www.epa.gov
April 2014
EPA 402-R14-006
Revision 0
Rapid Radiochemical Method for
Plutonium-238 and Plutonium-239/240
in Building Materials
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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Rapid Radiochemical Method for Plutonium-238 & Plutonium-239/240 in Building Materials
Revision History
Revision 0 | Original release. | 04-16-2014
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. It was prepared by Environmental
Management Support, Inc., of Silver Spring, Maryland, under contract EP-W-07-037, work assignments B-
41, 1-41, and 2-43, managed by David Carman and Dan Askren. This document has been reviewed in
accordance with U.S. Environmental Protection Agency (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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RAPID RADIOCHEMICAL METHOD FOR PmroNiUM-238 AND PLUTONiUM-239/240 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 238Pu and 239/240Pu in solid samples such as building
materials (concrete, brick, etc.).
1.3. The method uses rapid radiochemical separation techniques to determine alpha-
emitting plutonium isotopes in building material samples following a nuclear or
radiological incident.
OQQ 9/10
1.4. The method cannot distinguish between Pu and Pu and any results are reported
as the total activity of the two radionuclides.
1.5. The method is capable of achieving a required method uncertainty (WMR) for 238Pu or
239/24opu of o 25 pCi/g at an analytical action level of 1.89 pCi/g. To attain the stated
measurement quality objectives (MQOs) (see Sections 9.3 and 9.4), 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 MQOs,
the time for analysis of the sample test source, and initial sample weight/volume. The
method must be validated prior to use following the protocols provided in Method
Validation Guide for Qualifying Methods Used by Radiological Laboratories
Participating in Incident Response Activities (EPA 2009, Reference 16.1).
1.6. The rapid plutonium method was evaluated following the guidance presented for
"Level E Method Validation: Adapted or Newly Developed Methods, Including
Rapid Methods" in Method Validation Guide for Qualifying Methods Used by
Radiological Laboratories Participating in Incident Response Activities (EPA 2009,
Reference 16.1) and Chapter 6 of Multi-Agency Radiological Laboratory Analytical
Protocols Manual (MARLAP 2004, Reference 16.2). Note that this method cannot
OQQ 9 AH
distinguish between Pu and Pu and only the sum of the activities of these two
isotopes can be determined.
1.7. Multi-radionuclide analysis using sequential separation may be possible using this
method in conjunction with other rapid methods (see appendix). Rapid methods can
also be used for routine analyses with appropriate (typically longer) count times.
1.8. Other solid samples such as soil can be digested using the rapid sodium hydroxide
fusion procedure as an alternative to other digestion techniques, but this procedure
will have to be validated by the laboratory.
1.9. This method may also be used in combination with the fusion procedure for RTG
(Radioisotope Thermoelectric Generator) materials in water and air filter samples.
1.10. This method has also been used to determine 237Np by using 236Pu tracer. This was
not tested, however, and would require validation by the laboratory.
1.11. Other methods for sample test source (STS) preparation, such or microprecipitation
with neodymium fluoride, may be used in lieu of the cerium fluoride microprecipita-
tion, but any such substitution must be validated as described in Step 1.5.
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Rapid Radiochemical Method for Plutonium-238 & Plutonium-239/240 in Building Materials
1.12. Electroplating may not be used with the Pu strip solution containing titanium, which
interferes with electrodeposition. A reductant such as rongalite (sodium formaldehyde
sulfoxylate) may be used instead of titanium if electrodeposition is used but this must
be validated by the laboratory.
2. Summary of Method
2.1. This method is based on the use of TEVA® Resin (Aliquat 336 extractant-coated
resin) to isolate and purify plutonium by removing interfering radionuclides as well as
other components of the matrix in order to prepare the plutonium fraction for
counting by alpha spectrometry. The method utilizes vacuum-assisted flow to
improve the speed of the separations. The sample may be fused 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),
with the plutonium isotopes then removed from the fusion matrix using iron
9A9 9^^
hydroxide and lanthanum fluoride precipitation steps. Pu or Pu tracer, added to
the building materials sample, is used as a yield monitor. The STS is prepared by
microprecipitation with CeFs. Standard laboratory protocol for the use of an alpha
spectrometer should be used when the sample is ready for counting.
