Southern California Edison could face up to five violations from the U.S. Nuclear Regulatory Commission for a mishap in placing a canister of used nuclear fuel into storage at the San Onofre Nuclear Generating Station (SONGS).
Two potential violations are considered “escalated” — a major classification, according to an NRC online briefing Thursday on its investigation of the Aug. 3 incident. Those violations are: SCE’s failure to maintain redundant protection to keep a 50-ton canister from dropping 18 feet and failing to report the incident in a timely manner.
Three other serious, but not “escalated,” potential violations involve the lack of procedures to deal with the incident; inadequate training of personnel conducting the fuel transfer; and failure to take proper, timely action when the mishap occurred.
“This event could’ve been prevented by effective management oversight,” Troy Pruett, director of the NRC’s Region 4 Division of Nuclear Safety, said during the webinar.
The agency on Oct. 19 issued preliminary findings on the incident, which it said resulted from “Multiple performance deficiencies.” It is expected to take several months to complete the report and finalize a decision on any financial penalties, which could range from $0 to $72,500.
Roughly 500 people across the country plugged into the webinar for the briefing and question-and-answer session.
Southern California Edison is the majority owner and licensee for SONGS, a San Diego County nuclear power plant that closed permanently in 2013 after faulty steam generators were placed in its two operational reactors. The utility and contractor Holtec International early this year began moving the reactors’ remaining used fuel from wet to dry storage ahead of the start of decommissioning by an AECOM-EnergySolutions contracting team. The project was originally scheduled for completion by mid-2019.
As one of the 100,000-pound Holtec canisters was ready to be lowered into place on the ocean-side storage pad on Aug. 3, it was held by two thick straps — each capable of holding 113,000 pounds. This was a redundant safety feature in case one of the straps broke.
Two workers were with the mobile machinery used to lower the canister into place — an operator and a spotter. In this case, it was the first time those employees had performed the procedure. Supervisors and all other personnel were 150 feet away to avoid unnecessary exposure to radiation. The supervisors could not properly see what was happening.
As the canister was being lowered, the spotter was out of position and the operator did not properly watch his instrument panel. “They weren’t paying attention,” said Eric Simpson, leader of the NRC inspection team for the incident.
The canister went slightly off-target while entering the below-ground slot, hanging up on the shield ring rather than slotting into place. An unanswered question is why the gussets — slanted meal pieces on top of the shield ring — did not do their job of guiding the canister through, Pruett said.
When the canister hung up on the shield ring, the machinery kept lowering the two straps. “The slings bunched up on the ground. … Those slings were in no position to stop that drop” of 18 feet if the canister slipped off the shield ring, Simpson said. That was the loss in redundancy that could be a potential violation, according to NRC officials.
It took about 53 minutes to identify and fix the problem.
Simpson said SCE had no procedures to deal with this particular problem and had not properly trained the operators. On top of that, the supervisors were in no position to oversee the operations that resulted in the mishap, he said.
The utility was supposed to inform the NRC of the incident within 24 hours, but did not provide informal notice by telephone until Aug. 6. A report that should have been filed within 24 hours was not submitted to until Sept. 14. On the delay in reporting, Simpson said “San Onofre simply didn’t interpret the event the same way we did. It boils down to interpretation.”
No radiation escaped in the incident, Pruett said. Southern California Edison concluded the canister was not damaged in the incident, but the NRC wants to double-check the utility’s analysis.
A similar incident almost occurred on July 22 at SONGS, but the slings did not go slack and the operators quickly corrected the misalignment, Simpson said.
The NRC conducted an on-site inspection from Sept. 10-14. The regulator’s final report is expected sometime between just before Thanksgiving and mid-December. If the potential violations are formalized, SCE will have 10 days to respond. That would set up a conference between the two parties. Pruett said the decision on whether to issue a fine would likely come two or three months from now.
In a statement Friday, Southern California Edison said its findings on the incident, “developed through rigorous evaluations, match many of the commission’s findings. SCE looks forward to reviewing the final special inspection report when it’s completed and continuing discussions with the commission.”
The used fuel transfer has been on hold since Aug. 3 and won’t resume until all the issues are resolved to SCE’s and the NRC’s satisfaction. The NRC is expected to check up on the SCE’s fix-it measures in December.
In the wake of the incident, SCE on Monday will officially install a new top manager for SONGS. Company Vice President of Operational Services Doug Bauder will take over as chief nuclear officer and project leader for facility.
Current Chief Nuclear Officer Tom Palmisano will stay on as external engagement officer. In that role he will be the direct point of contract for the Nuclear Regulatory Commission, the Community Engagement Panel, area government bodies, and other stakeholders.
Bauder previously served as site vice president at SONGS from June 2010 to September 2013.
“The decommissioning, permitting and spent fuel transfer efforts at SONGS continue to require extensive leadership and support,” according to the SCE statement. “The efforts required to ultimately undertake the physical decommissioning will be even greater and require more depth in our team than do current activities. This leadership addition is a key part of SCE’s commitment to continually support the decommissioning effort at SONGS.”
