www.epa.gov
                                         April 2014
                                     EPA 402-R14-003
                                         Revision 0
        Rapid Method for Sodium
 Hydroxide/Sodium Peroxide Fusion of
 Radioisotope Thermoelectric Generator
Materials in Water and Air Filter Matrices
     Prior to Plutonium Analyses 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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                                       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 Method for Sodium Hydroxide/Sodium Peroxide Fusion of Radioisotope
    Thermoelectric Generator Materials in Water and Air Filter Matrices Prior to
                                 Plutonium Analyses

1.   Scope and Application
    1.1.   This method is applicable to the total dissolution of refractory radioisotope
         thermoelectric generator (RTG) materials in water and air samples collected following
         a radiological or nuclear incident. The fusion is rapid, rigorous, and effectively
         dissolves refractory radionuclide particles present in waters and air filter matrices.
    1.2.   This method is a sample dissolution and pretreatment technique used prior to other
         separation and analysis methods. It was validated together with the chemical
         separation and analysis process described m Rapid Radiochemical Method for Pu-238
         and Pu-2 39/240 in Building Materials for Environmental Remediation Following
         Radiological Incidents (Reference 16.1).
    1.3.   Highly refractory ("high-fired") plutonium in particulate material isolated from water
         samples by filtration is less likely to be absorbed in the digestive tract (and is therefore
         determined separately) than the more bioavailable plutonium isolated in the aqueous
         sample filtrate. Results for the two fractions may be reported separately,  or they may
         be combined mathematically and reported as a single result for activity and associated
         combined uncertainty.
    1.4.   The user should refer to project-specific  requirements for the determination of
         applicable measurement quality objectives (MQOs). In the absence of project-specific
         guidance, MQOs for water and air samples may be based on the Analytical Action
         Levels (AALs) and required method uncertainties (MMR and ^MR) found in the
         Radiological Sample Analysis Guide for Incidents of National Significance 
         Radionuclides in Water (Reference 16.4), and Radiological Sample Analysis Guide for
         Incidents of National Significance  Radionuclides in Air (Reference 16.5).
    1.5.   For air filters, this method is capable of meeting a required method uncertainty of 1.9
         pCi/filter at and below the AAL of 15.0 pCi/filter, and a required relative method
         uncertainty of 13% above the AAL. This assumes that the filter sample is split
         following acid dissolution with one-half of the sample being processed through
         chemical separations  and a 360 minute count duration. With a 68 m3 air volume, this
         would equate to a required method uncertainty of 0.028 pCi/m3 at the action level of
         0.22 pCi/m3. Minimum detectable concentration (MDC) values of 0.20 pCi/filter or
         below may be achieved with the same aliquant and a count time of 240 minutes.
         Assuming a 68 m3  air volume, the method would be capable of meeting a required
         MDC of 0.003 pCi/m3 or below.
    1.6.   For water samples  (filtered solids, filtrate, or combined result), this method is capable
         of satisfying a required method uncertainty of 2.1 pCi/L at and below an AAL of 16.3
         pCi/L, and  a required relative method uncertainty of 13% above the AAL. This
         assumes a 1 liter aliquant and a count duration of 360 minutes. Required MDCs of
         0.23  pCi/L may be achieved with the same aliquant and a count time of 240 minutes.
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices


    1.7.   Application of this method must be validated by the laboratory using the protocols
         provided in Method Validation Guide for Qualifying Methods Used by Radiological
         Laboratories Participating in Incident Response Activities (Reference 16.3) or the
         protocols for method validation published by a recognized standards organization. The
         sample turnaround time and throughput may vary based on additional project MQOs,
         the time for analysis of the final counting form and initial sample volume.
    1.8.   Although this method may be applicable to other matrices that potentially contain
         RTG material, such as soils, concrete, or brick after destruction of organics in the
         sample, it is the laboratory's responsibility to perform method validation on the
         modified method prior to use.

2.   Summary of Method
    2.1.   Air filters: The method is based on total dissolution of RTG materials in water or air
         filter samples. The air filter is fused using rapid sodium hydroxide/sodium peroxide at
         700 C.
    2.2.   Water samples: refractory RTG particles are collected on  a 0.45-um filter using
         vacuum. RTG activity remaining in the aqueous filtrate is preconcentrated using
         calcium phosphate precipitation. The filtered solids fraction and the filtrate fraction are
         processed separately by fusing with sodium hydroxide/sodium peroxide prior to
         subsequent chemical separation and alpha spectrometric analysis.
    2.3.   The fusion method requires approximately one hour per batch of twenty samples using
         multiple furnaces. Preconcentration steps to eliminate the alkaline fusion matrix and
         collect the radionuclides and require approximately two hours.
    2.4.   Plutonium (Pu) is separated from the fusion matrix using a lanthanum/calcium fluoride
         matrix removal step in preparation for separation and analysis using the Rapid
         Radiochemical Method for Pu-238 andPu-239/240 in Building Materials for
         Environmental Remediation Follow ing Radiological Incidents (Reference 16.1).

3.   Definitions, Abbreviations and Acronyms
    NOTE: Common laboratory and chemical acronyms and abbreviations not included
    3.1.   AAL - analytical action level
    3.2.   APS - analytical  protocol specifications
    3.3.   C SU - combined standard uncertainty
    3.4.   DRP - discrete radioactive particle
    3.5.   FWHM - full-width-at-half-maximum
    3.6.   keV - kilo electron volt
    3.7.   LCS - laboratory control sample
    3.8.   MCE - mixed cellulose ester
    3.9.   MeV - mega electron volt


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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices


   3.10. MDC - minimum detectable concentration
   3.11. MQO - measurement quality obj ective
   3.12. MARLAP - Multi-Agency Radiological Analytical Laboratory Protocol Manual
         (Reference 16.6).
   3.13. QC - quality control
   3.14. RTG - radioisotope thermoelectric generator
   3.15. ROI - region of interest
   3.16. Sc - critical level concentration

