Evaluation of the ²³⁵ U resonance parameters to fit the standard recommended values

Journal Article · Wed Sep 13 00:00:00 EDT 2017 · EPJ Web of Conferences

DOI:https://doi.org/10.1051/epjconf/201714602021· OSTI ID:1411346

Leal, Luiz ^[1]; Noguere, Gilles ^[2]; Paradela, Carlos ^[3]; Durán, Ignacio ^[4]; Tassan-Got, Laurent ^[5]; Danon, Yaron ^[6]; Jandel, Marian ^[7]

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1. Inst. of Radioprotection and Nuclear Safety (IRSN), Fontenay-aux-Roses (France)
2. Alternative Energies and Atomic Energy Commission (CEA), Saint-Paul-les-Durance (France)
3. European Commission, Geel (Belgium). Inst. for Reference Materials and Methods Joint Research Center
4. Univ. of Santiago (Spain)
5. National Center for Scientific Research, Osay (France)
6. Rensselaer Polytechnic Inst., Troy, NY (United States)
7. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

A great deal of effort has been dedicated to the revision of the standard values in connection with the neutron interaction for some actinides. While standard data compilation are available for decades nuclear data evaluations included in existing nuclear data libraries (ENDF, JEFF, JENDL, etc.) do not follow the standard recommended values. Indeed, the majority of evaluations for major actinides do not conform to the standards whatsoever. In particular, for the n + ²³⁵U interaction the only value in agreement with the standard is the thermal fission cross section. We performed a resonance re-evaluation of the n + ²³⁵U interaction in order to address the issues regarding standard values in the energy range from 10-5 eV to 2250 eV. Recently, ²³⁵U fission cross-section measurements have been performed at the CERN Neutron Time-o-Flight facility (TOF), known as n_TOF, in the energy range from 0.7 eV to 10 keV. The data were normalized according to the recommended standard of the fission integral in the energy range 7.8 eV to 11 eV. As a result, the n_TOF averaged fission cross sections above 100 eV are in good agreement with the standard recommended values. The n_TOF data were included in the ²³⁵U resonance analysis that was performed with the code SAMMY. In addition to the average standard values related to the fission cross section, standard thermal values for fission, capture, and elastic cross sections were also included in the evaluation. Our paper presents the procedure used for re-evaluating the ²³⁵U resonance parameters including the recommended standard values as well as new cross section measurements.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC). Nuclear Physics (NP) (SC-26)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1411346
• Report Number(s): LA-UR-16-26633; TRN: US1800214
• Journal Information: EPJ Web of Conferences, Vol. 146; ISSN 2100-014X
• Publisher: EDP Sciences
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS