EPA402-R-14-012
www.epa.gov/narel
September 2014
Validation of
Rapid Radiochemical Method
for Isotopic Uranium 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 Uranium in Brick
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 Uranium in Brick
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 4
5. Measurement Quality Objectives 4
6. Method Validation Plan 5
6.1 Method Uncertainty 5
6.2 Detection Capability 6
6.3 Method Bias 6
6.4 Analyte Concentration Range 8
6.5 Method Specificity 8
6.6 Method Ruggedness 9
7. Techniques Used to Evaluate the Measurement Quality Objectives for the
Rapid Methods Development Project 9
7.1 Required Method Uncertainty 9
7.2 Required Minimum Detectable Concentration 10
8. Evaluation of Experimental Results 11
8.1 Summary of the Combined Rapid Isotopic Uranium - Brick Method 11
8.2 Required Method Uncertainty 11
8.3 Required Minimum Detectable Concentration 14
8.4 Evaluation of the Absolute and Relative Bias 18
8.5 Method Ruggedness and Specificity 19
9. Timeline to Complete a Batch of Samples 20
10. Reported Modifications and Recommendations 21
11. Summary and Conclusions 21
12. References 22
Attachment I: Estimated Elapsed Times 24
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 25
Appendix: Rapid Technique for Milling and Homogenizing Concrete and
Brick Samples 46
Attachment III: Rapid Radiochemical Method for Isotopic Uranium in Building Materials
for Environmental Remediation Following Radiological Incidents 55
Appendix A: Preparation of Self-Cleaning 232U Tracer 73
Appendix B: Example of Sequential Separation Using Am-241, Pu-238 + Pu-239/240,
and Isotopic U in Building Materials 74
Attachment IV: Composition of Brick Used for Spiking in this Study 75
September 2014
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Validation of Rapid Radiochemical Method for Uranium in Brick
Figure
Figure 1 - Yields for Method Based on Measurement of 232U 20
Tables
Table 1 -natU Method Validation Test Concentrations and Results, pCi/g (k =1) 5
Table 2 - Sample Identification and Test Concentration Level for Evaluating the Required
Minimum Detectable Concentration 6
Table 3 -MARLAP Level E Acceptance Criteria 9
Table 4A - 234U Analytical Results for Required Method Uncertainty Evaluation 12
OQ .1
Table 4B - Experimental Standard Deviation of the Five PT Samples by Test Level for U... 13
Table 4C - 238U Analytical Results for Required Method Uncertainty Evaluation 13
Table 4D - Experimental Standard Deviation of the Five PT Samples by Test Level for 238U... 14
Table 5 A - Reported 234U Concentration Method Reagent Blank Samples 15
ryy Q
Table 5B - Reported U Concentration Method Reagent Blank Samples 15
Table 5C-Reported 234U Concentration for Blank Brick Samples 16
/^T O
Table 5D -Reported U Concentration for Blank Brick Samples 16
Table 6A - Reported Results for Samples Containing 234U at the As-Tested MDC Value (pCi/g)
17
Table 6B - Reported Results for Samples Containing 238U at the As-Tested MDC Value (pCi/g)
17
Table 7 - Absolute and Relative Bias Evaluation of the Combined Rapid Isotopic U Brick
Method 18
Table 8 - Summary of U Radiochemical % Yield Results for Test and Quality Control (QC)
Samples Based on 232U Tracer 20
September 2014 ii
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Validation of Rapid Radiochemical Method for Uranium in Brick
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
g gram
gal gallon
G-M Geiger-Muller [counter or probe]
h hour
ICP-AES inductively coupled plasma - atomic emission spectrometry
ID identifier/identification number
IND improvised nuclear device
IUPAC International Union of Pure and Applied Chemistry
kg kilogram (103 gram)
L liter
LC critical level concentration
LCS laboratory control sample
m meter
M molar
MARLAP Multi-Agency Radiological Laboratory Analytical Protocols Manual
MDC minimum detectable concentration
MeV million 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 and Radiation Environmental Laboratory,
Montgomery, AL
NHSRC EPA's National Homeland Security Research Center, Cincinnati, OH
NIST National Institute of Standards and Technology
ORD U.S. EPA Office of Research and Development
September 2014 iii
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Validation of Rapid Radiochemical Method for Uranium in Brick
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 project 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
STS sample test source
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 Uranium in Brick
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)
picocuries (pCi)
pCi/gram (g)
pCi/L
Bq/L
pCi/L
jiCi
pCi
m3
liters (L)
rad
sievert (Sv)
Multiply by
3.16xl07
5.26xl05
8.77xl03
3.65xl02
1
27.0
2.70xl(T2
2.70xl(T2
10~3
109
4.50xlO~7
4.50X10"1
2.83xlO~2
3.78
102
io-2
To Convert
s
min
h
d
Bq
pCi
pCi/g
pCi/L
Bq/L
pCi/L
pCi
m3
L
rad
Sv
To
y
dps
Bq
Bq/kg
Bq/m3
Bq/m3
(iCi/mL
dpm
ft3
gal
Gy
rem
Multiply by
3.17xl(T8
1.90xl(T6
1.14x10^
2.74xl(T3
1
3.70xlO~2
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 Uranium in Brick
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 U in Brick
1. Introduction
Rapid methods need to be developed and validated for processing samples taken in response to a
radiological incident. In order to address this need, EPA initiated a project to develop rapid
methods that can be used to prioritize environmental sample processing as well as provide
quantitative results that meet measurement quality objectives (MQOs) that apply to the
intermediate and recovery phases of an incident.l Similar to the rapid method project initiated in
2007 for other radionuclides in water (EPA 2008), this rapid method development project for
brick addressed four different radionuclides in addition to uranium (natU): americium-241
(241Am), plutonium-239/240 (239/240Pu), radium-226 (226Ra), and strontium-90 (90Sr). Each of
these radionuclides will have separate method validation reports for the brick matrix. The
91'7
methodology used for this validation process makes use of U tracer (validated for water
matrices) and a new process for fusing brick samples. The combination of these two techniques
provides a unique approach for rapid analysis of brick samples.
The term natU used in this report had an isotopic concentration 234U: 235U: 238U ratio of 0.982:
0.0461: 1.00. All three isotopes had known concentration values and were analyzed by the
laboratory. However, for method validation purposes that requires a certain level of measurement
uncertainty, only 234U and 238U results are presented in this report.
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 (EPA 2004). The method
was evaluated according to the Multi-Agency Radiological Laboratory Analytical Protocols
Manual (MARLAP) method validation "Level C" (see MARLAP Sections 6.1 and .6.3.5). The
method formulated was preliminarily tested at EPA's National Analytical Radiation
Environmental Laboratory (NAREL) and refinements to the method were made according to the
feedback from the laboratory and the quality of the generated results. For the method validation
process, the laboratory analyzed several sets of blind proficiency test (PT) samples according to
specifications that meet established MQOs and guidance outlined in Radiological Sample
Analysis Guide for Radiological Incidents - Radionuclides in Soil (EPA 2012). The proposed
MQO specification for the required method uncertainty (wmr) at the analytical action level (AAL)
was based on a natU concentration of approximately 12 pCi/g. Performance test samples were
prepared to meet this proposed AAL, and the final tested AAL value was 12.20 pCi/g and 12.35
pCi/g for 234U and 238U, respectively. These values are the combined natU spike value of the brick
plus the inherent natU in the blank brick. The required method uncertainty at these AALs was
calculated to be 1.6 pCi/g for both 234U and 238U, respectively.
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 Isotopic Uranium in Brick for Environmental Remediation Following Radiological
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 U in Brick
Incidents (Attachment III). In this document, the combined methods are referred to as "combined
rapid Isotopic U - Brick method." The method validation process is applied to the separation and
quantitative analysis of natUusing alpha spectrometry to detect the 4.2- and 4.8-million electron
volt (MeV) alpha particles from the decay of 238U and 234U, respectively and the 5.3-MeV alpha
particle from 32U that is used as the tracer yield monitor. The laboratory's complete report,
including a case narrative and a compilation of the reported results for this study, can be obtained
by contacting NAREL (http://www.epa.gov/narel/contactus.html).
2. Radioanalytical Methods
The combined rapid Isotopic U - Brick method was written in a format consistent with EPA
guidance and conventions. The rapid method was formulated to optimize analytical throughput
for sample preparation, chemical processing, and radiation detection.
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 counting time of 500 minutes for three test level samples
for the method uncertainty evaluation and a counting time of 360 minutes for the required
minimum detectable concentration (MDC) verification samples. A 1-g sample size was used
throughout the validation process. A summary of the rapid method is presented in Section 8.1
prior to presenting the experimental results of the method validation analyses.
The combined rapid Isotopic U - Brick method is included in Attachments II and III of this
report. The validation process was performed using this final method as in the attachments.
3. Method Validation Process Summary
The method validation plan for the combined rapid Isotopic U - 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 Isotopic U - Brick method is
considered a "new application/similar matrix" of an existing isotopic uranium method for soil
and concrete matrices (EPA 2004, Section 6.6.3.5). Therefore, the combined rapid Isotopic U -
Concrete method was evaluated according to MARLAP method validation "Level C." More
specifically, the method was validated against acceptance criteria for the required method
uncertainty at a specified AAL concentration and the required MDC. In addition, analytical
results were evaluated for radiochemical yield (as a characteristic of method ruggedness), and
relative bias at each of the three test-level radionuclide activities. The absolute bias of the
method was evaluated using the laboratory's seven reagent blanks because the brick material
used as the method validation reference material (MVRM) had native natU that was not removed
prior to spiking the external PT samples.
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
The method validation process was divided into four phases as follows:
1. Phase I
a. Laboratory familiarization with the fusion method for brick samples.
b. Set-up of the laboratory and acquisition of reagents, standards and preparation of
in-house PT samples.
c. Perform preliminary tests of the new fusion method and continue the analysis
using the dissolved flux from that process with the slightly modified existing
rapid method for natU in concrete, having the brick samples spiked with natU and
the 232U tracer.
d. Make changes to improve the method based on consultation with Environmental
Management Support, Inc. consultants and the results of the preliminary tests.
2. Phase II
a. Conduct blank sample analyses to assess the method 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, laboratory
control sample (LCS), and a sample duplicate.2
The dual objectives of the first (preliminary) phase were to familiarize the laboratory with the
formulated rapid method and then gain hands-on experience using the rapid method to identify
areas that might require optimization. During this phase, the laboratory processed samples of
blank brick material as well as blank brick material that was spiked in-house with natU activities
consistent with evaluating the required method uncertainty at the AAL and the required MDC
(see "natu Method Validation Test Concentrations and Results," Table 1; see footnote 3 on the
next page). Blank brick material (supplied by Eckert & Ziegler Analytics (E&Z), Atlanta, GA)
and laboratory spiked samples (spiked blank brick material) were used in Phase I in order to
assess the original feasibility of the proposed method. Based on information and experience
gained during Phase I practice runs, the rapid natU method was optimized without compromising
data collected during the validation process in Phases II and III.
During Phases II and III of the method validation process, the laboratory analyzed pulverized
brick PT samples provided by an external, National Institute of Standards and Technology
(NIST)-traceable source manufacturer (Eckert & Ziegler Analytics). The external blank brick
was prepared and homogenized prior to spiking by Eckert and Ziegler (see Attachment IV). The
laboratory was instructed to analyze specific blind PT samples having concentration levels
consistent with validation test levels for the required method uncertainty and the required MDC.
2 During the validation study, the laboratory prepared an LCS, substituted PT blanks for their lab blank, and used
replicate PT samples for their lab duplicates.
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Validation of Rapid Radiochemical Method for U in Brick
The test levels of the PT samples are listed in Tables 1 and 2. Following completion of the
method validation studies, comments from the labs were evaluated and the method revised to
conform to the documented "as-tested" conditions in Phases II and III. Thus, the validation data
presented in this report reflect the combined final method included in the attachments to this
document.
4. Participating Laboratory
NAREL validated the rapid fusion method for U using NIST-traceable test samples prepared in
a brick medium.
5. Measurement Quality Objectives
The combined rapid Isotopic U - Brick method was developed to meet MQOs for the rapid
methods project. The selected MQOs included the radionuclide concentration range, the required
method uncertainty at a specified radionuclide concentration (e.g., AAL), and the required MDC.
The required relative method uncertainty (cpMn) for the combined rapid Isotopic U - Brick method
was set at 13%3 at a targeted AAL equal to -12 pCi/g. This particular value is consistent with the
concentration limit for site cleanup activities. Also, this value is approximately on an order of
magnitude greater than natU concentration that existed in the blank brick material used in the
study (-1.1 pCi/g). The specific action levels for natU in brick are based on the action levels for
soil provided in the Radiological Sample Analysis Guide for Incidents of National Significance -
Radionuclides in Soil (draft EPA 2012). The target natU concentration values for the method
uncertainty samples were slightly different than the calculated known values because of the
inherent uranium in the blank brick matrix plus the uranium that was spiked in the sample (see
Attachment IV for the chemical composition of the brick matrix). Table 1 summarizes the
targeted MQOs for the method validation process, the calculated known values for the samples
analyzed, and the average measured values as determined by this method. The AALs for the four
other radionuclides are 241Am (1.570 pCi/g), 239/240pu (1.890 pCi/g), 226Ra (4.755 pCi/g), and 90Sr
(2.440 pCi/g). The PT sample supplier provided test data for ten 1-gram (g) samples that
documents the spread in the spike in the samples as a 1.59% standard deviation in the
distribution of results.
3 Type I and II decision error rates were set at Z!_a= 0.01 and Z!_P= 0.05. The required method uncertainty is
calculated using the formula, WMR = (AAL-DL)/[z!_a + Zj.p] where the analytical action level (AAL) is as noted above
and the discrimination level (DL) is 1A the AAL.
