By John Stang
Southern California Edison said Thursday that training and procedural shortfalls led to a mishap last year in relocating spent reactor fuel at the San Onofre Nuclear Generating Station (SONGS) in California, but contended there was no danger of a storage canister falling hard enough to cause it to leak out radioactive material.
Representatives from the utility discussed mitigating factors in the incident at a meeting in Arlington, Texas, with officials from the U.S. Nuclear Regulatory Commission. With the pre-decisional enforcement conference now completed, the industry regulator will decide whether to fine or take other forms of “escalated enforcement” against SCE.
In the meantime, the spent fuel transfer remains on hold.
Southern California Edison permanently closed the San Diego County power plant in 2013 after faulty steam generators were installed in its two operational reactors. In December 2014, SONGS’ majority owner and licensee awarded the defueling contract for the reactors to New Jersey energy technology company Holtec, which built a new storage pad and is moving the used fuel from wet to dry storage.
On Aug. 3, one canister went off-target and became hung up on a ring while being lowered into its slot on the storage pad; the problem was not identified and fixed for nearly an hour. The situation also created the possibility that the canister could have dropped 18 feet and was not reported to the NRC for three days.
The utility faces two potential NRC violations, which may or may not lead to fines. First, the two straps being used to lower the canister into the storage hole went extremely slack, ending up with neither holding up the canister being lowered. Being hung up on the storage hole’s ring was the only thing keeping the canister from falling. The other potential violation is the three-day delay in notifying the NRC when the legal deadline was 24 hours after the mishap.
In its November special inspection report, the NRC also cited SCE for three more minor Severity Level IV violations of safety requirements, which would not lead to enforcement measures.
The regulator is holding SCE responsible for the incident because it is the license holder for San Onofre, while Holtec is a contractor.
Jerry Stephenson, manager of interim fuel storage at SCE, told NRC staff that “There was no significant damage to the canister. There was no damage to the fuel.” SCE officials said the hung-up canister could have fallen 25 feet without being damaged.
“We failed to recognize the complexity and the risk. …. SCE is taking these violations seriously,” said Jim Peattie, the company’s manager of maintenance support services.
Southern California Edison has worked to improve training for all personnel at the plant, including experienced workers. Written procedures have become more detailed. More cameras and monitoring screens have been installed for more workers and supervisors to double-check the canister’s movements, particularly since most of the workers are stationed 150 feet away because of concerns about exposures to radiation. More supervisors will have to check off on whether procedures are done property during a move. A loading machine will have an alarm to signal when the straps go slack.
An NRC decision on enforcement is expected in four to eight weeks.
At the time of the incident, Holtec had placed 29 canisters into dry storage. Another 44 had not been placed. Southern California Edison has said it intends to complete the fuel project in 2019.
In a Jan. 18 memo to the San Onofre Community Engagement Panel, the utility said: “Canister-downloading operations at San Onofre remain on hold and will resume only after we are satisfied that our team has successfully demonstrated fuel transfer can proceed utilizing the improved procedures, training and technology, and the NRC has an opportunity to inspect practice runs and has reviewed re-start plans.”
There was no specific timeline for that to occur as of Friday.
Primary decommissioning at SONGS, managed by AECOM-EnergySolutions partnership SONGS Decommissioning Solutions, has not begun on the two reactors: Units 2 and 3. At the time the joint venture received its $1 billion contract in December 2016, the 10-year project was anticipated to begin in 2018.
Unit 1 at San Onofre, which was retired in 1992 after 24 years of operation, has already been decommissioned.
