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Title: Subcritical neutron noise measurements for plutonium systems with varying geometry and mass

Journal Article · · Annals of Nuclear Energy
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  1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
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Recently, experiments were performed at the National Criticality Experiments Research Center (NCERC) with Zero Power Physics Reactor (ZPPR) plates in two very different geometries. The intent of this set of experiments was to provide the EUCLID (Experiments Underpinned by Computational Learning for Improvements in Nuclear Data) project team measured data of multiple radiation detector responses to be used in an adjustment of plutonium nuclear data. The work shown in this paper will focus on multiplicity results measured for subcritical arrangements of ZPPR plates in the two geometries. The Hageโ€“Cifarelli formalism of the Feynman variance to-mean method, a moments-based time-correlated neutron noise approach, was used. A validation of the methodology used to estimate uncertainties in the moments was performed and is presented. The effective neutron multiplication factor (keff) value were inferred from this analysis. The keff values were compared to simulated values using the radiation transport code Monte Carlo N-Particleยฎ (MCNP). The results shown in this work provide evidence of larger bias in keff values as the geometric buckling of the system increases. This effect will be important for nuclear data validation and future adjustments of plutonium nuclear data.

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); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
89233218CNA000001
OSTI ID:
2203965
Alternate ID(s):
OSTI ID: 2281514
Report Number(s):
LA-UR-23-28560; TRN: US2408339
Journal Information:
Annals of Nuclear Energy, Vol. 195; ISSN 0306-4549
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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neutron multiplicity