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Validation of Rapid Radiochemical Method for U in Brick
Table 1 - mtU Method Validation Test Concentrations and Results, pCi/
Sample
MDC
MDC
!/2 x AAL
E&Z UO-U1
!/2 xAAL
E&Z UO-U1
AAL
E&Z UO-U2
AAL
E&Z UO-U2
3xAAL
E&Z UO-U3
SxAAL
E&Z UO-U3
Nuclide
234U
238U
234U
238U
234U
238U
234U
238U
natu
Target Value
pCi/g
Inherent 234U
Inherent 238U
-
6.337
-
12.35
-
37.85
Calculated
Known
Value [1]
1.102 ±0.021
1.054 ±0.020
6.282 ±0.123
6.337 ±0.056
12.20 ±0.29
12.35±0.11
37.20 ±0.81
37.85 ±0.37
Average
Measured
Value
1.19
1.11
6.33
6.14
12.25
12.27
37.38
37.7
Required
Method
Uncertainty
(«MR) P1
-
-
1.6
1.6
1.6
1.6
4.84
4.92
?(*=!)
Standard
Deviation [2]
0.16
0.14
0.16
0.33
0.69
0.51
0.95
1.1
[1] The calculated known values listed here are the sum of the spike added plus the inherent U (1.102 ± 0.021)
pCi/g and 238U (1.054 + 0.020), (k = 1 for both) in the brick. The uncertainties for the spike and the standard
error of the mean result from the brick analyses have been calculated in quadrature.
[2] Calculated standard deviation of the 10 and 5 measurement results for the MDC and Test Level samples,
respectively.
[3] The values of 4.8 and 4.9 pCi/g (234U and 238U, respectively) are the absolute required method uncertainties and
represent 13% of 37.20 and 37.85 pCi/g.
6. Method Validation Plan
The combined rapid Isotopic U - 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 required method uncertainty of the combined rapid Isotopic U - Brick method was evaluated
234T
23 8T
at the AAL concentration (12.20 and 12.35 pCi/g for U and U, respectively) specified in the
MQOs presented in Table 1. In accordance with MARLAP method validation "Level C," this is
a new application and was evaluated at each of three test concentration levels. The laboratory
analyzed five replicate external PT samples containing natU activities at approximately one-half
the AAL, the AAL, and three times the AAL. The method was evaluated against the required
9^4 9^R
method uncertainty (MMR =1.6 pCi/g for both U and U), at and below the AAL, and against
the required relative method uncertainty (^MR= 13% of the known test value) above the AAL.
The test level concentrations analyzed are listed in Table 1 "Calculated Known Value." One-
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
gram (g) sample aliquants were taken from each level, chemically processed and counted by
alpha spectrometry for 500 minutes.
6.2 Detection Capability
In the statement of work to the laboratory, the detection capability of the combined rapid Isotopic
U - Brick method was to be evaluated to meet an MDC of approximately 1.0 pCi/g, which was
the inherent uranium in the blank brick material. The laboratory estimated the counting time,
chemical yield and sample size to meet this 1.0 pCi/g MDC. The final calculated MDC known
9^4 9^R
values of U and U were 1.102 and 1.054 pCi/g, respectively, as presented in Table 2.
In accordance with the guidance provided in Method Validation Guide for Qualifying Methods
Used by Radiological Laboratories Participating in Incident Response Activities (EPA 2009),
the laboratory estimated the critical net concentration based on the results of seven reagent blank
samples. For this study, seven reagent blank samples were analyzed to determine the (C£NC).
Results from 10 replicate MDC brick samples having an "as tested" concentration at the required
MDC were to be compared to the critical net concentrations to determine method detection
capability. Both the reagent blank samples and the MDC brick test samples were to be counted
for a length of time (determined to be 360 minutes) to meet the proposed MDC requirement.
Table 2 - Sample Identification and Test Concentration Level for Evaluating the Required
Minimum Detectable Concentration
Test Sample
Designation
U30-U39
(Brick MDC samples)
US41-US47
(Reagent blanks)
U41-U47
(Brick3 matrix blanks)
Number of
Samples
Prepared
10
7
7
Nuclide
234U
238U
234U
238U
234U
238U
Calculated Known
Value for MDC [1]
(pCi/g)
1.102 ±0.021
1.054 ±0.020
—
—
—
—
Mean Measured
Concentration P1
(pCi/g)
1.19±0.16
1.11±0.14
0.012 ±0.015
0.014 ±0.015
1.13±0.13
1.05 ±0.14
[1] The calculated known values listed here are the inherent levels in the brick. The standard error of the mean
result for the inherent 234U and 238U are stated.
[2] Mean and standard deviation of 10 spiked samples. Because of the natU present in the brick, the reagent blank
results were used to test for an absolute bias.
[3] Blank brick matrix supplied by Eckert & Ziegler Analytics, Atlanta, Georgia.
6.3 Method Bias
Two types of method bias were evaluated, absolute and relative.
Absolute Bias
The brick material used for this method validation study contained natU (See Attachment IV).
The absolute bias for the method was determined using the method reagent blanks that were put
through the entire process.
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
The results from the seven blank 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). Absolute bias was to be determined as a method performance parameter;
however, there was no acceptance limit for bias established for the method in this method
validation process.
The following protocol was used to test the method reagent blanks for 234U and 238U 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 =-
sx,
3. An absolute bias in the measurement process is indicated if:
(1)
•t^/2(N-V) (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.
The method was evaluated for absolute bias by comparing the results of the reagent blank
samples taken through the entire digestion/fusion process to a value of zero.
Relative Bias
The results from the five samples for each of the three test levels, blank brick samples and the 10
MDC samples were evaluated for relative bias according to the protocol and equation presented
in the Method Validation Requirements for Qualifying Methods Used by Radioanalytical
Laboratories Participating in Incident Response Activities (EPA 2009). No acceptable relative
bias limit was specified for this method validation process.
The following protocol was used to test the combined rapid Isotopic U - 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= I2 2 (3)
where:
September 2014 7
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Validation of Rapid Radiochemical Method for U in Brick
X is the average measured value
5X 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
The number of effective degrees of freedom for the T statistic is calculated as follows:
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-a/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 Isotopic U -Brick method was evaluated for the required method
uncertainty at three test level activities. The five replicate PT samples from each test level
concentration were analyzed. The proposed (target) and "as tested" (calculated known) test level
activities are presented in Table 1. Note that the final test concentration values for the PT
samples varied from 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 U isotopes from the alkaline
matrix is accomplished using iron/titanium hydroxide followed by lanthanum fluoride
precipitation steps to remove brick matrix interferences and remove silicates. U is separated and
purified using a rapid column method that utilizes TEVA® Resin plus TRU Resin. After
vizi OIS
purification, U and U isotopes are measured using alpha spectrometry. The column
separation provides effective removal of interferences and good chemical yields. For very high
levels of uranium, additional cerium is required to ensure effective microprecipitation during the
alpha source preparation.
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
6.6 Method Ruggedness
The sodium hydroxide fusion has been used successfully in laboratories on 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 and inhibit column flow.
Plutonium (Pu) and thorium (Th) isotopes are removed using TEVA Resin. TRU Resin has
very high retention for uranium (VI), providing good chemical yields and effective removal of
interferences.
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 Isotopic U - Brick method was evaluated following the guidance presented
for "Level C Method Validation: Adapted, Newly Developed Methods, Including Rapid
Methods" in Method Validation Guide for Qualifying Methods Used by Radiological
Laboratories Participating in Incident Response Activities (EPA 2009) and Chapter 6 of Multi-
Agency Radiological Laboratory Analytical Protocols Manual (EPA 2004).
MARLAP "Level C" method validation requires the laboratory to conduct a method validation
study wherein five replicate samples from each of the three concentration levels are analyzed
according to the method. The concentration test levels analyzed are listed in Table 1. For
validation "Level C," externally prepared PT samples consisting of NIST-traceable natU were
used to spike the MVRM. In order to determine if the proposed method met the rapid methods
development project MQO requirements for the required method uncertainty (MMR =1.6 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
New
Application
Sample
Type111
Internal or
External PT
Samples
Acceptance
Criteria [2]
Measured value
within ± 2.9 UMR
validation value
Number of
Test Levels
3
Number of
Replicates
5
Total Number
of
Analyses
15
[1] "Method Validation Reference Materials" is not a requirement of MARLAP for these test levels. However, in
order to assure laboratory independence in the method validation process, a NIST-traceable source
manufacturer was contracted to produce the testing materials for Phases II and III of the project.
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
[2] The measured value must be within ± 2.9 MMR for test level concentrations at or less than the AAL and within
±2.9 0MR for a test level concentration above the AAL. It was assumed that the uncertainty of a test sample
concentration will be negligible compared to the method uncertainty acceptance criteria and was not
incorporated in the acceptance criteria.
7.2 Required Minimum Detectable Concentration
___ ___ O'lA 9^R
The analytical results reported for the PT samples having U and U concentrations at the
tested MDC of 1.102 + 0.021 and 1.054 + 0.020 pCi/g, respectively, were evaluated according to
Sections 5.5.1 and 5.5.2 of Testing for the Required MDC in Method Validation Guide for
Qualifying Methods Used by Radiological Laboratories Participating in Incident Response
Activities (EPA 2009). NAREL analyzed the external PT samples in accordance with the
proposed rapid method.
Critical Net Concentration
In order to evaluate whether the combined method can meet the required MDC (-1.0 pCi/g), the
critical net concentration, as determined from the results of method blanks, must be calculated.
The critical net concentration (CL^c) with a Type I error probability of a = 0.05 was calculated
using the following equation (consistent with MARLAP, Chapter 20, Equation 20.35):
CL^c (pCi) = t^ (n - 1) x sBlanks (5)
where sBlanks is the standard deviation of the n blank-sample net results (corrected for instrument
background) in radionuclide concentration units of pCi/g, and ^i-a(n-l) is the (1 - a)-quantile of
the ^-distribution with n-\ degrees of freedom (see MARLAP Table G.2 in Appendix G). For
this method validation study a Type I error rate of 0.05 was chosen.
For seven (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 natU (approximately 1.0 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 (reagent water in this case) blank samples for the
radionuclide.
II. From the blank sample net results, calculate the estimated Critical Net Concentration.,
C£NC-
III. Analyze 10 replicate samples spiked at the required MDC.
September 20 14 10
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Validation of Rapid Radiochemical Method for U in Brick
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 CZ/NC-
V. If Y < 2, the method evaluated at the required MDC passes the test for the required MDC
specification.
VI. If Y > 2, the method evaluated at the required MDC fails the test for the required MDC
specification.
8. Evaluation of Experimental Results
Only the experimental results for Phases II and III of the method validation process are reported
and evaluated in this study. Information presented in this section will include results for Sections
6 and 7. The 234U and 238U 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 Isotopic Uranium - Brick Method
The brick sample is fused with sodium hydroxide in zirconium crucibles for -15 minutes at
600 °C in a furnace. The fused material is dissolved using water and transferred to a centrifuge
tube. A preconcentration step with iron/titanium hydroxide enhanced with calcium phosphate is
used to remove the U 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 TEVA® Resin plus TRU Resin cartridges. Pu and Th are retained on
TEVA® Resin in 3 molar (M) HNOs and Am and U are retained on TRU Resin. Am, Th, and
polonium (Po) were removed from TRU Resin using a 4M HC1-0.2M HF-0.002M TiCl3 rinse
solution. U is eluted from TRU Resin with ammonium bioxalate and alpha spectrometry mounts
are prepared using cerium fluoride microprecipitation. Rapid flow rates using vacuum box
technology are used to minimize sample preparation time.
8.2 Required Method Uncertainty
oQ/i 9^R
Tables 4A and 4C summarize the U and U results and the acceptability of each result
compared to the acceptance criteria presented in Section 7.1. Based on the results of the
individual analyses, it may be concluded that this method for 234U and 238U is capable of meeting
a required method uncertainty of-1.6 pCi/g at and below the AAL of-12.3 pCi/g (actual 234U
and 38U tested concentrations of 12.20 and 12.35 pCi/g, respectively) for a 500-minute counting
time and a 1-g sample. The count times used were longer than the times in concrete validation
(EPA 2014) 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.
September 2014 11
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Validation of Rapid Radiochemical Method for U in Brick
234
Table 4A - U Analytical Results for Required Method Uncertainty Evaluation
Nuclide: 234U
Proposed Method: Combined I
Required Method Validation L
Matrix: Brick AAL Tested: 12.20 pCi/a
lapid Isotopic U - Brick Method
evel: MARLAP "C"
Required Method Uncertainty, WMR: 1.6 pC
Acceptance Criteria:
Test Levels 1 : 2.9 x
Test Levels 2 and 3: 2.9 x <;
_l_ A £*.
^MR — T~.O
OMR = ± 37.'
-i/g at and below AAL; 13% above AAL
0 pCi/g of quoted known value of sample in test level
/% of quoted known value of sample in test level
Test Level 1
Sample
U01
U02
U03
U04
U05
pCi/g
Known
6.28
CSU [1]
(pCi/g)
0.12
pCi/g
Measured
6.17
6.48
6.19
6.58
6.25
CSU [2]
(pCi/g)
0.36
0.39
0.36
0.40
0.38
Allowable Range
(pCi/g)
1.7- 11
Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 2
Sample
U06
U07
U08
U09
U10
pCi/g
Known
12.20
CSU [1]
(pCi/g)
0.29
pCi/g
Measured
12.54
12.88
12.06
11.13
12.63
CSU [2]
(pCi/g)
0.68
0.68
0.65
0.58
0.69
Allowable Range
131 (pCi/g)
7.6- 17
Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 3
Sample
Ull
U12
U13
U14
U15
pCi/g
Known
37.20
CSU [1]
(pCi/g)
0.81
pCi/g
Measured
36.8
37.9
36.2
38.7
37.3
CSU [2]
(pCi/g)
1.9
1.9
1.9
2.0
1.9
Allowable Range
(pCi/g)
23-51
Acceptable
Y/N
Y
Y
Y
Y
Y
[1] Quoted combined standard uncertainty (CSU; one sigma) determined by combining in quadrature the standard
error of the mean inherent 234U in blank brick and the reported uncertainty (coverage factor k= 1) by the
radioactive source manufacturer.
[2] Coverage factor k= 1.
[3] Because the test level is actually above the proposed action level the relative required method uncertainty was
used to calculate the acceptable range.
