1、ANSI/ANS-5.1-2005decay heat power inlight water reactorsANSI/ANS-5.1-2005Copyright American Nuclear Society Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-ANSI/ANS-5.1-2005American National StandardDecay Heat Powerin Light Wat
2、er ReactorsSecretariatAmerican Nuclear SocietyPrepared by theAmerican Nuclear SocietyStandards CommitteeWorking Group ANS-5.1Published by theAmerican Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USAApproved April 1, 2005by theAmerican National Standards Institute, Inc.Cop
3、yright American Nuclear Society Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-AmericanNationalStandardDesignation of this document as an American National Standard attests thatthe principles of openness and due process have b
4、een followed in the approvalprocedure and that a consensus of those directly and materially affected bythe standard has been achieved.This standard was developed under procedures of the Standards Committee ofthe American Nuclear Society; these procedures are accredited by the Amer-ican National Stan
5、dards Institute, Inc., as meeting the criteria for AmericanNational Standards. The consensus committee that approved the standardwas balanced to ensure that competent, concerned, and varied interests havehad an opportunity to participate.An American National Standard is intended to aid industry, con
6、sumers, gov-ernmental agencies, and general interest groups. Its use is entirely voluntary.The existence of an American National Standard, in and of itself, does notpreclude anyone from manufacturing, marketing, purchasing, or using prod-ucts, processes, or procedures not conforming to the standard.
7、By publication of this standard, the American Nuclear Society does not insureanyone utilizing the standard against liability allegedly arising from or afterits use. The content of this standard reflects acceptable practice at the time ofits approval and publication. Changes, if any, occurring throug
8、h developmentsin the state of the art, may be considered at the time that the standard issubjected to periodic review. It may be reaffirmed, revised, or withdrawn atany time in accordance with established procedures. Users of this standardare cautioned to determine the validity of copies in their po
9、ssession and toestablish that they are of the latest issue.The American Nuclear Society accepts no responsibility for interpretations ofthis standard made by any individual or by any ad hoc group of individuals.Requests for interpretation should be sent to the Standards Department atSociety Headquar
10、ters. Action will be taken to provide appropriate response inaccordance with established procedures that ensure consensus on theinterpretation.Comments on this standard are encouraged and should be sent to SocietyHeadquarters.Published byAmerican Nuclear Society555 North Kensington AvenueLa Grange P
11、ark, Illinois 60526 USACopyright 2005 by American Nuclear Society.Any part of this standard may be quoted. Credit lines should read “Extracted fromAmerican National Standard ANSI0ANS-5.1-2005 with permission of the publisher,the American Nuclear Society.” Reproduction prohibited under copyright conv
12、entionunless written permission is granted by the American Nuclear Society.Printed in the United States of AmericaCopyright American Nuclear Society Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword(This Foreword is not
13、a part of American National Standard “Decay Heat Power in LightWater Reactors,” ANSI0ANS-5.1-2005.)The American Nuclear Society Nuclear Power Plant Standards Committee ap-proved the American National Standard “Decay Heat Power in Light WaterReactors” in August 1994, which was released in 1995 11), s
14、uperceding the 1979version. The standard was developed to fulfill a need for evaluations of fissionreactor performance dependent upon knowledge of decay heat power in the fuelelements. The standard replaced a 1971 draft standard 2 (see Appendix A).The 1994 revision to the standard incorporated addit
15、ional measurements ofdecay heat that were published 36 and updated evaluations of decay heatusing summation calculations based on improved nuclear databases 7,8. In1991, comparisons of elements of the standard with results of the new measure-ments and the new summation calculations were published 9.
