The U.S. Nuclear Regulatory Commission says its regulatory framework accounts for potential effects from “changing environmental conditions” on spent fuel storage installations at U.S. nuclear power plants.
The agency on May 29 responded to an April 23 letter from Sen. Edward Markey (D-Mass.), who had expressed concerns about potential impacts of climate change on used fuel storage. The lawmaker highlighted plans for dry storage of spent fuel at the Pilgrim Nuclear Power Station just 25 feet above sea level and 200 feet from the Atlantic coast. The facility is due to close by May 31, 2019.
The NRC regulates storage of used reactor fuel, in both wet and dry storage, through means including licensing and on-site inspections.
“The NRC’s existing regulatory framework accounts for any changing environmental conditions that could cause or accelerate degradation of [independent spent fuel storage installations] or otherwise challenge the safety of spent fuel storage,” the agency said in its response to Markey, posted Tuesday to the NRC website. “The NRC’s oversight of licensees’ ISFSI operations ensures the safe storage of spent fuel, regardless of whether an ISFSI is at an operating reactor or a decommissioned reactor site.”
Markey’s office this week did not respond to multiple requests for comment on the NRC’s letter.
The regulator did not use the term climate change in answering four questions from the lawmaker. But it noted that federal regulations covering licensing for storage of spent fuel mandate that licensees evaluate possible natural dangers in the safety basis document for a storage site or container design. “This includes consideration of potential impacts of natural phenomena such as flooding,” according to the response.
The NRC undertook a years-long effort to improve safety of U.S. reactors following the post-earthquake and tsunami 2011 Fukushima Daiichi nuclear power plant disaster in Japan. As part of that effort, the regulator studied the potential for storage systems to end up fully or partially underwater. In such cases, the used fuel would be expected to remain cool without any release of radiation, the agency told Markey.
On Markey’s question about potential flooding affecting the Pilgrim site, which sits on Cape Cod Bay, the NRC said its studies showed no danger to spent fuel storage.
“While recent scientific reports discuss the potential for more than a half-foot of sea level rise by 2065, the multiple conservatisms in other aspects of the storm surge calculation provide a significant safety margin in the event that sea level rise at the site exceeds a half-foot,” according to its response. “As part of its post-Fukushima evaluations, the NRC staff determined that there is no need for additional regulatory action related to flooding for facilities other than operating power reactors.”
Markey also asked about future loitering of the spent fuel sites. The NRC response that the agency’s protocols account for the age of the storage canisters and storage sites during its inspections.
The NRC has also studied how to manage degradation and aging of the casks, including the possibility of corrosion. Exposure to airborne salts and to hot and humid air have also been studied, the agency said.
Finally, Markey pointed out that Pilgrim has received an exemption from a post-Fukushima seismic probabilistic risk assessment ahead of its closure. He asked how the NRC will assure that dry storage casks will be safe from seismic activity, along with how such risks will be incorporated into the agency’s ongoing rulemaking for decommissioning reactors.
“As the NRC’s current regulatory framework ensures the safety of spent fuel storage from seismic activity, the NRC does not plan to develop further seismic requirements in the reactor decommissioning rulemaking,” the NRC’s response said.
