The U.S. Nuclear Regulatory Commission since July has conducted more than a dozen unannounced inspections of spent fuel transfer operations at the San Onofre Nuclear Generating Station (SONGS) in California.
The inspections are part of the agency’s response to several problems in the project, notably an August 2018 incident in which a canister was put at risk of a nearly 20-foot drop into its storage slot alongside the Pacific Ocean. That mishap led to a nearly yearlong suspension of fuel loading and a $116,000 fine from the NRC on plant majority owner Southern California Edison (SCE).
Ten unannounced, mostly multi-day inspections were conducted between July 1 and Oct. 25, according to information sent on Dec. 6 by NRC Chairman Kristine Svinicki to U.S. Rep. Mike Levin (D-Calif.), whose congressional district covers SONGS. The agency has since then performed another four inspections at the property on U.S. Navy land in San Diego County, a spokesman said Thursday.
During the visits, agency inspectors monitored the loading of used-fuel assemblies into storage canisters, the transport of the canisters to the plant’s dry-storage pad, and their installation into underground slots.
“Specifically, NRC inspections looked at (1) licensee practice runs; (2) training for personnel to perform the fuel loading campaign; (3) transfer and downloading of three canisters from the spent fuel pool into the UMAX [independent spent fuel storage installation]; (4) canister flushing activities on site; (5) loading of a fuel canister containing damaged fuel and (6) activities related to four additional canisters including processing, welding, and preparing to move them,” according to the material sent to Levin.
Agency inspectors also conducted a quarterly decommissioning inspection at the plant from Aug. 26-29.
The message was a response to an Oct. 17 letter from the first-term lawmaker with several questions on NRC oversight at the plant. A spokesman for Levin did not respond this week to queries on the matter.
Southern California Edison closed SONGS’ final two operational reactors in 2013 after they were installed with faulty steam generators. It hired energy technology firm Holtec International the following year to move the spent fuel from Units 2 and 3 from wet storage to dry storage.
As of last week, 43 of 73 spent-fuel canisters had been placed into storage. Southern California Edison expects to complete the offload by the middle of 2020. At that point, about 3.5 million pounds of spent fuel from SONGS’ three reactors will be in dry storage. The assemblies from reactor Unit 1, which closed in 1992, are already on the dry-storage pad.
In his letter, Levin also asked whether some sort of change to regulatory paperwork is needed after canisters have been scratched on their way into storage.
The scratching has been a key element of the arguments from local watchdog organizations to stop the fuel offload. The groups say the “gouging” could weaken the canisters to the point that a radiation release becomes possible. The Nuclear Regulatory Commission, SCE, and Holtec say the what they describe as harmless marks have no impact on the actual function of the containers.
In its message to Levin, the agency acknowledged that the final safety evaluation report (FSAR) for Holtec’s UMAX used-fuel storage system at San Onofre wrongly said the canisters were not at risk of being scratched while being placed into or removed from the dry storage slots. Southern California Edison subsequently updated the FSAR to address the scratching, according to the NRC.
“After conducting an independent technical analysis, the NRC staff found that the licensee’s site-specific evaluation was adequate to demonstrate that scratches resulting from incidental contact between canisters and cavity exposure containers would not affect the confinement design functions as specified in the FSAR and the American Society of Mechanical Engineers Section III code tolerances and therefore, did not require a change to the UMAX storage system’s technical specifications,” the agency said in its response to Levin.
Advocacy groups in the San Diego area have for years expressed concern about the risks of storing highly radioactive material in a seismically active, highly populated region next to the Pacific Ocean. They heightened their criticism of NRC oversight in the wake of the 2018 incident.
State and federal courts, though, have to date rejected legal efforts by these groups to force a halt to the used-fuel transfer and broader decommissioning operations at SONGS.
Southern California Edison has received final regulatory approval from the state to begin major decommissioning of the two remaining reactors. The $4.4 billion project, overseen by contractor SONGS Decommissioning Solutions, is due to be complete by 2028.
