While power plant officials say canisters can withstand an18-foot drop, NRC said drop conditions are not analyzed in safety report
By Eric Heinz
The Nuclear Regulatory Commission (NRC) on Friday, Aug. 24, announced that it would start conducting a special inspection at San Onofre Nuclear Generating Station (SONGS) after it was announced that a canister holding spent nuclear fuel could have been compromised.
The announcement of the inspection comes after an incident that took place Aug. 3 involving improper loading of one of the canisters into a cavity enclosure container (CEC). It was first reported publicly by a contractor working with Holtec and Southern California Edison (SCE) who said that while the canister was being loaded, it hung on the edge of the CEC and the crane lost its tension to the canister, creating the risk of it dropping about 17 to 18 feet.
SCE is the majority owner of SONGS, which has been in the process of storing spent nuclear fuel on-site, about 100 feet from the ocean, since late 2017.
The energy company had stated in press releases and at public meetings that Holtec’s HI-STORM UMAX canisters can withstand a 25-foot drop, but in its Friday announcement the NRC said that has not been evaluated in its safety practices. The canisters can weigh between 50 and 100 tons, according to documents from SCE and Holtec.
“It was estimated that the canister could have experienced an approximately 17-18 foot drop into the storage vault if the canister had slipped off the metal flange or if the metal flange failed,” the announcement stated. “This load drop accident is not a condition analyzed in the dry fuel storage system’s Final Safety Analysis Report (FSAR).”
The NRC’s statement continued to say a radiation protection technician “identified elevated radiation readings that were not consistent with a fully lowered canister,” and that was how the inspection began.
David Fritch, who has become eponymous among nonprofit organizations as a whistleblower and safety standard-bearer at SONGS, said at a public Community Engagement Panel (CEP) meeting on Aug. 9 that the process of loading the canister was done with workers who were either underqualified to handle them or people who were not informed enough with the operating procedures. Fritch is a contractor working with Holtec and SCE.
The NRC’s charter for inspecting the incident will inspect records related to spent nuclear fuel procedures as well as qualifications of employees and training, evaluating the efficiency of the process, corrective actions and ability to adhere to the NRC’s standards, as well as other safety standards.
NRC officials said the inspection is expected to begin Sept. 10 with a report to be completed within 45 days after it has concluded gathering information and conducting interviews.
Some of the nonprofit organizations that constantly monitor activities at SONGS said earlier this month that they would take action against SCE in order to stop the storage of spent nuclear fuel until a safety inspection of some kind was initiated by the NRC. Another organization called for an injunction against SCE administered by the California Coastal Commission, the agency that permitted the storage of spent nuclear fuel.
“Southern California Edison has been notified by the U.S. Nuclear Regulatory Commission (NRC) of its upcoming special inspection regarding the Aug. 3 canister loading incident and the follow-up corrective actions underway at the San Onofre nuclear plant,” SCE stated in a press release on Friday, adding that it would be supportive throughout the commission’s inspection. “Spent fuel loading work will not restart until SCE is satisfied that all appropriate actions have been taken, and the NRC has an opportunity to complete its on-site inspection activities.”
Currently, 29 of the expected total of 73 spent fuel canisters have been stored at SONGS since the end of last year when SCE began the dry-cask storage procedures. There are already 51 other canisters built by AREVA stored on-site at the shuttered nuclear power plant from a unit that was decommissioned decades ago.
Another incident took place at SONGS earlier this year when the shims (small pins that help ensure the natural, cooling flow of air in a canister) in one canister were found damaged or broken. SCE officials said the canister did not reach levels of critical heat within the canister, but it’s still put many residents and contributors to the spent nuclear fuel storage process on edge.
SCE still plans to have the remaining 44 canisters in dry storage by mid-2019.