3. Definitions, Abbreviations, and Acronyms
3.1. Analytical Protocol Specifications (APS). The output of a directed planning process
that contains the project's analytical data needs and requirements in an organized,
concise form.
3.2. Analytical Action Level (AAL). The term "analytical action level" is used to denote
the value of a quantity that will cause the decision-maker to choose one of the
alternative actions.
3.3. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is contained
in a tiny particle (|im range).
3.4. Multi-Agency Radiological Analytical Laboratory Protocols Manual (MARLAP)
provides guidance for the planning, implementation, and assessment phases of those
projects that require the laboratory analysis of radionuclides (Reference 16.2).
3.5. Measurement Quality Objective (MQO). MQOs are the analytical data requirements
of the data quality objectives and are project- or program-specific. They can be
quantitative or qualitative. MQOs serve as measurement performance criteria or
objectives of the analytical process.
3.6. Radiological Dispersal Device (RDD), i.e., a "dirty bomb." This device is an
unconventional weapon constructed to distribute radioactive material(s) into the
environment either by incorporating them into a conventional bomb or by using
sprays, canisters, or manual dispersal.
3.7. Required Method Uncertainty (WMR). 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.
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3.8. Relative Required Method Uncertainty ((PMR). The relative required method
uncertainty is the WMR divided by the AAL and is typically expressed as a percentage.
It is applicable above the AAL.
3.9. Sample Test Source (STS). This is the final form of the sample that is used for
nuclear counting. This form is usually specific for the nuclear counting technique
used in the method such as a solid deposited on a filter for alpha spectrometry
analysis.
4. Interferences
4.1. Radiological
4.1.1. Alpha-emitting radionuclides with irresolvable alpha energies, such as 238Pu
(5.50 MeV), 2ftAm (5.48 MeV), and 228Th (5.42 MeV) must be chemically
separated to enable measurement. This method separates these radionuclides
effectively. The significance of peak overlap will be determined by the
individual detector's alpha energy resolution characteristics and the quality
of the final precipitate that is counted.
4.1.2. Vacuum box lid and holes must be cleaned frequently to prevent cross-
contamination of samples.
4.2. Non-Radiological: Very high levels of anions such as phosphates may lead to lower
yields due to competition with active sites on the resin and/or complexation with
plutonium ions. Aluminum is added in the column load solution to complex
interfering anions such as fluoride and phosphate.
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.
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Rapid Radiochemical Method for Plutonium-238 & Plutonium-239/240 in Building Materials
6. Equipment and Supplies
6.1. Alpha spectrometer calibrated for use over the range of ~3.5-10 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.
25 mm polypropylene filter, 0.1 um pore size, or equivalent.
Graduated cylinders, 500 mL and 1000 mL.
Stainless steel planchets or other adhesive sample mounts (Ex. Environmental
Express, Inc. P/N R2200) able to hold the 25 mm filter.
6.10. Tweezers.
6.11. 100 uL, 200 uL, 500 uL and 1 mL pipets or equivalent and appropriate plastic tips.
6.12. 1-10 mL electronic pipet.
6.13. Vacuum pump or laboratory vacuum system.
6.14. Vacuum box tips, white inner, Eichrom part number AC-1000-IT, or PFA 5/32"x 1/4"
heavywall tubing connectors, natural, Ref P/N 00070EE, cut to 1 inch, Cole Farmer,
or equivalent.
6.15. Vacuum box tips, yellow outer, Eichrom part number AC-1000-OT, or equivalent.
6.16. Vacuum box, such as Eichrom part number AC-24-BOX, or equivalent.
6.17. Vortex mixer.
6.18. Miscellaneous laboratory ware of plastic or glass; 250 and 500 mL capacities.
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 16.5). 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 16.5).
7.2. Aluminum nitrate (A1(NO3)3' 9H2O)
7.2.1. Aluminum nitrate solution, 2M (AlfNTOs^): Add 750 g of aluminum nitrate
(A1(NO3)3' 9H2O) to -700 mL of water and dilute to 1 liter with water.
