                           4.   Column rinse: 5 mL 0.02M HCI @ 1-2 mL/min.
                           5.   Collect load and rinse solution containing Ra.
                           6.   Add 3 mL concentrated HCI to each eluate. Cap and
                               mix.
                            Microprecipitation (Step 11.3)
                            1.  Add 3 g ammonium sulf ate to each tube
                            2.  Cap and mix on vortex stirrer to completely dissolve
                               ammonium sulf ate
                            3.  Add 50 ug barium to each tube. Cap  and mix well.
                            4.  Add 5 mL isopropanol to each tube. Cap and mix well
                               using vortex stirrer
                            5.  Place in ice/water mixture bath for 15 minutes,
                               periodically removing and stirring ( 2-3 times ) using
                               vortex stirrer.
                            6.  Filter and  rinse tube with  3 mL 20% isopropanol. Add
                               to filterfunnel.
                            7.  Rinse filter with methanol orethanol.
                            8.  Place on mounting disk and warm 5 minutes under
                               heat lamp.
                                       Count sample test source (STS)
                                        alphaspectrometry forSh or as
                                           needed (Step 11.4.11)
                                    71/2 hours
                                    8 hours
                                    9 hours
                                                                                      13-22 hours
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
                                       Appendix:

    Preparation and Standardization of 225Ra Tracer Following Separation from 229Th

Al. Summary Description of Procedure

This procedure describes a 225Ra generator to make tracer amounts of 225Ra using a 229Th
         99Q,                  v/S                                99Q,
solution.   Th is separated from   Ra using Y(OH)3 co-precipitation.   Th is carried in the
                         99S                                             99O	
precipitate and most of the   Ra remains in solution. Centrifugation to remove    Th in the
precipitate and filtration of the supernate produces the 225Ra tracer solution. The 225Ra activity of
the tracer solution is standardized by counting sample test sources prepared from at least five
replicate aliquants of the 225Ra solution, each spiked with a known quantity of a 226Ra standard.
This standardized activity concentration, referenced to the date and time of the 225Ra separation
described in Step A4.10.9 below, is then decay-corrected to the date and time of subsequent
sample analyses.
	     	                                                               ooc
The Y[Th](OH)3 precipitate may be stored and re-used later to generate more   Ra tracer
solution. 22 Ra ingrows in the 229Th fraction (Y(OH)3 precipitate) and after 50 days will be about
90% ingrown. After sufficient ingrowth time 225Ra may be harvested to make a fresh 225Ra tracer
                                                                       99Q,       99S
solution by dissolving the precipitate and re-precipitating Y(OH)3 to separate   Th from   Ra.
Multiple 225Ra generators may be prepared to ensure that 225Ra tracer will be continuously
available. The 2 5Ra tracer solution produced is usable for 2-3 half-lives (-30-45 days). To
minimize effort involved with standardization of the 225Ra solution, it is recommended that the
                              OOP	
laboratory prepare an amount of   Th sufficient to support the laboratory's expected workload
                       99Q,                                     99O	
for 3-5 weeks. Since the   Th solution is reused, and the half-life of   Th is long (7,342 years),
the need to purchase a new certified 229Th solution is kept to a minimum.

A2. Equipment and Supplies
    A2.1. Refer to Section 6 of the main procedure.