4.  Interferences and Limitations
   4.1.   Organic-based vs. Glass-fiber Filters
         4.1.1.   Organic-based filters, such as cellulose nitrate or cellulose acetate filters,
                  may react vigorously upon addition of peroxide or during charring steps.
                  Wet-ashing with nitric-acid and hydrogen peroxide is needed to  destroy
                  organic constituents in the air filter matrix prior to fusion.
         4.1.2.   Glass fiber filter samples may be fused without any wet-ashing.
   4.2.   Samples with elevated activity or samples that require multiple analyses from a single
         RTG sample may need to be split after dissolution.
         4.2.1.   Tracer or carrier amounts added for radiochemical yield determinations
                  should be increased so that the split being processed contains the normal
                  amount of tracer or carrier.
         4.2.2.   For very high activity samples, the addition of the tracer or carrier may be
                  postponed until following the sample split. Special care must be taken to
                  ensure that isotopic exchange of the sample with the radiochemical  yield
                  tracer is achieved (i.e., following total dissolution and initial valence
                  adjustment). This deviation from the method must be thoroughly documented
                  and reported in the case narrative.
         4.2.3.   When this method is employed as written, the entire volume of sample is
                  fused and processed through subsequent chemical separation method. The
                  original sample size is used in all calculations.
         4.2.4.   In cases where the sample is split or diluted prior to analysis, the fractional
                  size of splits and dilutions may be used determine the chemical yield and
                  possibly the size of the sample aliquant. Therefore, the mass/volume of the
                  respective split fraction(s) and dilutions must be measured accurately. The
                  calculation of sample  aliquant size and the tracer activity for chemical yield
                  are described in Section 12, below.
   4.3.   Analytical parameters, such as the duration of the sample count and the aliquant size,
         should be modified to achieve optimal throughput while leveraging those  resources
         available to the laboratory. For example, longer count times combined with smaller
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
         aliquant sizes may achieve optimal throughput when facilities and equipment are more
         limited than instrumentation. If instrumentation is limiting, however, higher
         throughput might be achieved with larger aliquant sizes and shorter count times. In
         either case, the laboratory must validate the method using those analytical parameters
         that will be employed when  in analyzing samples.
   4.4.  Batch quality control samples (blanks, laboratory control samples (LCS), duplicates,
         and if required, matrix spikes) shall be created as early in the process as possible and
         subjected to the same processes as associated field samples, including filtration,
         tracer/carrier addition,  sample  dissolution and splitting, chemical separations, source
         preparation and counting.
   4.5.  Centrifuge speeds of 3000 rpm or greater are suggested, but lower centrifuge speeds,
         down to 2500 rpm, would be acceptable as long as the supernatant solution can be
         effectively removed.
   4.6.  Valence control of plutonium is very important, both in the preconcentration steps and
         column separation steps used in this method. Pu+6 typically forms when plutonium
         oxide is fused using  sodium  peroxide. All plutonium must be reduced to Pu+4 or Pu+3
         before isotopic exchange with  the tracer can be achieved with reasonable certainty.
         Additionally, only Pu+4 or Pu+3 will precipitate in the lanthanum fluoride/calcium
         fluoride preconcentration step. Although peroxide may reduce Pu+6  to Pu+4, the Pu
         valence must be controlled with certainty. The alkaline fusion cake  is dissolved using
         HC1.  The solution is allowed to stand for a sufficient period of time for peroxide ions
         to react with the HC1 minimizing residual peroxide present prior to  adjusting the
         valence of plutonium with titanium (III) chloride. The iron added facilitates removal of
         peroxide that may be present. Valence controls also ensure that plutonium will be
         present in the Pu+4 form prior to separation on TEVA Resin  in the Rapid
         Radiochemical Method for Pu-238 andPu-239/240 in Building Materials (Reference
         16.1)
   4.7.  Although this method was validated using 242Pu tracer, 236Pu tracer  may be  used
         assuming traceable material  can be obtained with sufficient purity. Pu-242 is the
         optimal tracer to use for samples expected to contain little or no activity since tailing
         counts from the tracer peak will not fall in analyte peaks of higher energy. In contrast,
         236Pu offers  an  advantage for samples expected to contain high activities of plutonium
                                  9^&       9^0/9/10
         since its energy falls above   Pu and     Pu and the tracer peak is not be  affected by
         tailing from high levels of analyte in  samples. Typically, a total of 2-10 pCi of tracer
         is added for each  sample test source depending on the count time and the total tracer
         counts desired. The tracer activity and count time may be adjusted,  however, if the
         sample is split or diluted, depending  on count times, and the total number tracer counts
         needed to meet method uncertainty requirements.
         	                                                                       949
   4.8.  The alpha spectrometry regions of interest (ROIs) should encompass the entire   Pu
                        9^R   9^Q/9zin        949
         peak. ROIs for   Pu,     Pu, and   Pu tracer peak should be of similar width, and
         should ideally capture all peak counts. If high activities of 238Pu are present, the 238Pu
         alpha peak may tail into the  239/240Pu  region of interest, even in samples with very good
         resolution. Although efforts  should be made to minimize peak overlap, if 239240Pu is
                                                    	                           OQ Q
         known not to be present in the sample (e.g., RTG material consisting of pure  Pu),
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
          tailing of 238Pu into 239/240Pu ROI may not be a large concern. When peak overlap
          compromises sample quantitation, sample test sources may need to be reprocessed or
          reprepared.l
   4.9.   Zirconium crucibles used in the fusion process may be reused.
          4.9.1.    It was found that fused RTG material may be lost on crucible walls and that
                  additional rinsing with HC1 at the point of dissolving the fusion cake will
                  enhance removal of residual material from the crucible.
          4.9.2.    The laboratory must have a process for cleaning and contamination
                  assessment of the reused zirconium crucibles. The crucibles should be
                  cleaned using soap and water, followed by warm nitric acid (multiple rinses)
                  and water. Blank measurements should be monitored to ensure effective
                  cleaning.
          4.9.3.    Segregation of crucibles used for low- and high-activity samples is needed to
                  minimize the risk of cross-contamination.
          4.9.4.    The heating of crucibles at 700 C will oxidize the zirconium metal over time
                  and the crucibles will need to be replaced.
                                                                          9^R
   4.10.  Although this fusion and preconcentration method was validated for   Pu, it could be
          modified for use in determining most actinides in refractory air and water samples.
          Chemical yield tracers appropriate to the respective determinations of actinides would
          be added in place of, or in addition to 242Pu. The product of the fusion and
          preconcentration would then be processed according to an appropriate chemical
          separation scheme for the radionuclide(s) of concern.

