1、Designation:C100105 Designation: C1001 11Standard Test Method forRadiochemical Determination of Plutonium in Soil by AlphaSpectroscopy1This standard is issued under the fixed designation C1001; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of plutonium in soils at levels of detection dependen
3、t on count time, sample size,detector efficiency,detector, background, and tracer yield. This test method describes one acceptable approach to the determinationof plutonium in soil.1.2 This test method is designed for 10 g of soil, previously collected and treated as described in Practices C998 and
4、C999, butsample sizes up to 50 g may be analyzed by this test method. This test method may not be able to completely dissolve all formsof plutonium in the soil matrix.1.31.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.4 Thi
5、s standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific hazard stateme
6、nts are given in Section 9.2. Referenced Documents2.1 ASTM Standards: ASTM Standards:2C859 Terminology Relating to Nuclear MaterialsC998 Practice for Sampling Surface Soil for RadionuclidesC999 Practice for Soil Sample Preparation for the Determination of RadionuclidesC1163 Practice for Mounting Act
7、inides for Alpha Spectrometry Using Neodymium FluorideC1284 Practice for Electrodeposition of the Actinides for Alpha SpectrometryD1193 Specification for Reagent WaterD3084 Practice for Alpha-Particle Spectrometry of WaterD3648 Practices for the Measurement of Radioactivity Practices for the Measure
8、ment of RadioactivityD7282 Practice for Set-up, Calibration, and Quality Control of Instruments Used for Radioactivity Measurements3. Summary of Test Method3.1 Plutonium is extracted from the soil with a mixture of nitric, hydrofluoric, and hydrochloric acids in the presence of242Pu or236Pu isotopic
9、 tracer (See Appendix for purification and standardization of236Pu tracer). Plutonium is isolated by anionexchange, then electrodeposited onto a polished metal disk for determination by alpha spectrometry. As an option, the plutoniummay be prepared for alpha spectrometry measurement by using copreci
10、pitation with neodymium fluoride. The range of chemicalyield is between 40 and 90 %. The test method is based on a published procedure (1) .34. Significance and Use4.1 A soil sampling and analysis program provides a direct means of determining the concentration and distribution ofradionuclides in so
11、il. A soil analysis program has the most significance for the preoperational monitoring program to establishbaseline concentrations prior to the operation of a nuclear facility. Soil analysis, although useful in special cases involvingunexpected releases, is a poor technique for assessing small incr
12、emental releases and is therefore not recommended as a method1This test method is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Test Methods.Current edition approved June 1, 2005. Published July 2005. Originally approved
13、 in 1983. Last previous edition approved in 2000 as C100100. DOI:10.1520/C1001-05.on Methods of Test.Current edition approved Feb. 15, 2011. Published February 2011. Originally approved in 1983. Last previous edition approved in 2005 as C1001 05. DOI:10.1520/C1001-11.2For referenced ASTM standards,
14、visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3The boldface numbers in parentheses refer to the list of references at the end of this sta
15、ndard.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult pr
16、ior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.for routine monitoring releases of radioa
17、ctive material. Nevertheless, because soil is an integrator and a reservoir of long-livedradionuclides, and serves as an intermediary in several of the plutonium pathways of potential importance to humans, knowledgeof the concentration of plutonium in soil is essential.5. Apparatus5.1 Electrodeposit
18、ion Apparatus (2), see Practice C1284.5.2 Alpha Spectrometer, capable of 40 to 50 keV resolution on actual samples electrodeposited on a flat, mirror-finished metalplanchet, and a fractional counting efficiency greater than 17 %, and a background less than 0.010 cpm over each designated energyregion
19、. Resolution is defined as the full width half maximum (FWHM) in keV, the distance between those points on either sideof the alpha peak where the count is equal to one-half the maximum count. Also see Practices D3084 and D3648.NOTE 1A regular program of measurement control operations should be condu