A3. Reagents and Standards
   A3.1.  Refer to Section 7 of the main procedure.
A4. Procedure
                                   229n
   A4.1.  Add a sufficient amount of   Th solution (that which will yield at least 150-600
                         99S                                    1
          dpm/mL of the   Ra solution) to a 50 mL centrifuge tube.
   A4.2.  Add 20 mg yttrium (Y) (2 mL of 10 mg/mL Y metals standard stock solution).
   A4.3.  Add 1 mg Ba (0.1 mL of 10 mg/mL Ba metals standard stock solution).
   A4.4.  Add 4 mL  of concentrated ammonium hydroxide to form Y(OH)3 precipitate.
   A4.5.  Centrifuge and decant the supernatant into the open barrel of a 50 mL syringe, fitted
          with a 0.45-|im syringe filter. Hold the syringe barrel over a new 50-mL centrifuge
          tube while  decanting. Insert the syringe plunger and filter the supernatant into the new
          centrifuge tube. Discard the filter as potentially contaminated rad waste.
1 For example, if 40 mL of a 229Th solution of 600 dpm/mL is used, the maximum final activity of 225Ra will be ~510
dpm/mL at Step B4.8. This solution would require about 1.4 mL for the standardization process and about 8 mL for
a batch of 20 samples.

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                    Rapid Radiochemical Method for Radium-226 in Building Materials
   A4.6.  Cap the centrifuge tube with the precipitate, label clearly with the standard ID,
          precipitation date, and the technician's initials and store for future use.
   A4.7.  Properly label the new centrifuge tube with the supernate. This is the 225Ra tracer
          solution.
                                         99S
   A4.8.  Add 3 mL of concentrated HC1 to   Ra tracer solution. Cap centrifuge tube and mix
          well.
   A4.9.  Prepare the following solutions in 10 mL of 2M HC1 for standardization of 225Ra
          tracer.

           Solution           Spike(s)
           Standardization     -80 dpm  of the 225Ra tracer solution, and
           Replicates          ~8 dpm of a 226Ra standard traceable to the National
           (5 replicates)       Institute of Standards and Technology (NIST) or
                              equivalent

           Blank              -80 dpm  of the 225Ra tracer solution (the blank
                              should be evaluated to confirm that 226Ra is not
                              detected in the 225Ra tracer solution at levels that
                              may compromise sample results when used in the
                              method)

           Standardization     -80 dpm  of the 225Ra tracer solution, and
           Control Sample     -8 dpm of a second source independent traceable
                              226Ra standard (the Standardization Control Sample
                              should be evaluated to confirm that the standardiza-
                              tion process does not introduce significant bias into
                              the standardized value for the 225Ra tracer).

   A4.10. Process the solutions to prepare sources for alpha spectrometry as follows:
          A4.10.1.  Evaporate aliquants in 50 mL glass beakers on a hot plate.
          A4.10.2.  Add 2 mL of 0.1M  HC1 to each beaker, warming on hot plate to dissolve.
          A4.10.3.  Add 8 mL water and swirl to mix. Warm to ensure sample is dissolved.
          A4.10.4.  Place a 2 mL Ln Resin cartridge on the vacuum box.
          A4.10.5.  Add 5 mL of 0.02M HC1 into each column to precondition resin at -1
                    mL/min. Discard rinse.
          A4.10.6.  Transfer each sample solution from Step A4.10.3 into the appropriate
                    reservoir. Allow solution to pass through the Ln Resin cartridge at a flow
                    rate of-1 mL/min.
          A4.10.7.  Add 5 mL of 0.02M HC1 to each beaker (from Step A4.10.3) as a rinse
                    and transfer each solution into the appropriate reservoir at -1 mL/min.
          A4.10.8.  Add 5 mL of 0.02M HC1 into each column to rinse at -1 mL/min.
          A4.10.9.  Record the date and time of the last rinse as the date and time of
                                                     99S
                    separation of radium (beginning of  Ac ingrowth).
                    NOTE: The activity reference date and time established during standardization of
                    the 225Ra tracer is used as the reference date for the 225Ra solution.
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
          A4.10.10. Remove tubes from vacuum box and add 3 mL concentrated HC1 to each
                    tube. Cap and mix.
          A4.10.11. Add -3.0 g of (NH4)2SO4 to the purified sample solution Mix well to
                    completely dissolve the salt (dissolves readily).
          A4.10.12. Add 75 |ig of Ba carrier (75 |iL of 1000 |ig Ba/mL) into each tube. Cap
                    and mix well with vortex stirrer.
          A4.10.13. Add 5.0 mL of isopropanol and mix well  using a vortex stirrer.
          A4.10.14. Place each tube in an ice bath filled with cold tap water for at least 20
                    minutes, periodically stirring on vortex stirrer.
                    NOTE: Sonication may be used instead of occasional stirring using a vortex stirrer.
          A4.10.15. Pre-wet a 0.1-micron filter using methanol or ethanol. Filter the
                    suspension through the filter using vacuum. The precipitate will not be
                    visually apparent.
          A4.10.16. Rinse the sample container with 3 mL of 20% isopropanol solution.
          A4.10.17. Rinse the filter apparatus with about 2 mL of methanol or ethanol to
                    facilitate drying. Turn off vacuum.
          A4.10.18. Mount the filter on a labeled adhesive mounting disk (or equivalent)
                    ensuring that the filter is not wrinkled and is centered on mounting disk.
          A4.10.19. Place the filter under a heat lamp for ~5 minutes or more until it is
                    completely dry.
          A4.10.20. Count filters for an appropriate period of time by alpha spectrometry.
          A4.10.21. Mount the dried filter on a support appropriate for the counting system to
                    be used.
          A4.10.22. Store the filter for at least 24 hours to allow sufficient 217At (third progeny
                    of 225Ra) to ingrow into the sample test source allowing a measurement
                    uncertainty for the 217At of < ~5 %.
          A4.10.23. After allowing about 24-hours ingrowth, count the standardization sources
                    by alpha spectrometry.
   A4.11. Calculate the activity of 225Ra, in units of dpm/mL, in the standardization replicates,
          at the 225Ra time of separation as follows:


                            '*>"*   A
          ARa ~ '
                    ^-^]x[(3.0408)(/()
                     *r,      *h  I
ff-W _e-W U^
                 Ra
   where:
      A22s     =   Activity concentration of 225Ra, in dpm/mL [at the time of separation from
                  229Th, StepB4.4.10]
      N      =   Total counts beneath the 217At peak at 7.07 MeV
        217At                                   f
      N      =   Total counts beneath the 226Ra peak at 4.78 MeV
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                Rapid Radiochemical Method for Radium-226 in Building Materials
      4
      tb
      A
       226
V
  2
V
  2
d
        26Ra
              Background count rate for the corresponding region of interest,
              Duration of the count for the sample test source, minutes
              Duration of the background count, minutes
                         99^
              Activity of  Ra added to each aliquant, in dpm/mL
              Volume of 226Ra solution taken for the analysis (mL)
                                                      J    \   J
              Volume of 225Ra solution taken for the analysis (mL)
                                                      J    \   J
              Elapsed ingrowth time for 225Ac [and the progeny 217At], from separation to
              the midpoint of the sample count, days
  AI      =   0.04652 d"1 (decay constant for 225Ra - half-life = 14.9 days)
  X2      =   0.0693 1 d"1 (decay constant for 225Ac) - half-life = 10.0 days)
  /t      =   Fractional  abundance for the 7.07 MeV alpha peak counted (= 0.9999)
  3 .0408 =    X2dj(X2d - \d] [a good approximation as the half lives of 221Fr and 217At are
              short enough so secular equilibrium with 225Ac is ensured]
       NOTE: The activity of the separated A22SKa will need to be decay corrected to the point of
       separation in the main procedure (Step 11.3.6) so that the results can be accurately determined.
A4. 12. Calculate the uncertainty of the activity concentration of the 225Ra tracer at the
       reference date/time:
                                           - + ACl, x
                                                 Ra
   where:
      u(AC^J
                                                                 9S
       225 Ra
              = Standard uncertainty of the activity concentration of  Ra, in dpm/mL
    217
  N
   4
  AC
      26
   V226Ra