16、 In that report,proposed improvements to the standard were outlined. In response to that re-port, the tabular data in the tables entitled “Data for Standard Decay HeatPower” and associated uncertainties were reevaluated for the three fuel isotopes235U,238U, and239Pu and evaluated for the fuel isotop
17、e241Pu and were thenadded to the 1994 revision.In the interim between the release of the 1994 standard and this revision, fewnew decay heat measurements have been reported in the literature. At the timethis revision was completed, these new data had been integrated into the JENDLfiles 10. These data
18、 were not incorporated into the fission yield evaluations forENDF0B-VI since they were direct fission yield measurements. However, decayheat values calculated using the updated JENDL libraries have been comparedwith the recommended decay heat values in the 1994 standard 1 and werefound to agree with
19、in the uncertainties cited in the standard 11.The revised 2005 standard contains the main features of the 1994 standardexcept that the specific “simplified method” as described in the 1994 standard isincorporated in the 2005 standard in a new Appendix D as one example of asimplified model. A correct
20、ion for Eq. (D.2) formerly Eq. (13) in the 1994 stan-dard is included in the Appendix D example. Section 3.6 has been modified topermit substitution of a user-provided simplified model under the conditionsspecified. Minor corrections have also been made to Eqs. (10) and (C.6) and tothe text in Secti
21、on 3.5. The Gmax(t) values reported in Table 13 have beenrecalculated using CINDER90 and ENDF0B-VI data 12. The 1994 Gmaxvalues13 were based on calculations performed with ENDF0B-IV data. The empiricalrepresentation of the correction factor for short times Eq. (11) is based on aparametric study of t
22、he influence of neutron capture on fission products asreported by Spinrad and Tripathi 14 and is not changed from the 1994 versionof the standard.The revised 2005 standard is the same as the previous versions of the standardin that(1) the standard prescribes fission product decay heat power and its
23、uncer-tainty for reactor operating histories;(2) the standard prescribes data that are applicable to light water reactors(LWRs) of the type currently operating in the United States;1)Numbers in brackets refer to corresponding numbers in “Foreword References” on p. iv.iCopyright American Nuclear Soci
24、ety Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-(3) the standard prescribes the recoverable energy release rates from fissionproduct decay but does not specify the spatial distribution of the deposition ofthe energy in reac
25、tor materials;(4) decay heat power for239U and239Np are separately prescribed and are tobe added to the fission product decay heat power;(5) in the standard, the uncertainty is expressed in a statistical sense as onestandard deviation in a normal distribution;(6) the standard presents decay power fo
26、r two irradiation conditions: (a) afission pulse and (b) an irradiation of 1013s to represent infinite reactoroperation;(7) the effect of neutron capture in fission products during reactor operationis accounted for in the revised standard. An upper bound for the effect ofneutron capture in fission p
27、roducts that provides conservative values of decayheat power is given for the case of a long operation of a235U-fueled LWR athigh neutron flux;(8) for cooling times greater than 105s, the standard is based solely uponsummation calculations rather than empirical data and summation calcula-tions as at
28、 shorter decay times;(9) the formulations are based upon the assumption that the energy releaseper fission during operation Qifor each nuclide is independent of time;(10) a method is prescribed for obtaining decay heat power for arbitrary reac-tor operating histories from the standard;(11) the decay
29、 heat power is related to the operating power of the reactor viathe fission rate and the recoverable energy per fission during operation;(12) decay heat power from activation products in reactor materials is notspecified in the standard.Features that distinguish the revised standard from the 1979 st
30、andard but areconsistent with the 1994 standard are the following:(1) The cooling-time region of validity has been extended to 1010s. In the 1979standard the time region of validity was 109s;(2) Data are prescribed for decay heat power from fission products from fis-sioning of the major fissionable
31、nuclides present in LWRs, i.e.,235U,239Pu, and241Pu thermal, and238U fast, and methods are prescribed for evaluating thetotal fission product decay heat power from the data given for these specificfuel nuclides. The 1979 standard gave standard curves for235U and239Puthermal, and238U fast;(3) The sta
32、ndard values adopted for238U are based upon an evaluation of newexperimental data and summation calculations. In the 1979 standard, thevalues for238U were obtained solely from summation calculations;(4) The standard values adopted for241Pu are based upon evaluation of exper-imental data and summatio
