1、Designation: E 321 96 (Reapproved 2005)Standard Test Method forAtom Percent Fission in Uranium and Plutonium Fuel(Neodymium-148 Method)1This standard is issued under the fixed designation E 321; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 (U) 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 de
4、sired, it can be obtained by pre-cisely measuring the spike and sample volumes and followingthe instructions in Test Method E 267.1.3 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 establis
5、h appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 1193 Specification for Reagent WaterE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial Chemi
6、calsE 244 Test Method for Atom Percent Fission in Uraniumand Plutonium Fuel (Mass Spectrometric Method)E 267 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 and dete
7、rmined 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 fission p
8、roduct142Ce 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 analysis.
9、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 ng148Nd minim
10、um 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 analysis, th
11、e 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 be shield
12、ed 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) filament for
13、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.)4. Significance and U
14、se4.1 The burnup 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 t
15、heir1This test method 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 Jan. 1, 2005. Published March 2005. Originallyapproved in 1967 . Last previous edition approved in 1996 as E 3
16、21 96.2The 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 the standards
17、 Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.recrystallization temperature, and has no volatile precursors.(2) It is nonradioactive and requires no decay corrections. ( 3)It has a low dest
18、ruction cross section and formation fromadjacent mass chains can be corrected for. (4) It has goodemission characteristics for mass analysis. (5) Its fission yieldis nearly the same for235U and239Pu and is essentiallyindependent of neutron energy (6). (6) It has a shielded isotope,142Nd, which can b
19、e 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 the availability of preirradiation sample data or irradiationhistory. Atom percent fission is directly proportional to the148Nd-to-fu
20、el ratio in irradiated fuel. However, the productionof148Nd from147Nd by neutron capture will introduce asystematic error whose contribution must be corrected for. Inpower reactor fuels, this correction is relatively small. In testreactor irradiations where fluxes can be very high, this correc-tion
21、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 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. R
22、eagents and Materials5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are availa
23、ble.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of Water Unless otherwise indicated, refer-ences to water shall be understood to mean reagent water asdefined
24、in Specification D 1193.5.3 Blended148Nd,239Pu, and238U Calibration StandardPrepare a solution containing about 0.0400 mg148Nd/litre, 50mg238U/litre, and 2.5 mg239Pu/litre, in nitric acid (HNO3,1 + 1) with 0.01 M hydrofluoric acid (HF) as follows. With anew calibrated, clean, Kirk-type micropipet, a
25、dd 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 manner, add 0.500 mL of238Uknown solution (see 5.12) and 1.000 mL of148Nd knownsolution (see 5.9). Add 10 drops of concentrated HF an
26、d 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:C1485mL148Nd known solution1000 mL calibration standard3 K148(1)5.3.2 From K238(see 5.12), calculate the atoms of238U/mLof calibrat
27、ion 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 standard, C23 9, as follows:C2395mL239Pu known solution1000 mL calibration standard3 K239(3)5.3.4 Flame seal 3 to 5-mL portions in gl
28、ass 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 solution. If more convenient,calibration solution can be flame-sealed in pre-measured1000-L portions for quantitative transfer wh
29、en 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 0.01 MHF. These isotopes are obtained in greater than 95, 99, and99 % isotopic purity, respectively, from the Isotopes SalesDepart
30、ment 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 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
31、 mL of calibrationstandard 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).4“Reagent Chemicals, American Chemical Society Specifications,” Am. Chemi-c
32、al Soc., Washington, DC. For suggestions on the testing of reagents not listed bytheAmerican Chemical Society, see “Reagent Chemicals and Standards,” by JosephRosin, D. Van Nostrand Co., Inc., New York, NY, and the “United StatesPharmacopeia.”TABLE 1 K Factors to Correct148Nd for147Nd Thermal Neutro
33、n CaptureATotal 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
34、10140.9835 0.9592 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 se
35、ction (7) measured at 20C to a Maxwellian spectrum at a neutron temperature of 300C.E 321 96 (2005)25.4.2 Follow 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 t
36、he Pu fractions, record the atomratios of242Pu to239Pu in the calibration standard, C2/9; in thespike solution, 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
37、-148Nd ratios, C50/48, S50/48, and M50/48.Correct all average measured ratios for mass discriminationbias (see 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 f
38、ollows: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 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
39、 the tip of an ampoule, pipetpromptly the amount required, and discard any unused solu-tion. If more convenient, 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
40、sulfate (Fe(NH4)2(SO4)26H2O) and1 drop of concentrated H2SO4to 5 mL of redistilled water.Dilute to 100 mL with 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 AcidR
41、eagent grade concentrated HF (28M).5.8 Methanol, absolute.5.9148Nd Known SolutionHeat natural Nd2O3(99.9 %pure) 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
42、HNO3(1 + 1) and dilute to the 500-mLmark with HNO3(1 + 1) and mix thoroughly. By using theweight of Nd2O3in 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
43、)5.10 Perchloric Acid 70 % HCIO4.5.11239Pu Known SolutionAdd 10 mL of HCl (1 + 1) toa clean calibrated 100-mL 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). W
44、ithin the glove box, open the U.S.National Institute of Standards and Technology PlutoniumMetal Standard Sample 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
45、 mL of HNO3(1 + 1) and swirl.Place the flask in a stainless-steel beaker for protection andinvert a 50-mL beaker 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
46、 Pu in grams, the purity, and themolecular weight of the Pu given on the NIST certificate, withthe atom fraction, 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
47、)5.12238U Known SolutionHeat U3O8from the NationalInstitute of Standards and Technology Natural Uranium OxideStandard 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
48、mg and place it in a calibrated 100-mLvolumetric flask. Dissolve the oxide in HNO3(1 + 1). Dilute tothe 100-mL 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
49、 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 resin5to nitrate form bywashing 200 mL of resin in a suitable column (for example, a250-mL buret) with HNO3(1 + 1) until a drop of effluentfalling into an AgNO3solution remains clear. Finally, rinsewith water, and dry overnight in a vacuum dessicator
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