Application of the Rossi-alpha method to simulations of HEU and organic scintillators

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

DOI:https://doi.org/10.13182/t123-32976· OSTI ID:1906362

McSpaden, Alexander Thomas ^[1]; McKenzie IV, Geordie Espy ^[1]; Hutchinson, Jesson D. ^[1]; Sanchez, Rene Gerardo ^[1]; Cutler, Theresa Elizabeth ^[1]; Myers, William L. ^[1]; Weldon Jr., Robert Allen ^[1]

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

The International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook contains thousands of high-quality benchmark measurements that include detailed descriptions of experiment designs and exhaustive accounting of uncertainties. These benchmarks are used extensively by the criticality safety and nuclear data communities. A subcritical benchmark involving bare, highly enriched uranium (HEU) has yet to be accepted to the handbook. The Measurement of Uranium Subcritical and Critical (MUSiC) was proposed to address this gap. MUSiC will be performed at the National Criticality Experiments Research Center (NCERC) and will leverage bare HEU hemisphere shells that can be assembled in a variety of configurations. The measurement has the following key benefits: it will be the first set of fast, subcritical measurements of HEU to be submitted to ICSBEP; ten configurations will be measured spanning from nearly no multiplication to critical (e.g., it is a measurement of similar systems with different re activities); measurements of an all-HEU system will be of value for nuclear data validation, providing results that assist in determining biases in both measurements and simulations. A variety of detector systems will be used including a Neutron Multiplicity Array Detector (NoMAD) system (similar to the MC-15), four small volume 0.635 cm (#8960;) × 7.59 cm 3He detectors (ideal for measuring prompt neutron decay constants due to their fast recovery speed), and an array of eight 5.08 cm (#8960;) × 5.08 cm EJ-309 organic scintillator detectors. The focus of this work is the simulation of the subcritical MUSiC configurations including the EJ-309 detectors and the application of the Rossi-α method. The EJ-309 organic scintillator detector array is a new detection system that will be deployed at NCERC. Organic scintillators are ideal for measurements of fast, subcritical systems due to their short time response on the order of nanoseconds.

• 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)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 1906362
• 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

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
EJ-309 Organic Scintillator Detector Array
Integral Experiments
International Criticality Safety Benchmark Evaluation Project (ICSBEP)
Measurement of Uranium Subcritical and Critical (MUSiC)
National Criticality Experiments Research Center (NCERC)
Neutron Multiplicity Array Detector (NoMAD) system
Nuclear Criticality Safety Program (NCSP)