LESSONS LEARNED FROM ACCIDENT PRECURSOR EVENTS INVOLVING ENRICHED URANIUM

The NRC statThas reviewed the causes of a considerable number of serious events and accident precursors involving the processing of enriched uraniumat facilities licensed by this agency, Eight specific events were selected for review based on their seriousness. In addition, all reported case4 of degradationof nuclear criticality safety controls from 1991-94 were reviewed (64 reports). The pwpose of the staff review was to determine whetherthe causes for such events and precursors were simply anticipatedrandom failurea, or insteadwere unanticipatedsystemic deficiencies thatmightbe remedied. The 72 events were categorized by seriousnessaod by cause. The major lesson learned from the study was the identitkation of 11 systemic program deficiencies that are consistentcauses of serious precursors. These 11 are: personnel knowledge, poor safety labeling, hazardsnot identified, inadequatecontrols, poor configuration management,poor management response, poor measurement,and defective fire, chemical, criticality, and maintenanceprograms.