The US Nuclear Regulatory Commission (NRC) has outlined the corrective actions that need to be completed before Westinghouse’s nuclear fuel fabrication facility in Columbia, South Carolina can resume some of its uranium processing operations following the discovery of a build-up of uranium in a plant component.
In May, plant employees discovered an accumulation of uranium-bearing material in a scrubber system, which is designed to remove unwanted material from a number of plant processes, during an annual maintenance outage. NRC ordered an augmented inspection of the facility after further analysis found the amount of uranium was higher than anticipated and potentially exceeded set limits. There were no safety-related consequences as a result of the build-up, but the "potential for such consequences may have existed”, NRC said.
The Confirmatory Action Letter sent by the NRC to the facility on 11 August was prompted by the findings of the still-ongoing inspection and acknowledges the actions that Westinghouse has already undertaken or has committed to undertake. These include shutting down the affected system, performing a root cause analysis of the event, reviewing and revising safety culture, updating maintenance and management procedures, installing physical modifications to the system, personnel training, and a review of other potentially affected systems. Westinghouse must also retain an external nuclear criticality safety expert to oversee criticality safety functions at the site at Columbia to assist in the oversight of nuclear criticality safety functions until all corrective actions identified in the root cause analysis have been completed.
According to Westinghouse's event report filed with the NRC on 14 July and updated on 31 July, the accumulated material was found to contain 87 kg of uranium. The licensed limit for the scrubber section involved is 29kg of uranium.