1、Designation: E 705 08Standard Test Method forMeasuring Reaction Rates by Radioactivation of Neptunium-2371This standard is issued under the fixed designation E 705; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 procedures for measuring reac-tion rates by assaying a fission product (F.P.) from the fissionreacti
3、on237Np(n,f)F.P.1.2 The reaction is useful for measuring neutrons withenergies from approximately 0.7 to 6 MeV and for irradiationtimes up to 30 to 40 years.1.3 Equivalent fission neutron fluence rates as defined inPractice E 261 can be determined.1.4 Detailed procedures for other fast-neutron detec
4、tors arereferenced in Practice E 261.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the us
5、er of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 170 Terminology Relating to Radiation Measurementsand DosimetryE 181 Test Methods for Detector Calibration an
6、d Analysisof RadionuclidesE 261 Practice for Determining Neutron Fluence, FluenceRate, and Spectra by Radioactivation TechniquesE 262 Test Method for Determining Thermal Neutron Re-action and Fluence Rates by Radioactivation TechniquesE 320 Test Method for Cesium-137 in Nuclear Fuel Solu-tions by Ra
7、diochemical Analysis3E 393 Test Method for Measuring Reaction Rates byAnaly-sis of Barium-140 From Fission DosimetersE 704 Test Method for Measuring Reaction Rates by Ra-dioactivation of Uranium-238E 844 Guide for Sensor Set Design and Irradiation forReactor Surveillance, E 706(IIC)E 944 Guide for A
8、pplication of Neutron Spectrum Adjust-ment Methods in Reactor Surveillance, E 706 (IIA)E 1005 Test Method forApplication andAnalysis of Radio-metric Monitors for Reactor Vessel Surveillance, E706(IIIA)E 1018 Guide for Application of ASTM Evaluated CrossSection Data File, Matrix E 706 (IIB)3. Termino
9、logy3.1 Definitions:3.1.1 Refer to Terminology E 170.4. Summary of Test Method4.1 High-purity237Np ( 1 MeV) fluence rate of 1 3 1011cm2s1,provided the237Np is shielded from thermal neutrons (seeFig. 2 of Guide E 844).5.4.2 Fission product production from photonuclear reac-tions, that is, (g,f) react
10、ions, while negligible near-power andresearchreactor cores, can be large for deep-water penetrations(1).55.5 Good agreement between neutron fluence measured by237Np fission and the54Fe(n,p)54Mn reaction has been dem-onstrated (2). The reaction237Np(n,f) F.P. is useful since it isresponsive to a broa
11、der range of neutron energies than mostthreshold detectors.5.6 The237Np fission neutron spectrum-averaged crosssection in several benchmark neutron fields are given inTable 3 of Practice E 261. Sources for the latest recommendedcross sections are given in Guide E 1018. In the case of the237Np(n,f)F.
12、P. reaction, the recommended cross section sourceis the ENDF/B-VI cross section (MAT = 9346) revision 1 (3).Fig. 1 shows a plot of the recommended cross section versusneutron energy for the fast-neutron reaction237Np(n,f)F.P.NOTE 1The data are taken from the Evaluated Nuclear Data file,ENDF/B-VI, ra
13、ther than the later ENDF/B-VII. This is in accordance withGuide E 1018 Guide for Application of ASTM Evaluated Cross SectionData File, 6.1. since the later ENDF/B-VII data files do not includecovariance information. For more details see Section H of (10)6. Apparatus6.1 Gamma-Ray Detection Equipment
14、that can be used toaccurately measure the decay rate of fission product activity arethe following two types (4):6.1.1 NaI(T1) Gamma-Ray Scintillation Spectrometer (seeTest Methods E 181 and E 1005).6.1.2 Germanium Gamma-Ray Spectrometer (see TestMethods E 181 and E 1005)Because of its high resolutio
15、n,the germanium detector is useful when contaminant activitiesare present.6.2 Balance, providing the accuracy and precision requiredby the experiment.6.3 Digital Computer, useful for data analysis, but is notnecessary (optional).4The sole source of supply of Vanadium-encapsulated monitors of high pu
16、rityknown to the committee at this time in the United States is Isotope Sales Div., OakRidge, TN 37830. In Europe, the sole source of supply is European Commission,JRC, Institute for Reference Materials and Measurements (IRMM) ReferenceMaterials Unit Retieseweg 111, B-2440 Geel, Belgium. If you are
17、aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5The boldface numbers in parentheses refer to the list of references appended to