20、cted for the alpha spectrometry system, such as regular backgroundchecks, source check to determine system stability, control charting, and careful handling of samples during changing. See Practice D7282.5.3 PTFE-polytetrafluoroethylene beakers, 250-mL.6. Reagents6.1 Purity of ReagentsReagent grade
21、chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available (3). Other grades may be used, provided it is first a
22、scertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of the determination.6.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water as defined inSpecification D1193, Type III.6.3 Reagent blanks s
23、hould be run to determine their contribution to the sample result.6.4 Ammonium Hydroxide (sp gr 0.90)Concentrated ammonium hydroxide (NH4OH).6.5 Ammonium Iodide (NH4I) (1 M)Dissolve 14.5 g of NH4I in 100 mL water.6.6 Ammonium Iodide, Hydrochloric Acid Solution (NH4I-HCl)Add 25 mL 1 M ammonium iodide
24、 to 500 mL concentratedhydrochloric acid. Prepare fresh prior to use.6.7 Analytical Grade Anion Exchange Resin Type 1, 8 % cross-linked, 100 to 200 mesh, chloride form4Store the resin inwater in a wash bottle, transfer sufficient resin to a 1.3-cm ID ion exchange column to give a 10-cm bed of settle
25、d resin. Convertthe resin to the nitrate form by passing 100 mL of HNO3(8M) through the column at maximum flow rate.6.8 Boric Acid (H3BO3).6.9 Hydrochloric Acid (sp gr 1.19)Concentrated hydrochloric acid (HCl).6.10 Hydrochloric Acid (3M)Add 250 mL of concentrated HCl (sp gr 1.19) to 500 mL of water,
26、 mix, and dilute to 1.0 L withwater.6.11 Hydrochloric Acid (1.7M)Add 142 mL of concentrated HCl (sp gr 1.19) to 500 mL of water, mix, and dilute to 1.0 Lwith water.6.12 Hydrofluoric Acid (48 to 51 %)Concentrated hydrofluoric acid (HF).6.13 Iron Carrier solution (10 g Iron (III)/L)Dissolve 10.0 g iro
27、n metal in HCl (1.7M) and dilute to 1 L with HCl (1.7M).6.14 Nitric Acid (sp gr 1.42)Concentrated nitric acid (HNO3).6.15 Nitric Acid (8M)Add 500 mL of concentrated HNO3(sp gr 1.42) to 400 mL of water, mix, and dilute to 1.0 L with water.6.16 Nitric Acid (1.8M)Add 112 mL of concentrated HNO3(sp gr 1
28、.42) to 500 mL of water, mix, and dilute to 1.0 L withwater.6.17 Octyl alcohol.6.18 Sodium Bisulfite (NaHSO3).6.19 Sodium Hydroxide (50 %)Dissolve 500 g of NaOH in 500 mL water. A 50 % NaOH solution is available commercially.6.20 Sodium Nitrite (NaNO2).6.21 Thymol Blue Indicator, Sodium Salt, 0.02 %
29、 Solution.6.22 National Standard Traceable Plutonium-236 Reagent. National Standard Traceable Plutonium-236 Reagent.46.23 National Standard Traceable Plutonium-242 Reagent . National Standard Traceable Plutonium-242 Reagent.47. Sampling7.1 Collect the sample in accordance with Practice C998.7.2 Prep
30、are the sample for analysis in accordance with Practice C999.7.3 Samples consisting of 10 to 50 g of soil can be readily analyzed by the procedure. In order to obtain more representativesamples, as well as lowering the minimum detectable concentration, the analyses of large soil samples is desirable
31、. In general, itis poor practice to use less than 10 g of sample, unless replicate analyses are performed, because of needed sensitivity to determinelower levels of activity.4Resin obtainable from BioRad Laboratories (Hercules, CA) and from Eichrom Technologies, Inc. (Darien, IL).4Plutonium-236 is a
32、vailable from NBL and is traceable to NIST. Plutonium-242 is available as a Standard Reference Material from the National Institute of Standardsand Technology, Gaithersburg, MD 20899.C1001 1128. Calibration and Standardization8.1The counting efficiency of the alpha spectrometer is used to determine
33、the minimum detectable concentration (MDC), lowerlimit of detection (LLD), and chemical recovery. The efficiency of the alpha spectrometer is determined as the ratio of the observedcount rate to the known disintegration rate times the counting efficiency of the 2p counter. The procedure is as follow
34、s:8.1.1Count a241Am source traceable to a national standards organization on a 2p alpha counter. The 2p counter efficiency isdetermined by:(1) CE2p5C1/A1!T!1.023!where:C1= net counts of the241Am source,A1= certified activity of the241Am source (cps), corrected for decay,T = duration of the count tim
35、e, s, and1.023 = backscatter factor correcting the counting efficiency of a source on platinum to that on stainless steel.8.1.2Electrodeposit239Pu on a polished metal disk, using the equipment and procedure listed in this method, and counting onthe 2p counter. This gives the known disintegration rat
