1、Designation: E264 08 (Reapproved 2013)Standard Test Method forMeasuring Fast-Neutron Reaction Rates by Radioactivationof Nickel1This standard is issued under the fixed designation E264; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method cover
3、s procedures for measuring reac-tion rates by the activation reaction58Ni(n,p)58Co.1.2 This activation reaction is useful for measuring neutronswith energies above approximately 2.1 MeV and for irradiationtimes up to about 200 days in the absence of high thermalneutron fluence rates (for longer irra
4、diations, see PracticeE261).1.3 With suitable techniques fission-neutron fluence ratesdensities above 107cm2s1can be determined.1.4 Detailed procedures for other fast-neutron detectors arereferenced in Practice E261.1.5 The values stated in SI units are to be regarded asstandard. No other units of m
5、easurement 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 user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory
6、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E170 Terminology Relating to Radiation Measurements andDosimetryE181 Test Methods for Detector Calibration and Analysis ofRadionuclidesE261 Practice for Determining Neutron Fluence, FluenceRate, and Spectra by Radioactivation Techni
7、quesE844 Guide for Sensor Set Design and Irradiation forReactor Surveillance, E 706 (IIC)E944 Guide for Application of Neutron Spectrum Adjust-ment Methods in Reactor Surveillance, E 706 (IIA)E1005 Test Method for Application and Analysis of Radio-metric Monitors for Reactor Vessel Surveillance, E 7
8、06(IIIA)E1018 Guide for Application of ASTM Evaluated CrossSection Data File, Matrix E706 (IIB)3. Terminology3.1 Definitions:3.1.1 Refer to Terminology E170.4. Summary of Test Method4.1 High-purity nickel is irradiated in a neutron field,thereby producing radioactive58Co from the58Ni(n,p)58Coactivat
9、ion reaction.4.2 The gamma rays emitted by the radioactive decay of58Co are counted in accordance with Test Methods E181 andthe reaction rate, as defined by Practice E261, is calculatedfrom the decay rate and irradiation conditions.4.3 The neutron fluence rate above about 2.1 MeV can thenbe calculat
10、ed from the spectral-weighted neutron activationcross section as defined by Practice E261.5. Significance and Use5.1 Refer to Guide E844 for the selection, irradiation, andquality control of neutron dosimeters.5.2 Refer to Practice E261 for a general discussion of thedetermination of fast-neutron fl
11、uence rate with threshold de-tectors.5.3 Pure nickel in the form of foil or wire is readilyavailable, and easily handled.1This test method is under the jurisdiction ofASTM Committee E10 on NuclearTechnology and Applicationsand is the direct responsibility of SubcommitteeE10.05 on Nuclear Radiation M
12、etrology.Current edition approved Jan. 1, 2013. Published January 2013. Originallyapproved in 1965. Last edition approved in 2008 as E264 08. DOI: 10.1520/E0264-08R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
13、Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.458Co has a half-life of 70.86 days3and emits a gammaray with an energy of 0.8
14、107593-MeV.45.5 Competing activities65Ni(2.5172 h) and57Ni(35.60 h)are formed by the reactions64Ni(n,)65Ni, and58Ni(n,2n)57Ni,respectively.5.6 Asecond 9.04 h isomer,58mCo, is formed that decays to70.86-day58Co. Loss of58Co and58mCo by thermal-neutronburnout will occur in environments5,6having therma
15、l fluencerates of 3 1012cm2s1and above. Burnout correctionfactors, R, are plotted as a function of time for several thermalfluxes in Fig. 1. Tabulated values for a continuous irradiationtime are provided in Hogg, et al.65.7 Fig. 2 shows a plot of cross section7versus energy forthe fast-neutron react
16、ion58Ni(n,p)58Co. This figure is forillustrative purposes only to indicate the range of response ofthe58Ni(n,p) reaction. Refer to Guide E1018 for descriptionsof recommended tabulated dosimetry cross sections.NOTE 1The data is taken from the Evaluated Nuclear Data File,ENDF/B-VI, rather than the lat
17、er ENDF/B-VII. This is in accordance withE1018, section 6.1, since the later ENDF/B-VII data files do not includecovariance information. For more details see Section H of reference 8.86. Apparatus6.1 NaI (T1) or High Resolution Gamma-Ray Spectrometer.Because of its high resolution, the germanium det
18、ector isuseful when contaminant activities are present (see Test Meth-ods E181 and E1005).6.2 Precision Balance, able to achieve the required accu-racy.6.3 Digital Computer, useful for data analysis (optional).7. Materials7.1 The nickel metal must be low in contained cobalt toprevent the production
19、of60Co by thermal-neutron capture.Nickel produced by the carbonyl (Mond) process is sufficientlyfree of cobalt for even the most adverse conditions. Wheneverpossible, all nickel should be tested for interfering impuritiesby neutron activation.7.2 Encapsulating MaterialsBrass, stainless steel, copper
20、,aluminum, quartz, or vanadium have been used as primaryencapsulating materials. The container should be constructedin such a manner that it will not create significant fluxperturbation and that it may be opened easily, especially if thecapsule is to be opened remotely (see Guide E844).8. Procedure8
21、.1 Decide on the size and shape of nickel sample to beirradiated. This is influenced by the irradiation space and theexpected production of58Co. Calculate the expected produc-tion rate of58Co from the activation equation described inSection 9, and adjust the sample size and irradiation time sothat t
22、he58Co may be counted accurately.8.2 Determine the level of thermal-neutron fluence rate byincluding a thermal-fluence rate monitor. Place the sample in aboron or cadmium shield if required.8.3 Weigh the sample.3J. K. Tulti, “Nuclear Wallet Cards,” National Nuclear Data Center, BrookhavenNational La
23、boratory, Upton, New York, April 2005.4Evaluated Nuclear Structure Data File (ENSDF), a computer file of evaluatednuclear structure and radioactive decay data, which is maintained by the NationalNuclear Data Center (NNDC), Brookhaven National Laboratory (BNL), on behalfof the International Network f
24、or Nuclear Structure Data Evaluation, which functionsunder the auspices of the Nuclear Data Section of the International Atomic EnergyAgency (IAEA). The URL is http;/www.nndc.bnl.gov/nndc/ensdf. The data quotedhere comes from the database as of January 1, 2002.5Hogg, C. H., Weber, L. D., and Yates,
25、E. C., “Isomers and the Effects on FastFlux Measurements Using Nickel,” Atomic Energy Commission R and DReport IDO-16744, 1962.6Hogg, C. H., Weber, L. D.,Yates, E.C., “Thermal Neutron Cross Sections of theCo58Isomers and the Effect on Fast Flux Measurements Using Nickel,” IDO-16744AEC Research activ
26、ation reaction; cross section; dosim-etry; fast-neutron monitor; neutron metrology; nickel; pressurevessel surveillance; reaction rateASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standa
27、rd 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 responsible technical committee and must be reviewed every five years andif
28、 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 consideration at a meeting of theresponsible technical committee, whi
29、ch 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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,U
30、nited 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). Permission rights to photocopy the standard ma
31、y also be secured from the ASTM website (www.astm.org/COPYRIGHT/).9B. N. Taylor, C.E. Kuyatt, Guidelines for Evaluating and Expressing theUncertainty of NIST Measurement Results, NIST Technical Note 1297, NationalInstitute of Standards and Technology, Gaithersburg, MD, 1994.10Guide in the Expression of Uncertainty in Measurements, InternationalOrganization for Standardization, 1995, ISBN 9267101889.E264 08 (2013)3
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