5.  Safety
   5.1.   General
          5.1.1.    Refer to the laboratory safety manual for concerns of contamination control,
                  personal exposure monitoring and radiation dose monitoring.
          5.1.2.    Refer to the laboratory 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 mm or less. DRPs are
                           typically not evenly distributed in the media and their radiation
                           emissions are not uniform in all directions (anisotropic).
                           NOTE: Information regarding DRPs should accompany the samples during
                           processing as well as be described in the case narrative that accompanies the
                           sample results.
1 Reprocessing might include redissolving the sample from the sample test source and repurifying using the Pu
separation procedure to remove chemical or radioactive impurities.
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices

   5.3.   Procedure-Specific Non-Radiological Hazards:
         5.3.1.    The sodium peroxide/sodium hydroxide fusion is performed in a furnace at
                  700 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
                  method. The fusion furnace should be used in a ventilated area (hood, trunk
                  exhaust, etc.).

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, 1000 mL or as needed.
   6.4.   Centrifuge able to accommodate 225-mL tubes.
   6.5.   Centrifuge tubes, 50 mL and 225-mL (or 250 mL) capacity.
   6.6.   Crucibles, 250 mL, zirconium, with lids, (e.g., low-form 250-mL crucibles, P/N 10-
         0250LF and 10-0250C lid from Metal Technology, Inc., Albany, or equivalent).
   6.7.   Filters, 0.45 micron mixed cellulose ester (e.g., MCE) filter, Millipore HA, or
         equivalent.
   6.8.   100-uL, 200-uL, 500-uL, and 1-mL pipets or equivalent and appropriate plastic tips.
   6.9.   1 mL-10 mL electronic/adjustable pipet.
   6.10. Muffle furnace capable of reaching at least 700 C.
   6.11. Reusable vacuum filter units to hold 47mm filters with 500-mL receivers or equivalent
         filter apparatus, (e.g., Thermo Scientific Nalgene Reusable Filter Holders, P/N 300-
         4050, transparent polysulfone; capacity: upper chamber 500 mL, receiver 500 mL, or
         equivalent).
   6.12. Tongs for handling crucibles (small and long tongs).
   6.13. Tweezers or forcep s.
   6.14. Vacuum, building vacuum source or portable pump.
   6.15. Vortex stirrer.

7.  Reagents and Standards
          Note: Unless otherwise indicated, all references to water should be understood to mean Type I
          Reagent water (ASTM D1193; Reference 16.7).
          NOTE: All reagents are American Chemical Society grade or equivalent unless otherwise
          specified.
   7.1.   Aluminum nitrate (A1(NO3)3' 9 H2O)
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
         7.1.1.    Aluminum nitrate solution, 2M (A1(NO3)3): Dissolve 750 g of aluminum
                  nitrate (A1(NC>3)3' 9 H2O) in -700 mL of water and dilute to 1 L with water.
   7.2.  Ammonium hydrogen phosphate (3.2 M): Dissolve 106 g of (NH/^HPC^ in 200 mL
         of water, heat gently to dissolve and dilute to 250 mL with water.
   7.3.  Ammonium hydroxide (NH/iOH), concentrated.
   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.  Hydrochloric acid (12 M): Concentrated HC1, available commercially.
         7.6.1.    Hydrochloric acid (0.01 M): Add 0.83 mL of concentrated HC1 to 800 mL of
                  water and dilute with water to 1 L.
         7.6.2.    Hydrochloric acid (4 M): Add 333 mL of concentrated HC1 to 500 mL of
                  water and dilute with water to 1 L.
         7.6.3.    Hydrochloric acid (6 M): Add 500 mL of concentrated HC1 to 400 mL of
                  water and dilute with water to 1 L.
   7.7.  Hydrofluoric acid (28 M): Concentrated HF, available commercially.
   7.8.  Iron carrier (50 mg/mL): dissolve 181 g of ferric nitrate (Fe(NO3)3  9H2O) in 300 mL
         997 water and dilute to 500 mL with water.
   7.9.  Lanthanum carrier, 1.0 mg La/mL: add  1.56 g lanthanum (III) nitrate hexahydrate
         [La(NO3)3'6 H2O] in 300 mL water, diluted to 500 mL with water.
   7.10. Nitric acid (15.8 M): Concentrated HNO3, available commercially.
         7.10.1.   Nitric acid (3 M): 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, 3 M-0.25 M: add 15.4 g of boric acid and
                  190 mL of concentrated HNO3 to 500 mL of water, heat to dissolve, and
                  dilute to 1 L with water.
         7.10.3.   Nitric acid (7 M): Add 443 mL of concentrated HNO3 to 400 mL of water
                  and dilute to 1 L with water.
   7.11. Phenolphthalein solution: dissolve 1 g of phenolphthalein in 100 mL 95% ethanol and
         dilute with 100 mL water.
   7.12. Sodium Hydroxide (NaOH) pellets.
   7.13. Sodium Peroxide (Na2O2) pellets.
   7.14. Titanium (III) chloride solution (TiCl3), 20 wt % solution in 20-30 wt % hydrochloric
         acid.
   7.15. Radioactive tracers/carriers (used as radiochemical yield monitors) and spiking
         solutions. 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

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          allows for monitoring and correction for of chemical losses in the combined
          dissolution 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), should be added where indicated.

8.   Sample Collection, Preservation, and Storage
    8.1.    Samples should be collected in 1-L plastic containers.
    8.2.    No sample perseveration is required if sample is delivered to the laboratory within 3 days of sampling
    8.3.    If separate dissolved and/or suspended concentrations of plutonium are sought, the insoluble fraction r
    8.4.    If the sample is to be held  for more than three days, HNOs shall be added until pH<2.

