Testing new actinide cross sections proposed for ENDF/B-VII.

Conference · Thu Jan 01 00:00:00 EST 2004

DOI:https://doi.org/10.1063/1.1945053· OSTI ID:977885

MacFarlane, R E ^[1]

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1. Robert E.

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.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• OSTI ID: 977885
• Report Number(s): LA-UR-04-6948; TRN: US1003752
• Resource Relation: Journal Volume: 769; Conference: Submitted to: Proceedings - Intl. Conf. on Nuclear Data for Science&, Technology ND2004, Santa Fe, NM, Sept. 26 - Oct. 1, 2004
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
22 GENERAL STUDIES OF NUCLEAR REACTORS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDES
CROSS SECTIONS
DELAYED NEUTRONS
ELASTIC SCATTERING
FISSION
FISSION SPECTRA
INELASTIC SCATTERING
NEUTRONS
NUCLEAR PHYSICS
ORNL
RESONANCE
TESTING
URANIUM OXIDES
ZERO POWER REACTORS