As a measure of the expected variability of results for a test level, the calculated standard
deviation of the five measurements of each test level is provided in Table 4B. The standard
September 2014
12
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Validation of Rapid Radiochemical Method for U in Brick
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 PT Samples by Test Level for 234U
Test Level
1
2 (AAL)
3
Mean
Concentration Measured
(pCi/g)
6.33
12.25
37.38
Standard Deviation of
Measurements [1]
(pCi/g)
0.16
0.69
0.95 (2.5%)
Required Method
Uncertainty
(pCi/g)
1.6
1.6
4.8 (13%) [2]
[1] Standard deviation of the five measurements.
[2] This value 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 (0.13).
Table 4C - U Analytical Results for Required Method Uncertainty Evaluation
Nuclide:238U
Proposed Method: Combined
Required Method Validation
Matrix:
Rapid Isot
Level: MA
Required Method Uncertainty, U-MR: 1.6 \
Acceptance Criteria:
Brick AAL Tested: 12.35 pCi/g
opic U - Brick Method
RLAP "C"
)Ci/g at and below AAL; 13% above AAL
Test Levels 1 : 2.9 x MMR = ± 4.66 pCi/g of quoted known value of sample in test level
Test Level 2 and 3: 2.9 x ^MR = ± 37.7% of quoted known value of sample in test level ( pCi/g)
Test Level 1
Test Value = 6.337 pCi/g
Sample
U01
U02
U03
U04
U05
pCi/g
Known
6.337
csu [1]
(pCi/g)
0.056
pCi/L
Measured
5.96
6.09
6.07
6.71
5.87
CSU [2]
(pCi/g)
0.35
0.37
0.36
0.41
0.36
Allowable Range
(pCi/g)
1.7-11
Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 2
Test Value = 12.35 pCi/g
Sample
U06
U07
U08
U09
U10
pCi/g
Known
12.35
csu[1]
(pCi/g)
0.11
pCi/g
Measured
12.12
13.05
11.72
11.99
12.46
CSU [2]
(pCi/g)
0.68
0.69
0.64
0.62
0.68
Allowable Range
[3](pCi/g)
7.7-17
Acceptable
Y/N
Y
Y
Y
Y
Y
Test Level 3
Test Value = 37.85 pCi/g
Sample
Ull
U12
pCi/g
Known
37.85
csu [1]
(pCi/g)
0.37
pCi/g
Measured
36.6
36.4
CSU [2]
(pCi/g)
1.9
1.8
Allowable Range
(pCi/g)
"IA ^T
Z4 JZ
Acceptable
Y/N
Y
Y
September 2014
13
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Validation of Rapid Radiochemical Method for U in Brick
U13
U14
U15
38.1
39.2
38.5
2.0
2.1
2.0
Y
Y
Y
[1] Quoted uncertainty (one sigma) determined by combining in quadrature the standard error of the mean inherent
238U in blank brick and the reported uncertainty (k=l) by the radioactive source manufacturer.
[2] Coverage factor k= I.
[3] Because the test level is actually above the proposed action level the relative required method uncertainty of
37.7% was used to calculate the acceptable range.
As a measure of the expected variability of results for a test level, the calculated standard
deviation of the five measurements of each test level is provided in Table 4D. The standard
deviation of the analytical results for a test level was much smaller than the required method
uncertainty.
Table 4D - Experimental Standard Deviation of the Five PT Samples by Test Level for 238U
Test Level
1
2 (AAL)
3
Mean
Concentration Measured
(pCi/g)
6.14
12.27
37.7
Standard Deviation of
Measurements [11
(pCi/g)
0.33
0.51
1.1 (2.9%)
Required Method
Uncertainty
1.6
1.6
4.9(13%)[2J
[1] Standard deviation of the five measurements.
[2] Calculated by multiplying the mean known value of Test Level 3 by the required relative method uncertainty
(0.13).
8.3 Required Minimum Detectable Concentration
232
The combined rapid Isotopic U - Brick method was validated for the required MDC using ZJZU as
a tracer, a sample aliquant of approximately 1 gram, and an alpha spectrometry count time of 360
minutes.
234T
23 8T
Tables 5 A and 5B summarize the U and U results and the acceptability of the method's
performance specified in Section 7.2 to meet the tested required MDC of 1.102 and 1.054 pCi/g,
respectively. Results of the analyses of the seven blank brick samples are summarized in Tables
5C and 5D.
Tables 5 A and 5B document that the reported 234U and 238U CSUs for the blank reagent sample
measurements were consistent with the calculated standard deviation of the seven sample results,
indicating that the standard uncertainties of the parameters of the reported CSUs have been
properly estimated.
September 2014
14
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Validation of Rapid Radiochemical Method for U in Brick
,234
Table 5A - Reported U Concentration Method Reagent Blank Samples
Sample ID [1]
US41
US42
US43
US44
US45
US46
US47
Mean [3]
Standard Deviation of
Results
Critical Net Concentration
(pCi/g) - Reagent Blank
Concentration (pCi/g)
-0.001
0.034
0.011
0.009
0.000
0.032
0.000
0.012
0.015
0.029
csu [2]
(pCi/g)
0.011
0.025
0.018
0.018
0.014
0.024
0.012
0.018 [4]
,238
Table SB - Reported U Concentration Method Reagent Blank Samples
Sample ID [1]
US41
US42
US43
US44
US45
US46
US47
Mean [3]
Standard Deviation of
Results
Critical Net Concentration
(pCi/g) - Reagent Blank
Concentration (pCi/g)
0.011
0.023
-0.004
-0.003
0.037
0.021
0.011
0.014
0.015
0.029
CSU [2]
(pCi/g)
0.011
0.022
0.013
0.013
0.027
0.021
0.017
0.014 [4]
[1] NAREL prepared these samples using method reagents and analyzed using the rapid uranium
method.
[2] Combined standard uncertainty, k=l or coverage factor of 1.
[3] Mean and standard deviation were calculated before rounding.
[4] This value was calculated using the CSU values in the last column.
September 2014
15
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Validation of Rapid Radiochemical Method for U in Brick
,234
Table 5C - Reported U Concentration for Blank Brick Samples
Sample ID [1]
U41
U42
U43
U44
U45
U46
U47
Mean [3]
Standard Deviation of
Results
Concentration (pCi/g)
1.18
1.18
1.11
1.25
1.24
0.87
1.08
1.13
0.13
csu [2]
(pCi/g)
0.12
0.12
0.12
0.13
0.13
0.10
0.11
0.12 [4]
,238
Table 5D - Reported U Concentration for Blank Brick Samples
Sample ID [1]
U41
U42
U43
U44
U45
U46
U47
Mean [3]
Standard Deviation of
Results
Concentration (pCi/g)
0.95
1.06
0.824
1.20
1.23
1.07
1.02
1.05
0.14
CSU [2]
(pCi/g)
0.11
0.11
0.097
0.13
0.13
0.11
0.11
0.11 [4]
[1] These samples were prepared at Eckert & Ziegler Analytics and analyzed by NAREL using the rapid
uranium method.
[2] Combined standard uncertainty, k=l or coverage factor of 1.
[3] Mean and standard deviation were calculated before rounding.
[4] This value was calculated using the CSU values in the last column.
Critical Net Concentration
The critical net concentration for the method under evaluation was calculated using Equation 6
r-*-, 9^4
from Section 7.2. Based on the results of the seven reagent blanks (Table 5A and 5B), the U
and 238U critical net concentrations for the combined method was determined to be 0.029 pCi/g
for a 360-minute counting time. An estimate of the theoretical a priori MDC for the reagent
blank samples of the same aliquant weight, chemical yield, and counting time would be
approximately twice the critical net concentrations or ~ 0.06 pCi/g for the two isotopes.
RequiredMDC
9^4 91&
A summary of the reported results for samples containing U and U at the required MDC is
91zl 918
presented in Tables 6A and 6B. The mean measured concentration values for U and U in the
10 MDC test samples were calculated as 1.19 ± 0.16 and 1.05 + 0.14 pCi/g, respectively (k=\).
September 2014
16
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Validation of Rapid Radiochemical Method for U in Brick
It should be noted that the laboratory was requested to calculate a counting time to meet a MDC
of-1.0 pCi/g. The laboratory used a 360 minute counting time for the critical level and MDC
samples. The laboratory's reported critical level value associated with each of the test sample
results was on the average 0.0135 pCi/g for both isotopes, which is approximately one-half the
calculated critical net concentration stated above for the isotopes. In addition, the mean relative
uncertainty of the MDC sample measurements was -12% for both isotopes, rather than the
expected -30%. As such, the method definitely was capable of meeting a required MDC of - 1
pCi/g in a 360 minute count.
Table 6A - Reported Results for Samples Containing U at the As-Tested MDC Value (pCi/g)
Sample ID
U30
U31
U32
U33
U34
U35
U36
U37
U38
U39
Mean [2]
Standard Deviation of Results
Concentration
(pCi/g)
.13
.46
.31
.00
.10
.11
.25
.14
.40
.00
1.19
0.16
CJ Pi
«-^NC
Acceptable maximum values < CLNC
Number of results > C£NC
Number of results < C£NC
csu [1]
(pCi/g)
0.14
0.16
0.14
0.13
0.13
0.13
0.16
0.14
0.15
0.13
—
2
—
—
Evaluation
Test Result
< Reagent Blank
CLNC
N
N
N
N
N
N
N
N
N
N
—
0.029 pCi/g
—
10
0
Pass
[1] Combined standard uncertainty, k=\ or coverage factor of 1.
[2] Mean and standard deviation were calculated before rounding.
[3] Critical net concentration.
Table 6B - Reported Results for Samples Containing -"'U at the As-Tested MDC Value (pCi/g)
Sample ID
U30
U31
U32
U33
U34
U35
U36
U37
U38
Concentration
(pCi/g)
0.79
1.19
1.30
1.08
0.97
1.09
1.18
1.14
1.19
CSU [1]
(pCi/g)
0.11
0.14
0.14
0.13
0.12
0.13
0.15
0.14
0.14
Test Result
< Reagent Blank
(-L^c
N
N
N
N
N
N
N
N
N
September 2014
17
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Validation of Rapid Radiochemical Method for U in Brick
Sample ID
U39
Mean P1
Standard Deviation of
Results
Concentration
(pCi/g)
1.13
1.11
0.14
CLN™
Acceptable maximum values < CLNC
Number of results > CZ,NC
Number of results < CLNC
csu [1]
(pCi/g)
0.14
—
2
—
—
Evaluation
Test Result
< Reagent Blank
CL-Nc
N
—
—
0.029 pCi/g
—
10
0
Pass
[1] Combined standard uncertainty, k=l or coverage factor of 1.
[2] Mean and standard deviation were calculated before rounding.
[3] Critical net concentration.
8.4 Evaluation of the Absolute and Relative Bias
The 234U and 238U results for the seven reagent blank samples (Tables 5 A and 5B), blank seven
brick samples (Tables 5C and 5D), 10 MDC samples (Table 6), and five replicate PT samples
on the three test levels (Tables 4A and 4C) were evaluated for bias according to the equations
presented in Section 6.3. The results and interpretation of the evaluation are presented below in
Table 7.
Table 7 - Absolute and Relative Bias Evaluation of the Combined Rapid Isotopic U Brick
Method
Type of
Bias
Absolute
Reagent
Method
blanks
Relative
Blank
Brick
Relative
MDC
Relative
Level 1
Isotope
234U
238U
234U
238U
234U
238U
234U
238U
Known
Value
± CSU [1]
(pCi/g)
0.000
0.000
1.102+0.021
1.054+0.020
1.102+0.021
1.054+0.020
6.28 + 0.12
6.337+0.056
Mean of
Measurements ±
Standard Deviation
PI
(pCi/g)
0.012 + 0.015
0.014 + 0.015
1.129+0.129
1.051+0.139
1.19+0.16
1.11+0.14
6.33+0.16
6.14+0.33
Difference
from
Known
0.012
0.014
0.027
-0.003
0.088
0.056
0.048
-0.197
Number of
Measurement
s/Degrees of
Freedom
7/6
7/6
7/6
7/6
10/12
10/12
5/58
5/5
|T|
2.13
2.44
0.22
0.021
1.62
1.07
0.36
1.24
tdf
2.45
2.45
2.45
2.45
2.18
2.18
2.00
2.57
Bias
Yes/N
0
N
N
N
N
N
N
N
N
September 2014
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Validation of Rapid Radiochemical Method for U in Brick
Relative
Level 2
Relative
Level 3
234U
238U
234U
238U
12.20 + 0.29
12.35+0.11
37.20+0.81
37.85+0.37
12.25+0.69
12.27 + 0.51
37.38 + 0.95
37.7+1.1
0.05
-0.08
0.18
-0.15
5/14
5/6
5/85
5/9
0.11
0.32
0.19
0.20
2.1.4
2.45
1.99
2.26
N
N
N
N
[1] The stated CSU includes the uncertainty in the 234U and 238U reference standard used to prepare the samples and
the standard error of the mean of the seven blank brick samples. Coverage factor k = 1.
[2] Standard deviation of the measurements.
Only the method reagent blank samples prepared by NAREL could be evaluated for absolute
bias since the brick had natU as part of its makeup. These reagent blank samples were taken
through the entire method described in Attachment III. The 234U and 238U results listed in Table 7
indicates that no positive absolute bias exists for the method reagent blanks used.
The results for the samples identified as brick blanks had a mean and standard deviation (of the
10 results) of 1.051 +0.0139 and 1.13 + 0.13 and 1.05 + 0.14 pCi/g for 234U and 238U,
respectively. For determination of a relative bias, these measurement results were compared to
the inherent concentration of the uranium isotopes in the brick blanks (234U = 1.102 + 0.021
pCi/g and 238U = 1.054 + 0.020). The relative bias test indicated that there was no bias in the
results for either isotope.
The 10 MDC test level samples (U30-U39) for 234U and 238U contained the inherent
concentration known value of 1.102 + 0.021 and 1.054 + 0.020 pCi/g, respectively. The mean
measured concentrations of these samples was 1.19 + 0.16 and 1.11 +0.14 pCi/g, respectively. A
t-test of the 10 MDC results was performed for the two isotopes as provided in Table 7. Based on
the results of the statistical test, it can be concluded that there was no statistical difference
between the MDC test brick sample results and the calculated known MDC values for the two
isotopes.