Low-levels of uranium are typically present in A1(NO3)3 solution.
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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. Cerium (III) nitrate hexahydrate (Ce(NO3)3' 6 H2O)
7.4.1. 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.
7.5. Ethanol, 100%: Anhydrous C2HsOH, available commercially, or mix 95 mL 100%
ethanol and 5 mL water.
7.6. Ferric nitrate solution (5 mg/mL): Dissolve 18.1 g of ferric nitrate (Fe(NO3)3 9 FbO)
in 300 mL water and dilute to 500 mL with water.
7.7. Hydrochloric acid (12M): Concentrated HC1, available commercially.
7.7.1. Hydrochloric acid (0.1M) - Hydrofluoric acid (0.05M) solution: Add 1.8 mL
concentrated HF and 8.3 mL concentrated HC1 to 500 mL of water. Dilute to
1 liter with water and mix well.
7.7.1.1. Hydrochloric acid (0.1M) - Hydrofluoric acid (0.05M) - TiCl3
(0.01 M): Add 1 mL of 10 wt% solution TiCl3 per 100 mL of
hydrochloric acid (0.1M) - hydrofluoric acid (0.05M) solution;
prepare fresh daily as needed.
7.7.2. Hydrochloric acid (9M): Add 750 mL of concentrated HC1 to 100 mL of
water and dilute to 1 L with water.
7.8. Hydrofluoric acid (28M): Concentrated HF, available commercially.
7.9. Hydrogen peroxide ^62), 30%, available commercially.
7.10. Nitric acid (16M): Concentrated HNO3, 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.
7.11. Plutonium-242 tracer solution: Add 15-25 dpm of 242Pu per aliquant, activity known
to at least 5% (combined standard uncertainty of no more than 5%).
NOTE: If it is suspected that 242Pu or 237Np may be present in the sample at levels significant to
interfere, 236Pu tracer is an acceptable substitute. The 242Pu (4.90 MeV) tracer peak may overlap
slightly with the alpha energy of 237Np (4.78 MeV).
7.12. Sodium nitrite (NaNO2).
7.12.1. Sodium nitrite solution, 3.5M (NaNO2): Dissolve 6.1 g of sodium nitrite in
25 mL of water. Prepare fresh daily.
7.13. Sulfamic acid (H3NSO3).
7.13.1. Sulfamic acid solution, 1.5M (H3NSO3): Dissolve 72.7 g of sulfamic acid in
400 mL of water and dilute to 500 mL with water.
7.14. TEVA® Resin - 2 mL cartridge, 50 to 100 |j,m mesh size, Eichrom part number TE-
R50-S and TE-R200-S, or equivalent.
7.15. Titanium (III) chloride solution (TiCl3), 10 wt % solution in 20-30 wt% hydrochloric
acid.
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8. Sample Collection, Preservation, and Storage
Not Applicable.
9. Quality Control
9.1. Batch quality control results shall be evaluated and meet applicable Analytical
Protocol Specifications (APS) prior to release of unqualified data. In the absence of
project-defined APS or a project specific quality assurance project plan (QAPP), the
quality control sample acceptance criteria defined in the laboratory quality manual
and procedures shall be used to determine acceptable performance for this method.
9.1.1. A Laboratory Control Sample (LCS) shall be run with each batch of
samples. The concentration of the LCS should be at or near the action level
or level of interest for the project.
9.1.2. One method blank shall be run with each batch of samples. The laboratory
blank should consist of an acceptable simulant or empty crucible blank
processed through the fusion procedure (Reference 16.3).
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. This is typically not required.
9.2. The source preparation method should produce a sample test source that produces a
spectrum with the full width at half maximum (FWHM) of 0.01-0.1 MeV for each
peak in the spectrum. Precipitate reprocessing should be considered if this range of
FWHM cannot be achieved.
9.3. This method is capable of achieving a required method uncertainty (MMR) of 0.25
pCi/g at or below an action level of 1.89 pCi/g. This may be adjusted if the event
specific MQOs are different.
9.4. This method is capable of achieving a required relative method uncertainty (cpMn) of
13% above 1.89pCi/g. This may be adjusted if the event specific MQOs are different.
