Southern California Edison on Monday resumed transferring used reactor fuel at the San Onofre Nuclear Generating Station (SONGS) into dry storage.
The 30th of 77 storage canisters was this week placed in the expanded independent spent fuel storage installation (ISFSI) at the retired San Diego County nuclear power plant. The project in total is expected to be completed next spring.
The restart follows a nearly yearlong recovery from a high-profile mishap in moving one spent-fuel canister. On Aug. 3, 2018, the container of fuel assemblies became lodged on the shield ring of its underground storage slot. It took workers nearly an hour to identify and fix the problem, during which the canister was at risk of an uncontrolled 18-foot drop.
The U.S. Nuclear Regulatory Commission investigated the event, and in March fined SCE $116,000 for two violations of federal nuclear safety rules: failure to have backup equipment in place to prevent the canister drop and failure to notify with the agency within 24 hours. The regulator in May OK’d Southern California Edison to resume the fuel offload.
In a press release, SCE said it and fuel-transfer contractor Holtec International have improved fuel-transfer procedures, oversight, and training over more than 11 months. Cameras and load-monitoring gauges have also been deployed, and the companies conducted a series of practice runs before the real work resumed.
A follow-up inspection by the NRC determined SCE understood the causes of the incident and had taken necessary steps to prevent a repeat, even as the agency found five more low-level breaches of federal nuclear safety requirements.
“We’ve done a lot of work to ensure that going forward we will be successful in safely loading and storing each and every spent fuel canister,” Doug Bauder, SCE vice president and chief nuclear officer, said in the press release. “We’re confident the improvements we’ve made are effective and sustainable. Our job now is to demonstrate that to our stakeholders.”
The announcement was met with skepticism from local watchdogs, including U.S. Rep. Mike Levin (D-Calif.), whose congressional district covers SONGS. “I am concerned that the Nuclear Regulatory Commission has allowed Southern California Edison to restart spent nuclear fuel loading without committing an NRC inspector to the facility at all times that fuel transfer activities take place,” the first-term lawmaker said in a prepared statement. “Southern California Edison’s safety record includes incidents as recent as this year, and there is a clear need for continuous oversight at the facility.”
In a meeting last week with NRC Chairman Kristine Svinicki, Levin reaffirmed his call for the agency to keep a full-time inspector in place at SONGS until the fuel transfer is complete. The agency, to date, has said that is not necessary given the reduced hazards posed by nuclear plants following retirement.
Southern California Edison, SONGS’ majority owner and federal licensee, permanently closed the facility’s last two operational reactors, Units 2 and 3, in 2013 after they were equipped with faulty steam generators. Unit 1 was shut down in 1992; it has been mostly decommissioned and its used fuel placed into dry storage.
The utility in 2014 hired Holtec, a New Jersey-based energy technology company, to build an additional underground storage facility at SONGS and then move the used fuel and other waste from the two reactors out of the plant’s cooling pools. Each Holtec canister holds 37 fuel assemblies, for a total of 2,668.
Even before the 2018 incident, there had been local concern about keeping roughly 3.5 million pounds of radioactive waste on-site next to the Pacific Ocean in a high-population region that is known for its earthquakes. To settle a lawsuit against state approval for the ISFSI expansion, Southern California Edison in 2017 agreed to take “commercially reasonable” steps to find an off-site location for the material. Planning for that effort remains in progress.
The fuel transfer has faced several challenges, including the March 2018 finding of a loose bolt in one of the Holtec fuel canisters. The contractor then switched to an older-design cask as it proceeded with the fuel transfer.
Southern California Edison has said the potential 18-foot drop during the 29th fuel offload would have damaged, but not compromised, the Holtec canister.
Critics have also called attention to “scratches” or “gouges” – depending on your point of view – found on some canisters following the transfer into storage. They worry the canisters could be compromised, creating a danger of a radiation release. Southern California Edison has said what it calls “wear marks” would not undermine the canisters’ functioning. It has committed to inspecting the vessels again in the near future.
“That refers to a maintenance and inspection program we are developing for the California Coastal Commission as part of the coastal development permit we received for the Holtec storage facility,” SCE spokesman John Dobken said Thursday by email. “We will deliver that to the CCC by October of 2020.”
Offloading the 30th canister began Monday and wrapped up Thursday morning, Dobken stated. A specific completion date for the fuel offload should be identified as work proceeds. The project had been expected to be completed in the fourth quarter of 2018 prior to the incident.
“We cannot provide final project costs at this time as we are still working toward completing the project,” according to Dobken. “When the ISFSI project has been completed, SCE will report the final project costs to the California Public Utilities Commission for reasonableness review.”
Completion of the fuel transfer would be a major step toward beginning full decommissioning at SONGS. While contractor SONGS Decommissioning Solutions has done some preparatory work, it is waiting on final regulatory approval from the state to begin the core decontamination and demolition.
The California Coastal Commission is expected in September or October to consider a coastal development permit necessary for onshore decommissioning of reactor Units 2 and 3, Dobken said. The permit had been on the agenda for the agency’s June meeting, but was delayed to give staff more time to submit information to the commissioners.