9.   Quality Control
    9.1.    Where the subsequent chemical separation technique requires the addition of carriers
          and radioactive tracers for chemical or radiochemical yield  determinations, these are to
          be added prior to beginning the fusion procedure, unless there is good technical
          justification for doing otherwise.
    9.2.    The source preparation method should produce a sample test source with full-width-at-
          half-maximum values (FWHM) of less than  100 keV for the tracer peak.2 Precipitate
          reprocessing should be considered if this range of FWHM cannot be achieved.3
    9.3.    Quality control samples shall be analyzed with each batch of twenty or fewer samples
          and shall be created as early in the process as possible. They shall be subjected to the
          same processes as associated field samples, including filtration, tracer/carrier addition,
          sample dissolution and splitting,  chemical separations, source preparation, counting,
          and calculation of sample activities.
          9.3.1.    One laboratory control sample (LCS) shall be run with each batch of
                   samples. The LCS consists of analyte-free matrix (where available) spiked
                  with a known quantity of radionuclide spiking solution. The concentration of
                  the LCS should be at or near the action level or level of interest for the
                  project.
          9.3.2.    One blank shall be run with each batch of samples. The reagent blank should
                   consist of the analyte-free matrix (where available).
          9.3.3.    One sample duplicate that is equivalent in size to the original aliquant should
                  be analyzed with each batch of samples. If sample volumes are limited, an
                  LCS duplicate may be substituted for the  sample duplicate.
          9.3.4.   A matrix  spike is not required with this method.
2 This is a rule of thumb that works for Pu, Am, and U determinations but would be problematic for 229Th, which
consists of numerous lower abundance peaks distributed across a wider energy range.
3 Reprocessing might include redissolving the sample from the sample test source and repurifying using the Pu
separation procedure to remove chemical or radioactive impurities.
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
   9.4.  Efforts should be made to obtain analyte-free quality control (QC) materials that have
         similar composition as the samples to be analyzed (e.g., deionized water or a blank air
         filter from the same lot of filters as the samples). A reagent blank shall be substituted
         for analyte-free matrix when analyte-free matrix is not available.
   9.5.  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 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.

10. Calibration and Standardization.
   10.1. Set up the alpha spectrometry system consistent with manufacturer recommendations
         following laboratory quality manual specifications. The energy range of the
         spectrometry system should at least include the region between 3 and 8 MeV.
   10.2. Calibrate each detector used to count samples according to ASTM Standard Practice
         D7282, Section 18, "Alpha Spectrometry Instrument Calibrations" (Reference 16.8).
   10.3. Continuing instrument QC testing shall be performed according to ASTM Standard
         Practice  D7282, Sections 20, 21, and 24 (Reference 16.8).

11. Procedure
   11.1. RTG Materials in Water Samples
         11.1.1.  Acidify the water sample with concentrated HNCb to a pH of < 2.0 by adding
                  enough HNOs (usually about 2 mL of concentrated HNOs per 1,000 mL of
                  sample).
         11.1.2.  Perform screening analysis of the water sample using an appropriate gross
                  alpha/gross beta counting technique such as liquid scintillation counting or
                  gas proportional counting per laboratory protocol. Mix the sample well prior
                  to removing the screening aliquant to minimize the risk of removing a non-
                  representative sample.
         11.1.3.  Place a 47-mm membrane filter (0.45 micron mixed cellulose ester filter) on
                  a clean, reusable filter unit with a 500 mL reservoir (or alternate volume as
                  needed).
                  NOTE: For very high level water samples where a small aliquant volume must be used,
                  a filter unit with a smaller collection reservoir may be used.
         11.1.4.  Filter the entire water sample using vacuum to collect any RTG particles on
                  the filter.
         11.1.5.  Rinse the sample container with 10-15 mL of water and add to the filter.
                  Rinse the sample reservoir above the filter with -10 to 15 mL of water.
         11.1.6.  Remove the filter containing the filtered solids and place in a labeled 250 mL
                  zirconium crucible.
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          11.1.7.  Pour the filtrate into a large beaker. Rinse collection container well with -10
                  mL of water and transferring the rinse volumes to the beaker.
          11.1.8.  Add appropriate tracer to the crucible or beaker to determine radiochemical
                  yield as needed.
                  NOTE: For plutonium analysis, 2-10 pCi of 242Pu or 236Pu tracer are typically added
                  depending on the count time, the total tracer counts desired to meet the required
                  method uncertainty, and any sample splits or dilutions that will be performed.
          11.1.9.  Add 10 mL of concentrated nitric acid and 3-4 mL of hydrogen peroxide to
                  the zirconium crucible to wet ash the filter. Heat on medium heat to dryness
                  and remove from heat.
                  NOTE: The filter contains cellulose and needs to be digested to destroy organics since
                  sodium peroxide will be used in the fusion process.
          11.1.10. Proceed to section 11.3 for fusion of the filtered solids of the water sample
          11.1.11. Add 1.5 mL of 1.25 M calcium nitrate solution, 3 mL of 3.2 M ammonium
                  hydrogen phosphate solution and about -5-10 drops of phenolphthalein
                  indicator to the beaker containing the sample filtrate.
          11.1.12. Add enough concentrated NH/iOH to the beaker to reach a dark pink
                  phenolphthalein end point.
          11.1.13. Heat the beaker on a hot plate for -15 minutes to help aggregate precipitate.
                  Remove beaker and allow precipitate to settle so that enough clear
                  supernatant solution can be poured off. The remaining supernate with the
                  precipitate is added to a 225 mL centrifuge tube.
          11.1.14. Centrifuge the sample for at least 6 minutes at 3000 rpm or more.
          11.1.15. Decant supernate from the centrifuge tube. Discard supernate to waste.
          11.1.16. Add enough concentrated NH/iOH to the centrifuge tube to reach a dark pink
                  phenolphthalein end point.
          11.1.17. Add 10 mL concentrated HNOs to the centrifuge tube. Cap and mix well to
                  dissolve the precipitate, and transfer to a 250 mL zirconium crucible.
          11.1.18. Rinse the tube twice more with -5 mL of concentrated HNCb and transfer to
                  the zirconium crucible.
          11.1.19. Evaporate the rinse solutions to dryness using medium heat and remove
                  crucibles from hotplate.
          11.1.20. Proceed to Step 11.3 for fusion of the precipitate from the water sample
                  filtrate.
    11.2.  RTG Materials in Air Filter Samples
          11.2.1.  Perform appropriate screening analysis of the air filter sample using an
                  appropriate hand held alpha/beta monitoring probes.
          11.2.2.  Place a sample filter into a 250 mL zirconium (Zr) crucible.
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          11.2.3.   Add appropriate activity of tracer to the crucible to determine radiochemical
                   yield. If activity levels are too high, do not add yield tracer to the sample
                   aliquant until a smaller aliquant can be taken after the fusion and
                   preconcentration steps. Additional care should be taken to avoid losses of
                   sample material until an aliquant of suitable activity is obtained and
                   equilibrated with tracer.
                   NOTE: For plutonium analysis, 2-10 pCi of 242Pu or 236Pu tracer are typically added
                   depending on the count time, the total tracer counts desired  to meet the required
                   method uncertainty, and any sample splits or dilutions that will be performed. For
                   example, it is often desirable to reserve % the final dissolved air filter solution for the
                   event that analytical rework is required. If this is approach is planned, twice the
                   normal amounts of Pu tracer may be added to compensate for analyzing only one-half
                   of the dissolved filter.
          11.2.4.   Add 10 mL of concentrated nitric acid and 3-4 mL of hydrogen peroxide to
                   the zirconium crucible to wet ash the filter.
          11.2.5.   Heat on medium heat to dryness and remove from heat.
          11.2.6.   Proceed to  Step 11.3 for fusion.
    11.3.  Fusion
          11.3.1.   Prepare the crucible  from Step 11.1 (water sample) or Section 11.2 (air filter
                   sample) for fusion.
          11.3.2.   Add 8 g of sodium hydroxide and 4 g of sodium peroxide to the crucible.
          11.3.3.   Place the crucible with lid in the 700 C furnace using tongs.
          11.3.4.   Heat the  crucible for -30 minutes or longer as needed to obtain a clear melt.
          11.3.5.   Using tongs, very carefully remove crucible containing hot liquid melt from
                   furnace and transfer  to hood. Allow the crucible to cool for 8-10 minutes (or
                   longer).
          11.3.6.   Add -25 mL of water to the crucible and allow the sample to react with water
                   until the  fusion cake is dissolved. Place the crucible on a hot plate at medium
                   heat to help in dissolving the fusion cake. Transfer the solution to a labeled
                   225-mL centrifuge tube rinsing the crucible with water.
          11.3.7.   Rinse the crucible with a 25-mL portion of 6 M HC1.  Warm on a hotplate,
                   and then carefully pour each rinse into the 225 mL centrifuge tube. Pour rinse
                   slowly to prevent splattering  of the sample. Repeat two more times.
          11.3.8.   Dilute the sample to  -170 mL with deionized water and swirl to mix.
          11.3.9.   Allow sample solution to cool for 40 minutes in the open centrifuge tube.
          11.3.10.  Cap centrifuge tube and place in ice bath for 3 minutes to cool solution to
                   room temperature.
    11.4.  Preconcentration of Pu from Fusion  Matrix
          NOTE: These steps also preconcentrate other actinides besides plutonium from the fusion matrix.
          For example, if the appropriate tracers are added, americium and uranium isotopes may be
          assayed using Rapid Radiochemical Method for 241Am in Building Materials and Rapid


