1、Designation: E321 96 (Reapproved 2012)Standard Test Method forAtom Percent Fission in Uranium and Plutonium Fuel(Neodymium-148 Method)1This standard is issued under the fixed designation E321; 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 stablefission product148Nd in irradiated uranium (U
3、) fuel (withinitial plutonium (Pu) content from 0 to 50 %) as a measure offuel burnup (1-3).21.2 It is possible to obtain additional information about theuranium and plutonium concentrations and isotopic abun-dances on the same sample taken for burnup analysis. If thisadditional information is desir
4、ed, it can be obtained by pre-cisely measuring the spike and sample volumes and followingthe instructions in Test Method E267.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish ap
5、pro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1193 Specification for Reagent WaterE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cia
6、lty Chemicals4E244 Test Method forAtom Percent Fission in Uranium andPlutonium Fuel (Mass Spectrometric Method)4E267 Test Method for Uranium and Plutonium Concentra-tions and Isotopic Abundances3. Summary of Test Method3.1 Fission product neodymium (Nd) is chemically sepa-rated from irradiated fuel
7、and determined by isotopic dilutionmass spectrometry. Enriched150Nd is selected as the Ndisotope diluent, and the mass-142 position is used to monitorfor natural Nd contamination. The two rare earths immediatelyadjacent to Nd do not interfere. Interference from other rareearths, such as natural or f
8、ission product142Ce or natural148Smand150Sm is avoided by removing them in the chemicalpurification (4 and 5).3.2 After addition of a blended150Nd,233U, and242Pu spiketo the sample, the Nd, U, and Pu fractions are separated fromeach other by ion exchange. Each fraction is further purified formass an
9、alysis. Two alternative separation procedures are pro-vided.3.3 The gross alpha, beta, and gamma decontaminationfactors are in excess of 103and are normally limited to thatvalue by traces of242Cm,147Pm, and241Am, respectively (andsometimes106Ru), none of which interferes in the analysis. The70 ng148
10、Nd minimum sample size recommended in theprocedure is large enough to exceed by 100-fold a typicalnatural Nd blank of 0.7 6 0.7 ng148Nd (for which a correctionis made) without exceeding radiation dose rates of 20 Sv/h(20 mR/h) at 1 m. Since a constant amount of fission productsis taken for each anal
11、ysis, the radiation dose from each sampleis similar for all burnup values and depends principally uponcooling time. Gamma dose rates vary from 200 Sv/h (20mR/h) at 1 m for 60-day cooled fuel to 20 Sv/h (2 mR/h) at1 m for 1-year cooled fuel. Beta dose rates are an order ofmagnitude greater, but can b
12、e shielded out with a12-in.(12.7-mm) thick plastic sheet. By use of such simple localshielding, dilute solutions of irradiated nuclear fuel dissolversolutions can be analyzed for burnup without an elaborateshielded analytical facility. The decontaminated Nd fraction ismounted on a rhenium (Re) filam
13、ent for mass analysis.Samples from 20 ng to 20 g run well in the mass spectrometerwith both NdO+and Nd+ion beams present. The metal ion isenhanced by deposition of carbonaceous material on thefilament as oxygen getter. (Double and triple filament designsdo not require an oxygen getter.)1This test me
14、thod is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1, 2012. Published June 2012. Originallyapproved in 1967 . Last previous edition approved in 2005 as E321 96(2005).DOI: 10
15、.1520/E0321-96R12.2The boldface numbers in parentheses refer to the list of references appended tothis test method.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to t
16、he standards Document Summary page onthe ASTM website.4Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 The burnu
17、p of an irradiated nuclear fuel can be deter-mined from the amount of a fission product formed duringirradiation. Among the fission products,148Nd has the follow-ing properties to recommend it as an ideal burnup indicator: (1)It is not volatile, does not migrate in solid fuels below theirrecrystalli
18、zation temperature, and has no volatile precursors.(2) It is nonradioactive and requires no decay corrections. ( 3)It has a low destruction cross section and formation fromadjacent mass chains can be corrected for. (4) It has goodemission characteristics for mass analysis. (5) Its fission yieldis ne
