Exploiting fission chain reaction dynamics to image fissile materials

Chapman, Pete; Mueller, Jonathan; Newby, Jason; Mattingly, John

doi:10.1016/j.nima.2019.05.001

Title: Exploiting fission chain reaction dynamics to image fissile materials

Abstract

Radiation imaging is one potential method to verify nuclear weapons dismantlement. In this work, we present a method to discriminate between non-multiplying and multiplying neutron sources using a neutron coded aperture imaging system. This method applies time-correlated pulse-height (TCPH) analysis to identify neutrons in fission chain reactions and recreate images using only these events. This analysis was applied to measurements of weapons-grade plutonium (WGPu) metal and ²⁵²Cf performed at the Nevada National Security Site (NNSS) Device Assembly Facility in July 2015. The results demonstrate it is possible to eliminate the non-fissile ²⁵²Cf source from the image while preserving the fissile WGPu source. TCPH analysis was also applied to additional scenes in which the WGPu and ²⁵²Cf sources were measured individually. The results of these separate measurements further demonstrate the ability to remove the non-fissile ²⁵²Cf source and retain the fissile WGPu source. Simulations performed using MCNPX-PoliMi indicate that in a one hour measurement, hollow WGPu spheres are retained at a 1σ level for neutron multiplications M ≃ 2:7 and above. This work has potential application to dismantlement verification where it may be valuable to verify that all neutron sources in an image are multiplying.

Authors:

Chapman, Pete ^[1]; Mueller, Jonathan ^[2]; Newby, Jason ^[3]; Mattingly, John ^[2]

North Carolina State Univ., Raleigh, NC (United States); United States Military Academy, West Point, NY (United States)
North Carolina State Univ., Raleigh, NC (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Publication Date:: Tue May 07 00:00:00 EDT 2019

Research Org.:: Univ. of Michigan, Ann Arbor, MI (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development (NA-22)

OSTI Identifier:: 1798653

Grant/Contract Number:: 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: 935; Journal ID: ISSN 0168-9002

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Disarmament verification; Neutron coded aperture imaging; Time-correlated pulse-height analysis

Citation Formats


                    Chapman, Pete, Mueller, Jonathan, Newby, Jason, and Mattingly, John. Exploiting fission chain reaction dynamics to image fissile materials.  United States: N. p., 2019. 
Web.  doi:10.1016/j.nima.2019.05.001.

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                    Chapman, Pete, Mueller, Jonathan, Newby, Jason, & Mattingly, John. Exploiting fission chain reaction dynamics to image fissile materials.  United States.  https://doi.org/10.1016/j.nima.2019.05.001

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                    Chapman, Pete, Mueller, Jonathan, Newby, Jason, and Mattingly, John. Tue .  
"Exploiting fission chain reaction dynamics to image fissile materials".  United States.  https://doi.org/10.1016/j.nima.2019.05.001.  https://www.osti.gov/servlets/purl/1798653.

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@article{osti_1798653,

  title        = {Exploiting fission chain reaction dynamics to image fissile materials},

  author       = {Chapman, Pete and Mueller, Jonathan and Newby, Jason and Mattingly, John},

  abstractNote = {Radiation imaging is one potential method to verify nuclear weapons dismantlement. In this work, we present a method to discriminate between non-multiplying and multiplying neutron sources using a neutron coded aperture imaging system. This method applies time-correlated pulse-height (TCPH) analysis to identify neutrons in fission chain reactions and recreate images using only these events. This analysis was applied to measurements of weapons-grade plutonium (WGPu) metal and 252Cf performed at the Nevada National Security Site (NNSS) Device Assembly Facility in July 2015. The results demonstrate it is possible to eliminate the non-fissile 252Cf source from the image while preserving the fissile WGPu source. TCPH analysis was also applied to additional scenes in which the WGPu and 252Cf sources were measured individually. The results of these separate measurements further demonstrate the ability to remove the non-fissile 252Cf source and retain the fissile WGPu source. Simulations performed using MCNPX-PoliMi indicate that in a one hour measurement, hollow WGPu spheres are retained at a 1σ level for neutron multiplications M ≃ 2:7 and above. This work has potential application to dismantlement verification where it may be valuable to verify that all neutron sources in an image are multiplying.},

  doi          = {10.1016/j.nima.2019.05.001},

  journal      = {Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment},

  number       = ,

  volume       = 935,

  place        = {United States},

  year         = {Tue May 07 00:00:00 EDT 2019},

  month        = {Tue May 07 00:00:00 EDT 2019}

}

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Works referenced in this record:

Time-correlated pulse-height measurements of low-multiplying nuclear materials
journal, November 2013

Miller, E. C.; Dolan, J. L.; Clarke, S. D.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 729
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Gamma/neutron time-correlation for special nuclear material detection – Active stimulation of highly enriched uranium
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Paff, Marc G.; Monterial, Mateusz; Marleau, Peter
Annals of Nuclear Energy, Vol. 72
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Correlated statistical uncertainties in coded-aperture imaging
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Fleenor, Matthew C.; Blackston, Matthew A.; Ziock, Klaus P.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 784
DOI: 10.1016/j.nima.2014.12.028

Polyethylene-reflected plutonium metal sphere : subcritical neutron and gamma measurements.
report, November 2009

Mattingly, John K.
DOI: 10.2172/974870

Correlation Analysis with Neutron Count Distributions in Randomly or Signal Triggered Time Intervals for Assay of Special Fissile Materials
journal, February 1985

Hage, W.; Cifarelli, D. M.
Nuclear Science and Engineering, Vol. 89, Issue 2, p. 159-176
DOI: 10.13182/NSE85-8

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Title: Exploiting fission chain reaction dynamics to image fissile materials

Abstract

Citation Formats

Time-correlated pulse-height measurements of low-multiplying nuclear materials journal, November 2013

Gamma/neutron time-correlation for special nuclear material detection – Active stimulation of highly enriched uranium journal, October 2014

Correlated statistical uncertainties in coded-aperture imaging journal, June 2015

Polyethylene-reflected plutonium metal sphere : subcritical neutron and gamma measurements. report, November 2009

Correlation Analysis with Neutron Count Distributions in Randomly or Signal Triggered Time Intervals for Assay of Special Fissile Materials journal, February 1985

Time-correlated pulse-height measurements of low-multiplying nuclear materials
journal, November 2013

Gamma/neutron time-correlation for special nuclear material detection – Active stimulation of highly enriched uranium
journal, October 2014

Correlated statistical uncertainties in coded-aperture imaging
journal, June 2015

Polyethylene-reflected plutonium metal sphere : subcritical neutron and gamma measurements.
report, November 2009

Correlation Analysis with Neutron Count Distributions in Randomly or Signal Triggered Time Intervals for Assay of Special Fissile Materials
journal, February 1985