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Title: Criticality frequency determination using a human-error-based fault tree

Journal Article · · Transactions of the American Nuclear Society
OSTI ID:91994

The Central Laboratory at the Savannah River site provides chemical analysis support for various operations at the site, primarily the separations (reprocessing of nuclear materials) areas. As a result of performing chemical analyses, recyclable liquid is generated that contains various levels of fissile plutonium and uranium. This recyclable liquid is disposed of in a high-level transfer (HLT) system that initially collects in two tanks before being transferred for further processing. The authorization basis for the facility was based in part on the assumption of no accumulation of fissile containing solids in the tanks. As part of a continuing program to ensure criticality safety, a significant accumulation of fissile-containing solids was detected in both tanks. As a result, all operations involving the HLT tanks were suspended. The tanks have been in use since the commencement of operations in the 1950s. Since that time fissile material has precipitated or settled out of the liquid and remained in a sand-like layer at the bottom of the tanks. Prior to the recent discovery of the accumulation of fissile material, the tanks had not been sampled because no accumulation was expected to occur. A fault tree was prepared to evaluate the potenetial to exceed the criticality safety limit and determine waht controls were necessary to ensure the limit was met.

OSTI ID:
91994
Report Number(s):
CONF-941102-; ISSN 0003-018X; TRN: 95:004215-0215
Journal Information:
Transactions of the American Nuclear Society, Vol. 71; Conference: Winter meeting of the American Nuclear Society (ANS), Washington, DC (United States), 13-18 Nov 1994; Other Information: PBD: 1994
Country of Publication:
United States
Language:
English