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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
          Radiochemical Method for Isotopic Uranium in Building Materials respectively (available at
          www.epa. gov/nareD. It is the laboratory's responsibility, however, to validate these methods prior
          to use.
          11.4.1.  Pipet 10 mL of 1 mg La/mL into the centrifuge tube, swirling to mix.
          11.4.2.  Pipet 1 mL of iron carrier (50 mg/mL) into the centrifuge tube, swirling to
                  mix.
          11.4.3.  For water sample solids, pipet 1.5 mL of 1.25M calcium nitrate into the
                  centrifuge tube. The water sample filtrate fraction does not need additional
                  calcium. For air filter samples, add 1.5 mL of 1.25M calcium nitrate into the
                  centrifuge tube. Swirl to mix.
          11.4.4.  Pipet 10 mL of 20 wt %.  TiCl3 into the centrifuge tube and cap to mix.
          11.4.5.  Add 24 mL of concentrated HF to the centrifuge tube and cap to mix. Shake
                  well to mix.
          11.4.6.  Thoroughly mix and allow the sample to  sit for 10 minutes. .
          11.4.7.  Centrifuge the sample for ~6 minutes at 3000 rpm or more as needed.
          11.4.8.  Pour off supernatant liquid and discard to waste.
          11.4.9.  Pipet 5 mL of 3 M HNO3-0.25 M boric acid into the 225 mL centrifuge tube
                  containing the calcium/lanthanum precipitate.
          11.4.10. Cap, mix and transfer contents of the 225 mL centrifuge tube into a new,
                  labeled 50 mL centrifuge tube.
          11.4.11. Add 6 mL of 7 M HNO3  and 10 mL of 2  M aluminum nitrate into the 225
                  mL tube, cap and mix, and transfer rinse  to 50 mL centrifuge tube.
          11.4.12. Pipet 5 mL of 3 M HNO3 directly into the 50 mL centrifuge tube.
          11.4.13. Mix the sample load solution in a 50 mL  centrifuge tube using a vortex stirrer
                  to dissolve residual precipitate.
          11.4.14. Centrifuge the sample at  3000 rpm or higher for 6 minutes  to remove any
                  traces of solids. These may not be visible prior to centrifuging. Transfer the
                  solution to labeled 50 mL centrifuge tubes for further processing. If
                  undissolved solids are present, rinse the solids with 5  mL of 3M FDSTO3 and
                  vortex to dissolve. Centrifuge the tube with residual solids  (if any) and add
                  the supernate to the sample solution.
                  NOTE:  For samples that will be split such that  Vz is held in reserve, the tracer added to
                  the initial air filter in Step 11.1.8 should have been increased accordingly (e.g., if one-
                  half the sample is taken, the  tracer amount would be doubled).  The fractional splitting
                  of the sample will be accounted for properly in the calculations.
          11.4.15. For air filter samples, set aside one-half of the sample by carefully splitting
                  the dissolved filter, either by mass or volume, into a labeled 50-mL
                  centrifuge tube.
          11.4.16. For Pu analysis, follow Steps 11.1.2 through 11.3.15 oftheRapid
                  Radiochemical Method for Pu-238 and Pu-2 39/240 in Building Materials
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                  (Reference 16.1), incorporating steps in Sections 6, 7, and 10 as they support
                  Section 11, and making the following adjustments:

                     Change Step 11.2.1.4 to: Add 1.5 mL of 1.5M ascorbic acid to the
                      solution, swirling to mix. Wait 3 min.

                     Change Step 11.2.1.5 to: Add 1.5 mL 3.5MNaNO2to the sample,
                      swirling to mix.

                     Change Step 11.2.3.2 to: Add 5 mL of 3M HNO3 to the beaker (from
                      Step 10.2.1.5) as a rinse. Transfer the solution into the appropriate
                      reservoir (the flow rate may be adjusted to ~3 mL/min).

                     Change Step 11.2.3.7 to: Add 5 mL of 3M HNO3 to the reservoir to
                      reduce bleed-off of organic extraction during Pu strip step (flow rate ~3
                      mL/min).

