Source term characterization for SNM pit storage facilities

Conference · Sun Jul 01 04:00:00 EDT 2012

OSTI ID:22105900

Chin, M.; Paul, J.; Sjoden, G. ^[1]

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1. Nuclear and Radiological Engineering Program, George W. Woodruff School of Mechanical Engineering, Georgia Inst. of Technology, 770 State St, Atlanta, GA 30332-0745 (United States)

In order to properly design a mobile system to validate and verify the presence of special nuclear materials for non-proliferation and safeguards applications, accurate modeling of source materials is imperative. In this work, models were developed for use in design assessments based on an AL-R8 SNM standardized container specification to determine the radioactive signatures for both highly enriched uranium (HEU) and weapons plutonium (WGPu) special nuclear materials (SNM) housed in the containers. Intrinsic gamma boundary leakage currents were evaluated for this system, performed using 3D fixed-source deterministic SN photon transport (PENTRAN) as well as with stochastic Monte Carlo methods (MCNP5). Group-dependent leakage radiation terms were calculated at two 'source box' interfaces within the models, one directly surrounding the SNM source, and one immediately surrounding the canister. Analysis showed good agreement between the two models for energy groups of interest, based on a 24 group gamma library established for HEU and WGPu gamma signatures of interest. Intrinsic and neutron induced gamma leakage was determined using Monte Carlo calculations, and the combined gamma signatures were then treated as a net gamma leakage to be used in subsequent photon transport calculations. Neutron leakage based on the BUGLE-96 47 group structure was determined using Monte Carlo calculations for the WGPu canisters. These results will be used to evaluate the source term from stored nuclear materials and augment our efforts to design a detection system to validate the presence of these materials for safeguards purposes. (authors)

• Research Organization: American Nuclear Society, Inc., 555 N. Kensington Avenue, La Grange Park, Illinois 60526 (United States)
• OSTI ID: 22105900
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
22 GENERAL STUDIES OF NUCLEAR REACTORS
CONTAINERS
DESIGN
DISCRETE ORDINATE METHOD
FISSIONABLE MATERIALS
HIGHLY ENRICHED URANIUM
LEAKAGE CURRENT
MONTE CARLO METHOD
NEUTRON LEAKAGE
NEUTRONS
PHOTON TRANSPORT
PLUTONIUM
RADIOACTIVE MATERIALS
SAFEGUARDS
STOCHASTIC PROCESSES
STORAGE FACILITIES