Massachusetts Senator Edward Markey submitted a letter on April 23 to Chairman Kristine Svinicki of the Nuclear Regulatory Commission (NRC) expressing serious concerns over the storage of spent nuclear fuel at US nuclear sites, particularly at shutdown nuclear plants. Mr. Markey stated that the “NRC regulations must ensure that dry casks are not vulnerable to flooding, corrosion, and other damage, especially as climate change contributes to rising sea levels and increasingly severe and unpredictable storms.” About a month earlier, following the March 21, 2018, oversight hearing in the Senate Environment and Public Works Committee, Mr. Markey had submitted similar questions to the NRC, including “how and whether climate change projections are integrated into the NRC’s Safety Standards and how they will be included in the NRC’s forthcoming rule governing decommissioned nuclear plants.” In his most recent letter, he requested responses to four specific questions on the issue, including: “What is the protocol for continual monitoring of spent fuel sites?”, “What time span and which climate models are used for post-Fukushima flooding reevaluation?”, and “What research has the NRC done on possible corrosion of the dry casks by exposure to salt water?”

Ms. Svinicki recently provided a detailed response to Mr. Markey’s concerns, outlining the NRC’s comprehensive existing and expanding regulatory regime governing long-term safe storage of spent fuel in dry casks. As licensees of both operating and shutdown nuclear plants know from experience, the NRC’s existing regulatory framework already accounts for changing environmental conditions that could challenge the safety of spent fuel storage. Specifically, operating experience is continually assessed by the NRC and licensees, and if significant environmental changes are identified, NRC would evaluate and take action as necessary. Ms. Svinicki also noted that while recent scientific reports mention the potential for a half-foot rise in sea level over the next century, “multiple conservatisms” in required storm surge calculations provide a significant margin of safety even if the sea level rise exceeds those predictions.

Ms. Svinicki also highlighted an ongoing NRC initiative known as the Process for Ongoing Assessment of Natural Hazard Information (POANHI)—an “enhanced process to proactively and routinely aggregate and assess natural hazards information for nuclear plants.” The goal of POANHI is to “identify and evaluate new data, models, and assessment methods to determine if a change in natural hazard information” requires further action to ensure public health and safety. As the POANHI effort is still a work-in-progress, we will continue to follow its development and, in particular, potential impacts on shutdown and decommissioning nuclear plants.

Finally, Ms. Svinicki addressed the commonly-expressed concern that salt air adversely affects the safe storage of spent fuel in dry canisters. She noted that while exposure to certain airborne chloride salts and hot-humid air potentially could affect welded stainless steel canisters over a long period of time, NRC already considers this potential phenomenon in both the original licensing of the canisters and canister aging management programs, and NRC requires licensees to take measures to detect and mitigate the condition if found.

NRC’s response to Mr. Markey’s letter can be found here. NRC’s POANHI program is discussed in SECY-16-0144 here.