                     Change Step 11.3.3 to: Pipet 2 mL (or alternately 1 mL) of concentrated
                      HF into the centrifuge tube.

12. Data Analysis and Calculations
   12.1. Equations for calculating final results for the activity (concentration) and associated
         combined standard uncertainty, the radiochemical yield (if required), the critical level,
         and the MDC are found below. Ensure that the units used for the aliquant, and for
         reporting are consistent with those established in analytical protocol specifications.
         12.1.1.  If the sample is split or serially diluted, the actual activity of tracer added to
                  the sample is used for calculations. The aliquant size used for calculations,
                  Wa, must be the effective amount of sample in the aliquant into which the
                  tracer is added. It is calculated as follows:
                                      Wa=Wsxdlxd2x d3                       (Eq.
                  Where
                  and
                  Ws   =   initial size of the sample aliquant taken for fusion in the units
                            designated in analytical protocol specifications (e.g., 0.020 L, or 67
                            m3, 0.500 filter).
                  Da#  =   mass or volume of the aliquant taken (i.e., the redissolved fusion
                            cake or subsequent dilution thereof) where # denotes the respective
                            number of the serial dilution from /' to w, (e.g., 5.0 mL, etc.).
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                  Ds#   =   mass or volume of the dissolved residues of fusion, or the dilution
                            thereof, from which Da# is taken, where # denotes the number of
                            the respective serial dilution from /' to n (e.g., 20 mL, etc.).
           NOTE: Da# and Ds# must use the same units of mass or volume. If no splits or dilutions are
           performed, Ws = Wa. If fewer than three splits or dilutions are made, not all three of the d1? d2,
           or d3 terms will be needed. A factor of one (1) may be substituted for the unused terms.


          12. 1 .2.  The actual activity of tracer added to the sample is used in the calculation of
                  the final sample results as described in  12.1.1. If the sample has been split or
                  diluted, the tracer activity used to calculate the radiochemical yield must be
                  modified to reflect the activity of tracer that would be present theoretically in
                  the final sample test source assuming 100% radiochemical yield. It is
                  calculated as follows:
                                     4-yld=4xdixd2xd3                       (Eq.2)
                  Where
                  At.yid =    theoretical activity in sample test source assuming 100%
                            radiochemical yield.
                  At    =    activity of the tracer added to the sample aliquant at the reference
                            date/time for the tracer.
                  and
                  di,  d2 and ds are defined as described in 12.1.1.

          NOTE: Da# and Ds# must use the same units of mass or volume. If fewer than three splits/dilutions
          are made, a factor of one (1) is substituted for the unneeded Da and Ds terms. If no splits or
          dilutions are performed, At.yid = At
    12.2.  The activity  concentration of an analyte and its combined standard uncertainty are
          calculated using the following equations:


                             AC =4**-*Ax/t
                                    WaxRtxDaxIa
           and
                                                +AC;x -      + -f+-        (Eq 4)
                                 oooT   -   a       oo
                              JT.'x.R.'x.D.'x/.'             4!      W;      R;
          where:
              ACa     =  activity concentration of the analyte at time of count, in picocuries
                          per liter, cubic meter or sample (pCi/L, pCi/m3, or pCi/filter)
              At       =  activity of the tracer added to the sample aliquant at its reference
                          date/time (pCi)


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              Ra       =  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       =  the size of the sample aliquant from Eq. 2, consistent with units
                           required in analytical protocol specifications (L, m3, or filter, as
                           appropriate)
              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(A\)     =  standard uncertainty of the activity of the tracer added to the sample
                           (pCi)
                        =  standard uncertainty of the volume of sample aliquant (L, m3,  or
                           filter, as appropriate)
                        =  standard uncertainty of the net count rate of the analyte (s l)
                        =  standard uncertainty of the net count rate of the tracer (s  l)
           NOTE: Since the tracer is used as the basis for quantitation, terms for the chemical yield and
           efficiency do not appear in the equations for activity, uncertainty, critical level, and minimum
           detectable concentration.
           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 of the activity concentration
           (uc(ACa)) is arranged to eliminate the possibility of dividing by zero if Ra = 0.
           NOTE: The standard uncertainty of the activity of the tracer added to the sample must reflect
           that associated with the activity of the tracer 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.
           12.2.1.   The net count rate of an analyte or tracer and its standard uncertainty are
                    calculated using the following equations:
                             Rx=^-^-                                             (Eq. 5)
                                   ts     ^b
                     and
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                                                                                      (Eq-6)
                    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 second4

                     If the radiochemical yield of the tracer is requested, the yield and its
                     combined standard uncertainty can be calculated using the following
                     equations:
                             RY =	                            (Eq. 7)
                                  0.037x4   xDtx/txs
                    and
                    where:
                         RY    =      radiochemical yield of the tracer, expressed as a
                                       fraction
                         Rt     =      net count rate of the tracer, in counts per second
                         At.yid   =      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
4 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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                         u(Rt)   =      standard uncertainty of the net count rate of the tracer,
                                        in counts per second

                         tt(4t-yid) =     standard uncertainty of^t-yid (pCi)
                         u(s)    =      standard uncertainty of the detector efficiency


           12.2.2.   If the critical level concentration (Sc) or the MDC are requested (at  an error
                    rate of 5%), they can be calculated using the following equations: 5
s =
0
4x
'^-ll + O
^ J
677 x
1 + M + l
V *>)
645 x^
\(R*A
+ 0
4)x-^x 1 + ^-
t> ( tb)_
xA,

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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
         AC fiitrate     = the activity concentration of filtrate (pCi/L of original sample from Eq.
          uc(ACfntrate)  = the CSU of ACfiitate in pCi/L of original sample from Eq. 4 (k=\)
    12.4.  Results Reporting
           12.4. 1 .   The following data should be reported for each result: volume of sample
                   used; radiochemical yield and its uncertainty; and FWHM of each peak used
                   in the analysis.
           12.4.2.   The following conventions should be used for each result:
                   12.4.2. 1 . Result  combined standard uncertainty.
                   12.4.2.2. For water samples, report results as specified in the analytical
                            protocol specifications. If no guidance is provided, the results for
                            each of the two fractions (or the mathematically combined result)
                            may be reported as pCi/L of original sample. For example:
                            239/240pu for Sample 12-1-99:
                                   Filtrate Result:             (1.28  0.15) x 101 pCi/L
                                   Filtered Residue Result:    (2.50  0.32) x 10 pCi/L
                   12.4.2.3. For air filter samples, report results as specified in the analytical
                            protocol specifications. If no guidance is provided, the results
                            should be reported  as pCi/m3. For example:
                                   239/240pu for Sample i2-l-99:(1.28  0.15) x 101 pCi/m3