   "VJ
   7226Ra
   F225Ra

   "OW
   d
    25
                 = Total counts beneath the 217At peak at 7.07 MeV,
                   	                     99^
                 = Total counts beneath the  Ra tracer peak at 4.78 MeV
                 = Background count rate for the corresponding region of interest,
                 = Duration of the count for the sample test source, minutes
                 = Duration of the background count, minutes
                 = Activity of 226Ra added to each aliquant, in dpm/mL
                 = Activity of 225Ra, in dpm/mL
                              99^
                 = Volume of   Ra solution taken for the analysis (mL)
                              99^
                 = Volume of   Ra solution taken for the analysis (mL)
                 = Fractional abundance for the 226Ra peak at 4.78 MeV (= 1.000)
                 = Volume of 225Ra solution taken for the analysis (mL)
                 = Volume of 225Ra solution taken for the analysis (mL)
                 = Elapsed ingrowth time for 225Ac [and the progeny 217At], from separation to
                   the midpoint of the sample count, days
                 = 0.04652 d"1 (decay constant for 225Ra - half-life = 14.9 days)
                 = 0.06931 d"1 (decay constant for 225Ac) - half-life =10.0 days)
                 = Fractional abundance for the 7.07 MeV alpha peak counted (= 0.9999)
September 20 14
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                    Rapid Radiochemical Method for Radium-226 in Building Materials
      3.0408     =  A2d/(A2d - \d] [a good approximation as the half lives of221Fr and 217At
                    are short enough so secular equilibrium with 225Ac is ensured]
      u(R226  )   =  Standard uncertainty of net count rate for 226Ra, in cpm
                 =  Net count rate for 226Ra, in cpm

          NOTE: The uncertainty of half-lives and abundance values are a negligible contributor to the
          combined uncertainty and are considered during the evaluation of combined uncertainty.
   A4.13. Calculate the mean and standard deviation  of the mean (standard error) for the
          replicate determinations, to determine the acceptability of the tracer solution for use.
          The calculated standard deviation of the mean should be equal to or less than 5% of
          the calculated mean value.
   A4.14. Store the centrifuge tube containing the Y(OH)3/Th(OH)4 precipitate. After sufficient
          time has elapsed a fresh 225Ra tracer solution may be generated by dissolving the
          precipitate with 40 mL of 0.5M HNOs and repeating Steps A4.4 through A4.10 of
          this Appendix.
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               Validation of Rapid Radiochemical Method for Ra-226 in Building Materials
                                        Attachment IV:
                  Composition of Brick Used for Spiking in this Study
Metals by ICP-AES [4]
Silicon Dioxide
Aluminum
Barium
Calcium
Iron
Magnesium
Potassium
Sodium
Titanium
Manganese
Strontium
Uranium
Thorium
Non-Metals
Chloride
Sulfur
Phosphorus
Radionuclide
Uranium 238, 234
Plutonium 239/240
Americium 24 1
Strontium 90
Radium 226
Concentration (ppm) [11
721,700
78,700
400
1,600
40,000
4,600
15,300
1,500
4,400
600
100
<30
<30


5,600
1,500
Concentration (pCi/g) [2'3]
1.054 0.020, 1.102 0.021
-0.0003 0.0041
0.048 0.039
0.1190.077
1.025 0.027
           NOTE: Analyses conducted by an independent laboratory.
           [1]  Values below the reporting level are presented as less than (<) values.
               No measurement uncertainty was reported with the elemental analysis values. Parts
               per million (ppm).
           [2]  Reported values represent the average value of seven blank samples analyzed except
               for 226Ra and U by NAREL. Ten blank brick samples were analyzed for 226Ra.
               Sixteen blank brick samples were analyzed for the uranium isotopes.
           [3]  Reported uncertainty is the standard deviation of the results (k=l).
           [4] ICP-AES=Inductively Coupled Plasma - Atomic Emission Spectrometry
05-01-2014
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