18、this test method.TABLE 1 Recommended Nuclear Parameters for Certain FissionProductsFissionProductParentHalf-LifeA(6)PrimaryRadiationA(7) (keV)g Probability ofDecayA(7)MaximumUsefulIrradiationDuration95Zr 64.032 (6) d 724.192 (4) 0.4427 (22) 6 months756.725 (12) 0.543899Mo 2.7489 (6) d 739.500 (17) 0
19、.1213 (22) 300 hours777.921 (20) 0.0426 (8)103Ru 39.26 (2) d 497.084 (6) 0.910 (12) 4 months137Cs 30.3 (5) yr 661.657 (3)B0.8510B3040 years140Ba140La 12.752 (5) d 537.261 (9) 0.2439 (23) 11.5 months1596.21 (4) 0.954 (14)C1.1515D144Ce 289.91 (5) d 133.515 (2) 0.1109 (10) 23 yearsAThe lightface number
20、s in parentheses are the magnitude of plus or minusuncertainties in the last digit(s) listed.BWith137mBa (2.552 min) in equilibrium.CProbability of daughter140La decay.DWith140La (1.6781 d) in transient equilibrium.TABLE 2 Recommended Fission Yields for Certain FissionProductsAFissileIsotopeNeutronE
21、nergyReactionProductTypeYieldENDF/B-VIIB,AFission Yield (%)237Np(n,f) 0.5 MeV95Zr RC 5.66915 6 2%99Mo RC 6.11804 6 4%103Ru RC 5.5583 6 2.8 %137Cs RC 6.25127 6 2%137mBa RI 1.141e-3 6 64 %140Ba RC 5.48848 6 2%140La RI 5.121e-3 6 64 %144Ce RC 4.13935 6 2%ASpecial issue on Evaluated Nuclear Data File EN
22、DF/B-VII.0.” Nuclear DataSheets, J.K. Tull Editor. Vol. 107 December 2006. Data available on the ENDF/B-VII website at URL:http:/www.nndc.bnl.gov/exfor/endf00.htm.BAll yield data given as a %; RC represents a cumulative yield; RI represents anindependent yield.E7050827. Materials7.1 Neptunium-237 Al
23、loy or OxideHigh-purity237Np inthe form of alloy wire, foil, or oxide powder is available.7.1.1 The237Np target material should be furnished with acertificate of analysis indicating any impurity concentrations.7.2 Encapsulating MaterialsBrass, stainless steel, copper,aluminum, vanadium, and quartz h
24、ave been used as primaryencapsulating materials. The container should be constructedin such a manner that it will not create significant perturbationof the neutron spectrum or fluence rate and that it may beopened easily, especially if the capsule is to be openedremotely. Certain encapsulation mater
25、ials, for example, quartzand vanadium, allow gamma-ray counting without opening thecapsule since there are no interfering activities.8. Procedure8.1 Select the size and shape of the sample to be irradiated,taking into consideration the size and shape of the irradiationspace. The mass and exposure ti
26、me are parameters that can bevaried to obtain a desired count rate for a given neutron fluencerate.8.2 Weigh the sample to the accuracy and precision requiredof the experiment; encapsulate; and, if irradiated in a thermalneutron environment, surround with a suitable high-meltingthermal neutron absor
27、ber.NOTE 2The melting point of elemental cadmium is 321C. Foradditional precautions, see Test Method E 262.8.3 Irradiate the sample for the predetermined time period.Record the power level and any changes in power during theirradiation, the time at the beginning and end of each powerlevel, and the r
28、elative position of the monitors in the irradiationfacility.8.4 Check the sample for activity from cross contaminationby other monitors or material irradiated in the vicinity or fromany foreign substance adhering to the sample. Clean andreweigh, if necessary. If the sample is encapsulated oxidepowde
29、r and if it is necessary to open the capsule, suitablecontainment will be required.8.4.1 If chemical separation is necessary, dissolution can beachieved in 6 N HCl-1 N HF with periodic additions of H2O2,followed by fuming with H2SO4.NOTE 3Fuming with H2SO4may expel volatile fission productruthenium
30、and, unless performed with care, losses of other fissionproducts by spattering can occur.8.5 Analyze the sample for fission-product content in dis-integrations per second (see Test Methods E 181, E 320, andE 1005).8.5.1 It is assumed that the available apparatus has beencalibrated to measure F.P. ac
31、tivity, and that the experimenter iswell versed in the operation of the apparatus.8.5.2 Disintegration of137Cs nuclei produces 0.662-MeVgamma rays with a probability per decay of 0.852. It isrecommended that a137Cs activity standard is used.8.5.3 If the analyst is well versed in germanium countingan
32、d carefully calibrates the system, it is feasible to count137Cs-137mBa,140Ba-140La,95Zr, and144Ce directly withoutchemical separation. A x-ray shield, at least 2 mm thickness,will be required in the counting process.9. Calculation9.1 Calculate the saturation activity, As, as follows:As5 A/y1 2 e2lti
