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Measurement uncertainty of rossi-alpha neutron experiments

Journal Article · · Annals of Nuclear Energy (Oxford)
 [1];  [2];  [2];  [3];  [3];  [3];  [3]
  1. Univ. of Michigan, Ann Arbor, MI (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); University of Michigan
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of Michigan, Ann Arbor, MI (United States)
+ Show Author Affiliations
Rossi-alpha neutron experiments are used to estimate the prompt neutron decay constant of a fissile assembly, a quantity of widespread interest in applications including in nuclear nonproliferation and criticality safety. This work develops a mathematical model to efficiently estimate measurement uncertainty of Rossi-alpha neutron experiments inferred from a two-exponential fit model with histogram binning. The derived uncertainty estimates were validated using repeated Rossi-alpha measurements of a subcritical, 4.5-kg sphere of weapons-grade, alpha-phase plutonium with nickel, copper, tungsten, and polyethylene reflectors. The estimates of uncertainty for the histogram data produced by the model were conservative and agree with the reference uncertainties within noise. The estimates of the prompt neutron decay constant uncertainty agreed with the reference uncertainties within one standard deviation. In conclusion, the proposed model will reduce total measurement times, ultimately reducing operational and procedural costs in application.
Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development
Grant/Contract Number:
NA0003920
OSTI ID:
1698019
Alternate ID(s):
OSTI ID: 2325553
Journal Information:
Annals of Nuclear Energy (Oxford), Journal Name: Annals of Nuclear Energy (Oxford) Vol. 147; ISSN 0306-4549
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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Figures / Tables (10)

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Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Error bars
Integral Experiments
Neutron noise
Nuclear Criticality Safety Program (NCSP)
Prompt neutron decay constant
Prompt period
Rossi-alpha
Subcritical measurements
Uncertainty