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U.S. Department of Energy
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NWIS MEASUREMENTS FOR URANIUM METAL ANNULAR CASTINGS

Technical Report ·
DOI:https://doi.org/10.2172/2739· OSTI ID:2739

This report describes measurements performed with annular uranium metal castings of different enrichments to investigate the use of {sup 252}Cf-source-driven noise analysis measurements as a means to quantify the amount of special nuclear material (SNM) in the casting. This work in FY 97 was sponsored by the Oak Ridge Y-12 Plant and the DOE Office of Technology Development Programs. Previous measurements and calculational studies have shown that many of the signatures obtained from the source-driven measurement are very sensitive to fissile mass. Measurements were performed to assess the applicability of this method to standard annular uranium metal castings at the Oak Ridge Y-12 plant under verification by the International Atomic Energy Agency (IAEA) using the Nuclear Weapons Identification System (NWIS) processor. Before the measurements with different enrichments, a limited study of source-detector-casting moderator configurations was performed to enhance the correlated information. These configurations consisted of a casting with no reflector and with various thicknesses of polyethylene reflectors up to 10.16 cm in 2.54 cm steps. The polyethylene moderator thickness of 7.62 cm was used for measurements with castings of different enrichments reported here. The sensitivity of the measured parameters to fissile mass was investigated using four castings each with a different enrichment. The high sensitivity of this measurement method to fissile mass and to other material and configurations provides some advantages over existing safeguards methods.

Research Organization:
Oak Ridge Y-12 Plant, TN (US)
Sponsoring Organization:
USDOE Office of Defense Programs (DP) (US)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
2739
Report Number(s):
Y/LB-15,971
Country of Publication:
United States
Language:
English