33、n calculations. The 1979 standard did not give aseparate set of values and prescribed that235U values should be used forcontributions from all other fissioning actinides other than239Pu and238U;(5) Standard values and uncertainties for pulse thermal fission235U have beenrevised for times after shutd
34、own of 1.0, 1.5, and 2.0 s, based upon a recentlypublished evaluation by Tobias 15 of all available experimental data for235U.iiCopyright American Nuclear Society Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-These changes in
35、volve increases of decay heat power of 16.2, 8.0, and 3.3%,respectively. Corresponding uncertainties have been reduced for these valuesfrom those given in the 1979 standard, also based on the Tobias evaluation;(6) Standard values and uncertainties for pulse thermal fission of235U havebeen revised fo
36、r times after shutdown greater than 1.5H11003109s. These changesreflect improved nuclear data and uncertainties used in summation calcula-tions for long-lived fission products, principally99Tc and126Sn;(7) Standard uncertainties for pulse thermal fission of239Pu have been re-vised for times after sh
37、utdown of 1.0, 1.5, and 2.0 s and between 20 and15,000 s, based on the Tobias evaluation 15 of all available experimental datafor239Pu, as well as the excellent agreement of the experimental results ofAkiyama et al. 5 with the results of Dickens et al. 3;(8) Standard values and uncertainties for pul
38、se thermal fission of239Pu havebeen revised for times after shutdown greater than 5 H11003 109s, reflectingimproved nuclear data and uncertainties used in summation calculations forlong-lived fission products, principally99Tc and126Sn.Summation calculations by Ryman et al. 16 for long cooling times
39、in support ofU.S. Nuclear Regulatory Commission Regulatory Guide (RG) 3.54 17 on spent-fuel storage are in good agreement with data predicted by the 1979 standard; RG3.54 accepts the use of the 1979 standard in its cooling-time region of validity.Isotope inventory codes 13 that use summation techniq
40、ues to predict decayheat power have been subjected to a controlled intercomparison 18,19 andfound to provide essentially equivalent results. Dickens et al. 9 compare the1979 standard with international decay heat power standards or proposed stan-dards 2022.Further revisions of the standard are plann
41、ed to(1) improve the capture effect specification;(2) include contributions from actinides not already included;(3) specify total recoverable energy Q for major elements;(4) separate beta-ray and gamma-ray components;(5) complete separate data sets for other fuel elements and other neutronenergies.T
42、he foregoing items (1), (2), and (3) were included in the recommendations fornear-term improvements to the standard by Dickens et al. 9.The formal presentation of the revised standard is the same as for the 1994standard, thus allowing ease in upgrading computer programs. Users applyingthe standard t
43、o reactor safety analysis should justify that the inputs (e.g., therecoverable energy Q) to the standard are appropriate.Fission product yields and uncertainties used in summation calculations for therevised standard are consistent with ANS-19.8, “Fission-Product Yields for235U,238U, and239Pu” (in d
44、raft form).The American National Standard ANSI0ANS-5.1-1994 1 is superseded by thepresent revision. iii Copyright American Nuclear Society Provided by IHS under license with ANSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Foreword References1 ANSI0ANS-5.1-1994,
45、“Decay Heat Power in Light Water Reactors,” Ameri-can Nuclear Society (1994).2 Proposed ANS Standard, “Decay Energy Release Rates Following Shut-down of Uranium-Fueled Thermal Reactors,” Approved by SubcommitteeANS-5, American Nuclear Society Standards Committee (Oct. 1971) (Re-vised Oct. 1973).3 J.
46、 K. Dickens, T. A. Love, J. W. McConnell, and R. W. Peelle, “Fission-Product Energy Release for Times Following Thermal-Neutron Fission ofPlutonium-239 and Plutonium-241 Between 2 and 14000 s,” Nucl. Sci.Eng., 78, 126 (1981); see also J. K. Dickens, T. A. Love, J. W. McConnell,and R. W. Peelle, “Fis
47、sion-Product Energy Release for Times FollowingThermal-Neutron Fission of235U Between 2 and 14000 s,” Nucl. Sci. Eng.,74, 106 (1980).4 K. Baumung, “Measurements of235U Fission-Product Decay Heat Between15 s and 4000 s,” KFK-3262, Kernforschungszentrum Karlsruhe (1981).5 M. Akiyama, K. Furuta, T. Ida
48、, H. Hashikura, Y. Oka, and S. An, “DecayHeat Curve Evaluation Test (V),” ORNL-tr-4784, Oak Ridge National Lab-oratory (1981); see also M. Akiyama and S. An, “Gamma Decay Heat for 14MeV Neutron Fission of235U,238U, and232Th,” Proc. NEANDC SpecialistsMtg. Yields and Decay Data of Fission Product Nucl
49、ides, October 2427,1983, Nuclear EnergyAgency Nuclear Data Committee, BNL-51778, pp. 305312 (1983); see also M. Akiyama and J. Katakura, “Measured Data ofDelayed Gamma-Ray Spectra from Fissions of232Th,233U,235U,238U and239Pu by Fast Neutrons: Tabular Data,” JAERI-M-88-252, Japan AtomicEnergy Research Institute (Dec. 1988).6 P. I. Johansson, “Integral Determination of the Beta and Gamma He
