The Nuclear Regulatory Commission has launched a special inspection at the Browns Ferry nuclear power plant to determine how and why a diver received a dose rate alarm during underwater work in the Unit 1 equipment pit.

The plant, operated by the Tennessee Valley Authority, is located near Athens, Ala., about 32 miles west of Huntsville. On Nov. 7, a diver working on an underwater steam dryer system received an electronic dose rate alarm when he approached the equipment pit wall to manipulate a cable. Upon receiving the alarm, the diver immediately left the pit and his unintended dose did not exceed regulatory limits. The licensee later determined that a basket of used filters had been moved from the spent fuel pool into a position near the equipment wall and this was not communicated to the next shift.

NRC’s two-person inspection team will identify the circumstances surrounding the event, review the licensee’s immediate response to the alarm, evaluate their corrective actions and causal analysis, and assess the program for diving, work control, radiological surveys and movement of highly radioactive material.

The onsite portion of the inspection is expected to take several days. A report documenting the results of the inspection is expected to be issued within 45 days of its completion.

Source: U.S. Nuclear Regulatory Commission