Today’s Event Reports on the NRC website contains two events that stem from operator error:
1. Yesterday morning, Diablo Canyon in California experienced an unplanned start of the system’s emergency diesel generators when employees working on an electrical relay for the Unit 1 reactor activated a relay that the automatic systems interpreted as a loss of off-site power, prompting the start of the generators.
2. Also yesterday morning, Dresden in Illinois suffered a loss of suction for the Containment Cooling Water System (CCSW) when workers mistakenly put two intake bay stop logs in place during routine bay cleaning. The resulting loss of suction rendered inoperable the CCSW for the Unit 2 & 3 reactors. It took almost four hours for the stop logs to be removed and CCSW restored.
For more information, go to the NRC web www.nrc.gov and click on Event Reports at the bottom of the page.