EPA 402-R-14-008
www.epa.gov/narel
September 2014
Validation of
Rapid Radiochemical Method
for Am-241 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 Am-241 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 Am-241 in Brick Samples
Contents
Acronyms, Abbreviations, Units, and Symbols iii
Radiometric and General Unit Conversions v
Acknowledgments vi
1. Introduction 1
2. Radioanalytical Methods 2
3. Method Validation Process Summary 2
4. Participating Laboratory 3
5. Measurement Quality Objectives 4
6. Method Validation Plan 5
6.1 Method Uncertainty 5
6.2 Detection Capability 5
6.3 Method Bias 6
6.4 Analyte Concentration Range 7
6.5 Method Specificity 8
6.6 Method Ruggedness 8
7. Techniques Used to Evaluate the Measurement Quality Objectives for the Rapid Methods
Development Project 8
7.1 Required Method Uncertainty 8
7.2 Required Minimum Detectable Concentration 9
8. Evaluation of Experimental Results 10
8.1 Summary of the Combined Rapid 241Am - BrickMethod 10
8.2 Required Method Uncertainty 11
8.3 Required Minimum Detectable Concentration 12
8.4 Evaluation of the Absolute and Relative Bias 14
8.5 Method Ruggedness and Specificity 15
9. Timeline to Complete aBatch of Samples 16
10. Reported Modifications and Recommendations 17
11. Summary and Conclusions 17
12. References 18
Attachment I: Estimated Elapsed Times: Combined Rapid 241Am -BrickMethod 20
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 21
Appendix: Rapid Technique for Milling and Homogenizing Concrete and
Brick Samples 42
Attachment III: Rapid Radiochemical Method for Am-241 in Building Materials for
Environmental Remediation Following Radiological Incidents 51
Attachment IV: Composition of Brick Used for Spiking in this Study 69
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Figure
Figure 1 - Yields for Method Based on Measurement of 243Am 16
Tables
Table 1 -Am-241 Method Validation Test Concentrations and Results 4
Table 2 - Sample Identification and Test Concentration Level for Evaluating the Required
Minimum Detectable Concentration 6
TableS -MARLAP Level C Acceptance Criteria 9
Table 4 A - Am-241 Analytical Results for Required Method Uncertainty Evaluation 11
Table 4B - Experimental Standard Deviation of the Five PT Samples by Test Level 12
Table 5 -Reported 241Am Concentration Blank Brick Samples 13
Table 6 - Reported Results for Samples Containing 241 Am at the As-Tested MDC Value
(0.2000 pCi/g) 14
Table 7 - Absolute and Relative Bias Evaluation of the Combined Rapid 241Am - Brick Method
15
Table 8 - Summary of 243Am Radiochemical Yield Results for Test and Quality Control Samples
-Brick 16
September 2014 ii
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Validation of Rapid Radiochemical Method for Am-241 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
E&Z Eckert & Ziegler Analytics
EPA U.S. Environmental Protection Agency
ft foot
FWHM full width at half maximum
FRMAC Federal Radiological Monitoring and Assessment Center
g gram
gal gallon
G-M Geiger-Muller [counter or probe]
h hour
ICP-AES inductively coupled plasma - atomic emission spectrometry
ID identifier or identification number
IND improvised nuclear device
IUPAC International Union of Pure and Applied Chemistry
kg kilogram (103 gram)
L liter
LC critical level concentration
LCS laboratory control sample
m meter
M molar
MARL AP Multi-Agency Radiological Laboratory Analytical Protocols Manual
MDC minimum detectable concentration
MeV mega electron volts (106 electron volts)
min minute
mL milliliter (10"3 liter)
MQO measurement quality obj ective
MVRM method validation reference material
uCi microcurie (1CT6 curie)
um micrometer [micron]
NAREL EPA's National Analytical Radiation Environmental Laboratory, Montgomery,
Alabama
NHSRC EPA's National Homeland Security Research Center, Cincinnati, Ohio
NIST National Institute of Standards and Technology
September 2014 iii
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
ORIA U.S. EPA Office of Radiation and Indoor Air
^MR required relative method uncertainty
pCi picocurie (1CT12 curie)
PPE personal protective equipment
ppm parts per million
PT proficiency test or performance test
QAPP quality assurance proj ect plan
R Roentgen - unit of X or y radiation exposure in air
rad unit of radiation absorbed dose in any material
ROD radiological dispersal device
rem roentgen equivalent: man
ROI region of interest
s second
SI International System of Units
Sv sievert
MMR required method uncertainty
wt% percent by mass
y year
September 2014 iv
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Validation of Rapid Radiochemical Method for Am-241 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)
becquerel (Bq)
picocurie (pCi)
pCi/gram (g)
pCi/g
Bq/L
pCi/g
jiCi
pCi
m3
liters (L)
rad
sievert (Sv)
Multiply by
3.16xl07
5.26xl05
8.77xl03
3.65xl02
1
27.0
2.70xlO~2
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/g
Bq/L
pCi/g
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^
2.74xlO~3
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
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Validation of Rapid Radiochemical Method for Am-241 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.
September 2014 vi
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Validation of Rapid Radiochemical Method for Am-241 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, a project was initiated 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.1 Similar to the rapid method project initiated in
2007 for other radionuclides in water samples (EPA 2008), this rapid method development
project for a brick matrix addressed four different radionuclides in addition to 241Am: 239240Pu,
natU, 226Ra, and 90Sr. Each of these radionuclides will have separate method validation reports for
the brick matrix.
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." The method
formulated was preliminarily tested at the National Analytical Radiation Environmental
Laboratory (NAREL) and refinements to the method 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 Radiological Incidents - Radionuclides in Soil (EPA 2012). The MQO
specification for the required method uncertainty (MMR) of 0.20 pCi/g was based on a 241Am brick
concentration similar to the MQO for the soil matrix, i.e., at approximately 1 xlO 5 risk limit for a
50-year exposure of 1.5 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 Am-241 in Building Materials for Environmental Remediation Following
Radiological Incidents (Attachment III). In this document, the combined methods are referred to
as "combined rapid 241Am - Brick method." The method validation process is applied to the
fusion dissolution of brick using sodium hydroxide and the subsequent separation and
941
quantitative analysis of Amusing alpha spectrometry to detect the 5.48 million electron volt
(MeV) alpha particle from the decay of 241Am. Americium-243 was used as a tracer to quantify
the chemical yield and account for overall detection efficiency. The laboratory's complete report,
including a case narrative and a compilation of the reported results for this study, can be obtained
by contacting NAREL (http://www.epa.gov/narel/contactus.html).
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.
September 2014 1
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
2. Radioanalytical Methods
The combined rapid 241 Am - 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, fusion process, chemical processing and radiation detection. Specifications for
sample processing were incorporated into the rapid 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 500-minute counting time for three test level samples and the required
minimum detectable concentration (MDC) samples. A 1-g sample size was used. A summary of
the rapid method is presented in Section 8.1 prior to presenting the experimental results of the
method validation analyses.
The final combined rapid 241Am - Brick method is included as Attachments II and III to this
report. Although this final method is a slight 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 the final method in Attachment III.
3. Method Validation Process Summary
The method validation plan for the combined rapid 241 Am - 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 combined rapid 241Am - Brick method is considered a
"new application/similar matrix" of an existing 90Sr method for soil and concrete matrices
(MARLAP 2004, Section 6.6.3.5). Therefore, the combined rapid 241Am - Brick method was
evaluated according to MARLAP method validation "Level C." More specifically, the method
was validated against acceptance criteria for the required method uncertainty (MMR) at a specified
analytical action level (AAL) concentration and the required MDC. In addition, analytical results
were evaluated for statistical bias, absolute bias for blank samples and relative bias at each of the
three test level radionuclide activities. The radiochemical yield of the method was also evaluated
as a characteristic of method ruggedness.
The method validation process was divided into four phases:
1. Phase I
a. Laboratory familiarization with the method concept.
b. Set-up of the laboratory and acquisition of reagents, standards and preparation of
in-house PT samples.
c. Perform preliminary tests of the rapid fusion method.
d. Make changes to improve the method based on the preliminary tests.
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
2. Phase II
a. Conduct blank sample analyses to assess the method critical level concentration.
b. Conduct method validation 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, a laboratory
control sample (LCS) and a sample duplicate.
