A comparison of Monte Carlo fission models for safeguards neutron coincidence counters
Abstract
Monte Carlo simulation is a powerful tool used to model neutron coincidence detectors for international safeguards. The simulation has typically sampled properties such as the fission neutron multiplicity, energy, and direction, from independent probability density functions. However, multiplicity counters detect event-based neutron correlations and thus more accurate fission event modeling is needed. To respond to this need, the Fission Reaction Event Yield Algorithm (FREYA) and the Cascading Gamma-ray Multiplicity with Fission (CGMF) models were added in the newest version of MCNP, MCNP6.2. The models simulate individual fission events conserving momentum, energy, and angular momentum such that correlated particles are emitted. The effects of the new models on simulations of safeguards neutron coincidence counters were studied and compared to standard MCNP simulations. The MCNPX-PoliMi model was also included in the comparison. The properties of fission neutrons from safeguards relevant isotopes were compared to literature references. Then a hypothetical simplified detector was modeled to isolate the effects of specific differences between models. Experimental measurements from previous work were modeled and agreements were compared. Lastly, the probabilities of correlated events occurring in the experimental measurements were calculated with the different models. For example, the probability was calculated of detecting neutrons from both inducedmore »
- Authors:
-
[1];
[2];
[2];
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Florida, Gainesville, FL (United States)
- Univ. of Florida, Gainesville, FL (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Publication Date:
- Research Org.:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Univ. of Michigan, Ann Arbor, MI (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA); USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development (NA-22)
- OSTI Identifier:
- 1458959
- Alternate Identifier(s):
- OSTI ID: 1523199; OSTI ID: 1575945
- Report Number(s):
- LA-UR-18-20887
Journal ID: ISSN 0168-9002; TRN: US1901537
- Grant/Contract Number:
- AC52-06NA25396; NA0002534
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
- Additional Journal Information:
- Journal Volume: 903; Journal Issue: C; Journal ID: ISSN 0168-9002
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; FREYA; CGMF; MCNP; Safeguards; Neutron coincidence and multiplicity counting
Citation Formats
Weinmann-Smith, Robert K., Swinhoe, Martyn Thomas, Trahan, Alexis Chanel, Andrews, Madison Theresa, Menlove, Howard Olsen, and Enqvist, Andreas. A comparison of Monte Carlo fission models for safeguards neutron coincidence counters. United States: N. p., 2018.
Web. doi:10.1016/j.nima.2018.06.055.
Weinmann-Smith, Robert K., Swinhoe, Martyn Thomas, Trahan, Alexis Chanel, Andrews, Madison Theresa, Menlove, Howard Olsen, & Enqvist, Andreas. A comparison of Monte Carlo fission models for safeguards neutron coincidence counters. United States. https://doi.org/10.1016/j.nima.2018.06.055
Weinmann-Smith, Robert K., Swinhoe, Martyn Thomas, Trahan, Alexis Chanel, Andrews, Madison Theresa, Menlove, Howard Olsen, and Enqvist, Andreas. Sat .
"A comparison of Monte Carlo fission models for safeguards neutron coincidence counters". United States. https://doi.org/10.1016/j.nima.2018.06.055. https://www.osti.gov/servlets/purl/1458959.
@article{osti_1458959,
title = {A comparison of Monte Carlo fission models for safeguards neutron coincidence counters},
author = {Weinmann-Smith, Robert K. and Swinhoe, Martyn Thomas and Trahan, Alexis Chanel and Andrews, Madison Theresa and Menlove, Howard Olsen and Enqvist, Andreas},
abstractNote = {Monte Carlo simulation is a powerful tool used to model neutron coincidence detectors for international safeguards. The simulation has typically sampled properties such as the fission neutron multiplicity, energy, and direction, from independent probability density functions. However, multiplicity counters detect event-based neutron correlations and thus more accurate fission event modeling is needed. To respond to this need, the Fission Reaction Event Yield Algorithm (FREYA) and the Cascading Gamma-ray Multiplicity with Fission (CGMF) models were added in the newest version of MCNP, MCNP6.2. The models simulate individual fission events conserving momentum, energy, and angular momentum such that correlated particles are emitted. The effects of the new models on simulations of safeguards neutron coincidence counters were studied and compared to standard MCNP simulations. The MCNPX-PoliMi model was also included in the comparison. The properties of fission neutrons from safeguards relevant isotopes were compared to literature references. Then a hypothetical simplified detector was modeled to isolate the effects of specific differences between models. Experimental measurements from previous work were modeled and agreements were compared. Lastly, the probabilities of correlated events occurring in the experimental measurements were calculated with the different models. For example, the probability was calculated of detecting neutrons from both induced fission in uranium and spontaneous fission of Cf-252 in the same fission chain.},
doi = {10.1016/j.nima.2018.06.055},
journal = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},
number = C,
volume = 903,
place = {United States},
year = {Sat Jun 23 00:00:00 EDT 2018},
month = {Sat Jun 23 00:00:00 EDT 2018}
}
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Figures / Tables:
Fig. 1: Average neutron multiplicity of spontaneous and induced fission for the fission models of MCNP compared to values from Santi and Miller [19] and Holden and Zucker [18].
Figures / Tables found in this record: