By Editors of Power Engineering
The Nuclear Regulatory Commission (NRC) has begun a special inspection at the Grand Gulf Nuclear Station in Mississippi to review circumstances surrounding several recent operational events. The Entergy plant has been shut down since September 8.
On September 23, following maintenance on the residual heat removal system, workers discovered that a misalignment of valves had rendered the plant’s alternate decay heat removal system unavailable. Technical specifications require that the alternate system be available when one of the plant’s two residual heat removal systems is out of service. The system is used to remove decay heat from the reactor following shutdown. The following day, when preparing to restart the reactor, control room operators caused an unexpected increase in reactor vessel water level due to a misalignment of valves.
Three NRC inspectors will spend about a week on site evaluating the cause of the problem and the adequacy of corrective actions to address performance issues. An inspection report documenting the team’s findings will be publicly available within 45 days of the end of the inspection.
“The purpose of this special inspection is to better understand the circumstances surrounding several recent operational events to determine if operator response was appropriate,” said NRC Region IV Administrator Kriss Kennedy. “We will also review the licensee’s corrective actions to ensure that their causes, including associated equipment problems and any contributing operator actions, have been effectively addressed.”