As determined by the t-test described in Section 7, no statistical relative bias was indicated for
any of the three 34U or 238U validation test levels. The relative percent difference from the
calculated known value for each test level is:
234
U
238
U
• Test Level 1: +0.8%
• Test Level 2: +0.4%
• Test Level 3: +0.5%
-3.1%.
-0.6%.
-0.4%.
The excellent measurement results for 234U and 238U versus the reference values indicate
910
effective removal of key radiological interferences, in particular, removal of Po, which has a
very similar alpha energy to the tracer 232U. The minimal bias at the three test levels indicates
efficient removal of 210Po, which can bias the tracer yield, and Th isotopes, which interfere with
the measurement of 234U and 238U alpha peak measurement.
8.5 Method Ruggedness and Specificity
The results summarized in Table 8 represent the 232U radiochemical yields for all three test
levels, all blanks, all LCSs, and all MDC samples that were processed in accordance with the
September 2014
19
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Validation of Rapid Radiochemical Method for U in Brick
232T
final method in Attachment III. A graphical representation of the 48 U yields is presented in
Figure 1. The mean and median yields for the 48 samples were 67.3% and 66.1%, indicating a
fairly normal distribution of results. The correlation coefficient for the mean was calculated to be
-13%. The observed yields are lower than those for the analysis of 241Am and 239Pu in brick by
the corresponding combined rapid methods but are consistent with uranium yields observed for
the concrete matrix. The highest yields were observed for the reagent blanks and laboratory
control samples - which are devoid of the inherent composition of the brick matrix. Ninety
percent of the yield results were between 57% and 85% of the distribution. The yields in the 60-
70% range had no adverse effect on the accuracy or precision of the results.
Table 8 - Summary of U Radiochemical % Yield Results for Test
232¥
and Quality Control Samples Based on U Tracer
Number of Samples
Mean Radiochemical Yield
Standard Deviation of Distribution (la)
Median
Minimum Value
5th Percentile
95th Percentile
Maximum Value
48
67.3%
8.7%
66.1%
49.1%
56.9%
84.6%
87.1%
The yields for samples evaluated using this method are shown on Figure 1.
%
Y
1
E
L
D
U-232 Tracer Yield
mn n
Qn n
an n
70.0
60.0
t.r\ r\
An n
3n n
9n n
m n
On
«%*
* ^ * * +++ A .7
+? a.*^* ^«^*V *
*^ *^^ ^W^
^^
w
0 10 20 30 40 50 60
SAMPLE
Figure 1 - Yields for Method Based on Measurement of U
9. Timeline to Complete a Batch of Samples
NAREL kept a timeline log on processing a batch of samples and associated internal quality
control samples. The total time to process a batch of samples, including counting of the samples
and data review/analysis, was about 14.5 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
20
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Validation of Rapid Radiochemical Method for U in Brick
10. Reported Modifications and Recommendations
NAREL performed the combined rapid Isotopic U - Brick method validation and made a few
minor modifications to the method prior to analyzing samples for Phases II and III of the project.
Selected modifications provided by NAREL are listed below.
Modifications of the Method During Phases II and III:
There was one modification made in the uranium column separation procedure. A note was
updated to emphasize the need for 100 jig Ce in preparation of the final sample test source if the
uranium level could be higher than 10 pCi in the final purified fraction, or if the level of uranium
is not known.
Rapid Radiochemical Method for Isotopic Uranium in Building Materials for Environmental
Remediation Following Radiological Incidents (Attachment III):
NOTE: The step numbers below may have changed in the post-validation method in Attachment III.
NOTE: Instructions below describe preparation of a single sample test source (STS). Several STSs can be
prepared simultaneously if a multi-channel vacuum manifold system is available. Additional Ce (150-200 uL)
is typically needed if the uranium is greater than 10-15 pCi in the final purified solution to ensure complete
precipitation. If it is not known that the 238U is < 10-15 pCi in the final purified solution, 200 uL Ce (100 jig
Ce) should be added instead of 100 uL Ce.
11.3.1 Pipet 100 jiL-200 jiL of the Ce carrier solution into each centrifuge tube.
11. Summary and Conclusions
The Combined Rapid Isotopic U - Brick method was successfully validated according to
"Method Validation Requirements for Qualifying Methods Used by Radioanalytical Laboratories
Participating in Incident Response Activities" and Chapter 6 of Multi-Agency Radiological
Laboratory Analytical Protocols Manual (EPA 2004). The method was evaluated using well-
characterized brick analyzed for its macro-constituents by an independent laboratory4 and for its
radiological constituents (Attachment IV) using the combined rapid U - brick method by
NAREL
The pulverized brick samples were spiked with three 234U and 238U concentrations consistent
with concentration ranges consistent with site remediation and above "normal" background
941 9^Q 99h"^ QO
concentrations in soil in the presence of low-level concentrations of Am, Pu, Ra, and Sr
(Table 1). The rapid Combined Rapid Isotopic U - Brick method met MARLAP Validation
Level "C" requirements for a required method uncertainty of 1.6 pCi/g at and below the AAL,
and for the required relative method uncertainty of 13% above the AAL concentration of-12
pCi/g for a 500-minute counting time and a 1-g sample.
The laboratory calculated a counting time (360 minutes) to meet a MDC of-1.0 pCi/g. This
counting time was also applied to the reagent blank and brick blank sample measurements.
Based on the seven reagent blank samples, a net critical concentration was determined to be
0.029 pCi/g for both isotopes. The laboratory's reported critical level concentration value
associated with each of the test sample results was approximately 0.0135 pCi/g for both isotopes,
4 Wyoming Analytical Laboratories, Inc. of Golden, Colorado, performed the macro analysis.
September 2014 21
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Validation of Rapid Radiochemical Method for U in Brick
which is approximately one-half the calculated critical net concentration stated above for the
isotopes. Each result passed the MDC verification testing protocol. As such, the method
definitely was capable of meeting a required MDC of ~1 pCi/g in a 360-minute count.
Predicated on the statistical tests provided in the Method Validation Guide for Qualifying
Methods Used by Radiological Laboratories Participating in Incident Response Activities (EPA
2009), the combined rapid Isotopic U - Brick method had no absolute bias for reagent blank
samples. The mean and standard error of the seven method reagent blank samples were
calculated as 0.0121 + 0.0057 and 0.0137 + 0.0057 pCi/g for 234U and 238U, respectively. This
result indicates that the rapid fusion digestion is rugged and reliable and the column separation
allows reliable measurements of uranium isotopes by alpha spectrometry.
As determined by the paired Mest described in Section 7, it can be concluded that there is no
statistical difference between the brick MDC test sample results and the calculated known MDC
values for the two isotopes. In addition, no statistical relative bias was indicated for the three
OQQ O'lA
U and U validation test levels.
The observed mean chemical yield and standard deviation of the 48 analyses evaluated were
67.3% ±8.7%. The observed yields are lower than those for the analysis of 241Am and 239Pu in
brick by the corresponding combined rapid methods but are consistent with uranium yields
observed for the concrete matrix.
The laboratory provided one minor modification to improve the combined rapid Isotopic U -
Brick method. The modification was applied to the analyses of samples during Phases II and III
of the method validation process. The rapid fusion method is rugged and effectively removes
interferences, providing a very good method to assess uranium content in brick samples in
response to a radiological emergency. As demonstrated by the very reliable measurements at the
three test levels, this new rapid method is a robust method to determine uranium isotopic levels
in brick samples that can be used with confidence following a radiological event.
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.
Revision 0. Office of Air and Radiation, Washington, DC. EPA 402-R-09-006, June.
Available at: www.epa.gov/narel/incident_guides.html.
September 2014 22
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Validation of Rapid Radiochemical Method for U in Brick
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 Air and 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 Methodfor Isotopic
Uranium 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 23
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Validation of Rapid Radiochemical Method for U in Brick
Attachment I:
Estimated Elapsed Times
Step
Rapid Fusion
Vacuum Box Setup
Load Sample to TEVA® & TRU cartridges
U separation on TRU 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.
September 2014
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
Attachment II:
Rapid Method for Sodium Hydroxide Fusion of Concrete5 and Brick Matrices Prior
to Americium, Plutonium, Strontium, Radium, and Uranium Analyses for
Environmental Remediation Following Radiological Incidents
1. Scope and Application
1.1. The method is applicable to the sodium hydroxide fusion of concrete and brick samples,
prior to the chemical separation procedures described in the following procedures:
1.1.1. Rapid Radiochemical Method for Americium-241 in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.1).
1.1.2. Rapid Radiochemical Method for Plutonium-238 and Plutonium-239/240 in
Building Materials for Environmental Remediation Following Radiological
Incidents (Reference 16.2).
1.1.3. Rapid Radiochemical Method for Radium-226 in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.3).
1.1.4. Rapid Radiochemical Method for Total Radiostrontium (Sr-90) in Building
Materials for Environmental Remediation Following Radiological Incidents
(Reference 16.4).
1.1.5. Rapid Radiochemical Method for Isotopic Uranium in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.5).
1.2. This general method for concrete and brick building material applies to samples
collected following a radiological or nuclear incident. The concrete and brick samples
may be received as core samples, pieces of various sizes, dust or particles (wet or dry)
from scabbling, or powder samples.
1.3. The fusion method is rapid and rigorous, effectively digesting refractory radionuclide
particles that may be present.
1.4. Concrete or brick samples should be ground to at least 50-100 mesh size prior to fusion,
if possible.
1.5. After a homogeneous, finely ground sample is obtained, the dissolution of concrete or
brick matrices by this fusion method is expected to take approximately 1 hour per batch
of 20 samples. This method assumes the laboratory starts with a representative, finely
ground, 1-1.5-g aliquant of sample and employs simultaneous heating in multiple
furnaces. The preconcentration steps to eliminate the alkaline fusion matrix and collect
the radionuclides are expected to take approximately 1 hour.
1.6. As this method is a sample digestion and pretreatment technique, to be used prior to
other separation and analysis methods, the user should refer to those individual methods
' U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method for Plutonium-238 and
Plutonium-239/240 in Building Materials for Environmental Remediation Following Radiological Incidents,
Office of Air and Radiation, Washington, DC, EPA 402-R-07-007, April 2014. Unpublished.
September 2014 25
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
and any project-specific requirements for the determination of applicable measurement
quality objectives (MQOs).
1.7. Application of this method by any laboratory should be validated by the laboratory using
the protocols provided in Method Validation Guide for Qualifying Methods Used by
Radioanalytical Laboratories Participating in Incident Response Activities (Reference
16.6), or the protocols published by a recognized standards organization for method
validation.
1.7.1. In the absence of project-specific guidance, MQOs for concrete or brick samples
may be based on the Analytical Action Levels (AALs), the Required Method
Uncertainty (MMR) and the Required Relative Method Uncertainty (cpMn) found in
the Radiological Laboratory Sample Analysis Guide for Incident Response —
Radionuclides in Soil (Reference 16.7).
2. Summary of Method
2.1. The method is based on the rapid fusion of a representative, finely ground 1-1.5-g
aliquant using rapid sodium hydroxide fusion at 600 °C.
2.2. Pu, U, and Am are separated from the alkaline matrix using an iron/titanium hydroxide
precipitation (enhanced with calcium phosphate precipitation) followed by a lanthanum
fluoride matrix removal step.
2.3. Sr is separated from the alkaline matrix using a carbonate precipitation, followed by a
calcium fluoride precipitation to remove silicates.
2.4. Ra is separated from the alkaline matrix using a carbonate precipitation.
3. Definitions, Abbreviations and Acronyms
3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a sample
of any matrix where a high concentration of radioactive material is present as a tiny
particle (|im range).
3.2. Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
(Reference 16.8).
3.3. The use of the term concrete or brick throughout this method is not intended to be
limiting or prescriptive, and the method described herein refers to all concrete or
masonry-related materials. In cases where the distinction is important, the specific issues
related to a particular sample type will be discussed.
4. Interferences and Limitations
NOTE: Large amounts of extraneous debris (pebbles larger than Vi", non-soil related debris) are not
generally considered to be part of a concrete or brick matrix. When consistent with data quality
objectives (DQOs), materials should be removed from the sample prior to drying. It is recommended this
step be verified with Incident Command before discarding any materials.
September 2014 26
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
4.1. Concrete or brick samples with larger particle size may require a longer fusion time
during Step 11.1.8.
4.2. As much information regarding the elemental composition of the sample should be
obtained as possible. For example some concrete or brick may have native
concentrations of uranium, radium, thorium, strontium or barium, all of which may have
an effect on the chemical separations used following the fusion of the sample. In some
cases (e.g., radium or strontium analysis), elemental analysis of the digest prior to
chemical separations may be necessary to determine native concentrations of carrier
elements present in the sample.
NOTE: In those samples where native constituents are present that could interfere with the
90C
determination of the chemical yield (e.g., strontium for Sr analysis) or with the creation of a
. 226T
sample test source (e.g., Ba for Ra analysis by alpha spectrometry), it may be necessary to
determine the concentration of these native constituents in advance of chemical separation (using a
separate aliquant of fused material) and make appropriate adjustments to the yield calculations or
amount of carrier added.
4.3. Matrix blanks for these matrices may not be practical to obtain. Efforts should be made
to obtain independent, analyte-free materials that have similar composition as the
samples to be analyzed. These blanks will serve as process monitors for the fusion, and
as potential monitors for cross contamination during batch processing.
4.4. Uncontaminated concrete or brick material may be acceptable blank material for Pu,
Am, and Sr analyses, but these materials will typically contain background levels of U
and Ra isotopes.
4.4.1. If analyte-free blank material is not available and an empty crucible is used to
generate a reagent blank sample, it is recommended that 100-125 milligram (mg)
calcium (Ca) per gram of samples be added as calcium nitrate to the empty
crucible as blank simulant. This step facilitates Sr/Ra carbonate precipitations
from the alkaline fusion matrix.
