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Title: Direct fissile assay of highly enriched UF/sub 6/ using random self-interrogation and neutron coincidence response

Conference ·
OSTI ID:5584817

A new nondestructive method for direct assay of /sup 235/U mass contained in Model 5A uranium hexafluoride (UF/sub 6/) product storage cylinders has been successfully tested in the laboratory and under field conditions. The technique employs passive neutron self-interrogation and uses the ratio of coincidences-to-totals counts as a measure of bulk fissile mass. The accuracy of the method is 6.8% (1 sigma) based on field measurements of 44 Model 5A cylinders, 11 of which were either only partially filled or contained reactor return material. The cylinders contained UF/sub 6/ with enrichments from 5.96% to 97.6%. Count times were 3 to 6 min depending on /sup 235/U mass. Samples ranged from below 1 kg to over 16 kg of /sup 235/U. Because the method relies primarily on fast neutron self-interrogation, complete sampling of the UF/sub 6/ takes place. This feature alleviates inhomogeneity problems and offers increased assurance of the presence of stated amounts of bulk fissile material as compared with current verification methods.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
5584817
Report Number(s):
LA-UR-83-3266; CONF-831106-12; ON: DE84003780
Resource Relation:
Conference: Topical meeting on safeguards technology - the process safeguards interface, Hilton Head Island, SC, USA, 28 Nov 1983; Other Information: Portions are illegible in microfiche products
Country of Publication:
United States
Language:
English

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