Two-Exponential Rossi-Alpha Analysis of Copper- and Polyethylene-Reflected Plutonium
Conference
·
· Transactions of the American Nuclear Society
- Univ. of Michigan, Ann Arbor, MI (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Michigan, Ann Arbor, MI (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
The prompt neutron decay constant $$\mathcal{α}$$, which is used to infer reactivity, is estimated using the Rossi-alpha technique that is predicated on fitting Rossi-alpha histograms. 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. Recent work also validated the two-exponential model for shields, a subset of reflectors, but not for reflectors in general. Ultimately, it is desirable to validate the two-exponential model for the general shield. This work will investigate if previous 3He measurements of plutonium reflected by copper and polyethylene, and replacement measurements where the plutonium is replaced by 252Cf are suitable for validating the new model. Since the 3He detectors (3He gas proportional counters embedded in a polyethylene matrix) inherently contain moderating/reflector material (to increase detection efficiency), this work also investigates the use of organic scintillation detectors that can directly detect fast, fission neutrons.
- 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:
- 1910013
- Report Number(s):
- LA-UR-19-28640
- Conference Information:
- Journal Name: Transactions of the American Nuclear Society Journal Issue: 1 Journal Volume: 121
- Country of Publication:
- United States
- Language:
- English
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