9.5. This method is capable of achieving a required minimum detectable concentration
(MDC)of0.20pCi/g.
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 10 MeV.
10.2. Calibrate each detector used to count samples according to ASTM Standard Practice
D7282, Section 18, "Alpha Spectrometry Instrument Calibrations" (Reference 16.4).
10.3. Continuing Instrument Quality Control Testing shall be performed according to
ASTM Standard Practice D7282, Sections 20, 21, and 24 (Reference 16.4).
11. Procedure
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11.1. Initial Sample Preparation for Plutonium
11.1.1. Pu 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 iron hydroxide and lanthanum fluoride
precipitation to preconcentrate Pu isotopes from the hydroxide matrix.1
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 HNCV
1M A1(NO3)3.
11.1.3. A smaller volume of the total load solution may be taken and analyzed as
needed for very high activity samples, with appropriate dilution factor
calculations applied.
11.2. Rapid Plutonium Separation using TEVA® Resin
NOTE: 237Np is separated along with Pu isotopes using this TEVA® Resin separation. 236Pu
has been used as a yield monitor so that237Np can be determined, but this was not tested as
part of the method validation testing.
11.2.1. Perform valence adjustment on column load solutions prepared in Rapid
Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior
to Americium, Plutonium, Strontium, Radium, and Uranium Analyses
(Reference 16.3).
11.2.1.1. If particles are observed suspended in the solution, centrifuge the
sample, collect the supernatant solution in small beaker and
discard the precipitate.
NOTE: If a smaller volume was taken instead of the total load solution, this smaller
volume should be diluted to ~15 mL with 3M HNO3 before proceeding with the
valence adjustment. The amounts of valence adjustment reagents may be adjusted
under certain conditions as needed, as long as adequate reduction to Pu+3 and
oxidation to Pu+4 is achieved.
11.2.1.2. Add 0.5 mL of 1.5M sulfamic acid to each solution. Swirl to
mix.
11.2.1.3. Add 0.2 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.
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 ImL 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.
11.2.2. Set up TEVA® cartridges on the vacuum box system
1 The fusion procedure provides a column load solution for each sample (consisting of 5 mL 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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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 on
the vacuum box system.
11.2.2.2. Place the yellow outer tips into all 24 openings of the lid of the
vacuum box. Fit in the inner white tip into each yellow tip.
11.2.2.3. For each sample solution, fit in the TEVA® cartridge on to the
inner white tip.
11.2.2.4. Place reservoirs on the top end of the TEVA cartridge.
11.2.2.5. Turn the vacuum on (building vacuum or pump) and ensure
proper fitting of the lid.
IMPORTANT: The unused openings on the vacuum box must be sealed
to have vacuum. Yellow caps (included with the vacuum box) can be used
to plug unused white tips to achieve good seal during the separation.
Alternately, plastic tape can be used to seal the unused lid holes as
needed.
11.2.2.6. Add 5 mL of 3M FDSTCb to the column reservoir to precondition
the TEVA® cartridges.
11.2.2.7. Adjust the vacuum to achieve a flow-rate of ~1 mL/min.
IMPORTANT: Unless otherwise specified in the procedure, use a flow
rate of ~ 1 mL/min for load and strip solutions and ~ 2-4 mL/min for
rinse solutions.
11.2.3. TEVA® Resin Separation
11.2.3.1. Transfer each sample solution from step 11.2.1.5 into the
appropriate reservoir. Allow solution to pass through the TEVA®
cartridge at a flow rate of ~1 mL/min.
11.2.3.2. Add 3 mL of 3M HNO3 to each beaker (from Step 11.2.1.4) as a
rinse and transfer each solution into the appropriate reservoir (the
flow rate can be adjusted to ~3 mL/min).
11.2.3.3. Add 10 mL of 3M FDSTOs into each reservoir to rinse column
(flow rate -3-4 mL/min).
11.2.3.4. Turn off vacuum and discard rinse solutions.
11.2.3.5. Add 10 mL of 3M FDSTCb into each reservoir to rinse column
(flow rate -3-4 mL/min).
