Attributes from NMIS Time Coincidence, Fast-Neutron Imaging, Fission Mapping, And Gamma-Ray Spectrometry Data

Conference · Thu Jul 19 04:00:00 EDT 2012

OSTI ID:1047631

Swift, Alicia L. ^[1]; Grogan, Brandon R. ^[1]; Mullens, James Allen ^[1]; Hayward, J. P. ^[2]; Mihalczo, John T. ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
2. University of Tennessee, Knoxville, TN (United States)

This work tests a systematic procedure for analyzing data acquired by the Nuclear Materials Identification System (NMIS) at Oak Ridge National Laboratory with fast-neutron imaging and high-purity germanium (HPGe) gamma spectrometry capabilities. NMIS has been under development by the US Department of Energy Office of Nuclear Verification since the mid-1990s, and prior to that by the National Nuclear Security Administration Y-12 National Security Complex, with NMIS having been used at Y-12 for template matching to confirm inventory and receipts. In this present work, a complete set of NMIS time coincidence, fast-neutron imaging, fission mapping, and HPGe gamma-ray spectrometry data was obtained from Monte Carlo simulations for a configuration of fissile and nonfissile materials. The data were then presented for analysis to someone who had no prior knowledge of the unknown object to accurately determine the description of the object by applying the previously mentioned procedure to the simulated data. The best approximation indicated that the unknown object was composed of concentric cylinders: a void inside highly enriched uranium (HEU) (84.7 {+-} 1.9 wt % ²³⁵U), surrounded by depleted uranium, surrounded by polyethylene. The final estimation of the unknown object had the correct materials and geometry, with error in the radius estimates of material regions varying from 1.58% at best and 4.25% at worst; error in the height estimates varied from 2% to 12%. The error in the HEU enrichment estimate was 5.9 wt % (within 2.5Σ of the true value). The accuracies of the determinations could be adequate for arms control applications. Future work will apply this iterative reconstructive procedure to other unknown objects to further test and refine it.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of Tennessee, Knoxville, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1047631
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
97 MATHEMATICS AND COMPUTING
APPROXIMATIONS
ARMS CONTROL
Active Interrogation
CONFIGURATION
DEPLETED URANIUM
FISSION
GAMMA SPECTROSCOPY
GEOMETRY
GERMANIUM
Gamma Spectroscopy
HIGHLY ENRICHED URANIUM
IDENTIFICATION SYSTEMS
NATIONAL SECURITY
Neutron Imaging
Nuclear Materials Identification System (NMIS)
ORNL
SECURITY
SPECTROSCOPY
Treaty Verification
VERIFICATION