4.4.2. Tracer yields may be slightly lower for reagent blank matrices, since the concrete
and brick matrix components typically enhance recoveries across the
precipitation steps.
4.5. Samples with elevated activity or samples that require multiple analyses from a single
concrete or brick sample may need to be split after dissolution. In these cases the initial
digestate and the split fractions should be carefully measured to ensure that the sample
aliquant for analysis is accurately determined.
4.5.1. Tracer or carrier amounts (added for yield determination) may be increased
where the split allows for the normal added amount to be present in the
subsequent aliquant. For very high activity samples, the addition of the tracer or
carrier may need to be postponed until following the split, in which case special
care must be taken to ensure that the process is quantitative until isotopic
exchange with the yield monitor is achieved. This deviation from the method
should be thoroughly documented and reported in the case narrative.
4.5.2. When this method is employed and the entire volume of fused sample is
processed in the subsequent chemical separation method, the original sample size
September 2014 27
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
and units are used in all calculations, with the final results reported in the units
requested by the project manager.
4.5.3. In cases where the sample digestate is split prior to analysis, the fractional
aliquant of the sample is used to determine the sample size. The calculation of
the appropriate sample size used for analysis is described in Section 12, below.
4.6. In the preparation of blank samples, laboratory control samples (LCSs) and duplicates,
care should be taken to create these quality control samples as early in the process as
possible, and to follow the same tracer/carrier additions, digestion process, and sample
splitting used for the field samples. In the case of this method, quality control samples
should be initiated at the point samples are aliquanted into crucibles for the fusion.
4.7. Although this method is applicable to a variety of subsequent chemical separation
procedures, it is not appropriate where the analysis of volatile constituents such as iodine
or polonium is required. The user of this method must ensure that analysis is not
required for any radionuclide that may be volatile under these sample preparation
conditions, prior to performing this procedure.
4.8. Zirconium crucibles used in the fusion process may be reused.
4.8.1. It is very important that the laboratory have a process for cleaning and residual
contamination assessment of the reused zirconium crucibles. The crucibles
should be cleaned very well using soap and water, followed by warm nitric acid
and then water. Blank measurements should be monitored to ensure effective
cleaning.
4.8.2. Segregation of crucibles used for low and high activity samples is recommended
to minimize the risk of cross-contamination while maximizing the efficient use
of crucibles.
4.9. Centrifuge speed of 3500 rpm is prescribed but lower rpm speeds (>2500 rpm) may be
used if 3500 rpm is not available.
4.10. Titanium chloride (TiCb) reductant is used during the co-precipitation step with iron
hydroxide for actinides to ensure tracer equilibrium and reduce uranium from U+6 to
U+4 to enhance chemical yields. This method adds 5 mL 10 percent by mass (wt%)
TiCb along with the Fe. Adding up to 10 mL of 10 wt% TiCb may increase uranium
chemical yields, but this will need to be validated by the laboratory.
oo/r r)r)f\
4.11. Trace levels of Ra may be present in Na2CC>3 used in the Ra pre-concentration step
used in this method. Adding less 2M Na2CC>3 (<25 mL used in this method) may reduce
226Ra reagent blank levels, while still effectively pre-concentrating 226Ra from the
fusion matrix. This will need to be validated by the laboratory.
4.12. La is used to pre-concentrate actinides along with LaF3 in this method to eliminate
matrix interferences, including silica, which can cause column flow problems. La
follows Am in subsequent column separations and must be removed. Less La (2 mg)
was used for brick samples to minimize the chance of La interference on alpha
spectrometry peaks. While this may also be effective for concrete samples, this will
have to be validated by the laboratory.
September 2014 28
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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).
September 2014 29
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
6.10. Hot water bath or dry bath equivalent.
6.11. Ice bath.
6.12. Muffle furnace capable of reaching at least 600 °C.
6.13. Tongs for handling crucibles (small and long tongs).
6.14. Tweezers or forceps.
6.15. Sample size reduction equipment (ball mill, paint shaker, etc.) and screens. The
necessary equipment will be based on a laboratory's specific method for the process of
producing a uniformly ground sample from which to procure an aliquant.
NOTE: See appendix for a method for ball-milling and homogenization of concrete or brick
6.16. Vortex stirrer.
7. Reagents and Standards
NOTES:
Unless otherwise indicated, all references to water should be understood to mean Type I reagent water
(ASTM D1193; Reference 16.9).
All reagents are American Chemical Society (ACS)-grade or equivalent unless otherwise specified.
7.1. Type I reagent water as defined in ASTM Standard Dl 193 (Reference 16.9).
7.2. Aluminum nitrate (A1(NO3)3' 9H2O)
7.2.1. Aluminum nitrate solution (2M): Add 750 g of aluminum nitrate (A1(NO3)3'
9H2O) to -700 mL of water and dilute to 1 L with water. Low-levels of
uranium are typically present in A1(NC>3)3 solution.
NOTE: Aluminum nitrate reagent typically contains trace levels of uranium
concentration. To achieve the lowest possible blanks for isotopic uranium measurements,
some labs have removed the trace uranium by passing ~250 mL of the 2M aluminum
nitrate reagent through ~7 mL TRU® Resin or UTEVA® Resin (Eichrom Technologies),
but this will have to be tested and validated by the laboratory.
7.3. Ammonium hydrogen phosphate (3.2M): Dissolve 106 g of (NH/^HPC^ in 200 mL of
water, heat on low to medium heat on a hot plate to dissolve and dilute to 250 mL with
water.
7.4. Boric Acid, H3BO3.
7.5. Calcium nitrate (1.25M): Dissolve 147 g of calcium nitrate tetrahydrate
(Ca(NO3)2'4H2O) in 300 mL of water and dilute to 500 mL with water.
7.6. Iron carrier (50 mg/mL): Dissolve 181 g of ferric nitrate (Fe(NC>3)3 • 9H2O) in 300 mL
water and dilute to 500 mL with water.
7.7. Hydrochloric acid (12M): Concentrated HC1, available commercially.
7.6.1. Hydrochloric acid (0.01M): Add 0.83 mL of concentrated HC1 to 800 mL of
water and dilute with water to 1 L.
7.6.2. Hydrochloric acid (1.5M): Add 125 mL of concentrated HC1 to 800 mL of
water and dilute with water to 1 L.
September 2014 30
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
7.8. Hydrofluoric acid (28M): Concentrated HF, available commercially.
7.9. Lanthanum carrier (1.0 mg La3+/mL): Add 1.56 g lanthanum (III) nitrate hexahydrate
[La(NO3) 3 . 6H2O] in 300 mL water, diluted to 500 mL with water.
7.10. Nitric acid (16M): Concentrated HNOs, available commercially.
7.10.1. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water and
dilute to 1 L with water.
7.10.2. Nitric acid-boric acid solution (3M-0.25M): Add 15.4 g of boric acid and 190
mL of concentrated HNOs to 500 mL of water, heat to dissolve, and dilute to 1
liter with water.
7.10.3. Nitric acid (7M): Add 443 mL of concentrated HNO3 to 400 mL of water and
dilute to 1 L with water.
7.10.4. Nitric acid (8M): Add 506 mL of concentrated HNO3 to 400 mL of water and
dilute to 1 L with water.
7.11. Sodium carbonate (2M): Dissolve 212 g anhydrous Na2CC>3 in 800 mL of water, then
dilute to 1 L with water.
7.12. Sodium hydroxide pellets.
7.13. Titanium (III) chloride solution (TiCl3), 10 wt% solution in 20-30 wt% hydrochloric
acid.
7.14. Radioactive tracers/carriers (used as yield monitors) and spiking solutions. A
radiotracer is a radioactive isotope of the analyte that is added to the sample to
measure any losses of the analyte. A carrier is a stable isotope form of a radionuclide
(usually the analyte) added to increase the total amount of that element so that a
measureable mass of the element is present. A carrier can be used to determine the
yield of the chemical process and/or to carry the analyte or radiotracer through the
chemical process. Refer to the chemical separation method(s) to be employed upon
completion of this dissolution technique. Tracers/carriers that are used to monitor
radiochemical/chemical yield should be added at the beginning of this procedure. This
timing allows for monitoring and correction of chemical losses in the combined
digestion process, as well as in the chemical separation method. Carriers used to
prepare sample test sources but not used for chemical yield determination (e.g., cerium
added for microprecipitation of plutonium or uranium), should be added where
indicated.
8. Sample Collection, Preservation, and Storage
Not Applicable.
9. Quality Control
9.1. Where the subsequent chemical separation technique requires the addition of carriers
and radioactive tracers for chemical yield determinations, these are to be added prior to
beginning the fusion procedure, unless there is good technical justification for doing
otherwise.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
9.2. Batch quality control results shall be evaluated and meet applicable analytical protocol
specifications (APS) prior to release of unqualified data. In the absence of project-
defined APS or a project-specific quality assurance project plan (QAPP), the quality
control sample acceptance criteria defined in the laboratory's Quality Manual and
procedures shall be used to determine acceptable performance for this method.
9.2.1. An exception to this approach may need to be taken for samples of
exceptionally high activity where human safety may be involved.
9.3. Quality control samples are generally specified in the laboratory's Quality Manual or
in a project's APS. At the very minimum the following are suggested:
9.3.1. A laboratory control sample (LCS), which consists solely of the reagents used
in this procedure and a known quantity of radionuclide spiking solution, shall
be run with each batch of samples. The concentration of the LCS should be at
or near the action level or level of interest for the project
9.3.2. One reagent blank shall be run with each batch of samples. The blank should
consist solely of the reagents used in this procedure (including tracer or carrier
from the analytical method added prior to the fusion process).
9.3.3. A sample duplicate that is equal in size to the original aliquant should be
analyzed with each batch of samples. This approach provides assurance that
the laboratory's sample size reduction and sub-sampling processes are
reproducible.
10. Calibration and Standardization
10.1. Refer to the individual chemical separation and analysis methods for calibration and
standardization protocols.
11. Procedure
11.1. Fusion
11.1.1. In accordance with the DQOs and sample processing requirements stated in
the project plan documents, remove extraneous materials from the concrete
or brick sample using a clean forceps or tweezers.
11.1.2. Weigh out a representative, finely ground 1-g aliquant of sample into a
labeled crucible (1.5-g aliquants for 90Sr analysis).
NOTES:
It is anticipated that concrete or brick powder sample material will be dry enough to
aliquant without a preliminary drying step. In the event samples are received that
contain moisture, the samples may be dried in a drying oven at 105 °C prior to taking
the aliquant.
For Sr and Ra analyses, a reagent blank of 100-150 mg calcium per gram of sample
(prepared by evaporating 2.5 mL of 1.25M calcium nitrate, Ca(NO3)2, for radium and 3
mL of 1.25M Ca(NO3)2 for strontium) should be added to the crucible as a blank
simulant to ensure the blank behaves like the concrete or brick samples during the
precipitation steps.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
11.1.3. Add the proper amount of tracer or carrier appropriate for the method being
used and the number of aliquants needed.
11.1.4. Place crucibles on a hot plate and heat to dryness on medium heat.
NOTE: Heat on medium heat to dry quickly but not so high as to cause splattering.
11.1.5. Remove crucibles from hot plate and allow to cool.
11.1.6. Add the following amounts of sodium hydroxide based on the aliquant
size/analysis required.
1 g for Pu, Am, U: 15 g NaOH
l.SgforSr: 15 g NaOH
IgforRa: 10 g NaOH
11.1.7. Place the crucibles with lids in the 600 °C furnace using tongs.
11.1.8. Fuse samples in the crucibles for-15 minutes.
NOTE: Longer times may be needed for larger particles.
11.1.9. Remove hot crucibles from furnace very carefully using tongs, andtransfer to
hood.
11.1.10. Add -25-50 mL of water to each crucible -8 to 10 minutes (or longer) after
removing crucibles from furnace, and heat on hotplate to loosen/dissolve
solids.
11.1.11. If necessary for dissolution, add more water, and warm as needed on a
hotplate.
11.1.12. Proceed to Section 11.2 for the actinide preconcentration procedure, 11.3 or
11.4 for Sr preconcentration, or 11.5 for Ra preconcentration steps.
11.2. Preconcentration of Actinides (Pu, U, or Am) from Hydroxide Matrix
11.2.1. Pipet 2.5 mL of iron carrier (50 mg/mL) into a labeled 225-mL centrifuge
tube for each sample.
11.2.2. Add La carrier to each 225-mL tube as follows:
Concrete: 5 mL of 1 mg La/mL for Pu, Am, U
Brick: 5 mL of 1 mg La/mL for Pu, and U; 2 mL 1 mg La/mL for Am
11.2.3. Transfer each fused sample to a labeled 225 mL centrifuge tube, rinse
crucibles well with water, and transfer rinses to each tube.
11.2.4. Dilute each sample to approximately 180 mL with water.
11.2.5. Cool the 225 mL centrifuge tubes in an ice bath to approximately room
temperature as needed.
11.2.6. Pipet 1.25M Ca(NO3) 2 and 3.2M (NH4)2HPO4 into each tube as follows:
Pu, Am: 2 mL 1.25M Ca(NO3) 2 and 3 mL 3.2M (NH4)2HPO4
U: 3 mL 1.25M Ca(NO3)2 and 5 mL 3.2M (NH4)2HPO4
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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).
on
11.3. Preconcentration of Sr from Hydroxide Matrix (Concrete)
NOTE: The preconcentration steps for 90Sr in this section can also be applied to brick samples, but
this will have to be validated by the laboratory. See Section 11.4 for steps validated for 90Sr in
brick samples.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
11.3.1. Transfer each fused sample to a 225-mL centrifuge tube, rinse crucibles well
with water, and transfer rinses to each tube.
11.3.2. Dilute to approximately 150 mL with water.
11.3.3. Add 15-mL concentrated HC1 to each tube.
11.3.4. Cap and mix solution in each tube.
11.3.5. Pipet 1-mL of 1.25M Ca(NO3)2into each tube.
11.3.6. Add 2-mL of 50-mg/mL iron carrier into each tube.
11.3.7. Add 25-mL of 2MNa2CO3to each tube.
11.3.8. Cap tubes and mix well.
11.3.9. Cool the 225-mL centrifuge tubes in an ice bath for -10 minutes.
11.3.10. Centrifuge tubes for 5 minutes at 3500 rpm.
11.3.11. Pour off the supernate, and discard to waste.
11.3.12. Add 1.5MHC1 to each tube to redissolve each sample in a total volume of
-50 mL.