36、e, C2p.8.1.3The counting efficiency of the alpha spectrometer is determined as follows:CE5Cs!CE2p!/C2p! (2)where:Cs= net count rate of the electroplated source over the entire energy region on the alpha spectrometer (cps); the observedcount rate,CE2p= counting efficiency of the 2p counter, andC2p= n
37、et counting rate of the same source on the 2p counter (cps).8.2The quantity of the tracer to be used should be in the expected range (but not less than 0.17 Bq) of the isotopic activity beingdetermined so that the statistical uncertainty in the yield determination will not be larger than that of the
38、 nuclide being determined.8.1 The fractional counting efficiency of the alpha spectrometer is used to determine the chemical yield. The fractional efficiencyof the alpha spectrometer is determined as the ratio of the observed count rate to the known disintegration rate.8.2 The quantity of the tracer
39、 to be used should be in the expected range (but not less than 0.17 Bq) of the isotopic activity beingdetermined so that the statistical uncertainty in the chemical yield determination will not be larger than that of the nuclide beingdetermined.9. Precautions9.1 Adequate laboratory facilities, such
40、as fume hoods and controlled ventilation, along with safe techniques, must be used inthis procedure. Extreme care should be exercised in using hydrofluoric and other hot, concentrated acids. Use of proper gloves isrecommended. Refer to the laboratorys chemical hygiene plan and other applicable guida
41、nce for handling chemical andradioactive materials and for the management of radioactive, mixed, and hazardous waste.9.2 Hydrofluoric acid is a highly corrosive acid that can severely burn skin, eyes, and mucous membranes. Hydrofluoric acidis similar to other acids in that the initial extent of a bu
42、rn depends on the concentration, the temperature, and the duration of contactwith the acid. Hydrofluoric acid differs from other acids because the fluoride ion readily penetrates the skin, causing destructionof deep tissue layers. Unlike other acids that are rapidly neutralized, hydrofluoric acid re
43、actions with tissue may continue for daysif left unattended. Due to the serious consequences of hydrofluoric acid burns, prevention of exposure or injury of personnel is theprimary goal. Utilization of appropriate laboratory controls (hoods) and wearing adequate personal protective equipment to prot
44、ectfrom skin and eye contact is essential.10. Procedure10.1 Weigh a 10.0 6 0.010.1 g soil aliquot into a 250 mL PTFE beaker.10.2 Wet sample with distilled water and add a known quantity of236Pu or242Pu tracer.10.3 Add concentrated HNO3(sp gr 1.42) a few drops at a time as fast as the frothing and vi
45、gor of the reaction will permit untilthe entire sample is covered.10.4 Add 60 mL more of the concentrated HNO3(sp gr 1.42) and 30 mL of concentrated HF (48 to 51 %) and digest on ahotplate with frequent stirring (TFE fluorocarbon stirring rod) for about 1 h (Note 2 and Note 3).NOTE 2For organic soil
46、s, first add the nitric acid only in small portions while stirring. If the solution threatens to overflow as a result of frothgeneration, add a few drops of octyl alcohol and stir. Digest on a hotplate until the evolution of reddish-brown fumes is reduced to a barely visible level.Cool to room tempe
47、rature before carefully adding the concentrated hydrofluoric acid (48 to 51 %) and digesting for an hour.NOTE 3For larger soil aliquots, larger amounts of the acids (in the same proportions) should be used. For example, for a 50 g sample, use 200 mLconcentrated. HNO3and 100 mL HF, etc., with appropr
48、iately sized containers.10.5 Remove from the hotplate and cool somewhat before adding 30 mL concentrated HNO3(sp gr 1.42) and 30 mLconcentrated HF (48 to 51 %). Digest on the hotplate with intermittent stirring for an additional 1 h.C1001 11310.6 Remove from the hotplate and cool. Carefully add 20 m
49、L concentrated HCl (sp gr 1.19) and stir. Heat on hotplate for 45min with occasional stirring.10.7 Add about5gofpowdered boric acid and digest for an additional 15 min with occasional stirring.10.8 Add approximately 200 mg of sodium bisulfite and continue heating until the solution has evaporated to a liquid volumeof approximately 20 mL.10.9 Add 50 mL of water and digest on a hotplate while stirring for 10 min to dissolve soluble salts.10.10 Cool and transfer approximately equal parts of the total sample into centrifuge bottles with a minimum of water fr
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