The objective of the first (preliminary) phase was to familiarize the laboratory with the
formulated rapid method and then gain hands-on experience in 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 241 Am activities consistent
with evaluating the targeted required method uncertainty at the AAL and the required MDC (see
Table 1 -Am-241 Method Validation Test Concentrations and Results). The analysis of the
blank and laboratory spiked brick samples used in Phase I provided insight into the feasibility of
the proposed method. Based on information and experience gained during Phase I practice runs,
the rapid 241 Am-Brick method was optimized without compromising data collected during the
validation process in Phases II and III. The method was not subjected to a "formal" method
validation evaluation process in Phase I.
During Phases II and III of the method validation process, the laboratory analyzed external PT
samples consisting of method validation reference materials (MVRM) provided by an external,
National Institute of Standards and Technology (NIST)-traceable source manufacturer (Eckert &
Ziegler Analytics (E&Z), Atlanta, GA). The MVRM were pulverized brick prepared by E&Z.
The macro-analysis of brick material is provided in Attachment IV. The laboratory was
instructed to analyze specific blind PT samples having concentration levels 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 laboratory 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 rapid fusion of brick samples using chemically characterized brick
samples spiked with NIST-traceable 241 Am sources.
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
5. Measurement Quality Objectives
The combined rapid 241 Am - Brick method was developed to meet pre-established MQOs for the
rapid methods project. The MQOs selected 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 241 Am -
Brick method was set at 13%2 at a targeted brick AAL equal to 1.5 pCi/g, which is
approximately the 1 xlCT5 risk concentration for a 50-year exposure period for a soil matrix. This
soil concentration value is based on guidance found in the Federal Radiological Monitoring and
Assessment Center (FRMAC) for soil.3 The target MDC for the combined rapid 241Am - Brick
method for the brick matrix was 0.2 pCi/g (-13% of the AAL). However, the PT sample supplier
generated method validation and MDC samples having 241Am concentrations slightly different
than the targeted values. Table 1 summarizes the targeted MQOs for the 241Am method
validation process and the study test values based on the actual spiked concentrations of the PT
samples. It should be noted that the method was validated for a brick matrix having a typical
chemical composition and four additional radionuclides in concentrations corresponding to a
10 5 risk AAL for brick (see Attachment IV for the chemical composition of the brick matrix).
The brick concentration for the four other radionuclides were 239/240Pu (1.890 pCi/g), 238U (12.35
pCi/g), 226Ra (4.755 pCi/g), and 90Sr (2.440 pCi/g). The homogeneity of the five added
radionuclides in the brick matrix was estimated by including 9 mTc as an additional radionuclide
and analyzing the 99mTc in ten 1-gram (g) samples from each of the method uncertainty test
levels and the MDC level. The average spread in the 99mTc activity in the 10 samples of the four
test levels was 1.54% (as the relative standard deviation in the distribution of the results
compared to the mean of the distribution), with individual relative standard deviations for the
four sets of data ranging between 1.04 to 2.40% of the respective mean result.
Table 1 - Am-241 Method Validation Test Concentrations and Results
MDC
!/2 x AAL
AAL
3xAAL
Target
Value
0.2
0.75
1.5
4.5
Known Value,
pCi/g (k = 1)
0.2000 ±0.0020
0.7730 ±0.0077
1.570 ±0.016
4.630 ±0.046
Average
Measured
Value
0.251
0.811
1.50
4.51
Required
Method
Uncertainty,
MMR
—
0.20
0.20
0.60 [1]
Standard Deviation
of Measurements P1
0.046
0.088
0.11
0.22
[1] The value of 0.60 pCi/g is the absolute value forthe required method uncertainty and represents 13% of 4.63
pCi/g.
[2] Calculated standard deviation of the 10 and 5 measurement results for the MDC and Test Level samples,
respectively.
2 Type I and II decision error rates were set at zl_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 l/i the AAL.
3 Federal Radiological Monitoring and Assessment Center. Appendix C of the FRMAC Manual (FRMAC 2010) or
calculated using Turbo. FRMAC 2010 available from Sandia National Laboratory.
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
6. Method Validation Plan
The combined rapid 241 Am - 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
The method uncertainty of the combined rapid 241Am - Brick method for 241Am was evaluated at
the AAL concentration (1.570 pCi/g known value) specified in the MQOs presented in Table 1.
In accordance with MARLAP method validation "Level C," this method was evaluated at each
of three test concentration levels, one of which was the AAL equivalent activity concentration to
approximately 1 x 10~5 risk for a soil matrix. The laboratory analyzed five replicate external
MVRM PT samples containing 241 Am activities at approximately one-half the AAL, the AAL
and three times the AAL. The method was evaluated against the required method uncertainty,
WMR= 0.20 pCi/g, at and below the AAL, and against the relative required method uncertainty,
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Table 2 - Sample Identification and Test Concentration Level for Evaluating the
KCC
Test Sample Designation
MA1-MA10
(Brick MDC samples)
BMDC1-BMDC7
(Brick2 matrix blanks)
uirea ivimimum uetectaoie concentration
Number of
Samples
Prepared
10
7
Nuclide
241Am
241Am
MDC Known Value
(pCi/g)
0.2000 ± 0.0020 (£=1)
—
Mean Measured
Concentration
(pCi/g)[1]
0.25 1± 0.046 (k= 1)
0.048 ±0.039
[1] Mean and standard deviation of 10 spiked samples and 7 blanks. The stated combined standard uncertainty
(CSU) includes the uncertainty in the 241 Am reference standard used to prepare the samples. The concentration
of241 Am in the blank brick sample matrix was statistically different from zero.
[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
Absolute bias was determined as a method performance parameter. The results from the seven
blank brick samples for the required MDC evaluation were evaluated 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).
There was no acceptance limit for bias established for the method in this method validation
process.
9/11
The following protocol was used to test the combined rapid Am - Brick method 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
X
T
3 . An absolute bias in the measurement process is indicated if
(1)
(2)
where £1-0/2 (TV-1) represents the (1 - a/2)-quantile of the ^-distribution with TV-1 degrees of
freedom. For seven blanks, an absolute bias is identified at a significance level of 0.05, when
|T|> 2.447.
Relative Bias
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
The results from the five external PT brick samples for each of the three test levels 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. No acceptable relative bias limit was specified for
this method validation process.
The following protocol was used to test the combined rapid 241 Am - 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
u(K) is the standard uncertainty of the reference value
A relative bias in the measurement process is indicated if
T >t ,. ,
l-a!2<.y,f-> (Ja)
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(veff)> 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
The combined rapid 241 Am - 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" (known) test level activities are presented in
September 20 14
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Table 1. Note that the final test concentration values for the PT samples varied from the
proposed test levels, but that these values were well within the sample preparation specifications
provided to the PT sample provider.
6.5 Method Specificity
The brick sample is fused using rapid sodium hydroxide fusion at 600 °C in a furnace using
zirconium crucibles. It digests refractory particles and eliminates significant interferences from
silica and other brick matrix components. Preconcentration of Am from the alkaline matrix is
accomplished using iron/titanium hydroxide followed by lanthanum fluoride precipitation steps
to remove brick matrix interferences and remove silicates. Am-241 is separated and purified
using a rapid column method that utilizes TEVA® and DGA® Resins. After purification, 241 Am is
measured using alpha spectrometry at 5.49 MeV. The column separation provides effective
removal of interferences and high chemical yields by using DGA Resin, which has a very high
affinity for Am.
6.6 Method Ruggedness
The sodium hydroxide fusion has been used successfully on the U.S. Department of Energy's
Mixed Analyte Performance Evaluation Program soil samples containing refractory actinides.
The method is rapid and simple yet very rugged. The lanthanum fluoride step with HF present
removes silicates, which tend to clog the resin cartridges. The lanthanum fluoride step also
removes the large amount of Fe present in brick and used in the preconcentration step so that a
small column load solution can be achieved, reducing column separation time.
The method validation external PT samples contained other alpha emitting radionuclides (239Pu,
U and 226Ra). The alpha spectra were absent of other alpha emitting radionuclides present in the
external PT 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
The combined rapid 241 Am - 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 (MARLAP 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
September 2014
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
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 241Am 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 (UUR = 0.20 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.
Table 3 - MARLAP Level C Acceptance Criteria
MARLAP
Validation
Level
C
Application
Similar
Matrix/New
Application
Sample
Type [1]
Internal/
External PT
Acceptance
Criteria [2]
Measured value
within ±2.9 UUR or
± 2.9 (PMR of
validation value
Number of
Test Levels
3
Number of
Replicates
5
Total Number
of
Analyses
15
[1] For this method validation, external PT samples from a NIST-traceable source supplier were 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
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
For seven (minimum) blank results (six degrees of freedom) and a Type I error probability of
0.05, the previous equation reduces to:
(6)
The use of the above equations assumes that the method being evaluated has no bias.
Verification of Required MDC
Each of the 10 analytical results reported for the PT samples having a concentration at the
required MDC for 241Am (0.2000 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 blank sample net results, calculate the estimated Critical Net Concentration,
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 CLNC.
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
941
6 and 7. The Am 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 Combined Rapid 241Am - Brick Method
A 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 with iron/titanium hydroxide enhanced with calcium phosphate is used to
remove the Am from the alkaline matrix. The precipitate is dissolved in dilute acid and a
lanthanum fluoride precipitation is performed to further remove brick matrix components such as
iron and silicates. The precipitate is redissolved in nitric acid with boric acid and aluminum
present and loaded to a stacked TEVA® + DGA® Resin cartridges. Plutonium, thorium, and
neptunium are removed on TEVA® Resin, and americium is retained on DGA® Resin, which has
a very high retention for trivalent actinides. Uranium has very little retention on DGA and is
removed by rinsing with dilute nitric acid. Any thorium that may have passed through TEVA®
September 2014 10
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Resin and made it to DGA Resin is removed using a 3 molar (M) HNO3-0.25M HF rinse.
Americium is eluted from DGA® with dilute hydrochloric acid and alpha spectrometry mounts
are prepared using cerium fluoride microprecipitation.
8.2 Required Method Uncertainty
Table 4 A summarizes the 241Am results and the acceptability of each result compared to the
acceptance criteria presented in Section 7.1. The final sample test sources were micro-
precipitated on 25 mm filters as CeFs counted on an alpha spectrometry system for 500 minutes.
The count times used were longer than the times in concrete validation because the alpha
detectors in this laboratory had an efficiency of only 16%, compared to -25% efficiency
detectors used in the laboratory validation of this method for concrete samples (EPA 2014). Each
measurement in a test level was within the acceptable range for that test level. Therefore, the
method is capable of meeting a required method uncertainty of 0.20 pCi/g at and below the AAL
of 1.570 pCi/g. An approximately 1 gram aliquant from the original sample was analyzed.
Table 4A - Am-241 Analytical Results for Required Method Uncertainty Evaluation
Nuclide: Am-241 Matrix: Brick AAL Tested: 1.570 pCi/g
Proposed Method: Combined Rapid 241 Am - Brick Method
Required Method Validation Level: MARLAP "C"
Required Method Uncertainty. MMR: 0.20 pCi/g at and below AAL; 13% of the known value above AAL
Acceptance Criteria:
Test Levels 1 and 2: 2.9 x MMR = ± 0.58 pCi/g of quoted known value of sample in test level
Test Level 3 : 2.9 x ^j^ = ± 37.7% of quoted known value of sample in test level (4.630 pCi/g)
Test Level 1
Known Value = 0.7730 pCi/g
Sample
(Analytics Batch SO-
Ul)
A01
A02
A03
A04
A05
Uncertainty [1]
(pCi/g)
0.0077
pCi/g
Measured
0.768
0.954
0.737
0.833
0.762
csu [2]
(pCi/g)
0.086
0.092
0.074
0.082
0.079
Allowable
Range
(pCi/g)
0.18-1.4
Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 2
Known Value = 1.570 pCi/g
Sample (Analytics
Batch SO-U2)
A06
A07
A08
A09
A10
Uncertainty [1]
(pCi/g)
0.016
pCi/g
Measured
.57
.36
.60
.40
.58
CSU [2]
(pCi/g)
0.12
0.11
0.12
0.11
0.12
Allowable
Range
(pCi/g)
0.98-2.2
Acceptable
Y/N
Y
Y
Y
Y
Y
September 2014
11
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Test Level 3
Known Value = 4.63 pCi/g
Sample (Analytics
Batch SO-U3)
All
A12
A13
A14
A15
Uncertainty [1]
(pCi/g)
0.046
pCi/g
Measured
4.20
4.78
4.63
4.42
4.50
csu [2]
(pCi/g)
0.23
0.25
0.25
0.23
0.24
Allowable
Range
(pCi/g)
2.9-6.4
Acceptable
Y/N
Y
Y
Y
Y
Y
[1] Quoted uncertainty (k= 1) by the radioactive source manufacturer. [2] Coverage factor k=l.
As a measure of the expected variability of results for a test level, the calculated standard
deviation of the five 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)
0.811
1.50
4.51
Standard Deviation of
Measurements
(pCi/g)
0.088
0.11
0.22 (4.9%)
Required Method
Uncertainty
(pCi/g)
0.20
0.20
0.60L1J(13%)
[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.
8.3 Required Minimum Detectable Concentration
The rapid combined 241 Am - Brick method was validated for the required MDC using 243Am as a
tracer and an alpha spectrometry counting time of 360 minutes to meet the required method
uncertainty at the AAL.
9/11
Tables 5 and 6 summarize the Am results for the blank samples and the acceptability of the
method's performance specified in Section 7.2 to meet the tested required MDC of 0.2000 pCi/g.
September 2014
12
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
241
Table 5 - Reported Am Concentration Blank Brick Samples
Sample ID
A41
A42
A43
A44
A45
A46
A47
Mean [2]
Standard Deviation
Critical Net Concentration
(pCi/g)
Concentration (pCi/g)
0.091
0.035
0.018
0.103
0.065
0.011
0.009
0.048
0.039
0.076
CSU [1] (pCi/g)
0.033
0.021
0.017
0.036
0.029
0.015
0.013
[1] Combined standard uncertainty, coverage factor k=l.
[2] Mean and standard deviation were calculated before rounding.
Critical Net Concentration
The critical net concentration for the method under evaluation was calculated using Equation 6
from Section 7.2. Based on the results of the seven blanks (Table 5), the critical net
concentration for the combined method was determined to be 0.076 pCi/g.
RequiredMDC
A summary of the reported results for samples containing 241Am at the required MDC is
presented in Table 6. The mean measured value and standard deviation of the ten 241Am in the
MDC test samples were calculated as 0.251 + 0.046 pCi/g (k=\). Each result was compared to
the critical net concentration of 0.076 pCi/g. If the result was at or below the critical net
concentration, a "Y" qualifier was applied to the sample result; otherwise an "N" qualifier was
applied. As presented in the table, the number of Y qualifiers is < 2, so the combined rapid
241 Am water method evaluated passes the test for the required MDC specification (see Method
Validation Guide for Qualifying Methods Used by Radiological Laboratories Participating in
Incident Response Activities [EPA 2009] for a description of the test).
September 2014
13
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Table 6 - Reported Results for Samples Containing
MDC Value (0.2000 pCi/g)
241
Am at the As-Tested
Sample ID
A30
A31
A32
A3 3
A34
A3 5
A36
A37
A3 8
A3 9
Mean P1
Standard Deviation of Results
Concentration
(pCi/g)
0.238
0.263
0.311
0.234
0.222
0.244
0.254
0.310
0.284
0.153
0.251
0.046
^-^NC
Acceptable maximum
values < CLNC (Y)
Number of results > CLNC
Number of results < CLNC
csu [1]
(pCi/g)
0.050
0.050
0.053
0.050
0.047
0.049
0.049
0.056
0.053
0.039
0.076 pCi/g
2
—
—
Evaluation
Test Result [3]
-------
Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
241
Table 7 - Absolute and Relative Bias Evaluation of the Combined Rapid Am - Brick Method
Type of
Bias
Absolute
Relative
Relative
Relative
Relative
Test
Level
Blanks
MDC
1
2-
AAL
o
J
Known Value
+ CSU (k=\)
(pCi/g)[11
0.0000
0.2000 ± 0.0020
0.7730 ± 0.0077
1.570 ±0.016
4.630 ±0.046
Mean of
Measurements +
Standard
Deviation pl
(pCi/g)
0.048 + 0.039
0.251 ±0.046
0.811 ±0.088
1.50 ±0.11
4.51 ±0.22
Difference
from
Known
0.048
0.051
0.038
-0.07
-0.12
Number of
Measurements/
Degrees of
Freedom
7/6
10/9
5/4
5/4
5/6
|T|
3.22
3.47
0.94
1.32
1.16
tdf
2.45
2.26
2.78
2.78
2.45
Bias
Yes/No
Y
Y
N
N
N
[1] The stated CSU includes the uncertainty in the Am reference standard used to prepare the samples and the
standard deviation of the spiked test samples.
[2] Standard deviation of the measurements.
The results for the seven blank brick samples had a mean and standard deviation of 0.048 +
0.039 pCi/g. A statistical analysis of the data indicated that there was an absolute bias for the
blank brick samples. However, the magnitude of the absolute bias was only 3.1% of the test level
2 (AAL) known value of 1.570 pCi/g and had no affect the outcome of the method uncertainty
evaluation tests.
A relative bias was noted for the measurements performed on the 10 MDC test samples. The
mean concentration of 0.251 pCi/g for the ten MDC test samples falls within 0.051 pCi/g (or
-26%) of the known value of 0.2000 pCi/g. This difference between the measured mean value
and the known MDC value is approximately the same magnitude as the mean brick blank 241 Am
concentration of 0.048 pCi/g.
As determined by the paired-^ test described in Section 6, no relative bias was indicated for any
of the three test levels for the method uncertainty evaluation. The relative percent difference for
each test level is:
• Test Level 1: 4.9%.
• Test Level 2: -4.5%.
• Test Level 3: -2.6%.
A measured mean difference from the known value less than 5 percent demonstrates the
capability and robustness of this combined rapid 241Am - Brick method.
8.5 Method Ruggedness and Specificity
The results summarized in Table 8 represent the radiochemical yields for all three test levels,
blanks, LCSs and MDC samples that were processed in accordance with the final methods in
Attachments II and III.
September 2014
15
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
• 243,
Table 8 - Summary of Am Radiochemical Yield Results for
Test and Quality Control Samples - Brick
Number of Samples
Mean Radiochemical Yield
Standard Deviation of Distribution (la)
Median
Minimum Value
5th Percentile
95th Percentile
Maximum Value
42
84.2%
4.3%
85.1%
68.0%
78.5%
89.2%
92.3%
O/1'}
The Am yields for samples evaluated using this method are shown in Figure 1. As indicated
by inspection of Figure 1, the method is capable of generating high yields with an observed mean
yield of 84.2% with 90% of the observed yields between 78.5% and 89.2%. The standard
deviation of the sample yield distribution was 4.3%, indicating a reproducible yield for this
method. A median tracer yield of 85.1% also indicates consistently high yields. A single low
yield of 68.0% was noted for a sample analyzed in the test level 1 group. A few of the samples
that had lower yields were blank samples and LCSs which do not contain the brick matrix
(empty crucibles); therefore, they have slightly lower chemical yields across the preconcentration
steps following the rapid sodium hydroxide fusion step. The Ca and Fe content in the brick
matrix enhance the tracer yields slightly.
Am-243 Percent Yield Brick
I
100.0
90.0
80.0
70.0
60.0
50.0
d 40.0
30.0
10
20 30
Sample Number
40
50
:
9.
Figure 1 - Yields for Method Based on Measurement of Am
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/analysis, was approximately 14.5 hours for the fusion and radiochemical
processing, including counting each sample -8.3 hours. 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).
September 2014
16
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
10. Reported Modifications and Recommendations
NAREL performed the method validation and made minor modifications to the method prior to
analyzing samples for Phases II and III of the project. The primary change was to add an
enhanced alpha peak resolution option with additional rinses of DGA Resin. NAREL provided
the modifications listed below.
NOTE: The step numbers below may have changed in the post-validation method.
Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to
Americium, Plutonium, Strontium, Radium, and Uranium Analyses
11.2.2 Add La carrier to each 225-mL tube as follows:
Concrete: 5 mL 1 mg La/mL for Pu, Am, U
Brick: 5 mL 1 mg La/mL for Pu, and U; 2 mL 1 mg La/mL for Am
Rapid Radiochemical Method for Am-241 in Building Materials for Environmental
Remediation Following Radiological Incidents
11.2.3.5 If enhanced alpha peak resolution is needed due to potential rare earth elements or
high Ca levels present in the sample matrix, rinse the DGA Resin as follows:
11.2.3.5.1 Add 10 mL of 3M HC1 into each reservoir to rinse column (flow rate
-1-2 mL/min).
11.2.3.5.2 Add 3 mL of 1M HNOs into each reservoir to rinse column (flow rate
-1-2 mL/min).
11. Summary and Conclusions
The combined rapid 241 Am - 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) for a typical brick matrix containing
239/240Pu, isotopic uranium, 226Ra, and 90Sr in similar concentrations corresponding to a 10~5 risk
for a soil exposure pathway. The method was evaluated using well-characterized brick analyzed
for its macro-constituents by an independent laboratory2 and for its radiological constituents
(Attachment IV) using the combined rapid 241 Am - Brick method by NAREL.
941
The pulverized brick samples were spiked with three low-level Am concentrations consistent
with a concentration range that incorporated the 10~5 exposure risk contaminant level in soil
(0.7730, 1.570, and 4.630 pCi/g) in the presence of low-level concentrations of 239/240Pu, 226Ra,
90Sr, and uranium (Table 1). The combined rapid 241Am - Brick method met MARLAP
Validation Level "C" requirements for required method uncertainty (0.20 pCi/g) at and below the
AAL, and for required relative method uncertainty of (13%) above the AAL concentration of
1.570pCi/g.
2 Wyoming Analytical Laboratories, Inc., of Golden, CO, peformed macro analysis.
September 2014 17
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Based on the results of the seven blank brick samples (Table 5), the critical net concentration for
the combined rapid 241Am - Brick method was determined to be 0.076 pCi/g. The results for the
seven blank brick samples had a mean and standard deviation of 0.048 + 0.039 pCi/g. A
statistical analysis of the data indicated an absolute bias (difference from zero concentration) for
the blank brick samples. This indicates that the rapid fusion digestion is rugged and reliable and
the column separation allows reliable measurements of 241Am by alpha spectrometry.
The mean measured value and standard deviation of the 10 MDC test samples were calculated as
0.251 + 0.046 pCi/g (k=\). Each result was compared to the critical net concentration of 0.076
pCi/g. All 10 measurements had a result greater than the critical net concentration, thus verifying
the method is capable of meeting a required MDC of 0.2000 pCi/g given a 1-g sample size and a
360-minute count on a typical alpha spectrometer.
Predicated on the statistical tests provided in the "Method Validation Requirements for
Qualifying Methods Used by Radioanalytical Laboratories Participating in Incident Response
Activities," the combined rapid 241Am - Brick method was not found to have a relative bias for
any of the three test levels for method uncertainty evaluation. The mean relative difference from
the known value was 4.9%, -4.5% and -2.6%, respectively for the three test levels.
Although radionuclide and chemical interferences (239/240Pu, uranium, 90Sr, 226Ra, and typical
constituents in the blank brick) were in the test samples, inspection of alpha spectral quality for
three sets of test samples support a conclusion that method specificity is adequate under
conditions as tested. Additionally, high and reproducible chemical yield results (90% of the
yields were between 78 and 89%) and excellent spectral resolution observed for the 42 analyses
evaluated are consistent with a conclusion that the method is rugged and robust under the
conditions tested. 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-04-001A, 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.
September 2014 18
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Revision 0. Office of Air and Radiation, Washington, DC. EPA 402-R-09-006, June.
Available at: www.epa.gov/narel/incident_guides.html.
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
Americium-241 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 19
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
Attachment I:
Estimated Elapsed Times:
241
Combined Rapid Am - Brick Method
Step
Rapid Fusion
Vacuum Box Setup
Load Sample to TEVA® & DGA® cartridges
Am separation on DGA® Resin
Microprecipitation
Count sample test source (1-8 hours)
Elapsed Time
(hours)*
3
3.25
4.5
5.5
6.5
7.5-14.5
* These estimates depend on the number of samples that can be processed
simultaneously. The samples evaluated for the required method uncertainty
were counted for 500 minutes.
September 2014
20
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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 Concrete3 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.
U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method for Plutonium-23 8 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 21
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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
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 (Z/MR) 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 22
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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
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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 99^
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.
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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(NC>3)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.
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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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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, and transfer 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)2and 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 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).
11.3. Preconcentration of 90Sr 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 2M Na2CO3 to 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 1.5M HC1 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 HNO3 and 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 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.
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11.3.26. Set aside for 90Sr analysis using RapidRadiochemicalMethodfor Total
Radiostrontium (Sr-90) In Building Materials for Environmental
Remediation Following Radiological Incidents (Reference 16.4).
