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Title: Review and Assessment of Neutron Cross Section and Nubar Covariances for Advanced Reactor Systems

In January 2007, the National Nuclear Data Center (NNDC) produced a set of preliminary neutron covariance data for the international project 'Nuclear Data Needs for Advanced Reactor Systems'. The project was sponsored by the OECD Nuclear Energy Agency (NEA), Paris, under the Subgroup 26 of the International Working Party on Evaluation Cooperation (WPEC). These preliminary covariances are described in two recent BNL reports. The NNDC used a simplified version of the method developed by BNL and LANL that combines the recent Atlas of Neutron Resonances, the nuclear reaction model code EMPIRE and the Bayesian code KALMAN with the experimental data used as guidance. There are numerous issues involved in these estimates of covariances and it was decided to perform an independent review and assessment of these results so that better covariances can be produced for the revised version in future. Reviewed and assessed are uncertainties for fission, capture, elastic scattering, inelastic scattering and (n,2n) cross sections as well as prompt nubars for 15 minor actinides ({sup 233,234,236}U, {sup 237}Np, {sup 238,240,241,242}Pu, {sup 241,242m,243}Am and {sup 242,243,244,245}Cm) and 4 major actinides ({sup 232}Th, {sup 235,238}U and {sup 239}Pu). We examined available evaluations, performed comparison with experimental data, taken into account uncertaintiesmore » in model parameterization and made use state-of-the-art nuclear reaction theory to produce the uncertainty assessment.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
946126
Report Number(s):
BNL--81884-2008-IR
R&D Project: 05055; KB0301041; TRN: US0901264
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Technical Report
Research Org:
Brookhaven National Laboratory
Sponsoring Org:
Doe - Office Of Science
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACTINIDES; BNL; CROSS SECTIONS; ELASTIC SCATTERING; EVALUATION; FISSION; INELASTIC SCATTERING; LANL; NEA; NEUTRONS; NUCLEAR REACTIONS; OECD