33、!e2ltw!# (1)FIG. 1 ENDF/B-VI Cross Section Versus Energy for the237Np(n,f)F.P. ReactionE705083where:l = disintegration constant for F.P., s1,A = number of disintegrations, measured during the count-ing period, s1,ti= irradiation duration, s,tw= elapsed time between the end of irradiation andcounting
34、, s, andy = fission yield.NOTE 4This equation applies where transient equilibrium has beenestablished, l is that of the parent species. This equation should not beapplied to the Ba/La line but can be applied to the other fission products.See Test Method E 393 for reading the140B/140La line.NOTE 5The
35、 equation for Asis valid if the reactor operated atessentially constant power and if corrections for other reactions (forexample, impurities, burnout, etc.) are negligible. Refer to Practice E 261for more generalized treatments.9.2 Calculate the reaction rate,6Rs, as follows:Rs5 As/No(2)where:No= nu
36、mber of target atoms.9.3 Refer to Practice E 261 and Guide E 944 for a discus-sion of the determination of fast neutron fluence rate.10. Report10.1 Practice E 261 describes how data should be reported.11. Precision and BiasNOTE 6Measurement of uncertainty is described by a precision andbias statemen
37、t in this standard.Another acceptable approach is to use TypeA and B uncertainty components (8, 9). This type A/B uncertaintyspecification is now used in International Organization for Standardization(ISO) Standards and this approach can be expected to play a moreprominent role in future uncertainty
38、 analyses.11.1 General practice indicates that disintegration rates canbe determined with a bias of 65 % (1S %) and with a precisionof 61 % (1S %). (11)11.2 The237Np cumulative fission product yields have anuncertainty between 2 % and 4 % (1S %) for the various fissionproducts as indicated in Table
39、1.12. Keywords12.1 fission dosimeter; fission product; fission reactionrates; Neptunium-237REFERENCES(1) Verbinski, V. V., et al, “Measurements and Calculations of PhotofissionEffects in a Swimming Pool Type Reactor,” Transactions of theAmerican Nuclear Society, Washington, DC, Vol 30, November 1978
40、.(2) Barry, K. M., and Corbett, J.A., “Measurement of Neutron Fluence byNeptunium-237 and Uranium-238 Fission Dosimeters,” Nuclear Tech-nology, Vol 11, May 1971.(3) ENDF/B-V Dosimetry Tape 531-G, Mat. No. 6399 (93-Np-237),October 1979.(4) Crouthamel, C. E. (Revised by Adams, F., and Dams, R.), Appli
41、edGamma-Ray Spectrometry, Pergamon Press, 1970.(5) “ENDF-201, ENDF/B-VI Summary Documentation,” P. F. Rose, Ed.Brookhaven National Laboratory Report BNL-NCS-174, 4th Edition,October, 1991.(6) Nuclear Wallet Cards, compiled by J. K. Tuli, National Nuclear DataCenter, April 2005.(7) Nuclear Data retri
42、eval program NUDAT, a computer file of evaluatednuclear structure and radioactive decay data, which is maintained bythe National Nuclear Data Center (NNDC), Brookhaven NationalLaboratory (BNL), on behalf of the International Network for NuclearStructure Data Evaluation, which functions under the aus
43、pices of theNuclear Data Section of the International Atomic Energy Agency(IAEA).(8) B.N. Taylor, C.E., Kuyatt, Guidelines for Evaluating and Expressingthe Uncertainty of NIST Measurement Results, NIST Technical Note1297. National Institute of Standards and Technology Gaithersburg,MD, 1994.(9) Guide
44、 in the Expression of Uncertainly in Measuremens, Interna-tional Organization for Standardization, 1995 ISBN 9267101889.(10) “Special Issue on Evaluated Nuclear Data file ENDF/B-VII.0.”Nuclear Data Sheets, J.K. Tuli Editor, Vol. 107, December 2006.(11) Adams, J.M., “Results for the NIST Round Robin
45、Test of FissionableDosimeters in Reactor Leakage Spectrum,” Reactor Dosimetry:Radiation Metrology and Assessment, ASTM STP 1389, AmericanSociety for Testing and Materials, West Conshohocken, PA 2001.ASTM International takes no position respecting the validity of any patent rights asserted in connect
46、ion with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsibl
47、e technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful cons
48、ideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 B
49、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).6Within the context of this standard, the terms “fission rate” and “reaction rate”can be used synonymously.E705084