11.4. Preconcentration 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. Pipet 2 mL 1.25M Ca(NO3)2into each tube.
11.4.4. Add 1 mL 50-mg/mL iron carrier into each tube.
11.4.5. Add 5 mL 3.2M (NH4)2HPO4to 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 HNChand 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.
on
11.4.23. Set aside for Sr analysi s 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. PipetO.5 mL of 1.25M Ca(NO3)2 into 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 lOmL 1.5MHC1 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 10 mL 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 Methodfor 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:
a s T^J \ )
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.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
14. Pollution Prevention
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.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
16.8. 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.
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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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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
V
Actinide
Precipitation
Procedure
Carbonate (concrete)
or Phosphate (brick)/
Fluoride
Precipitations for Sr
Procedure
Carbonate
Precipitation for Ra
Procedure
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
17.2. 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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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.
Al .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, 2^9/240Pu, 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.
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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).
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 Vi-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 Al6.3).
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 sub sampling 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
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process. SeeASTMC999 for an approach for homogenization and milling
of larger soil samples.
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.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.
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 um 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±l%.
A6.2. Drying oven, at 110 ± 10 °C.
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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).
A6.6. Disposable sieves, U.S. Series No. 50 (300 um or 48 mesh) and U.S. Series No.
100 (150 um 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.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.
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.4
Al0.2.2.1. 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.
Al 0.2.4.1. 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.
4 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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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
A10.2.4.2. 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, la bel 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
operationally by observing the time needed to ensure that 99% of all 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.
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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.
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 sub sampling 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
% Solids = — ^ - — x 100
M.^-M^
Where:
Mdry = mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
= 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:
T^ c i TI • i * ™ % Solids
Dry SampleEquivalent = Mtotal.asrec -
100
September 2014 49
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.
Not applicable
A15. Waste Management
A15.1. 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. MARL AP. 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.
September 2014 50
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Rapid Radiochemical Method for Am-241 in Building Materials
Attachment III:
Rapid Radiochemical Method for Am-241 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.
941
1.2. The method is specific for Am in building material samples such as concrete and
brick.. Curium-244 may also be determined in the same purified fraction, using 243Am
tracer as a yield monitor, since curium tracks closely with americium in this method
This laboratory practice is typical. The specific method parameters (yield, required
944
method uncertainty (WMR), minimum detectable activity, and critical level) for Cm
would need to be validated by the laboratory.
1.3. The method uses rapid radiochemical separation techniques for determining alpha-
emitting americium isotopes in building materials samples following a nuclear or
radiological incident.
941
1.4. The method is capable of achieving a required method uncertainty for Am of 0.20
pCi/g at an analytical action level (AAL) of 1.5 pCi/g, a required relative uncertainty
(cpMn) of 13% above the AAL, and a minimum detectable concentration (MDC) of
0.20 pCi/g. To attain the required method uncertainty at the AAL, a sample weight of
approximately 1 g and count time of at least 4 hours are recommended. 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. The
method must be validated prior to use following the protocols provided in Method
Validation Guide for Qualifying Methods Used by Radiological Laboratories
Participating in Incident Response Activities (EPA 2009, reference 16.1).
1.5. The rapid americium 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. Multi-radionuclide analysis using sequential separation may be possible using this
method in conjunction with other rapid methods (see the appendix of this method).
Rapid methods can also be used for routine analyses with appropriate (typically
longer) count times.
1.7. 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.
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Rapid Radiochemical Method for Am-241 in Building Materials
2. Summary of Method
2.1. This method5 is based on the use of extraction chromatography resins (TEVA® +
DGA® Resins) to isolate and purify americium by removing interfering radionuclides
as well as other matrix components in order to prepare the americium fraction for
counting by alpha spectrometry. The method utilizes vacuum-assisted flow to
improve the speed of the separations. Americium-243 tracer, added to the building
materials sample, is used as a yield monitor. The sample test source is prepared by
microprecipitation with CeFs. Standard laboratory protocol for the use of an alpha
spectrometer should be used when the sample is ready for counting.
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 decision-maker 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 (|im 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). MQOs are the analytical data requirements
of the data quality objectives and are project- or program-specific. They can be
quantitative or qualitative. MQOs serve as measurement performance criteria or
objectives of the analytical process.
3.6. Radiological Dispersal Device (ROD), 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 (MMR). 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 is applicable below an AAL.
3.8. Relative Required Method Uncertainty (
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Rapid Radiochemical Method for Am-241 in Building Materials
3.9. Sample Test Source. This is the final form of the sample is used for nuclear counting.
This form is usually specific for the nuclear counting technique used in the method
such as a solid deposited on a filter for alpha spectrometry analysis.
4. Interferences
4.1. Radiological
9^R
4.1.1 .Alpha-emitting radionuclides with irresolvable alpha energies, such as Pu
(5.50 MeV) and 228Th (5.42 MeV) must be chemically separated to enable
measurement. This method separates these radionuclides effectively. The
individual detector's alpha energy resuolution and the quality of the final
precipitate that is counted will determine the significance of peak overlap.
4.1.2.A thorium removal rinse is performed on DGA® Resin in the event that any
thorium ions pass through TEVA® Resin onto DGA® Resin.
4.1.3.Vacuum box lid and holes must be cleaned frequently to prevent cross-
contamination of samples.
4.1.4.A dilute nitric acid rinse is performed on DGA Resin to remove calcium (Ca)
and lanthanum (La) ions which could end up on the final alpha source filter
as fluoride solids. This volume may be increased slightly to better remove
Ca and La ions and possibly improve alpha peak resolution, but this will
have to be validated by the laboratory.
4.2. Non-Radiological: Anions that can complex americium such as fluoride and
phosphate may lead to lower yields. Boric acid added in the load solution complexes
fluoride ions while aluminum complexes both fluoride as well as any residual
phosphate that may be present. High levels of calcium can have an adverse impact on
americium retention on DGA Resin. This interference is minimized by increasing
the nitrate concentration to lower Ca retention and increase americium affinity on
DGA® Resin.
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.
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 .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 potential for cross contamination.
September 2014 53
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Rapid Radiochemical Method for Am-241 in Building Materials
5.3. Procedure-Specific Non-Radiological Hazards: 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. Alpha spectrometer calibrated for use over the range of-3.5-7 MeV.
6.2. Analytical balance with 10^ g readability, or better.
6.3. Cartridge reservoirs, 10 or 20 mL syringe style with locking device, or columns
(empty luer tip, CC-10-M) plus 12 mL reservoirs (CC-06-M), Image Molding,
Denver, CO (or equivalent).
6.4. Centrifuge tubes, plastic, 50 mL and 225 mL capacity.
6.5. Centrifuge flasks, 225 mL capacity.
6.6. 25 mm polypropylene filter, 0.1 um pore size, or equivalent.
6.7. Stainless steel planchets or other adhesive sample mounts (Ex Environmental
Express, Inc. P/N R2200) able to hold the 25 mm filter.
6.8. Tweezers.
6.9. 100 uL, 200 uL, 500 uL and 1 mL pipets or equivalent and appropriate plastic tips.
6.10. 1-10 mL electronic pipet.
6.11. Vacuum pump or laboratory vacuum system.
6.12. Vacuum box tips, white inner, Eichrom part number AC-1000-IT, or PFA 5/32" x y4"
heavywall tubing connectors, natural, Ref P/N 00070EE, cut to 1 inch, Cole Farmer,
or equivalent.
6.13. Vacuum box tips, yellow outer, Eichrom part number AC-1000-OT, or equivalent.
6.14. Vacuum box, such as Eichrom part number AC-24-BOX, or equivalent.
6.15. Vortex mixer.
6.16. Miscellaneous laboratory ware of plastic or glass; 250 and 500 mL capacities.
6.17. 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). All solutions used in microprecipitation should be prepared with water
filtered through a 0.45 um (or better) filter.
7.1. Type I reagent water as defined in ASTM Standard Dl 193 (Reference 16.4).
7.2. Aluminum nitrate (A1(NO3)3' 9H2O).
September 2014 54
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Rapid Radiochemical Method for Am-241 in Building Materials
7.2.1. Aluminum nitrate solution, 2M (A1(NO3)3): Add 750 g of aluminum nitrate
(A1(NO3)3' 9H2O) to -700 mL of water and dilute to 1 liter with water.
Low-levels of uranium are typically present in A1(NO3)3 solution.
7.3. Ascorbic acid (1.5 M): Dissolve 66 g of ascorbic acid (CeHgOe) in 200 mL of water,
warming gently to dissolve, and dilute to 250 mL with water. Shelf life is 30 days or
less.
7.4. Cerium (III) nitrate hexahydrate (Ce(NC>3)3' 6 IH^O) carrier, 0.5 mg Ce/mL: Dissolve
0.155 g cerium (III) nitrate hexahydrate in 50 mL water, and dilute to 100 mL with
water.
