The following news article originally appeared in NEI’s Nuclear Energy Overview.
Inspections related to flood protection have begun at nuclear energy facilities based on industry guidance endorsed by the Nuclear Regulatory Commission in late May. These inspections, or “walkdowns,” address part of the NRC’s March request for detailed information on several post-Fukushima issues the agency identified as the top priorities—Tier 1—among the 12 recommendations of the NRC’s task force. Seismic walkdowns got under way earlier this month. The industry is awaiting NRC comments on guidance for responding to three orders that address the other Tier 1 issues.
Amid discussions with the industry on guidance for flooding walkdowns, the NRC has asked for an evaluation of a flood-induced failure of any dam downstream from a nuclear energy facility that impounds water used as the plant’s cooling source. However, since downstream dam failure isn’t a flooding concern at the nuclear plant site, the industry believes it should be addressed with other external hazards through the Tier 2 recommendations, said Jim Riley, principal engineer at NEI.
Earlier this year, the NRC began a formal evaluation of potential safety implications for dam failures upstream of nuclear energy facilities. The staff identified it as a potential generic safety issue in 2010. The NRC formally added upstream dam failure to its generic safety issue program in March for further study and resolution. “New sources of information on this issue have accumulated over the past few years,” the NRC said. “This information includes … recent re-evaluations of dam failure frequencies and possible flood heights at some U.S. nuclear power plants, suggesting that flooding effects in some cases may be greater than previously expected.”
In a March information notice, the NRC said it will address upstream dam failure as the agency deals with the flood-related recommendations of the post-Fukushima task force.