Measurements for Flattop-HEU Benchmark Reevaluation

Technical Report · Wed Aug 31 04:00:00 EDT 2022

DOI:https://doi.org/10.2172/1885716· OSTI ID:1885716

Stolte, Kristin Nichole ^[1]; Cutler, Theresa Elizabeth ^[1]; Kiehne, Charlie William ^[1]; Amundson, Kelsey Marie ^[1]; Hayes, David Kirk ^[1]

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

In June 2022, high-fidelity measurements of the Flattop critical assembly were taken at the National Criticality Experiments Research Center (NCERC) at the Nevada National Security Site by a team from Los Alamos National Laboratory, Figure 1. Flattop-HEU is composed of a sphere of highly enriched uranium (HEU) surrounded by a thick spherical natural uranium (NU) reflector as shown in Figure 2 and Figure 3. These measurements were taken as part of the reevaluation of the Flattop-HEU benchmark evaluation for the International Criticality Safety Benchmark Evaluation Program (ICSBEP) Handbook. This reevaluation is being completed to update the benchmark to modern standards with significantly improved fidelity and uncertainty analysis. [1] The measurements address the largest identified uncertainties determined during a preliminary reevaluation in 2015. [2]

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 1885716
• Report Number(s): LA-UR-22-29086
• Country of Publication: United States
• Language: English

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