11.3.13. Cap and shake each tube to dissolve solids as well as possible.
11.3.14. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.3.15. Add 22 mL of concentrated HF into each tube. Cap and mix well.
11.3.16. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
11.3.17. Centrifuge for-6 minutes at 3500 rpm.
11.3.18. Pour off supernate, and discard to waste.
11.3.19. Pipet 5 mL of concentrated HNO3and 5 mL of 3M HNO3 - 0.25M boric acid
into each 225 mL tube to dissolve precipitate.
11.3.20. Cap and mix well. Transfer contents of the tube into a labeled 50-mL
centrifuge tube.
11.3.21. Pipet 5 mL of 3M HNOs and 5 mL of 2M aluminum nitrate into each tube,
cap tube and mix.
11.3.22. Transfer rinse solutions to labeled 50-mL centrifuge tubes and mix well
(shake or use vortex stirrer).
11.3.23. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.3.24. Transfer solutions to labeled beakers or new 50 mL tubes for further
processing.
11.3.25. If solids remain 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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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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).
on
11.4. Preconcentration of Sr from Hydroxide Matrix (Brick)
NOTE: The preconcentration steps for 90Sr in this section, using calcium phosphate instead of
calcium carbonate, can also be applied to concrete samples but this will have to be validated by
the laboratory. See Section 11.3 for steps validated for 90Sr in concrete samples.
11.4.1. Transfer each fused sample to a labeled 225-mL centrifuge tube, rinse
crucibles well with water, and transfer rinses to each tube.
11.4.2. Dilute to approximately 150 mL with water.
11.4.3. Pipet2mL 1.25M Ca(NO3)2 into each tube.
11.4.4. Add 1 mL 50-mg/mL iron carrier into each tube.
11.4.5. Add 5 mL 3.2M (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 HNOs and 5 mL of 2M aluminum nitrate into each tube,
cap tube and mix.
11.4.19. Transfer rinse solutions to labeled 50 mL centrifuge tubes and mix well
(shake or use vortex stirrer).
11.4.20. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.4.21. Transfer solutions to labeled beakers or new 50 mL tubes for further
processing.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.
..':.' Set aside for90 Sr analysis using Rapid Radiochemical Method for Total
Radiostrontium (Sr-90) In Building Materials for Environmental
Remediation Following Radiological Incidents (Reference 16.4).
11.5. Preconcentration of 226Ra from Hydroxide Matrix
11.5.1. Transfer each sample to a labeled 225 mL centrifuge tube, rinse crucibles
well with water, and transfer rinses to each tube.
11.5.2. Dilute to approximately 150 mL with water.
11.5.3. Add 10 mL of concentrated HC1 to each tube.
11.5.4. Cap and mix each tube well.
11.5.5. Pipet 0.5 mL of 1.25M Ca(NO3)2into each tube.
11.5.6. Add 25 mL of 2M Na2CO3 to each tube.
11.5.7. Cap tubes and mix.
11.5.8. Cool the 225-mL centrifuge tubes in an ice bath for -5-10 minutes.
11.5.9. Centrifuge tubes for 6 minutes at 3500 rpm.
11.5.10. Pour off the supernate, and discard to waste.
11.5.11. Pipet 10 mL 1.5M HC1 into each tube to dissolve precipitate. Cap and mix.
11.5.12. Transfer sample solution to a labeled 50-mL centrifuge tube.
11.5.13. Pipet lOmL 1.5MHC1 into each 225-mL tube to rinse. Cap and rinse well.
11.5.14. Transfer rinse solution to 50 mL-tube and mix well.
NOTE: Typically the HC1 added to dissolve the carbonate precipitate is sufficient to
acidify the sample. If the precipitate was unusually large and milky suspended solids
remain, indicating additional acid is needed, the pH can be checked to verify it is pH 1
or less. To acidify the pH <1,1 or 2 mL of concentrated hydrochloric acid may be added
to acidify the solution further and get it to clear. Undissolved solids may be more likely
to occur with brick samples. Tubes may be warmed in a water bath to help dissolve
samples.
11.5.15. If solids remain in the original 225 mL tubes, add 5 mL of 1.5MHC1 to each
tube containing solids, cap, and mix well. Centrifuge for 5 minutes and add
the supernate to the sample solution from step 11.5.14. Discard any
remaining solids.
11.5.16. Set aside for 226Ra analysis using Rapid Radiochemical Method for Radium-
226 in Building Materials for Environmental Remediation Following
Radiological Incidents (Reference 16.3).
12. Data Analysis and Calculations
12.1. Equations for determination of final result, combined standard uncertainty, and
radiochemical yield (if required) are found in the corresponding chemical separation
and analysis methods, with the project manager providing the units.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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:
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.
September 2014 39
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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
September 2014
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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
September 2014
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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
September 2014
44
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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
September 2014
45
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Appendix:
Rapid Technique for Milling and Homogenizing Concrete and Brick Samples
Al. Scope and Application
ALL Concrete or brick samples may be received as powder, core samples or other size
pieces or chunks. The goal is to obtain representative sample aliquants from
homogeneous amounts of sample.
A1.2. The ball mill method describes one approach for the rapid, gross preparation of
concrete or brick samples to yield representative 1-2-g aliquant for radiochemical
analysis of non-volatile radionuclides. The method addresses steps for splitting,
drying, and milling of 50-2,000 g concrete or brick samples. The concrete or brick
sample must be reduced to pieces or fragments less than -25 mm in diameter prior
to using the ball mill. This can be done with a hydraulic press or mallet.
Al .3. The method is designed to be used as a preparatory step for the attached methods
for fusion of concrete or brick for 241Am, 2J9/240Pu, U, *Sr, and 226Ra. It may also
be applied to other matrices whose physical form is amenable to pulverization in
the ball mill.
Al .4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 2 kg of concrete or brick can be processed.
Al .5. For smaller amounts of concrete or brick samples, a drill with masonry bit can be
used in a lab hood inside a plastic bag to collect the powder that results.
A2. Summary of Methods
A2.1. This method uses only disposable equipment to contact the sample, minimizing the
risk of contamination and cross-contamination and eliminating concerns about
adequate cleaning of equipment.
A2.2. Extraneous material, such as rocks or debris, may be removed prior to processing
the sample unless the project requires that they be processed as part of the sample.
NOTE: The sample mass is generally used for measuring the size of solid samples. The initial
process of acquiring a representative aliquant uses the volume of the sample, as the total
sample size is generally based on a certain volume of concrete or brick (e.g., 500 mL).
A2.3. The entire sample as received (after reducing fragment size to less than -25 mm
diameter) is split by coning and quartering until 75-150 mL of concrete or brick are
available for subsequent processing. If less than 450 mL of concrete or brick is
received, the entire sample is processed.
A2.4. The concrete or brick is transferred to a paint can or equivalent. Percent solids are
determined, if required, by drying in a drying oven. A mallet and plastic bag or
hydraulic press may be needed to break up larger pieces.
September 2014 46
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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 H-inch carbide bit is recommended. The
holes should be drilled in such a way as to obtain representative powdered samples.
The drill bit should be cleaned between uses on different samples using soap and
water.
A3. Definitions, Abbreviations, and Acronyms
A3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Paniculate matter in a
sample of any matrix where a high concentration of radioactive material is
contained in a tiny particle (um range).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
(Reference A16.3).
A3.3. ASTM C999 Standard Practice for Soil Sample Preparation for the Determination
of Radionuclides (Reference A16.4).
A4. Interferences
A4.1. Radi ol ogi cal Interference s
A4.1.1. Coning and quartering provides a mechanism for rapidly decreasing the
overall size of the sample that must be processed while optimizing the
representativeness of the subsampling process. By decreasing the time and
effort needed to prepare the sample for subsequent processing, sample
throughput can be significantly improved. Openly handling large amounts
of highly contaminated materials, however, even within the containment
provided by a fume hood, may pose an unacceptable risk of inhalation of
airborne contamination and exposure to laboratory personnel from
radioactive or other hazardous materials. Similarly, it may unacceptably
increase the risk of contamination of the laboratory.
A4.1.2. In such cases, the coning and quartering process may be eliminated in lieu
of processing the entire sample. The time needed to dry the sample will
increase significantly, and the container size and the number and size of
grinding media used will need to be adjusted to optimize the milling
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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 urn or
smaller filter may be needed following subsequent fusion to
identify the presence of smaller DRPs.
A5.2.3.2. Care should be taken to provide suitable containment for
filter media used in the pretreatment of samples that may
have DRPs, because the particles become highly statically
charged as they dry out and will "jump" to other surfaces
potentially creating contamination-control issues.
A5.3. Method-Specific Non-Radiological Hazards
A5.3.1. This method employs a mechanical shaker and should be evaluated for
personnel hazards associated with the high kinetic energy associated with
the milling process.
A5.3.2. This method employs a mechanical shaker and involves vigorous agitation
of steel or ceramic balls inside steel cans. The process should be evaluated
to determine whether hearing protection is needed to protect the hearing of
personnel present in the area in which the apparatus is operated.
A6. Equipment and supplies
A6.1. Balance, top-loading, range to accommodate sample size encountered, readability
to ±1%.
A6.2. Drying oven, at 110 ± 10 °C.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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.l
A10.2.2.1. Carefully pour the sample onto the paper.
Al0.2.2.2. Remove extraneous material, such as rocks or debris,
unless the project requires that such material be processed
as part of the sample. Continue with Step A10.2.5.
A10.2.3. If the sample volume is greater than -450 mL, carefully pour the entire
sample into a cone onto the paper.
Remove extraneous material, such as rocks or debris unless the project
requires that such material be processed as part of the sample.
A10.2.4. If levels of gross activity in the sample permit, the sample is split at
least twice using the coning and quartering steps that follow.
NOTE: Unused quarters are considered representative of the original sample and
may be reserved for additional testing. The process should be carried out
expediently to minimize loss of volatile components in the sample, especially if
volatile components or percent solids are to be determined.
A10.2.4.1. Spread the material into a flat circular cake of soil using a
tongue depressor or other suitable disposable implement.
Divide the cake radially and return two opposing quarters
to the original sample container.
Al0.2.4.2. Reshape the remaining two quarters into a smaller cone,
and repeat Step A10.2.2.1 until the total volume of the
remaining material is approximately 100-150 mL.
NOTE: Tare the can and lid together. Do not apply an adhesive
label. Rather, label the can with permanent marker since the can
1 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
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.
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
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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 subsampling for subsequent analyses.
A10.9. Sample fines may be stored in, and aliquanted directly from, the container used
for drying and pulverization.
Al 1 . Calibration and Standardization
Al 1 . 1 . Balances used shall be calibrated using National Institute of Standards and
Technology (NIST)-traceable weights according to the process defined by the
laboratory's quality manual.
A12. Data Analysis and Calculations
A12.1. The percent solids (dry-to-as-received mass ratio) for each sample is calculated
from data obtained during the preparation of the sample as follows:
% Solids = Md-y~Mtare
Masrec-Mtare
Where:
= mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
Mas rec = mass of sample as received + labeled can + lid (g)
A12.2. If requested, convert the equivalent mass of sample, as received, to dry mass. Dry
mass is calculated from a measurement of the total as received mass of the sample
received as follows:
T^ c i ^ • i . A*
Dry SampleEquivalent = Mt
% Solids
otal.asrec
x
Where:
Mtotai-as rec. = total mass of sample, as received (g)
A 12. 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.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
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
Al5.1. All radioactive and other regulated wastes shall be handled according to
prevailing regulations.
A16. References
A16.1. International Union of Pure and Applied Chemistry (IUPAC). 1997. Compendium
of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D.
McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford. XML
on-line corrected version: http://goldbook.iupac.org/C01265.html. (2006) created
by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. Last update: 2010-
12-22.
A16.2. ALS Laboratories, Fort Collins, SOP 736.
A16.3. MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
2004. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,
NTIS PB2004-105421, July. Available at: www.epa.gov/radiation/marlap.
A16.4. ASTM C 999-05, "Standard Practice for Soil Sample Preparation for the
Determination of Radionuclides," Volume 12.01, ASTM, 2005.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
Attachment III:
Rapid Radiochemical Method for Isotopic Uranium in Building Materials for
Environmental Remediation Following Radiological Incidents
1. Scope and Application
1.1. The method will be applicable to samples where contamination is either from known
or unknown origins.
1.2. The method is specific for 238U, 235U, and 234U in building materials such as concrete
and brick.
1.3. The method uses rapid radiochemical separation techniques for determining alpha-
emitting uranium isotopes in building material samples following a nuclear or
radiological incident.
OQQ 9^S
1.4. The method is capable of achieving a required method uncertainty for U, U, and
234U of 1.9 pCi/g at an analytical action level (AAL) of 14.7 pCi/g, a required relative
method uncertainty (cpMn) of 13% above the AAL and a MDC of-0.50 pCi/g. To
attain the required method uncertainty at the AAL, a sample weight of approximately
1 g and count time of at least 3 to 4 hours are recommended. The sample turnaround
time and throughput may vary based on additional project measurement quality
objectives (MQOs), the time for analysis of the sample test source (STS), 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 (Reference
16.1).
1.5. The rapid isotopic uranium method was initially validated 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
(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 Appendix B). 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.
2. Summary of Method
2.1. This method is based on the use of extraction chromatography resins to isolate and
purify uranium isotopes by removing interfering radionuclides as well as other
components of the matrix in order to prepare the uranium fraction for counting by
alpha spectrometry. The method utilizes vacuum-assisted flow to improve the speed
September 2014 55
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
of the separations. The sample was fused using 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 (16.3) and then the uranium isotopes were removed from the
fusion matrix using iron hydroxide (Fe(OH)2 and lanthanum fluoride (LaF)
precipitation steps. U-232 tracer, added to the building materials sample, is used as a
yield monitor. The STS is prepared by microprecipitation with cerium fluoride
(CeF3). 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 decisionmaker to choose one of the
alternative actions.