7.5. DGA® Resin - 2 mL cartridge, 50- to 100-|j,m mesh size, normal, Eichrom part
number DN-R50-S, or equivalent.
7.6. Ethanol, reagent (C2H5OH): Available commercially (or mix 95 mL 100% ethanol
and 5 mL water).
7.7. Graduated cylinders.
7.8. Hydrochloric acid (12M): Concentrated HC1, available commercially.
7.8.1. Hydrochloric acid (0.25M): Add 20.8 mL of concentrated HC1 to 500 mL of
water and dilute with water to 1 L.
7.9. Hydrofluoric acid (28M): Concentrated HF, available commercially.
7.10. Hydrogen peroxide (H^C^), 30%: Available commercially.
7.11. Nitric acid (16M): Concentrated HNOs, available commercially.
7.11.1. Nitric acid (0.05M): Add 3.2 mL of concentrated HNO3 to 700 mL of water
and dilute to 1 L with water.
7.11.2. Nitric acid (0.1M): Add 6.3 mL of concentrated HNO3 to 700 mL of water
and dilute to 1 L with water.
7.11.3. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water
and dilute to 1 L with water.
7.11.4. Nitric acid (6M): Add 382 mL of concentrated HNO3 to 500 mL of water
and dilute to 1 L with water.
7.11.5. Nitric acid (3M) + Hydrofluoric acid (0.25M) solution: Add 8.9 mL of
concentrated HF and 191 mL of concentrated HNOs to 700 mL of water.
Dilute to 1 liter with water and mix well.
94^
7.12. Americium-243 tracer solution: Add 15-25 dpm of Am per aliquant. The tracer
activity added and sample count time should be sufficient to obtain a combined
standard uncertainty of less than 5% for the chemical yield measurement.
NOTE: If count times longer than 1 hour are used, lower levels of tracer activity may be added
instead.
7.13. Sodium nitrite, (NaNC^), 3.5M (NaNC^): Dissolve 6.1 g of sodium nitrite in 25 mL
of water. Prepare fresh daily.
7.14. Sulfamic acid solution, 1.5M (H^NSOs): Dissolve 72.7 g of sulfamic acid in 400 mL
of water and dilute to 500 mL with water.
September 2014 55
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Rapid Radiochemical Method for Am-241 in Building Materials
7.15. TEVA Resin - 2 mL cartridge, 50 to 100 |j,m mesh size, Eichrom part number TE-
R50-S and TE-R200-S, or equivalent.
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
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 (Reference 16.5).
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 may compromise chemical yield
measurements or overall data quality.
9.2. The source preparation method should produce a sample test source with a tracer
peak full width at half maximum (FWHM) of less than 0.1 MeV. Sample test sources
may require redissolution and reprocessing through some or all of the chemical
separation steps of the method if this range of FWHM cannot be achieved.
10. Calibration and Standardization
10.1. Set up the alpha spectrometry system according to the manufacturer's
recommendations. The energy range of the spectrometry system should at least
include the region between 3.5 and 7 MeV.
10.2. Calibrate each detector used to count samples according to ASTM Standard Practice
D7282, Section 18, "Alpha Spectrometry Instrument Calibrations" (Reference 16.3).
10.3. Continuing Instrument Quality Control Testing shall be performed according to
ASTM Standard Practice D7282, Sections 20, 21, and 24.
11. Procedure
11.1. Initial Sample Preparation for Americium
11.1.1. Am isotopes may be 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
September 2014 56
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Rapid Radiochemical Method for Am-241 in Building Materials
Uranium Analyses (Reference 16.5), which fuses the samples using rapid
NaOH fusion followed by iron hydroxide and lanthanum fluoride
precipitation to preconcentrate Am isotopes from the hydroxide matrix.6
11.1.2. This separation can be used with other sample matrices if the initial sample
preparation steps result in a column load solution containing ~3M HNOs-
1M A1(NO3)3.
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.
11.2. Rapid Americium Separation using TEVA® and DGA® Resins
11.2.1. Perform valence adjustment on column load solutions prepared from the
fusion procedure (Reference 16.5) for building materials.
11.2.1.1. If particles are observed suspended in the solution, centrifuge the
sample, collect the supernatant solution in small beaker and
discard the precipitate.
NOTE: If a smaller volume was taken instead of the total load solutions,
this smaller volume should be diluted to ~15 mL with 3M HNOs before
proceeding with the valence adjustment.
11.2.1.2. Add 0.5 mL of 1.5M sulfamic acid to each solution. Swirl to
mix.
NOTE: If 237neptunium (Np) is potentially present in the sample, also add
2mg of Fe as iron nitrate to enhance Np reduction to Np4+. The addition
of ascorbic acid will convert Fe3+ to Fe2+, which ensures removal of Np on
TEVA® Resin.
11.2.1.3. Add 1.25 mL of 1.5M ascorbic acid to each solution. Swirl to
mix. Wait 3 minutes.
11.2.1.4. Add 1 mL of 3.5MNaNO2 to each sample. Swirl to mix.
NOTE: Pu, if present, is adjusted to Pu4+ to ensure retention and removal
ON TEVA® RESIN. A SMALL AMOUNT OF BROWN FUMES RESULTS FROM
NITRITE reaction with sulfamic acid. The solution should clear with
swirling. If the solution does not clear (is still dark), an additional small
volume of sodium nitrite may be added to clear the solution.
11.2.1.5. Add 1.5 mL concentrated HNO3to each sample and swirl to mix.
NOTE: The load solution nitrate concentration is increased after valence
adjustment to provide greater retention of Am more effective elution of
calcium ions on DGA® Resin.
11.2.2. Set up TEVA® and DGA® cartridges on the vacuum box system.
NOTE: This section deals with a commercially available filtration system. Other
vacuum systems developed by individual laboratories may be substituted here as long
as the laboratory has provided guidance to analysts for their use. The cartridges may
be set up and conditioned with nitric acid so that they are ready for column loading
6 The fusion procedure provides a column load solution for each sample (consisting of 5 mL 3M HNO3-0.25M
H3BO3 + 6 mL HNO3+7 mL 2M A1(NO3)3 + 3 mL 3M HNO3), ready for valence adjustment and column separation
on TEVA® Resin.
September 2014 57
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Rapid Radiochemical Method for Am-241 in Building Materials
just prior to completion of the valence adjustment steps. More than one vacuum box
may be used to increase throughput as needed.
11.2.2.1. Place the inner tube rack (supplied with vacuum box) into the
vacuum box with the centrifuge tubes in the rack. Place the lid on
the vacuum box system.
11.2.2.2. Place the yellow outer tips into all 24 openings of the lid of the
vacuum box. Fit in the inner white tip into each yellow tip.
11.2.2.3. For each sample solution, place a TEVA® plus DGA® cartridge
on to the inner white tip (DGA cartridge below TEVA ).
11.2.2.4. Place reservoirs on the top end of the TEVA cartridge.
11.2.2.5. Turn the vacuum on (building vacuum or pump) 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.
11.2.2.6. Add 5 mL of 3M FINOs to the column reservoir to precondition
the TEVA® cartridges.
11.2.2.7. Adjust the vacuum to achieve a flow-rate of ~1 mL/min.
IMPORTANT: Unless otherwise specified in the procedure, use a flow
rate of ~1 mL/min for load and strip solutions and ~2-3 mL/min for rinse
solutions.
11.2.3. TEVA® and DGA® Resin Separation
11.2.3.1. Transfer each solution from Step 11.2.1.5 into the appropriate
reservoir. Allow solution to pass through the stacked TEVA® +
DGA® cartridge at a flow rate of ~1 mL/min.
11.2.3.2. Add 5 mL of 6M FtNCb to each tube/beaker as a rinse and
transfer each solution into the appropriate reservoir (the flow rate
can be adjusted to ~2 mL/min).
11.2.3.3. Add 5 mL of 6M FINOs into each solution into the appropriate
reservoir (the flow rate can be adjusted to ~2 mL/min).
11.2.3.4. Turn off vacuum, discard rinse solutions and remove TEVA®
cartridges. Discard TEVA® cartridges and place new reservoirs
on the DGA® cartridges.
11.2.3.5. If enhanced alpha peak resolution is needed due to potential rare
earth elements or high Ca levels present in the sample matrix,
rinse the DGA Resin as follows:
11.2.3.5.1 Add 10 mL of 3MHC1 into each reservoir to rinse
column (flow rate -1-2 mL/min).
