Degraded electrical equipment caught fire in the control room of Unit 1, about 90 minutes after an electrical short led to an inadvertent shutdown of the reactor, on June 8, 2010.
Six months earlier, a fire had broken out in the Unit 2 control room – because of similarly degraded electrical components.
After putting out the Unit 2 fire in November 2009, workers had asked technicians to investigate, but the company closed the report without any investigation or evaluation.
After the second fire, workers tested electrical components in both control rooms and found many were degraded, including some that produced visible sparks during testing.
Because the company had taken no action to protect Unit 1 from the problem they had been warned of in Unit 2, NRC's investigation team sanctioned the company.