3.3. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is contained
in a tiny particle (|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 Isotopic Uranium in Building Materials
4. Interferences
4.1. Spectral Overlap: Alpha-emitting radionuclides (or their short-lived decay progeny)
with peaks at energies that cannot be adequately resolved from the tracer or analyte
(e.g., 210Po (5.304 MeV), 228Th (5.423 MeV, 5.340 MeV), and 243Am (5.275 MeV,
5.233 MeV)) must be chemically separated to enable radionuclide-specific
measurements. This method separates these radionuclides effectively. The individual
detector's alpha energy resolution and the quality of the final precipitate that is counted
will determine the significance of peak overlap.
910
4.1.1. Polonium-210 ( Po), in particular, must be effectively removed from the
uranium fraction because it cannot be distinguished from 232U. Its presence
can result in high tracer recoveries and negatively biased U isotopic results.
4.1.2. Thorium (Th) isotopes are removed on TEVA® Resin. Any residual Th that
makes it to TRU Resin is removed with a rinse step. If extremely high levels
of Th isotopes are still present, the 4M HC1-0.2M-0.002M TiCl3 rinse
volume may be increased for difficult samples containing high levels of
interferences.
4.1.3. Neptunium-237 (237Np) (4.78 MeV) can interfere with 234U (4.77 MeV)
analyses due to overlapping alpha energies so 237Np must be effectively
removed.
4.1.4. It may be possible, if very high levels of interferences are present on the
final STS filter, to redissolve the radionuclides in 15 mL of warm 3M
HNO3-0.25M boric acid and perform the column separation again without
digesting another concrete aliquant. This reprocessing step to remove
extremely high levels of Th isotopes, for example, will have to be validated
by the laboratory.
4.1.5. Higher levels of uranium may require more cerium (Ce) to quantitatively
precipitate uranium (150-200 u.L [75-100 u.g] instead of 100 u.L (50 u.g) if
238 U is 10 pCi or more in final purified fraction). There is a slight alpha
peak broadening but complete precipitation is more probable. When very
high activities are suspected, additional Ce should be added and/or aliquant
size reduced.
4.1.6. Iron (Fe) present in samples and used to preconcentrate samples after the
fusion procedure can interfere slightly with U retention on TRU Resin. The
CeF3 precipitation step typically removes Fe effectively.
4.1.7. Vacuum box lid and holes must be cleaned frequently to prevent cross-
contamination of samples.
4.2. Non-Radiological: Anions such as fluoride and phosphate that complex uranium ions
may cause lower chemical yields. Aluminum that is added in the column load
solution complexes fluoride present as well as any residual phosphate that may be
present. Lanthanum, added to preconcentrate uranium from the sample matrix as LaF,
can have a slight adverse impact on uranium retention on TRU Resin, but this impact
is minimal with the level added. Fe3+ can also have an adverse impact on uranium
retention on TRU Resin, but the residual Fe levels after preconcentration steps are
acceptable.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
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.
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 reservoir
columns (empty luer tip, CC-10-M) plus 12 mL reservoirs (CC-06-M), Image
Molding, Denver, CO, or equivalent.
6.4. Centrifuge able to accommodate 225 mL tubes.
6.5. Centrifuge tubes, 50 mL and 225 mL capacity.
6.6. Filter manifold apparatus with 25 mm-diameter polysulfone. A single use
(disposable) filter funnel/filter combination may be used to avoid cross-
contamination.
6.7. 25 mm polypropylene filter, 0.1 um pore size, or equivalent.
6.8. Stainless steel planchets or other adhesive sample mounts (Ex. Environmental
Express, Inc., P/N R2200) able to hold the 25 mm filter.
6.9. Tweezers.
6.10. 100 uL, 200 and 500 pipette or equivalent and appropriate plastic tips.
6.11. 1-10 mL electronic pipet or manual equivalent.
6.12. Vacuum pump or laboratory vacuum system.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
6.13. Vacuum box tips, white inner, Eichrom part number AC-1000-IT, or PFA 5/32"x 1/4"
heavy-wall tubing connectors, natural, Ref P/N 00070EE, cut to 1 inch, Cole Farmer
Inc., or equivalent.
6.14. Vacuum box tips, yellow outer, Eichrom part number AC-1000-OT, or equivalent.
6.15. Vacuum box, such as Eichrom part number AC-24-BOX, or equivalent.
6.16. Vortex mixer.
6.17. Miscellaneous laboratory ware of plastic or glass; 250 and 500 mL capacities.
6.18. 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).
7.2.1. Aluminum nitrate solution (2M): Add 750 g of aluminum nitrate (A1(NO3)3'
9H2O) to -700 mL of water and dilute to 1 L with water. Low-levels of
uranium are typically present in A1(NO3)3 solution.
NOTE: For low-level measurements, trace uranium contamination in the aluminum
nitrate may be removed by passing ~250 mL of 2M A1(NO3)3 through a large column
containing ~7 mL of UTEVA® Resin or TRU Resin (Eichrom Technologies, Lisle, II)
that has been previously preconditioned with ~5 mL of 3M HNO3.
7.3. Ascorbic acid (1.5M): 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. Ammonium bioxalate ((ML;)2C2O4' H2O)
7.4.1. Ammonium bioxalate solution (0.1M): Dissolve 6.3 g of oxalic acid and 7.1
g of ammonium oxalate in 900 mL of water, filter, and dilute to 1 liter with
water.
7.5. Barium chloride (~0.45%): Dissolve 4.5 grams of barium chloride (BaCb' H^O) in
500 mL of water and dilute to 1000 mL with water.
7.6. Cerium (III) nitrate hexahydrate (Ce(NO3)3' 6 H2O)
7.6.1. Cerium 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.
7.6.2. Ethanol, reagent (C2H5OH), available commercially (or mix 95 mL 100 %
ethanol and 5 mL water).
7.7. Ferric nitrate solution (5 mg/mL): Dissolve 18.1 g of ferric nitrate in 300 mL water
and dilute to 500 mL with water.
7.8. Hydrochloric acid (12 M): Concentrated HC1, available commercially.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
7.8.1. Hydrochloric acid (4 M): Add 333 mL of concentrated HC1 to 500 mL of
water and dilute with water to 1 L.
7.8.2. Hydrochloric acid (0.25 M): 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.
7.9.1. Hydrochloric acid (4M): Hydrofluoric acid (0.2M) solution: Add 7.14 mL of
concentrated HF to 1000 mL of 4M HC1 and mix well.
7.9.2. Hydrochloric acid (4M): Hydrofluoric acid (0.2M) - 0.002M TiCl3 solution:
Add 0.2 mL of 10 percent by mass (wt%) solution TiCl3 per 100 mL;
prepare fresh daily as needed.
7.10. Hydrogen peroxide, ^262), 30%, available commercially.
7.11. Nitric acid (16 M): Concentrated HNO3, available commercially.
7.11.1. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water
and dilute to 1 L with water.
7.11.2. Nitric acid (8M): Add 510 mL of concentrated HNO3 to 300 mL of water
and dilute to 1 L with water.
7.12. Oxalic acid (FL^C^' 2 H2O), available commercially.
7.13. Potassium sulfate (K^SO/i), available commercially.
7.14. Sodium nitrite (NaNC^) solution (3.5M): Dissolve 6.1 g of sodium nitrite (NaNC^) in
25 mL of water. Prepare fresh daily.
7.15. Sulfamic acid (H3NSO3) solution (1.5M): Dissolve 72.7 g of sulfamic acid (H3NSO3)
in 400 mL of water and dilute to 500 mL with water.
7.16. TEVA® Resin - 2 mL cartridge, 50 to 100 |j,m mesh size, Eichrom part number TE-
R50-S and TE-R200-S, or equivalent.
7.17. TRU Resin - 2 mL cartridge, 50 to 100 |j,m mesh size, Eichrom part number TR-R50-
S and TR-R200-S, or equivalent.
7.18. Titanium (III) chloride solution (TiCl3), 10 wt% solution in 20-30 wt% hydrochloric
acid.
7.19. Sodium sulfate (^2864), available commercially.
7.20. Sulfuric acid (H2SO4), 18M concentrated, available commercially.
7.21. Uranium-232 tracer solution: Add 15-25 dpm of 232U 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. Self-cleaning tracer to remove the 228Th progeny from the 232U tracer as described in
Appendix A reduces the chance of 228Th contamination in the purified uranium fraction, which
could overlap with the 232U tracer peak if levels are high enough.
Sample Collection, Preservation, and Storage
Not Applicable.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
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 fusion procedure.
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 STS with tracer peak full width at
half maximum (FWHM) of less than 0.1 MeV. STSs 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 16.5).
10.3. Continuing Instrument Quality Control Testing shall be performed according to
ASTM Standard Practice D7282, Sections 20, 21, and 24 (Reference 16.5).
11. Procedure
11.1. Initial Sample Preparation for Uranium
11.1.1. U isotopes may be preconcentrated from building material samples using the
procedure Rapid Method for Sodium Hydroxide Fusion of Concrete and
Brick Matrices Prior to Americium, Plutonium, Strontium, Radium, and
Uranium Analyses (Reference 16.3), which fuses the samples using rapid
NaOH fusion followed by Fe(OH)2 and LaF precipitation to preconcentrate
U isotopes from the hydroxide matrix.l
1 The fusion procedure provides a column load solution for each sample (consisting of 5mL 3M HNO3-0.25M
H3BO3+ 6mL HNO3+7 mL 2M A1(NO3)3 + 3mL 3M HNO3), ready for valence adjustment and column separation on
TEVA Resin.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
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.
NOTE: It should be noted that the LaF3 matrix removal step in the fusion procedure
(Reference 16.3) following the sodium hydroxide fusion removes Fe to minimal levels
that will not interfere with TRU Resin as Fe3+. If this column method is used on solid
samples (soil, etc.) with high Fe levels without the LaF3 matrix removal, there may be
a significant adverse impact on U retention on TRU Resin.
11.2. Rapid Uranium Separation using TEVA® and TRU Resins
11.2.1. Perform valence adjustment on column load solutions prepared from the
fusion procedure for building materials (Reference 16.3).
NOTE: If a smaller volume was taken instead of the total load solutions, this smaller
volume should be diluted to ~15 mL with 3M HNO3 before proceeding with the
valence adjustment.
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: Pu, if present, is valence adjusted to Pu4+ to ensure retention and
removal on TEVA® Resin.
11.2.1.2. Add 0.5 mL of 1.5M sulfamic acid to each solution. Swirl to
mix.
11.2.1.3. Add 0.1 mL of 5 mg/mL ferric nitrate solution.
NOTE: Ferric ions are added and are reduced to ferrous ions by ascorbic
acid to enhance valence reduction of Pu isotopes and 237Np.
11.2.1.4. Add 1.25 mL of 1.5M ascorbic acid to each solution, swirling to
mix. Wait 3 minutes.
11.2.1.5. Add 1 mL of 3.5MNaNO2 to each sample, swirling to mix.
NOTE: A small amount of brown fumes result from nitrite reaction with
sulfamic acid. The solution should clear with swirling and not remain
dark If the solution does not clear (is still dark) an additional small
volume of sodium nitrite may be added to clear the solution.
11.2.1.6. Add 1.5 mL of concentrated HNOs to each sample, swirling to
mix.
11.2.2. Set up TEVA® and TRU cartridges on the vacuum box system
NOTE: This section deals with a commercially available vacuum box system. Other
vacuum systems developed by individual laboratories may be substituted here as long
as the laboratory has provided guidance to analysts in their use. The cartridges may
be set up and conditioned with nitric acid so that they are ready for column loading
just prior to completion of the valence adjustment steps.
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
onto the vacuum box system.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
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. Place a TEVA cartridge above a TRU cartridge and place on
vacuum box.
11.2.2.4. Place reservoirs into top of stacked TEVA®+TRU Resin
cartridges, inserting reservoir into top of 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 HNCb to the column reservoir to precondition
the TEVA® and TRU 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 ~2-4 mL/min for rinse
solutions.
11.2.3. TEVA® and TRU Resin Separation
11.2.3.1. Transfer each solution from Step 11.2.1.5 into the appropriate
reservoir by pouring or by using a plastic transfer pipette.
11.2.3.2. Allow solution to pass through the stacked TEVA + TRU
cartridges at a flow rate of ~1 mL/min.
11.2.3.3. Add 3 mL of 3M HNO3 to each tube (from Step 11.2.1.5) as a
rinse and transfer each solution into the appropriate reservoir (the
flow rate can be adjusted to ~1 to 2 mL/min).
11.2.3.4. Add 10 mL of 3M HNOs into each reservoir to rinse column
(flow rate ~2 mL/min).
11.2.3.5. Turn off vacuum, discard rinse solutions. Remove and discard
the TEVA® cartridges.
11.2.3.6. To the TRU Resin cartridge only, add 15 mL of 4M HC1-0.2M
HF-0.002M TiCb into each reservoir as second column rinse
(flow rate -1-2 mL/min) to remove Am, Th and Po.
11.2.3.7. Add 5 mL of 8M HNCbinto each reservoir as second column
rinse (flow rate -1-2 mL/min) to reduce bleed-off of organic
extractant.
11.2.3.8. Ensure that clean, labeled plastic 50 mL centrifuge tubes are
placed in the tube rack under each cartridge.
NOTE: For maximum removal of interferences during elution, also
change reservoirs and connector tips prior to U elution.
11.2.3.9. Add 15 mL of 0.1M ammonium bioxalate (NH4HC2O4) to elute
the uranium from each cartridge, reducing the flow rate to -1
mL/min.
11.2.3.10. Set uranium fraction in the plastic centrifuge tube aside for
cerium fluoride coprecipitation, Step 11.3.
