NRC Seeks Comment on Proposed Guidance for Examining Plant Response to Updated Flooding Hazards
The NRC began examining flooding issues, in the form of upstream dam failures, prior to the Fukushima Dai-ichi accident. That work was incorporated into the agency’s post-Fukushima efforts, which include requiring all U.S. plants to re-analyze potential flooding hazards at their sites using the latest available information. The plants will use present day guidance and analysis methods that have been used in new reactor applications to analyze hazards including stream and river flooding, hurricane storm surges, tsunami, and dam failures. In May, the NRC announced a schedule for all U.S. nuclear power plants to complete the hazard re-analysis by March of 2015.
If the re-analyzed flood hazards exceed the levels a plant was originally designed for, the plant will tell the NRC what interim measures it will use to safely deal with the new hazard. The plant will also perform an “integrated assessment” to identify specific vulnerabilities and examine how existing or planned systems or procedures will prevent or mitigate flood damage.