ABSTRACT
On July 14, 2016, a nuclear fuel fabrication facility licensee notified the United States Nuclear Regulatory Commission (NRC) that significant amounts of uranium were discovered, potentially exceeding their Criticality Safety Evaluation (CSE) mass limits, during an annual inspection of a scrubber ventilation system. The licensee subsequently confirmed not only significant mass several times higher than the CSE mass limits in the scrubber and associated ventilation ductwork, but also significant concentrations of uranium. As part of the NRC’s platform of continuous improvement, a lessons-learned activity was initiated to explore opportunities for improving the NRC’s regulatory processes for early identification of facility operational issues and preventing such events in the future. This paper describes the event, some of the licensee’s root causes that led to this event, some of the reasons why the NRC did not identify this condition (and similar conditions at this and other facilities) through its regulatory processes prior to the event, and the improvements being considered to enhance these NRC regulatory processes.