11.2.3.11. Discard the TRU cartridge.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
11.3. Preparation of the STS
NOTE: Additional Ce (200 jiL) is typically needed if the uranium is greater than 10-15 pCi in
the final purified solution to ensure complete precipitation and prevent lower chemical yields. If
it is not known that the 238U is < 10-15 pCi in the final purified solution, 200 uL Ce (100 jig Ce)
should be added instead of 100 uL Ce. If it is not known that the 238U is < 10-15 pCi in the final
purified solution, 200 uL Ce (100 jig Ce) should be added instead of 100 uL Ce.
11.3.1. Pipet 100 jiL of the Ce carrier solution into each centrifuge tube.
11.3.2. Pipet 0.5 mL 10 wt% TiCb into each tube to reduce uranium to U4+.
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. Setup a filter apparatus to accommodate aO.l 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 filter 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 mounting disk.
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 STS 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 Section 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):
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
12.1.1. The activity concentration of an analyte and its combined standard
uncertainty are calculated using the following equations:
Wa X_K. XLJ X / ST^
t a a (]_)
and
where:
AC& = activity concentration of the analyte at time of count, in
picocuries per gram (pCi/g)
At = activity of the tracer added to the sample aliquant at its
reference date/time (pCi)
R& = net count rate of the analyte in the defined region of
interest (ROI), in counts per second
Rt = net count rate of the tracer in the defined ROI, in counts
per second
Wa = weight of the sample aliquant (g)
A = correction factor for decay of the tracer from its reference
date and time to the midpoint of the counting period
A = 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)
/t = probability of a emission in the defined ROI per decay of
the tracer (Table 17.1)
/a = probability of a emission in the defined ROI per decay of
the analyte (Table 17.1)
uc(ACa) = combined standard uncertainty of the activity
concentration of the analyte (pCi/L)
u(At) = standard uncertainty of the activity of the tracer added to
the sample (pCi)
u(Rn) = standard uncertainty of the net count rate of the analyte
u(Rt) = standard uncertainty of the net count rate of the tracer
u(Wa) = standard uncertainty of the weight of sample aliquant (g)
NOTES: The uncertainties of the decay-correction factors and of the
probability of decay factors are assumed to be negligible.
The equation for the combined standard uncertainty (uc(ACa)) calculation is
arranged to eliminate the possibility of dividing by zero if Ra = 0.
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
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
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:
^_^
'• '' (3)
and
(4)
where:
RK = 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
r\
analyte, in counts per second
If the radiochemical yield of the tracer is requested, the yield and its
combined standard uncertainty can be calculated using the following
equations:
p
RY =
and
0.037x4 xDt x/t
Uc(RY) = RYx
where:
RY = 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)
Dt = correction 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)
e = detector efficiency, expressed as a fraction
uc(RY) = combined standard uncertainty of the radiochemical yield
2 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 Isotopic Uranium in Building Materials
standard uncertainty of the net count rate of the tracer, in
counts per second
standard uncertainty of the activity of the tracer added to
the sample (pCi)
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: 3
L =
0.4:
-1 +0.677;
N
^ +1.645x l(Rbatb +0.4)x^
*b) V tb
4 x A x it
tsxWaxRtxDax!a
(7)
MDC =
2.71x In--?- +3.29x
f J
t xl+
4 x Dt x It
txWxRxDxI
(8)
where:
Rba = 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 sample aliquant, sample preparation and digestion
should take ~3 h.
3 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, a constant in equation 20.54 (the z value of 1.645 reflects the 1-a and l-(3 quantiles of the normal
distribution when a=P=0.05). For methods with very low numbers of counts, these expressions provide better
estimates than do the traditional formulas for the critical level concentration and MDC.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
13.2.2. Purification and separation of the uranium 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 3 to 4 hour counting time should be sufficient to meet the MQOs listed in
Step 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 -9.5 to 10.5 hours 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 uranium fraction.
15. Waste Management
15.1. Types of waste generated per sample analyzed.
15.1.1. Approximately 55 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. Used resins and columns
should be considered radioactive waste and disposed of in accordance with
restriction provided in the facility's radioactive materials license and any
prevailing government restrictions.
15.1.4. TRU cartridge - ready for appropriate disposal. Used resins and columns
should be considered radioactive waste and disposed of in accordance with
restriction provided in the facility's radioactive materials license and any
prevailing government restrictions.
15.2. Evaluate waste streams according to disposal requirements by applicable regulations.
16. References
Cited References
16.1. U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for
Radiological Laboratories Participating in Incident Response Activities. Revision 0.
Office of Air and Radiation, Washington, DC. EPA 402-R-09-006, June. Available
at: www.epa.gov/narel/incident_guides.html.
16.2. Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP).
2004. EPA 402-B-04-001A, July. Volume I, Chapters 6, 7, 20, Glossary; Volume II
and Volume III, Appendix G. Available at:
www.epa.gov/radiation/marlap/index.html.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
16.3. U.S. Environmental Protection Agency (EPA). 2014. Rapid Method for Sodium
Hydroxide Fusion of Concrete and Brick Matrices Prior to Americium, Plutonium,
Strontium, Radium, and Uranium Analyses. Revision 0, EPA 402-R-14-004. Office of
Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.4. ASTM Dl 193, "Standard Specification for Reagent Water," ASTM Book of
Standards 11.02, current version, ASTM International, West Conshohocken, PA.
16.5. ASTM D7282 "Standard Practice for Set-up, Calibration, and Quality Control of
Instruments Used for Radioactivity Measurements," ASTM Book of Standards 11.02,
current version, ASTM International, West Conshohocken, PA.
16.6. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Americium-241 in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R-14-007. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
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-R-14-006. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.8. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Radium-226 in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R-14-002. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.9. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Total Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents. Revision 0, EPA 402-R-14-001.
Office of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.10. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Isotopic Uranium in Building Materials for Environmental Remediation
Following Radiological Incidents. Revision 0, EPA 402-R-14-005. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
Other References
16.11. Maxwell, S., Culligan, B. andNoyes, G. 2010. Rapid method for actinides in
emergency soil samples, Radiochimica Acta. 98(12): 793-800.
16.12. Maxwell, S., Culligan, B., Kelsey-Wall, A. and Shaw, P. 2011. "Rapid Radiochemical
Method for Actinides in Emergency Concrete and Brick Samples," Analytica
ChimicaActa. 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).
September 2014 69
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
17. Tables, Diagrams, Flow Charts, and Validation Data
17.1. Tables
Table 17.1 - Decay and Radiation Data
Nuclide
238U
235U
234U
232U
Half-Life
(Years)
4.468xl09
7.038xl08
2.457xl05
68.9
'k
(s-1)
4.916xlO~18
3.121xlO~17
8.940xl(T14
3.19xlO~10
Abundance
0.79
0.21
0.050
0.042
0.0170
0.0070
0.0210
0.55
0.170
0.7138
0.2842
0.002
0.6815
0.3155
a Energy
(MeV)
4.198
4.151
4.596
4.556
4.502
4.435
4.414
4.398
4.366
4.775
4.722
4.604
5.320
5.263
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
Uranium Spectrum
91
82
73
64
~ 55
I »
8 37;
a 28
I 19
£ 10
i i i
i i ..
2362 2761 3164 3570 3SpO
Energy (keV)
5659 6089 6522 6959 7400
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
17.4. Decay Scheme: Ingrowth is not generally a large concern with this analysis unless
one is running sequential analysis for uranium and plutonium with 236Pu tracer (due to
9-f9 99 R
ingrowth of U tracer) or sequential analyses for uranium and thorium (due to Th
tracer ingrowth in the 232U tracer).
3.3x104y 7.04x10s y
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
17.5. Flowchart
Separation Scheme and Timeline for Determination of
Uranium Isotopes in Building Materials Samples
Elapsed Time
Rapid Fusion (See Separate Procedure)
1. Add 232U tracer and fuse with NaOH
2. Fe/Ti hydroxide then La/Ca fluoride precipitations
3. Dissolve in of 3M HNO3-0.25M H3BO3, 7M HNO3, 2M
AI(NO3)3i andSM HNO3 (column load solution)
Adjust Pu to Pu4+ for removal on TEVA
(Step 11.2.1)
1. Add sulfamic acid, Fe and ascorbic acid
2. Wait 3 minutes
3. Add sodium nitrite
Vacuum Box Setup (Step 11.2.2)
1. Place TEVA + TRU cartridges on
box
2. Condition column with 5 ml 3M
HNO3 @ 1 mL/min
Discard load and
rinse solutions and
TEVA cartridges
(Step 11.2.3.5)
Discard TRU
cartridge
(Step 11.2.3.11)
Discard filtrates
and rinses
(Step 11.3.1.15)
Load Sample to TEVA and TRU Cartridges
(Step 11.2.3.1)
1. Load sample @ 1 mL/min
2. Beaker/tube rinse: 3mL 3M HNO3 @ 1-2 mL/min
3. Column rinse: 10 mL 3M HNO3 @ 2 mL/min
U separation on TRU Resin (Step 11.2.3.6)
1. Column rinse: 15mL4-M HCI-0.2M HF-0.002-M TiCI3
@ 1-2 mL/min
2. Column rinse: 5 mL 8M HNO3 @ 1-2 mL/min
3. Elute U into new tubes with 15 mL 0.1M ammonium
bioxalate (5>~1 mL/min
Microprecipitation (Step 11.3)
1. Add 50 |jg Ce carrier
2. Add 0.5 mL 10 wt% TiCI3
3. Add 1 mL concentrated HF
4. Wait 15 min and filter
5. Place on mounting disks
6. Warm ~5 min under heat lamp
Count sample test source (STS)
by alpha spec for3-4 h or as
needed (Step 11.3.14)
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 Isotopic Uranium in Building Materials
Appendix A:
Preparation of Self-Cleaning 232U Tracer
NOTE: 228Th daughter is removed continually using barium sulfate precipitation to minimize 228Th when using
this tracer.
1. Add 45 g K2SO4, 20 g Na2SO4 and 20 mL cone. H2SO4 to a 1-L Erlenmeyer flask.
9^9
2. Pipet the volume prescribed from a U stock solution into the flask to prepare the
desired concentration of 232U tracer.
3. Heat solution on a hot plate on medium heat until the tracer solution is evaporated
and fumes of H2SO4 begins to form.
4. Heat until a thick sulfate solution forms with minimal fumes.
5. Remove flask from the hot plate with tongs and swirl flask until the sulfate fusion
cake forms.
6. Dissolve the fusion cake in 250 mL of water and 31.8 mL concentrated HNOs,
using heat as needed.
7. Add 3 mL 30% H2O2 to the flask. Swirl to mix.
8. With heating and stirring, add six 10-mL portions 0.45% BaCl2, waiting 1 minute
between each addition.
9. Remove flask from hotplate.
10. Cool flask to room temperature.
11. Transfer solution and solids to 1,000 mL volumetric flask. Rinse initial flask with
water and transfer rinse to the volumetric flask.
12. Dilute volume to 1000 mL with water.
13. Mix standard well.
14. Transfer standard with solids to a 1 L plastic bottle.
15. When volumes of this standard are transferred to smaller containers, make sure that
solids are transferred along with the liquid by swirling prior to transfer.
NOTE: The smaller bottles of 232U tracer used in the lab may be used with or without periodic shaking
and allowing the solids to settle. Tracer volumes should not be taken when volumes are low enough
such that suspended solids (containing 228Th) will also be pipetted. 228Th levels remain low with or
without shaking and either way is acceptable for this method, which contains Th removal steps. For
maximum Th removal, however, shaking and settling should be performed within 1 week of use. Ex. If
the tracer is also used for sequential work where U and Th separations are performed sequentially,
maximum 228Th removal is essential for accurate 228Th assay in samples.
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Rapid Radiochemical Method for Isotopic Uranium in Building Materials
Appendix B:
Example of Sequential Separation Using Am-241, Pu-238 + Pu-239/240, and Isotopic U in
Building Materials
241
238T
239/240T
This sequential combination of rapid procedures for Am, Pu + Pu, 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®
Add 3 ml_3M HNO3 beaker rinse.
Add 3 ml_3M HNO3 column rinse.
Split cartridges.
v
TEVA®
Rinse w/10mL3M HNO3
20 ml_ 9 M HCI (remove Th)
5mL3M HN03
DGA®
Rinse w/ 10 ml_ 0.1M HNO3
(remove U)
v
ElutePuw/20mL0.1M HCI -
0.05MHF-0.01MTiCI3
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
HNO3 + SmLO.OSM HNO3
(remove La)
Elute Am/Cm w/ 10 mL 0.25M
HCI
TRU®
Rinse w/15 mL4M HCI
0.2MHF-0.002MTiCI3
5mL8M HNO3
Elute Uw/ 15 mL 0.1M
V
Add0.5mL20%TiCI3
V
Add 50 |jg Ce to 1 mL 49% HF.
Filter and count by alpha spectrometry.
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Validation of Rapid Radiochemical Method for Uranium in Brick
Attachment IV:
Composition of Brick Used for Spiking in this Study
Metals by ICP-AES [4]
Silicon Dioxide
Aluminum
Barium
Calcium
Iron
Magnesium
Potassium
Sodium
Titanium
Manganese
Strontium
Uranium
Thorium
Non-Metals
Chloride
Sulfur
Phosphorus
Radionuclide
Uranium 238, 234
Plutonium 239/240
Americium 24 1
Strontium 90
Radium 226
Concentration (ppm) [11
721,700
78,700
400
1,600
40,000
4,600
15,300
1,500
4,400
600
100
<30
<30
—
5,600
1,500
Concentration (pCi/g) [2'3]
1.054 ±0.020, 1.102 ±0.021
-0.0003 ±0.0041
0.048 ±0.039
0.119± 0.077
1.025 ±0.027
NOTE: Wyoming Analytical Laboratories, Inc. of Golden, Colorado, performed the macro
analysis.
[1] Values below the reporting level are presented as less than (<) values.
No measurement uncertainty was reported with the elemental analysis values. Parts
per million (ppm).
[2] Reported values represent the average value of seven blank samples analyzed except
for 226Ra and U by NAREL. Ten blank brick samples were analyzed for 226Ra.
Sixteen blank brick samples were analyzed for the uranium isotopes.
[3] Reported uncertainty is the standard deviation of the results (k=l).
[4] ICP-AES=Inductively Coupled Plasma - Atomic Emission Spectrometry
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