Impact of MCNP Unresolved Resonance Probability-Table Treatment on Uranium and Plutonium Benchmarks

Conference · Mon Sep 20 00:00:00 EDT 1999

OSTI ID:761232

Mosteller, Russell D. ^[1]; Little, Robert C. ^[2]

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

A probability-table treatment recently has been incorporated into an intermediate version of the MCNP Monte Carlo code named MCNP4XS. This paper presents MCNP4XS results for a variety of uranium and plutonium criticality benchmarks, calculated with and without the probability-table treatment. It is shown that the probability-table treatment can produce small but significant reactivity changes for plutonium and ²³³U systems with intermediate spectra. More importantly, it can produce substantial reactivity increases for systems with large amounts of ²³⁸U and intermediate spectra.

• 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)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 761232
• Report Number(s): LA-UR-99-2300
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICS AND COMPUTING
BENCHMARKS
CRITICALITY
Cross Section Evaluation Working Groups (CSEWG)
Evaluated Nuclear Data File (ENDF)
Highly Enriched Uranium (HEU)
Intermediate Spectra
Intermediate-Enriched Uranium (IEU)
International Criticality Safety Benchmark Evaluation Program (ICSBEP)
Low-Enriched Uranium (LEU)
MCNP4XS
Monte Carlo Code
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM
RESONANCE
SAFETY
SPECTRA
URANIUM