11.2.3.5.2 Add 3 mL of 1M FINOs into each reservoir to rinse
column (flow rate -1-2 mL/min).
11.2.3.6. To DGA® Resin only, add 20 mL of 0.1M JFNO3 into each
reservoir to rinse column (flow rate -1-2 mL/min).
11.2.3.7. Add 10 mL of O.OSMFINOs into each reservoir as second
column rinse (flow rate -2 mL/min).
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Rapid Radiochemical Method for Am-241 in Building Materials
NOTE: The rinses with dilute nitric acid remove uranium while
americium is retained. Using more 0.05M HNOs (20 mL) rinse without
adding any 0.1M HNO3 rinse (Step 11.2.3.6) may be an alternative and
effective way to remove La/Ca with less total volume, but the laboratory
will have validate this.
11.2.3.8. Add 20 mL of 3M HNO3 -0.25M HF into each reservoir to
remove any Th from DGA® Resin (flow rate -1-2 mL/min).
11.2.3.9. Add 3 mL of 3M HNOs into each reservoir to rinse column of
residual fluoride (flow rate -1-2 mL/min).
11.2.3.10. Ensure that clean, labeled plastic tubes are placed in the tube
rack under each cartridge. For maximum removal of
interferences during elution, also change connector tips prior to
Am elution.
11.2.3.11. Add 10 mL of 0.25MHC1 solution to elute americium from each
cartridge, reducing the flow rate to -1 mL/min (or slightly
slower).
11.2.3.12. Set americium fraction in the plastic tube aside for cerium
fluoride coprecipitation, Step 11.3. Discard the DGA® cartridge.
11.3. Preparation of the Sample Test Source
Note: Instructions below describe preparation of a single sample test source. Several sample test
sources can be prepared simultaneously if a multi-channel vacuum manifold system is available.
11.3.1. Pipet 100 jiL of the cerium carrier solution into each tube.
11.3.2. Pipet 0.5 mL 30% H2O2 into each tube to prevent any residual uranium from
precipitating.
11.3.3. Pipet 1 mL of concentrated HF into each tube.
11.3.4. Cap the tube and mix. Allow solutions sit for -15 minutes before filtering.
11.3.5. Set up a filter apparatus to accommodate a 0.1 micron, 25-mm membrane
filter on a microprecipitation filtering apparatus.
Caution: There is no visible difference between the two sides of the filter. If the filter is
turned over accidentally, discard the filter and remove a fresh one from the box.
11.3.6. Add a few drops of 95% ethanol to wet each filter and apply vacuum.
Ensure that there are no leaks along the sides before proceeding.
11.3.7. While vacuum applied, add 2-3 mL of filtered Type I water to each filter
and allow the liquid to drain.
11.3.8. Add the sample to the reservoir, rinsing the sample tubes with -3 mL of
water and transfer this rinse to filter apparatus. Allow to drain.
11.3.9. Wash each filter with -2-3 mL of water and allow to drain.
11.3.10. Wash each filter with -1-2 mL of 95% ethanol to displace water.
11.3.11. Allow to drain completely before turning the vacuum off.
11.3.12. Mount the filter on a labeled adhesive mounting disk (or equivalent)
ensuring that the filter is not wrinkled and is centered on the mounting disk.
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Rapid Radiochemical Method for Am-241 in Building Materials
11.3.13. Place the filter under a heat lamp for approximately 5 minutes or more until
it is completely dry.
11.3.14. Count filters for an appropriate period of time by alpha spectrometry.
11.3.15. Discard the filtrate to waste for future disposal. If the filtrate is to be
retained, it should be placed in a plastic container to avoid dissolution of the
glass vessel by dilute HF.
NOTE: Other methods for sample test source preparation, such or microprecipitation
with neodymium fluoride (NdF3), may be used in lieu of the cerium fluoride micro-
precipitation, but any such substitution must be validated as described in Step 1.5. Nd
is typically interchangeable with Ce.
12. Data Analysis and Calculations
12.1. Equation for determination of final result, combined standard uncertainty, and
radiochemical yield (if required):
12.1.1. The activity concentration of an analyte and its combined standard
uncertainty are calculated using the following equations:
AtxRflxDtxI,
and
where:
Ra
Rt
Wa
A
D&
/t
/a
uc(ACa)
activity concentration of the analyte at time of count, in picocuries
per gram (pCi/g)
activity of the tracer added to the sample aliquant at its reference
date/time (pCi)
net count rate of the analyte in the defined region of interest (ROI),
in counts per second
net count rate of the tracer in the defined ROI, in counts per second
weight of the sample aliquant (g)
correction factor for decay of the tracer from its reference date and
time to the midpoint of the counting period
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)
probability of a emission in the defined ROI per decay of the tracer
(Table 17.1)
probability of a emission in the defined ROI per decay of the analyte
(Table 17.1)
combined standard uncertainty of the activity concentration of the
analyte (pCi/g)
September 20 14
60
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Rapid Radiochemical Method for Am-241 in Building Materials
u(At) = standard uncertainty of the activity of the tracer added to the sample
(pCi)
u(Ra) = standard uncertainty of the net count rate of the analyte (s l)
u(Rt) = standard uncertainty of the net count rate of the tracer (s^1)
tt(Wa) = standard uncertainty of the sample aliquant weight (g)
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 (uc(ACa)) 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.
12.1.2. The net count rate of an analyte or tracer and its standard uncertainty are
calculated using the following equations:
r r
^~ bx
and
(4)
where:
Rx = net count rate of analyte or tracer, in counts per second
Cx = sample counts in the analyte or the tracer ROI
ts = sample count time (s)
Cbx = background counts in the same ROI as for x
tb = background count time (s)
u(Rx) = standard uncertainty of the net count rate of tracer or analyte, in
counts per second7
If the radiochemical yield of the tracer is requested, the yield and its combined
standard uncertainty can be calculated using the following equations:
7 For methods with very low counts, MARLAP Section 19.5.2.2 recommends adding one count each to the gross
counts and the background counts when estimating the uncertainty of the respective net counts. This approach
minimizes negative bias in the estimate of uncertainty and protects against calculating zero uncertainty when a total
of zero counts are observed for the sample and background.
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Rapid Radiochemical Method for Am-241 in Building Materials
RY =
and
0.037x4 xDtx/txe ,~
V ^ ^t * (6)
where:
,R7 = radiochemical yield of the tracer, expressed as a fraction
Rt = net count rate of the tracer, in counts per second
At = activity of the tracer added to the sample (pCi)
A = correct!on factor for decay of the tracer from its reference date and
time to the midpoint of the counting period
It = probability of a emission in the defined ROI per decay of the tracer
(Table 17.1)
s = detector efficiency, expressed as a fraction
uc(RY) = combined standard uncertainty of the radiochemical yield
u(Rt) = standard uncertainty of the net count rate of the tracer, in counts per
second
u(At) = standard uncertainty of the activity of the tracer added to the sample
(pCi)
u(s) = standard uncertainty of the detector efficiency
12.1.3. If the critical level concentration (Lc) or the minimum detectable
concentration (MDC) are requested (at an error rate of 5%), they can be
calculated using the following equations: 8
L, =
0.4xK-l + 0.677 x 1 + ^ 1 + 1.645x \(Rbatb
\ th I \ ti I V
x A x D x I
t t t
t^WaxRtxDax!a (?)
MDC =
2.71 x 1 + - +3.29x R, t x 1 + --
S
4 x Dt x It
/„ x vy a x J\ x -LJ^ x j /o\
a H (8)
where:
8 The formulations for the critical level and minimum detectable concentrations are based on the Stapleton
Approximation as recommended in MARLAP Section 20A.2.2, Equations 20.54 and 20A.3.2, and Equation 20.74,
respectively. The formulations presented here assume an error rate of a = 0.05, ft = 0.05 (with zi-a = zi-p = 1.645)
and d = 0.4. For methods with very low numbers of counts, these expressions provide better estimates than do the
traditional formulas for the critical level and MDC.
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Rapid Radiochemical Method for Am-241 in Building Materials
= background count rate for the analyte in the defined ROI, in counts
per second
12.2. Results Reporting
12.2.1. The following data should be reported for each result: volume of sample
used; yield of tracer and its uncertainty; and FWHM of each peak used in
the analysis.
12.2.2. The following conventions should be used for each result:
12.2.2.1. Result in scientific notation ± combined standard uncertainty.
13. Method Performance
13.1. Method validation results are to be reported.
13.2. Expected turnaround time per batch of 14 samples plus quality control, assuming
microprecipitations for the whole batch are performed simultaneously using a vacuum
box system:
13.2.1. For an analysis of a 1-g aliquant, sample preparation, and digestion should
take ~3 h.
13.2.2. Purification and separation of the plutonium fraction using cartridges and
vacuum box system should take -2.5 h.
13.2.3. The sample test source preparation step takes ~1 h.
13.2.4. A four-hour counting time should be sufficient to meet the MQOs listed in
1.4, assuming detector efficiency of 0.2-0.3, and radiochemical yield of at
least 0.5. A different counting time may be necessary to meet these MQOs if
any of the relevant parameters are significantly different.
13.2.5. Data should be ready for reduction -7.5-14.5 h after beginning of analysis.
14. Pollution Prevention: The method utilizes small volume (2 mL) extraction chromatographic
resin columns. This approach leads to a significant reduction in the volumes of load, rinse
and strip solutions, as compared to classical methods using ion exchange resins to separate
and purify the plutonium fraction.
15. Waste Management
15.1. Types of waste generated per sample analyzed
15.1.1. Approximately 5 5 mL of acidic waste from loading and rinsing the two
extraction columns will be generated.
15.1.2. Approximately 25 mL of acidic waste from the microprecipitation method
for source preparation will be generated. The waste contains 1 mL of HF
and -5 mL of ethanol.
15.1.3. TEVA® cartridge - ready for appropriate disposal.
15.1.4. DGA® cartridge - ready for appropriate disposal.
15.2. Evaluate waste streams according to disposal requirements by applicable regulations.
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Rapid Radiochemical Method for Am-241 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 2009).
Available at: www.epa.gov/narel/incident_guides.html.
16.2. Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARL AP).
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/radiati on/marl ap/index.html.
16.3. 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.
16.4. ASTM Dl 193, "Standard Specification for Reagent Water," ASTM Book of
Standards 11.02, current version, ASTM International, West Conshohocken, PA.
16.5. 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-R14-004. Office of
Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
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-R14-007. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.7. 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-R14-006. 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-R14-002. 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-R14-001.
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-R14-005. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
Other References
16.11. Maxwell, S., Culligan, B. and Noyes, G. 2010. Rapid method for actinides in
emergency soil samples, Radiochimica Acta. 98(12): 793-800.
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Rapid Radiochemical Method for Am-241 in Building Materials
16.12. Maxwell, S., Culligan, B., Kelsey-Wall, A. and Shaw, P. 2011. "Rapid
Radiochemical Method for Actinides in Emergency Concrete and Brick Samples,"
Anafytica Chimica Acta. 701(1): 112-8.
16.13. VBS01, Rev.1.3, "Setup and Operation Instructions for Eichrom's Vacuum Box
System (VBS)," Eichrom Technologies, Inc., Lisle, Illinois (January 2004).
17. Tables, Diagrams, Flow Charts, and Validation Data
17.1. Tables
Table 17.1 Alpha Particle Energies and Abundances of Importance111
Nuclide
241Am
243Am
Half-Life
(Years)
432.6
7.37xl03
X
(s-1)
5.077x10""
2.98xlO~12
Abundance
0.848
0.131
0.0166
0.871
0.112
0.0136
a Energy
(MeV)
5.486
5.443
5.388
5.275
5.233
5.181
Only the most abundant particle energies and abundances have been noted here.
17.2. Ingrowth Curves and Ingrowth Factors
This section intentionally left blank
(In-growth is not applicable to the method)
17.3. Spectrum from a Processed Sample
Americium Spectrum
82
73
84
55
£ 4S
I 37
8 28
I 19
10
•\\- i I ill I I • I I I . . I ; , : I, .1 ' hi ..II
2358 2756 3157 3562 3970 4381 4^96
Energy (keV)
6467 6918 7352
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Rapid Radiochemical Method for Am-241 in Building Materials
17.4. Decay Scheme
241 Am and 243Am Decay Scheme
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Rapid Radiochemical Method for Am-241 in Building Materials
17.5. Flowchart
Separation Scheme and Timeline for Determination of
Am-241 in Building Materials Samples
Rapid Fusion (See Separate Procedure)
• Add 243Am tracer and fuse with NaOH
• Fe/Ti hydroxide then La/Ca fluoride precipitations
• Dissolve in of 3MHNO3-0.25M H3BO3, 7M HNO3, 2M
AI(NO3)3] andSM HNO3 (column load solution)
Adjust Pu to Pu4+
(for removal on TEVA®. Step 11.2.1)
1. Add sulfamic acid and ascorbic acid
2. Wait 3 minutes
3. Add sodium nitrite
Discard TEVA®
cartridge and load
and rinse solutions
(Step 11.2.3.4)
Discard DGA® resin
(Step 11.2.3.12)
Discard filtrates
and rinses
(Step 11.3.15)
Vacuum Box Setup (Step 11.2.2)
1. Place TEVA® + DGA® cartridges
on box
2. Condition column with 5 ml 3M
HNO3@1 mL/min
Load Sample to TEVA®& DGA® Cartridges
(Steps 11.2.3.1-11.2.3.3)
1. Load sample @ 1 mL/min
2. Beaker/tube rinse: 5 mL 6M HNO3 @ ~2 mL/min
3. Column rinse: 5 mL 6M HNO3 @ 2 mL/min
Am Separation on DGA Resin (Steps 11.2.3.6-11.2.3.11)
1. Column rinse: 20 mL 0.1M HNO3 @-1-2 mL/min
2. Column rinse: 10 mL 0.05M HNO3 @ ~2 mL/min
3. Elute Am into new tubes with 10 mL 0.25M HCI @ ~1-
2 mL/min
4. Remove tubes for microprecipitation
Microprecipitation (Step 11.3)
1. Add 50 |jg Ce carrier
2. Add 0.5 mL 30 wt% H2O2
3. Add 1 mL concentrated HF
4. Wait 15 min and filter
5. Add afewdrops ethanol and 2-3 mL Type I water
6. Filter samples under vacuum and rinse tubes. Rinse
filters with water and ethanol and dry thoroughly.
7. Place on mounting disks
8. Warm 5 min under heat lamp
N
f Count sample test source (STS)
by alpha spec for4h or as needed I
I (Step 11.3.14) J
Elapsed Time
3 hours
31/4 hours
41/2 hours
51/2 hours
61/2 hours
71/2-141/2 hours
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Rapid Radiochemical Method for Am-241 in Building Materials
Appendix:
Example of Sequential Separation Using Am-241, Pu-238+Pu-239/240, and Isotopic U in
Building Materials
This sequential combination of rapid procedures for Am-241, Pu-23 8+Pu-23 9/240, and isotopic
U in building materials (References 16.6, 16.7, and 16.10) has been used by some laboratories,
but this sequential approach was not included in this method validation.
TEVA®+ TRU®+DGA®
3 ml_ 3M HNO3 beaker rinse.
3 ml_ 3M HNO3 column rinse.
Split cartridges.
v
v
TEVA®
Rinse w/10mL3M HNO3
20 ml_ 9 M HCI (remove Th)
5mL3M HNO3
DGA®
Rinse w/ 10 ml_ 0.1M HNO3
(remove U)
Elute Pu w/ 20 ml_ 0.1M HCI -
0.05MHF -0.01M TiCI3
Stack TRU® + DGA®
Add 15mL3M HCI
(Move all Am/Cm to DGA)
V
V
Add 0.5 mL 30 wt% H2O2 to
oxidize any U
DGA®
Rinse w/ 5 mL 3M HCI,
3mL1M HN03 + 10ml_0.1M
HN03 + 5mL0.05M HNO3
(remove La)
Elute Am/Cm w/ 10 mL 0.25M
HCI
TRU®
Rinse w/15 mL4M HCI -
0.2MHF-0.002MTiCI3 +
5mL8M HN03
Elute Uw/ 15 mL 0.1M
V
Add0.5mL20%TiCI3
Add 50 ug Ce to 1 mL 49% HF.
Filter and count by alpha spectrometry.
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Validation of Rapid Radiochemical Method for Am-241 in Brick Samples
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
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
Radionuclide Concentration (pCi/g)'2'31
Uranium 238, 234
Plutonium 239/240
Americium 24 1
Strontium 90
Radium 226
1.054 ±0.020, 1.102 ±0.021
-0.0003 ±0.0041
0.048 ±0.039
0.119± 0.077
1.025 ±0.027
NOTE: Wyoming Analytical Laboratories, Inc. in Golden, Colorado, performed macro
analyses.
[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. 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
September 2014
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