11.2.3.6. Add 20 mL of 9M HC1 into each reservoir to remove any Th
isotopes present (flow rate -2-3 mL/min).
11.2.3.7. Add -3 mL of 3M FDSTOs into each reservoir to reduce bleed-off
of organic extraction during Pu strip step (flow rate -3 mL/min).
NOTE: The 3M HNO3 added reduces extractant bleedoff that can occur
with strong HC1 and may improves alpha peak resolution.
11.2.3.8. Turn off vacuum and discard rinse solutions.
11.2.3.9. Ensure that clean, labeled plastic 50 mL centrifuge tubes are
placed in the tube rack under each cartridge.
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NOTE: For maximum removal of interferences during elution, also
change reservoirs and connector tips prior to Pu elution.
11.2.3.10. Add 20 mL of 0.1MHCL-0.05MHF-0.01M TiCl3 solution to
elute plutonium from each cartridge, reducing the flow rate to
-1-2 mL/min.
11.2.3.11. Set plutonium fraction in the plastic centrifuge tube aside for
cerium fluoride coprecipitation, Step 11.3.
11.2.3.12. Discard the TEVA® cartridge.
11.3. Preparation of the Sample Test Source
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.
11.3.1. Pipet 100 jiL of the cerium carrier solution (0.5 mg Ce/mL) into each
centrifuge tube.
11.3.2. Pipet 0.5 mL 30 wt% H2O2 into each tube to prevent any residual uranium
ions from precipitating.
11.3.3. Pipet 1 mL of concentrated HF into each tube.
11.3.4. Cap the tube and mix. Allow solutions sit for -15 minutes before filtering.
11.3.5. 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, it is recommended that the filter be discarded and a fresh
one removed 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 3 to 5 minutes or more until it is
completely dry. Do not overheat.
11.3.14. Count filters for an appropriate period of time by alpha spectrometry.
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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
microprecipitation, 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. Equations for determination of final result, combined standard uncertainty and
radiochemical yield (if required):
The activity concentration of an analyte and its combined standard uncertainty are
calculated using the following equations:
WaxRtxDaxIa
and
where:
= activity concentration of the analyte at time of count, in picocuries
per gram(pCi/g)
A\ = activity of the tracer added to the sample aliquant at its reference
date/time (pCi)
Ra = net count rate of the analyte in the defined region of interest (RO I),
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
Z)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(ACz) = combined standard uncertainty of the activity concentration of the
analyte (pCi/L)
u(Ai) = standard uncertainty of the activity of the tracer added to the sample
(pCi)
u(Ra) = standard uncertainty of the net count rate of the analyte (s )
= standard uncertainty of the net count rate of the tracer (s^1)
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= standard uncertainty of the weight of sample aliquant (g)
NOTE: The uncertainties of the decay-correction factors and of the probability of decay factors
are assumed to be negligible.
NOTE: The equation for the combined standard uncertainty (uc(ACa)) calculation is arranged to
eliminate the possibility of dividing by zero if Ra = 0.
NOTE: The standard uncertainty of the activity of the tracer added to the sample shall be
calculated by propagating the standard uncertainty associated with the activity of the standard
reference material and any other significant sources of uncertainty such as those introduced
during the preparation of the tracer solution (e.g., weighing or dilution factors) and during the
process of adding the tracer to the sample.
12.1.1. The net count rate of an analyte or tracer and its standard uncertainty are
calculated using the following equations:
r r
^=7^--^
'. tb (3)
and
(4)
where:
Rx = net count rate of analyte or tracer, in counts per second
Cx = sample counts in the analyte or the tracer ROI
ts = sample count time (s)
Cbx = background counts in the same ROI as for x
t\, = background count time (s)
u(Rx) = standard uncertainty of the net count rate of tracer or
analyte, in counts per second2
If the radiochemical yield of the tracer is requested, the yield and its
combined standard uncertainty can be calculated using the following
equations:
RY =
and
0.037 xAtxDtx!txs
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 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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Uc(RY} = RY
where:
(6)
RY = radiochemical yield of the tracer, expressed as a
fraction
Rt = net count rate of the tracer, in counts per second
A\ = activity of the tracer added to the sample (pCi)
A = correction factor for decay of the tracer from its
reference date and time to the midpoint of the counting
period
/t = 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
u(Rt) = standard uncertainty of the net count rate of the tracer,
in counts per second
u(At) = standard uncertainty of the activity of the tracer added
to the sample (pCi)
u(e) = standard uncertainty of the detector efficiency
12. 1 .2. 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 x
^- +1.645 x l(Rbatb
ib) \
1 +
tsxWaxRtxDax!a
(7)
MDC = ^
where:
2
71x1
+ il + 3
tj
»xUxf, + i]
\ I *J_
x Ai
x Dt
x/t
(8)
3 The formulations for the critical level and minimum detectable concentration 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= (3=0.05). For methods with very low numbers of counts, these expressions provide better
estimates than do the traditional formulas for the critical level and MDC.
