A Proposal for Benchmarking {sup 235}U Nuclear Data

Journal Article · Mon Jan 15 04:00:00 EST 2001 · Nuclear Science and Engineering

OSTI ID:20804686

Santos, A dos ^[1]; Fuga, R ^[1]; Jerez, R ^[1]; Abe, A Y ^[2]; Filho, E A ^[2]

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1. Instituto de Pesquisas Energeticas e Nucleares (Brazil)
2. Centro Tecnologico da Marinha em Sao Paulo (Brazil)

Two experiments performed at the IPEN/MB-01 reactor are suggested to serve as a benchmark problem to verify mainly the adequacy of the {sup 235}U nuclear data for criticality analyses and for the isothermal reactivity coefficient determination of thermal reactors. The experiments are claimed to be well-defined, and they are suitable for a benchmark problem partially due to their small uncertainties and partially due to the lack of any sort of calculated correction factors or any quantity that comes either from the calculational methodologies or from another experiment. The isothermal experiment fulfills a specific need to introduce a reactor response that is sensitive to the {sup 235}U cross-section shape below 5 meV. This feature could be accomplished due mainly to the very precise control bank system characteristics of the IPEN/MB-01 reactor. The MCNP-4B calculational analyses reveal that the most recent {sup 235}U evaluation (Leal-Derrien-Larson's evaluation) incorporated in ENDF/B-VI release 5 performs well in the theory-experiment result comparisons of the aforementioned experiments. Particularly in the isothermal experiment, ENDF/B-VI release 5 produces results that even considering the deviations inherent to the Monte Carlo method meet the desired accuracy ({+-}1.0 pcm/deg. C) for the isothermal reactivity coefficient determination in contrast to the JEF-2.2 and JENDL-3.2 libraries, which produce unacceptably high k{sub eff} results. The main reasons are the {sup 235}U nuclear data in the case of JEF-2.2 and the nuclear data of both {sup 235}U and iron in the case of JENDL-3.2.

• OSTI ID: 20804686
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 1 Vol. 137; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCURACY
BENCHMARKS
COMPARATIVE EVALUATIONS
CONTROL
CORRECTIONS
CRITICALITY
CROSS SECTIONS
IRON
MEV RANGE
MONTE CARLO METHOD
NUCLEAR DATA COLLECTIONS
REACTIVITY COEFFICIENTS
THERMAL REACTORS
URANIUM 235