19、arly the same for235U and239Pu and is essentiallyindependent of neutron energy (6). (6) It has a shielded isotope,142Nd, which can be used for correcting natural Nd contami-nation. (7) It is not a normal constituent of unirradiated fuel.4.2 The analysis of148Nd in irradiated fuel does not dependon t
20、he availability of preirradiation sample data or irradiationhistory. Atom percent fission is directly proportional to the148Nd-to-fuel ratio in irradiated fuel. However, the productionof148Nd from147Nd by neutron capture will introduce asystematic error whose contribution must be corrected for. Inpo
21、wer reactor fuels, this correction is relatively small. In testreactor irradiations where fluxes can be very high, this correc-tion can be substantial (see Table 1).4.3 The test method can be applied directly to U fuelcontaining less than 0.5 % initial Pu with 1 to 100 GWdays/metric ton burnup. For
22、fuel containing 5 to 50 % initialPu, increase the Pu content by a factor of 10 to 100,respectively in both reagents 5.3 and 5.4.5. Reagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform
23、to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the det
24、ermination.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedin Specification D1193.5.3 Blended148Nd,239Pu, and238U Calibration StandardPrepare a solution containing about 0.0400 mg148Nd/litre, 50mg238U/litre, and 2.5 mg239Pu/litre,
25、 in nitric acid (HNO3,1 + 1) with 0.01 M hydrofluoric acid (HF) as follows. With anew calibrated, clean, Kirk-type micropipet, add 0.500 mL of239Pu known solution (see 5.11) to a calibrated 1-litre volu-metric flask. Rinse the micropipet into the flask three timeswith HNO3(1 + 1). In a similar manne
26、r, add 0.500 mL of238Uknown solution (see 5.12) and 1.000 mL of148Nd knownsolution (see 5.9). Add 10 drops of concentrated HF and diluteexactly to the 1-litre mark with HNO3(1 + 1) and mixthoroughly.5.3.1 From K148(see 5.9), calculate the atoms of148Nd/mLof calibration standard, C148, as follows:C14
27、85mL148Nd known solution1000 mL calibration standard3 K148(1)5.3.2 From K238(see 5.12), calculate the atoms of238U/mLof calibration standard, C238, as follows:C23 85mL238U known solution1000 mL calibration standard3 K238(2)5.3.3 From K239(see 5.11), calculate the atoms of239Pu/mLof calibration stand
28、ard, C23 9, as follows:C2395mL239Pu known solution1000 mL calibration standard3 K239(3)5.3.4 Flame seal 3 to 5-mL portions in glass ampoules toprevent evaporation after preparation until time of use. For use,break off the tip of an ampoule, pipet promptly the amountrequired, and discard any unused s
29、olution. If more convenient,calibration solution can be flame-sealed in pre-measured1000-L portions for quantitative transfer when needed.5.4 Blended150Nd,233U, and242Pu Spike SolutionPrepare a solution containing about 0.4 mg150Nd/litre, 50 mg233U/litre, and 2.5 mg242Pu/litre in HNO3(1 + 1) with 0.
30、01 MHF. These isotopes are obtained in greater than 95, 99, and99 % isotopic purity, respectively, from the Isotopes SalesDepartment of Oak Ridge National Laboratory. Standardize thespike solution as follows:5.4.1 In a 5-mL beaker, place about 0.1 mL of ferroussolution, exactly 500 L of calibration
31、standard (see 5.3) andexactly 500 L of spike solution (see 5.4). In a second beaker,place about 0.1 mL of ferrous solution and 1 mL of calibration5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlist
32、ed by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 K Factors to Correct148Nd for147Nd Thermal Neutron CaptureATota
33、l Neutron Flux,f (neutrons/cm2/s)Total Neutron Exposure, fI (neutrons/cm2)1 3 10203 3 10201 3 10212 3 10213 3 10213 3 10120.9985 0.9985 0.9985 0.9985 0.99851 3 10130.9956 0.9952 0.9950 0.9950 0.99503 3 10130.9906 0.9870 0.9856 0.9853 0.98521 3 10140.9858 0.9716 0.9598 0.9569 0.95593 3 10140.9835 0.9
34、592 0.9187 0.9008 0.89411 3 10150.9826 0.9526 0.8816 0.8284 0.8006AAssuming continuous reactor operation and a 274 6 91 barn147Nd effective neutron absorption cross section for a thermal neutron power reactor. This cross sectionwas obtained by adjusting the 440 6 150 barn147Nd cross section (7) meas
35、ured at 20C to a Maxwellian spectrum at a neutron temperature of 300C.E321 96 (2012)2standard without any spike. In a third beaker, place about 0.1mL of ferrous solution and 1 mL of spike solution withoutstandard. Mix well and allow to stand for 5 min to reduce Pu(VI) to Pu (III) or Pu (IV).5.4.2 Fo
36、llow the procedure described in 7.2.4-7.5.8 or7.6.2-7.7.11. Measure the Pu, U, and Nd isotopes by surfaceionization mass spectrometry following the procedure de-scribed in 7.8.1-7.8.3.2 . On the Pu fractions, record the atomratios of242Pu to239Pu in the calibration standard, C2/9; in thespike soluti
37、on, S2/9; and in the standard-plus-spike mixture,M2/9. On the U fractions record the corresponding233U-to-238Uratios, C3/8, S3/8, and M3/8. On the Nd fractions, record thecorresponding150Nd-to-148Nd ratios, C50/48, S50/48, and M50/48.Correct all average measured ratios for mass discriminationbias (s
38、ee 6.2).5.4.3 Calculate the number of atoms of150Nd/mL of Spike,A50, as follows:A505 C148M50/482 C50/48!/1 2 M50/48/S50/48!# (4)5.4.4 Calculate the number of atoms of233U/mL of spike,A33, as follows:A335 C238M3/82 C3/8!/1 2 M3/8/S3/8!# (5)5.4.5 Calculate the number of atoms of242Pu/mL spike, A42,as
39、follows:A425 C239M2/92 C2/9!/1 2 M2/9/S2/9!# (6)5.4.6 Store in the same manner as the calibration standard(see 5.3), that is, flame seal 3 to 5-mL portions in glassampoules. For use, break off the tip of an ampoule, pipetpromptly the amount required, and discard any unused solu-tion. If more conveni
40、ent, spike solution can be flame sealed ina premeasured 1000-L portions for quantitative transfer toindividual samples.5.5 Ferrous Solution (0.001 M)Add 40 mg of reagentgrade ferrous ammonium sulfate (Fe(NH4)2(SO4)26H2O) and1 drop of concentrated H2SO4to 5 mL of redistilled water.Dilute to 100 mL wi
41、th water and mix. This solution does notkeep well. Prepare fresh daily.5.6 Filament Mounting SolutionDissolve 70 mg of su-crose in 100 mL of water (single filament only).5.7 Hydrofluoric AcidReagent grade concentrated HF (28M).5.8 Methanol, absolute.5.9148Nd Known SolutionHeat natural Nd2O3(99.9 %pu
42、re) in an open crucible at 900C for1htodestroy anycarbonates present and cool in a dessicator. Weigh 0.4071 g ofNd2O3and place it in a calibrated 500-mL volumetric flask.Dissolve the oxide in HNO3(1 + 1) and dilute to the 500-mLmark with HNO3(1 + 1) and mix thoroughly. By using theweight of Nd2O3in
43、grams, and the purity, calculate the atomsof148Nd/mL of known solution, K148, as follows:K1485 gNd2O3/500 mL 3 % purity/1003 50.38mg148Nd/1 g Nd2O336.0253 1020atoms!/147.92 molecular weight (7)5.10 Perchloric Acid70 % HCIO4.5.11239Pu Known SolutionAdd 10 mL of HCl (1 + 1) toa clean calibrated 100-mL
44、 flask. Cool the flask in an ice waterbath. Allow time for the acid to reach approximately 0C andplace the flask in a glove box. Displace the air in the flask withinert gas (Ar, He, or N2). Within the glove box, open the U.S.National Institute of Standards and Technology PlutoniumMetal Standard Samp
45、le 949, containing about 0.5 g of Pu(actual weight individually certified), and add the metal to thecooled HCl. After dissolution of the metal is complete, add 1drop of concentrated HF and 40 mL of HNO3(1 + 1) and swirl.Place the flask in a stainless-steel beaker for protection andinvert a 50-mL bea
46、ker over the top and let it stand for at least8 days to allow any gaseous oxidation products to escape.Dilute to the mark with HNO3(1 + 1) and mix thoroughly. Byusing the individual weight of Pu in grams, the purity, and themolecular weight of the Pu given on the NIST certificate, withthe atom fract
47、ion, A9, determined as in 8.8, calculate the atomsof239Pu/mL of239Pu known solution, K239, as follows:K2395 mg Pu/100 mL solution!3 % purity/100!36.025 3 1020atoms/Pu molecular weight!3A9# (8)5.12238U Known SolutionHeat U3O8from the NationalInstitute of Standards and Technology Natural Uranium Oxide
48、Standard Sample 950 in an open crucible at 900C for1handcool in a dessicator in accordance with the certificate accom-panying the standard sample. Weigh about 12.0 g of U3O8accurately to 0.1 mg and place it in a calibrated 100-mLvolumetric flask. Dissolve the oxide in HNO3(1 + 1). Dilute tothe 100-m
49、L mark with HNO3(1 + 1) and mix thoroughly. Byusing the measured weight of U3O8in grams, the purity givenon the NIST certificate, and the atom fraction238U, A8,determined as in 8.5, calculate the atoms238U/mL of238Usolution, K238, as follows:K2385 g U3O8/100 mL solution! 3 % purity/1003 848.0 mg U/1 g U3O8! 3 6.0253 1020atoms/238.03 molecular weight! 3 A8# (9)5.13 Reagents and Materials for Procedure A:5.13.1 Dowex AGMP-1 ResinConvert Dowex AGMP-1(200 to 400 mesh) chloride form resin6to nitrate form bywashing 200 mL of resin in a suita
