The Nuclear Regulatory Commission (NRC) downgraded a safety rating at Diablo Canyon Nuclear Power Plant due to record-keeping errors.
Plant operators misidentified three drills as actual emergencies by checking the wrong boxes in forms that were submitted to the NRC. This caused the emergency exercise indicator to go from green, or satisfactory, to white, or low to moderate safety significance.
The drills were performed in the second and third quarters of this year. The level will remain at white for a minimum of three months as the agency continues to evaluate the plants performance.
"We are a tough regulator and we pay a lot of attention in the administrative areas," said Victor Dricks, NRC spokesman. "There is no question in the plant's ability to respond to a real-life emergency."
The agency evaluates 15 performance indicators. The plant received satisfactory ratings in the other 14 areas.
Diablo Canyon spokesman Jeff Lewis said, "Our goal is to improve the performance of the plant to where it returns to green by the end of the year by having additional training and drills."