U-235(n, f), U-233(n, f) and Pu-239(n, f) Prompt Fission NeUtron Spectra

作者：Maslov V M^*; Tetereva N A; Pronyaev V C; Kagalenko A B; Zolotarev K I; Capote R; Granier T; Morillon B; Hambsch F J; Sublet J C

来源：Journal of the Korean Physical Society, 2011, 59(2): 1337-1342.

DOI：10.3938/jkps.59.1337

• Prompt fission neutron spectra
• Uranium-233
• Uranium-235
• Plutonium-239

New prompt fission neutron spectra (PFNS) matrices for the n+U-235, n+U-233, and n+Pu-239 systems are prepared. Present and previous PFNS shapes are drastically different from each other, the former being consistent,with measured data base. A combined generalized least-squares fit of nth+U-235, nth+U-233, nth+Pu-239, and Cf-252(sf) measured data base is accomplished. The solution of the longstanding problem of inconsistency of U-235 integral data testing and differential prompt fission neutron spectra data (PFNS) is proposed. Similar problems for the n+U-233 and n+Pu-239 are envisaged, revealing arbitrary tweaking of relevant neutron cross sections. Fast U-235 integral critical assemblies like Codiva or Flattop benchmarks are reproduced with the same accuracy as with the PFNS of the major data libraries. That reveals a rather delicate compensation effect, tracking the success of the distorted PFNS of the major data libraries to the excessive number of neutrons at energies of 1-3 MeV. Thermal assembly benchmarking reveals positive biases in k(eff), which might be attributed to the influence of a soft energy tail of the present PFNS. For some of Valduc's LCT benchmarks biases in k(off) are less than 20 pcm. Fast Pu-239 integral critical experiments like jezebel reveal the influence of overestimated inelastic scattering for Pu-239, arbitrarily introduced previously to diminish the influence on the k(eff) of the distortion of the PFNS.

• 出版日期2011-8
• 单位中国地震局