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Rbn = 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 (QC),
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.
13.2.2. Purification and separation of the plutonium fraction using cartridges and
vacuum box system should take -2.25 h.
13.2.3. The sample test source preparation step takes ~1 h.
13.2.4. A one-hour counting time should be sufficient to meet the MQOs listed in
9.3 and 9.4, assuming detector efficiency of 0.2-0.3, and radiochemical
yield of at least 0.5. A different counting time may be necessary to meet
these MQOs if any of the relevant parameters are significantly different.
13.2.5. Data should be ready for reduction -7.25 h after beginning of analysis,
depending on the MQOs. In order to meet the MQOs for the method
validation process, a counting time of four hours was required.
14. Pollution Prevention: The method utilizes small volume (2 mL) extraction chromatographic
resin columns. This approach leads to a significant reduction in the volumes of load, rinse
and strip solutions, as compared to classical methods using ion exchange resins to separate
and purify the plutonium fraction.
15. Waste Management
15.1. Types of waste generated per sample analyzed
15.1.1. Approximately 65 mL of acidic waste from loading and rinsing the
extraction column will be generated. These solutions may contain an
unknown quantity of radionuclides such as Am, U, and Th isotopes if
present in the sample originally.
15.1.2. Approximately 45 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.
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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 local restrictions.
15.2. Evaluate all 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.
16.2. Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP).
2004. EPA 402-B-1304 04-001 A, July. Volume I, Chapters 6, 7, 20, Glossary;
Volume II and Volume III, Appendix G. Available at:
www. epa. gov/radiation/marlap.
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-R14-004. Office of
Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.4. 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.
16.5. ASTM Dl 193, "Standard Specification for Reagent Water," 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-R14-007. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.7. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Pu-238 and Pu-239/240 in Building Materials for Environmental Remediation
Following Radiological Incidents. Revision 0, EPA 402-R14-006. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.8. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Radium-226 in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R14-002. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.9. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Total Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents. Revision 0, EPA 402-R14-001.
Office of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
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16.10. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Isotopic Uranium in Building Materials for Environmental Remediation
Following Radiological Incidents. Revision 0, EPA 402-R14-005. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
Other References
16.11. Maxwell, S., Culligan, B. 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,"
AnalyticaChimicaActa. 701(1): 112-8.
16.13. VBS01, Rev.1.3, "Setup and Operation Instructions for Eichrom's Vacuum Box
System (VBS)," Eichrom Technologies, Inc., Lisle, Illinois (January 2004).
17. Tables, Diagrams, Flow Charts, and Validation Data
17.1. Tables
Table 17.1 Alpha Particle Energies and Abundances of Importance
Nuclide
238Pu
239/240Pu(Total)[3]
239Pu
240Pu
242pu
Half-Life
(Years)
87.7
2.411xl04
2.411xl04
6.561xl03
3.735xl05
>,
(s")
2.50xl(T10
9.110xl(T13
9.110xl(T13
3.348xl(T12
5.881xl(T14
Emission
Probability
(Abundance)'21
0.7091
0.2898
0.9986
0.7077
0.1711
0.1194
0.7280
0.2710
0.7649
0.2348
a Energy
(MeV)
5.499
5.456
(All at same peak)
5.157
5.144
5.105
5.168
5.124
4.902
4.858
[1] Only the most abundant particle energies and abundances have been noted here.
