Rossi-alpha Uncertainty Quantification by Analytic, Bootstrap, and Sample Methods to Inform Fitting Best Practices

Conference · Wed Nov 18 04:00:00 EST 2020 · Transactions of the American Nuclear Society

DOI:https://doi.org/10.13182/t123-33069· OSTI ID:1906453

Hua, M. Y. ^[1]; Bravo, C. A. ^[1]; Marchie, R. M. ^[2]; Hutchinson, J. D. ^[3]; McKenzie, G. E. ^[3]; Pozzi, S. A. ^[2]

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1. Univ. of Michigan, Ann Arbor, MI (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

The prompt neutron period (the negative reciprocal of the prompt neutron decay constant) can be estimated using the Rossi-alpha technique that is predicated on fitting Rossi alpha histograms and of interest in nuclear criticality safety and nonproliferation. The histograms are traditionally fit with a one-exponential model; however, recent work has proposed a two-exponential model to account for reflector induced phenomenon. Until recently, the uncertainty quantification for either model was inadequate (inaccurate and demanded large measurement times). Measurement uncertainty quantification by sample and analytic methods was developed and validated in Ref. The purpose of this transaction is to (i) validate a new bootstrap method by comparing bin-by-bin error bar estimates and (ii) demonstrate how to choose bin widths and reset times to optimize precision and accuracy.

• 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); National Science Foundation (NSF), Washington, DC (United States)
• DOE Contract Number: 89233218CNA000001; NA0002534; NA0003920
• OSTI ID: 1906453
• Conference Information: Journal Name: Transactions of the American Nuclear Society Journal Issue: 1 Journal Volume: 123
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Integral Experiments
Nuclear Criticality Safety Program (NCSP)
One-Exponential Model
Prompt Neutron Period
Two-Exponential Model