Comparison of results from the MCNP Criticality Validation Suite using ENDF/B-VI and Preliminary ENDF/B-VII Nuclear Data

Conference · Sun Sep 26 00:00:00 EDT 2004 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1945047· OSTI ID:977859

Mosteller, Russell D. ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

The MCNP Criticality Validation Suite is a collection of 31 benchmarks taken from the International Handbook of Evaluated Criticality Safety Benchmark Experiments. MCNP5 calculations clearly demonstrate that, overall, nuclear data for a preliminary version of ENDFB-VII produce better agreement with the benchmarks in the suite than do corresponding data from ENDF/B-VI. Additional calculations identify areas where improvements in the data still are needed. Based on results for the MCNP Criticality Validation Suite, the Pre-ENDF/B-VII nuclear data produce substantially better overall results than do their ENDF/B-VI counterparts. The calculated values for k_eff for bare metal spheres and for an IEU cylinder reflected by normal uranium are in much better agreement with the benchmark values. In addition, the values of k_efffor the bare metal spheres are much more consistent with those for corresponding metal spheres reflected by normal uranium or water. In addition, a long-standing controversy about the need for an ad hoc adjustment to the ²³⁸U resonance integral for thermal systems may finally be resolved. On the other hand, improvements still are needed in a number of areas. Those areas include intermediate-energy cross sections for ²³⁵U, angular distributions for elastic scattering in deuterium, and fast cross sections for ²³⁷Np.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• OSTI ID: 977859
• Report Number(s): LA-UR-04-6489; TRN: US201012%%775
• Journal Information: AIP Conference Proceedings, Vol. 769; Conference: International Conference on Nuclear Data for Science and Technology , Santa Fe, NM (United States), 26 Sep - 1 Oct 2004; ISSN 0094-243X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
97 MATHEMATICS AND COMPUTING
ANGULAR DISTRIBUTION
BENCHMARKS
CRITICALITY
CROSS SECTIONS
DEUTERIUM
ELASTIC SCATTERING
MANUALS
RESONANCE INTEGRALS
SAFETY
URANIUM
VALIDATION
WATER
Nuclear Criticality Safety Program (NCSP)
MCNP Criticality Validation Suite
Results
Comparision