By John Stang
The U.S. Nuclear Regulatory Commission gave the green light Tuesday for resumption of loading used nuclear fuel into dry storage at the retired San Onofre Nuclear Generating Station (SONGS) in California.
The decision puts plant majority owner Southern California Edison (SCE) and fuel offloading contractor Holtec International on a direct path to ending a suspension that began with an Aug. 3, 2018, mishap in fuel loading. That incident precipitated an NRC investigation that led to a $116,000 uncontested fine against SCE.
“The NRC made its determination following extensive review of technical data submitted by Edison regarding the possible effects of scratching on spent fuel canisters during fuel loading operations,” the agency said in a press release.
The fuel transfer will resume after Holtec and SCE review their readiness to restart operations. While it did not offer a schedule for that to happen, the utility has pushed back the project’s anticipated completion date from early 2019 to spring 2020. It has not yet calculated the cost ramifications of the delay.
Southern California Edison and Holtec “have performed a comprehensive review of spent nuclear fuel transfer operations and created a more robust program through better procedures, better training and more intrusive oversight,” SCE spokesman John Dobken said by email Tuesday. “This, in part, includes the addition of cameras and load monitoring equipment which will provide valuable information during download operations. We have demonstrated these improvements are effective and sustainable through numerous dry runs, regulatory inspections and independent reviews.”
The NRC decision drew scrutiny from Rep. Mike Levin (D-Calif.), whose congressional district covers SONGS, and at least one local watchdog group. In a press release, the first-term lawmaker questioned the regulator’s use of data provided by Southern California Edison in determining the used fuel operation could resume.
“The NRC’s decision-making process requires a greater degree of independence to best serve the public interest,” said Levin, who has established a task force on SONGS and this week introduced legislation that would prioritize removal of spent fuel from the plant.
San Diego-based Public Watchdogs was more critical of what it called a “sham investigation” by the NRC.
An NRC spokesman said the agency would discuss its decision in more detail during a webinar on June 3.
Southern California Edison in 2013 permanently retired the last two operational reactors at SONGS, Units 2 and 3, after faulty steam generators were installed in both. In 2014 it hired energy technology company Holtec, of Camden, N.J., to manage the fuel offloading.
While a 100,000-pound canister of spent fuel was last August being inserted into a cylindrical hole on the dry storage pad, the vessel became lodged on a shield ring and was at risk for a nearly 20-foot uncontrolled drop. It took personnel nearly an hour to identify and correct the problem.
Following an inspection, the NRC determined in November that SCE failed to maintain redundant protection to keep the 50-ton canister from dropping 18 feet by letting its loading straps go slack; failed to report the incident in a timely manner in taking three days instead of the required one day; lacked procedures to deal with the incident; inadequately trained the workers conducting the fuel transfer; and failed to take proper, timely action immediately after the mishap occurred.
Since last August, SCE has increased the size of the on-the-spot crew inserting the canisters into the storage pad from two to 10; added monitors to ensure tensions on both landing straps; added a quality assurance manager to the fuel movement program; installed low thresholds for to stop work for safety reasons; improved training; upgraded procedures to include covering as many scenarios as possible; and conducted numerous fuel-transfer practice runs with dummy canisters.
The NRC also confirmed SCE’s studies that a canister can fall 25 feet without cracking. In total, SCE responded to the incident with 71 corrective actions and nine corrective actions to preclude repetition.
The utility studied 29 canisters to demonstrate the scratching did not pose a danger to the viability of the canisters. Scratches have occurred at most points of the loading the canisters with fuel assemblies from wet storage, being carried by huge transporters, and being inserted into storage holes whose diameters are roughly an inch greater than the casks’ diameters.
Critics contend scratches weaken the canisters’ ability to hold in radiation, Holtec disputes that argument, noting the scratches are extremely shallow. The deepest scratch found on a SONGS canister was 0.026 inch in depth, compared to the thickness of the canister wall – five-eighths of an inch.
“Every single can of this deadly nuclear waste at San Onofre is creased by steel-on-steel contact during the process of loading the cans into the silos. The gouges in the canister could pave the way to an inevitable release of radiation,” Public Watchdogs Executive Director Charles Langley said in a Tuesday press release.
In a Thursday telephone interview, Langley said Public Watchdogs expects to take some type of legal action against the NRC’s decision, but has not decided on its specific approach.
At the time of the incident, SCE and Holtec had placed 29 of 73 canisters from SONGS reactor Units 2 and 3 into dry storage via the HI-STORM UMAX system. Roughly one-third of the plant’s spent reactor fuel was already held in 51 canisters in an on-site independent spent fuel storage installation. That radioactive waste is from the plant’s reactor Unit 1, which shut down in 1992.
The final disposition of the spent fuel remains unclear. To settle a lawsuit challenging its on-site storage plans, Southern California Edison in 2017 committed to “commercially reasonable” efforts to move it off-site. The company is preparing strategic and transportation plans as part of this effort.
One option could be a consolidated interim storage facility for spent nuclear reactor fuel that Holtec hopes to open in the early 2020s in Lea County, N.M. The NRC is reviewing the company’s license application.
Meanwhile, SCE could as early as next month receive the final state regulatory approval needed to begin decommissioning of the Units 2 and 3. An AECOM-EnergySolutions team would manage the $4.4 billion project, which is scheduled to be completed by 2028.
The NRC has scheduled a public webinar on the matter at noon Pacific time on June 3. The public can submit written comments and questions via the webinar user interface. The webinar will include an NRC briefing on the agency’s review of the scratches on the canisters.
