Quasi-differential neutron induced neutron emissions from ²³⁵U, and ²³⁹Pu

Journal Article · 13 September 2021 · Annals of Nuclear Energy

DOI: https://doi.org/10.1016/j.anucene.2021.108647 · OSTI ID:2477789

Mohindroo, Kumar S. ^[1]; Danon, Yaron ^[1]; Blain, Ezekiel ^[1]; Devlin, Matthew ^[2]; Kelly, Keegan J. ^[2]

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1. Rensselaer Polytechnic Inst., Troy, NY (United States)
2. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Uncertainty in nuclear reaction cross sections, angular distributions, and other nuclear data directly impact how well simulations of nuclear systems represent physical observations. Here, to determine how well the nuclear data in ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0 evaluations describe the physical behaviour of ²³⁵U, and ²³⁹Pu when subjected to a neutron flux, the neutron emission spectrum was measured for carbon, 93.0% ²³⁵U, and 93.9% ²³⁹Pu samples, and compared against detailed MCNP6 simulations. The measurements were performed at the Los Alamos Neutron Science Center using a quasi-differential method previously developed at Rensselaer Polytechnic Institute. The measurement spanned 0.82–20 MeV and 30–150 degrees. The measurements show there are a significant number of discrepancies between library predictions of the neutron yield and physical observation. A few of the main discrepancies found are described in this paper. Based on these results a new evaluation utilizing these results for carbon, ²³⁵U, and ²³⁹Pu is recommended.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP); USNRC
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2477789
• Report Number(s): LA-UR--20-30430
• Journal Information: Annals of Nuclear Energy, Journal Name: Annals of Nuclear Energy Vol. 165; ISSN 0306-4549
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English