13. Method Performance
    13.1.  Results of method validation performance are to be archived and available for reporting purposes.
    13.2.  Estimates of turnaround times for fusion and preconcentration steps assume that
          batches of twenty  samples are processed together with associated QC.
          13.2.1.  For water samples, initial filtration and preparation for the fusion require
                  approximately 1.75 hours per batch.
          13.2.2.  For water and air filter samples, the fusion requires approximately 1.75-2.75
                  hours per batch.
          13.2.3.  The preconcentration, chemical separation and source preparation steps
                  require approximately 2.5 hours per batch.
          13.2.4.  Sample count duration may vary depending on the validated configuration of
                  the method.
           NOTE: Turnaround times for the subsequent chemical separation methods are given in those
           methods for batch preparations.

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


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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
   if the sampled particulates include radionuclides which may be volatile under the fusion
   conditions, these constituents will be exhausted through fume hood system.
15. Waste Management
   15.1.  Refer to the appropriate chemical separation methods for waste disposal information.

16. References
   16.1.  U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
         for Pu-238 and Pu-239/240 in Building Materials for Environmental Remediation
         Following Radiological Incidents. Revision 0, EPA 402-R-14-006, September. Office
         of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
   16.2.  U.S. Environmental Protection Agency (EPA). 2010. "Plutonium-238 and Plutonium-
         239 in Water: Rapid Method for High-Activity Samples." Revision 0. In, Rapid
         Radiochemical Methods for Selected Radionuclides in Water for Environmental
         Restoration Follow ing Homeland Security Events, EPA 402-R-10-001, February.
         Office of Air and Radiation, Washington, DC. Revision 0.1 of rapid methods issued
         October 2011. Available at: www.epa.gov/narel.
   16.3.  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.
   16.4.  U.S. Environmental Protection Agency (EPA). 2008. Radiological Laboratory Sample
         Analysis Guide for Incident Response - Radionuclides in Water. Revision  0. Office of
         Air and Radiation, Washington, DC. EPA 402-R-07-007, January. Available at:
         www.epa.gov/erln/radiation.html and www.epa.gov/narel.
   16.5.  U.S. Environmental Protection Agency (EPA). 2009. Radiological Laboratory Sample
         Analysis Guide for Incident Response - Radionuclides in Air.  Revision 0. Office of Air
         and Radiation, Washington, DC. EPA 402-R-09-007, June. Available at:
         www.epa.gov/erln/radiation.html and www.epa.gov/narel.
   16.6.  MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
         Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,  NTIS
         PB2004-105421. (July 2004). Available at www.epa.gov/radiation/marlap/index.html.
   16.7.  ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of Standards
         11.01, current version, ASTM International, West Conshohocken, PA.
   16.8.  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.
   16.9.  Maxwell, S., Culligan, B. and Noyes, G. (2010), Rapid method for actinides in
         emergency soil samples, Radiochimica Acta:  Vol. 98, No.  12, pp. 793-800.
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      Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
    16. 10. Maxwell, S., Culligan, B., Shaw, P and Kelsey-Wall, A. (2011), Rapid method for
         actinides in emergency concrete and brick samples, Anal. Chim Acta, 201 1 Sep
    16.11. Milner, G.W.C., and Crossley, The Rapid Dissolution of Plutonium Oxide by a
         Sodium peroxide-Sodium Hydroxide Fusion, Followed by Determination of Plutonium
         by Controlled-potential Coulometry, Analyst, 1968, 93, 429-432
    16. 12. Pierce, R.A., Castiglione, D.C., and Edwards, T.B, The Suitability of Sodium Peroxide
         Fusion for Productions-Scale Plutonium Processing Operations-1 1 179, Proceedings of
         WM201 1 Conference, February 27-March 3, 201 1, Phoenix, AZ,
         www.wmsym.org/app/201 lcd/papers/1 1 179.pdf


17. Tables, Diagrams, and Flow Charts
    17.1. Tables
           Table 17.1 Alpha Particle Energies and Abundances of Importance
Nuclide
236Pu
238Pu
239Pu
240pu
239/24Pu (combmed)[3]
242pu
Half-Life
(Years)
2.858
87.7
2.411xl04
6.561xl03
2.411xl04
3.735xl05
X
(s-1)
9.685xl(T9
2.50xl(T10
9.110xl(T13
3.348xl(T12
9.110xl(T13
5.881xl(T14
Abundance'21
0.691
0.308
0.7091
0.2898
0.7077
0.1711
0.1194
0.7280
0.2710
0.9986
0.7649
0.2348
Alpha Emission
Energy
(MeV)
5.768
5.721
5.499
5.456
5.157
5.144
5.105
5.168
5.124
-5.16
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 I are based on 239Pu.
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       Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices



    17.2.  Ingrowth Curves and Ingrowth Factors

          This section intentionally left blank


    17.3.  Spectrum from a Processed Sample

                                    Plutonium Spectrum


51 \':':,l''^ ""',',
46 >>l!:'""^^.
41
36
2 26
0 21
y. is
f it
1 6
1
2749 314? 3550 3957 4388
Energy (keV)
 *,
4 -s






*

i ^


1

,1
1783
1
f






m
\ ,

r- 




1
) 5

^ \
^ i*





127
?







6055

    17.4.  Decay Scheme
  2,4SxW ,'
                                  Plutonium Decay Scheme
                         8??y     241x10' y
                             23SU
7 04x10' y
2,34x107y
                                    i 24{jpu I
                                    ;    U a


                                    6.56x10" y
                               3,74x10s y
                                                                           a
                                                                            4,47x10y
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       Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
    17.5.  Fusion Method Flow Chart
                    Timeline for Rapid Fusion and Preparation of
                Radioisotope Thermoelectric Generator Samples for
                              Precipitation and Analysis
  Water Samples (Step 11.1)
  1.  Perform screening analysis for gross
      alpha and beta.
  2.  Filter aliquant of water sample using
      0.45 |jm mixed cellulose ester filter.
  Filtered solids on membrane filter:
  3a. Transfer filter to crucible . Add tracer.
  3b. Wet-ash filterw/conc. HNO3 and
      H2C>2. Take to dryness on hotplate.
  3c. Proceed to rapid fusion in Step 11.3.
  Filtrate:
  4a. Transfer filtrate to beaker. Add tracer.
  4b. Add Ca carrier, (NH4J2HPO4 and
      indicator. Adjust to ~pH 10 with
      NhUOH. Allow precipitate to settle.
      Carefully decant supernate without
      precipitate.
  4c. Transfer remaining supernate.
      precipitate to 225 ml_ centrifuge tube
      and centrifuge for 6 min. Decant
      supernate to waste. Repeat process
      until the entire volume is centrifuged.
  4d. Dissolve precipitate w/10 ml_ cone.
      HNO3. Transfer to 250-mL  Zr
      crucible. Take to dryness on hotplate.
  4e. Proceed to rapid fusion in Step 11.3
Air Filter Samples (Step 11.2)
1.   Monitorsamples with alpha/beta
    hand-held probes.
2.   Place air filter in Zr crucible.
3.   Add Pu tracer.
4.   Add HNO3 and H2O2 to crucible.
5.   Evaporate solution to dryness on
    hotplate.
6.   Proceed to rapid fusion in Step
    11.3
                                     +13/4h
                          Rapid Fusion (Step 11.3)
                          1.  Add 8 g NaOH and 4 g Na2C>2 pellets to crucible.
                          2.  Heat -30 min. at 700 C.
                          3.  Remove from furnace and allow to cool.
                          4.  Proceed to precipitation steps.
                          Prepare for precipitations
                          1.  Add 25 mL water to crucibles to dissolve fused
                              sample, allow to react. Heat and transfer to 225 mL
                              centrifuge tubes.
                          2.  Rinse crucibles with 3 portions of 6M HCI warming
                              on hotplate, transferring solution to centrifuge tubes.
                              Dilute to volume of -170 mL.
                          3.  Cool to room temperature in  ice bath for 3 min.
                          4.  Allowto sitfor40 min.
                          5.  Fusion solution is ready for Pu preconcentration
                              steps.
                                                                                           (21/2-31/2 h)


                                                                     Continued on Precipitation  Chart
                                                                                            3/4-13/4h
04-16-2014
        22
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       Rapid Method for Sodium Hydroxide/Sodium Peroxide Fusion of RTG Materials in Water and Air Filter Matrices
                             Plutonium Precipitation Procedure
  Plutonium Precipitations (Step 11.4)
  1.  Add carriers (50 mg Fe,  10 mg La, and 75 mg Ca) to each tube; swirl to mix.
  2.  Add 10 ml 20% TiCI3 and swirl to mix.
  3.  Add 24 ml_ HF, cap,  mix well. Allow to stand for 10 min.
  4.  Centrifugefor~6 min. Decant supernatant solution to waste.
  5.  Add 5mL3M HNO3-0.25M  H3BO3 reagent to dissolve precipitate, Cap, mix, and
     transfer contents to clean 50 ml_ centrifuge tube.
  6.  Add 6 mL-7M  HNO3 and 10 ml -2M AI(NO3)3  to the 225 ml centrifuge tube. Cap, mix,
     and transfer the rinse to the 50 ml_ centrifuge tube.
  7.  Add 3 ml_-3M  HNO3 to the 50 ml_ centrifuge tube. Cap and mix well.
  8.  Centrifuge and transfer supernatant solution to a clean 50 ml_ centrifuge tube.
  9.  For air filters,  1/4 of the solution may be reserved at this point as back-up.
  10. Continue with steps 11.1.2 - 11.3.15 of Rapid Radiochemical Method for Pu-238 and
     Pu-239/240 in Building Materials. Use modifications in Step  11.4.16 of fusion method.
  Valence Adjustment of Pu to Pu*4
  1.  Add 0.5 ml 1.5M H3NSO3, 0.2 ml of
     5 mg/mLFe(NO3)3, and 1.5mLof
     1.5M CeHsOe mixing between
     additions. Wait 3 min.
  2.  Add 1.5mL3.5-M NaNO2 and mix.
Vacuum  Box Setup
1.  Assemble vacuum box and
   place TEVA cartridge on box.
2.  Condition cartridge with 5 mL
   3M HNO3 @ 1 mL/min.
            TEVA Cartridge -Sample load and rinses
            1.  Load sample @ 1  mL/min.
            2.  Rinse beaker/tube with 5 mL of 3M HNO3 - load @ ~3 mL/min.
            3.  Rinse column with 10 mL of 3M HNO3 @ 3-4 mL/min.
            4.  Turn off vacuum, discard rinse solutions, continue reuse tubes
            5.  Rinse column with 10 mL of 3M HNO3 @ 3^ mL/min.
            6.  Rinse column: 20 mL of 9M HCI @ 2-3 mL/min.
            7.  Rinse column: 5 mL of 3M HNO3 @ ~3 mL/min.
            8.  Discard load / rinse effluents. Place clean tubes under columns.
            Elute Pu from TEVA
            1.  Add20mL-0.1M HCI + 0.05M HF + 0.01M TiCI3
            2.  Remove tubes for microprecipitation.
            3.  Discard used TEVA column.
                1 mL/min.
            Microprecipitation
            1.  Add 100 |jL of 0.5 mg Ce/mL carrier and 0.5 mL 30 wt% H2O2 to
               tube and mix. Add 2 mL of 28M HF. Wait 15 minutes.
            2.  Assemble filtration apparatus with 25 mm 0.1 |jm filter.
            3.  Wetfilterwith ethanol, apply vacuum, rinse with Type I  water.
            4.  Add sample to reservoir, rinse tube w/ water & add to reservoir.
            5.  Wash filterwith -2-3 mL water. Dry filterwith -1-2 mL ethanol.
            6.  Mount filters and dry carefully for 5 minutes under heat lamp.
                       Count sample test source (STS) by alpha
                       spectrometry for 4-6 hours, or as needed.
                                                                                            + 1h

                                                                                            (31/2-41/2 h)
                                                                                                h
                                                                                           (51/4-61/4 h)
                                                                                           + 30 min
                                                                                           5%"-63/4 h
                                              +30 min

                                              61/4-71/4 h

                                              +4-6 h
04-16-2014
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