By John Stang
Workers at the San Onofre Nuclear Generating Station (SONGS) in California have successfully moved the first two canisters of used reactor fuel to dry storage since restarting transfers on July 18. A third canister is on deck to begin movement this week.
Officials with plant majority owner Southern California Edison (SCE) on Aug. 22 briefed the SONGS Community Engagement Panel regarding the status of the renewed fuel offload.
Both 50-ton canisters were successfully moved and inserted into their dry-storage chambers — cylindrical vertical holes in a concrete pad near the Pacific Ocean. The canisters were moved July 18 and July 30.
There were some brief suspensions and reviews during the transfers, in keeping with training and procedures that were revamped in the wake of an August 2018 mishap in the fuel offload at the retired power plant in San Diego County. All problems were fixed quickly in accordance with the site’s stricter procedures and standards, utility officials said last week. The movement of spent fuel “will stop when there is uncertainty,” said SONGS plant manager Lou Bosch at the meeting.
Southern California Edison permanently retired the last two operational reactors at SONGS in 2013 after faulty steam generators were installed in each. Ahead of still-pending decommissioning of the two reactors, the utility in 2014 hired New Jersey-based energy technology firm Holtec International to move spent fuel assemblies — gathered inside the 50-ton canisters – from wet storage in a pool across part of the SONGS complex and insert them into massive vertical holes in a concrete pad. Ultimately, 3.5 million pounds of fuel assemblies will be stored there.
One issue involved the temporary sliding door that covers the top of the cylindrical hole that holds a canister, then is ultimately replaced with a permanent lid, the summary said. Standard procedures at many dry storage pads at other nuclear power plants call for the door to be partly closed, leaving a 40-inch gap to allow air to circulate to cool the canister. SONGS procedures call for the door to be left completely open. Supervisors with experience at other sites left only a 40-inch opening on one of the sliding doors. Southern California Edison overruled that decision and fully opened the sliding door.
A third issue involved rainwater found in some canisters that were pre-positioned for fuel movement in the near future. The water was removed and analyzed.
The July 18 restart followed a nearly yearlong recovery from a high-profile failure in moving one spent-fuel canister — the 29th of 73. 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. The company and fuel-transfer contractor Holtec International finished their own reviews before restarting the transfer.
Movement of Canister No. 32 was scheduled begin this week. The last canister is expected.to be inserted in late spring 2020, SCE officials said at the meeting.
Separately, some members of the Community Engagement Panel are scheduled to visit Holtec’s headquarters in Camden, N.J., on Sept. 17. Issues for discussion include Holtec’s complex corporate governance situation, whether lessons learned from problems at one Holtec project are shared with other Holtec ventures, and very shallow scratches found on some canisters already inserted into dry storage at SONGS.
The scratches come from wear-and-tear of moving the canisters – essentially the vessels rubbing against the side of the storage slot during offload. Critics argue that the scratches could lead to the canisters’ sides weakening and increase the possibility of radiation leaking. Southern California Edison and Holtec say the scratches pose no danger.
So far, eight of the 31 transferred canisters have been inspected for scratches. Several extremely shallow scratches were found, but the depths of the scratches were within the engineering safety parameters. While SCE does not have immediate plans to check all of the canisters, SCE Chief Nuclear Officer Douglas Bauder said the utility has not ruled out that action.
Members of the public and watchdog organizations again voiced their concerns about the scratches during the public comment portion of the Aug. 22 meeting.
“Scratches are where the corrosion begins. We need two-layer canisters,” said Ray Lutz, executive director of the watchdog organization Citizens’ Oversight.
“Every canister needs to be inspected, not just those eight,” said Jackson Hinckle, a candidate for City Council in San Clemente, which is just a few miles from the plant.
They also renewed their opposition to continued storage of radioactive spent fuel on-site near the Pacific Ocean. To settle a 2017 lawsuit on expansion of its fuel storage pad, SCE is studying potential off-site locations for the material.
Meanwhile, the California Coastal Commission is expected at its September meeting to decide whether to issue a permit that is necessary for major decommissioning of the two retired reactors. The commission had been scheduled in June to take up Southern California Edison’s application for a coastal development permit, but delayed the matter on the advice of agency staff.
The coastal development permit is needed for onshore ground-disturbing work in decommissioning, which would include radiological remediation, dismantlement of the reactor vessel and containment structures, and extraction of other large equipment. Southern California Edison will eventually need a separate commission permit for offshore decommissioning activities, with an application anticipated in about two years.
In December 2016, SCE selected the AECOM-EnergySolutions joint venture as the general contractor for the $4.4 billion cleanup job at SONGS, covering radiological decommissioning, spent fuel management, and site restoration. The central work, dismantlement and decontamination of the reactors, is expected to last a decade.
The commission is scheduled to consider the permit application on Sept. 12, the second day of its three-day meeting in Newport Beach.