[2] Unless individual plutonium isotopes are present, the alpha emissions for 239/240pu or separately for 238Pu, should
use an abundance factor of 1.0.
[3] Half-life and A, are based on 239Pu.
17.2. Ingrowth Curves and Ingrowth Factors
This section intentionally left blank
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17.3, Spectrum from a Processed Sample
Plutonium Spectrum
Ill SI 5 i II i
II! i ill! i
«r
55!
4it
-, 3?
E «.
3 »
7.
1
2358 275? 3160 3Sfi? 3879
k
j
481
1
J
S!
X
1666
mm ess
:'!i,«
7421
17.4. Decay Scheme
Plutonium Decay Scheme
234|J H
2,48x10"
87 7 y
r
341X101 y
23SU
7.0*x10» y
8,56x10J y
236y
3.74x10' y
23SU k-
a
4.47X109 y
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17.5. Flowchart
Separation Scheme and Timeline for Determination of
Pu Isotopes in Building Materials Samples
Rapid Fusion (See Separate Procedure)
1. Add 242Pu 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)3, andSM HNO3 (column load solution)
Adjust Pu to Pu4+ (for removal on TEVA.
Step 11.2.1)
1. Add sulfamic acid, Fe, ascorbic acid
2. Wait 3 min
3. Add sodium nitrite
Vacuum Box Setup (Step 11.2.2)
1. Place TEVA cartridge on box
2. Condition column with 5 ml 3M
HNO3@ 1 mL/min
J
Discard load and
rinse solutions
(Step 11.2.3.8)
Load Sample to TEVA Cartridge (Step 11.2.3)
1. Load sample @1 mL/min
2. Beaker/tube rinse: 3mL 3M HNO3 @ 3 mL/min
3. Column rinse: 20 mL 3M HNO3 @ 3-4 mL/min
4. Column rinse: 20 mL 9M HCI @ 2-3 mL/min
5. Column Rinse: 3 mL 3M HNO3 @ 3 mL/min
V
Discard TEVA resin
(Step 11.2.3.12)
Elute Pu from TEVA (Step 11.2.3.10)
1. Add20mL0.1M HCL - 0.05M HF-0.01M TiCI3
mL/min
2. Remove tubes for micropreciptation
Discard filtrates
and rinses
(Step 11.3.15)
Microprecipitation (Step 11.3)
1. Add 50 |jg Ce carrier
2. Add 0.5 mL 30% H2O2
3. Add 1mLconcentrated HF
4. Wait 15 min and filter
5. Place on mounting disks
6. Warm 5 min under heat lamp
V
Count sample test source (STS)
by alpha spec for 1-4 h or as
needed (Step 11.3.14)
Elapsed Time
3 hours
21/4 hours
43/4 hours
51/4 hours
61/4 hours
71/4-141/4 hours
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Appendix:
Example of Sequential Separation Using Am-241, Pu-238+Pu-239/240, and Isotopic U in
Building Materials
This sequential combination of rapid procedures for Am-241, Pu-238+Pu-239/240, and isotopic
U in building materials (References 16.1, 16.2, and 16.5) 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/10 ml_ 3M HNO3
20 ml_ 9 M HCI (remove Th)
5mL3M HNO3
DGA®
Rinse w/ 10ml_0.1M HNO3
(remove U)
v
Elute Pu w/ 20 ml_ 0.1M HCI -
0.05MHF -0.01M TiCI3
Stack TRU® + DGA®
Add 15mL3M HCI
(Move all Am/Cm to DGA)
Add 0.5 mL 30 wt% H2O2 to
oxidize any U
DGA®
Rinse w/ 5 mL 3M HCI,
3mL1M HNO3 + 10ml_0.1M
HN03 + 5mL0.05M HNO3
(remove La)
Elute Am/Cm w/ 10 mL 0.25M
HCI
TRU®
Rinse w/ 15mL4M HCI -
0.2MHF -0.002M TiCI3 +
5mL8M HN03
Elute Uw/15 mLO.IM
Add0.5mL20%TiCI3
V
Add 50 ug Ce to 1 mL 49% HF.
Filter and count by alpha spectrometry.
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