Testing New Actinide Cross Sections Proposed for ENDF/B-VII
- Nuclear Physics Group, Theoretical Division, Los Alamos National Laboratory (United States)
Our Nuclear Physics Group has worked over the last several years to improve the ENDF/B actinide cross sections, especially as measured against the famous series of fast-spectrum critical experiments performed at Los Alamos under such names as Godiva, Jezebel, the Flattops, and Bigten. The new evaluations include changes in the high-energy fission cross sections, nubar, elastic scattering, inelastic scattering, fission spectra, and delayed neutrons that combine to significantly improve the calculated results for the Los Alamos critical assemblies. As a happy byproduct of this work, we found that the new evaluations also removed about half of a long-standing discrepancy in calculations of thermal-reactor critical experiments using lattices of low-enriched uranium oxide rods. In the meantime, work at the Oak Ridge National Laboratory has resulted in new proposed resonance parameters for U238. When these low-energy data are combined with the new high-energy data from Los Alamos, they have the effect of removing most of the rest of the problem for thermal lattices. Although more work will be done at both Los Alamos and Oak Ridge, including making the evaluations consistent with the new standards, the results presented in this talk provide promise that ENDF/B-VII will result in good improvements for users at both high and low neutron energies.
- OSTI ID:
- 20722603
- Journal Information:
- AIP Conference Proceedings, Vol. 769, Issue 1; Conference: International conference on nuclear data for science and technology, Santa Fe, NM (United States), 26 Sep - 1 Oct 2004; Other Information: DOI: 10.1063/1.1945053; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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