By John Stang
Southern California Edison apparently became confused on how soon it should alert the U.S. Nuclear Regulatory Commission to an Aug. 3 mishap in transferring spent fuel at the San Onofre Nuclear Generating Station (SONGS) in California.
Contractor Holtec International has been moving the spent fuel at the retired nuclear power plant in San Diego County facility from wet to dry storage. On Friday, Aug. 3, rigging for one canister went off target while being placed into an underground storage silo. The result was that a 50-ton canister teetered with slack rigging over an 18-foot drop, which required almost an hour’s worth of corrective work.
Southern California Edison, majority owner of SONGS, did not notify the NRC until late on the afternoon of Monday, Aug. 6.
“SCE made an original determination that the event did not require a report. However, SCE contacted the NRC [Region IV] on Monday August 6th and again on Tuesday August 7th to provide details of the event. It has now been determined that the event is reportable under 10CFR72.75(d)(1) and this late report is being made,” SCE said in a written notification dated Sept. 14.
The NRC on Sept. 14 finished a weeklong on-site inspection of the incident, and is now studying the matter — which might include a return trip to San Onofre. The regulator expects to issue a report within 45 days of the end of the inspection and follow-up work.
Agency spokesman Victor Dricks said issues being studied include whether this incident should be classified as “important-to-safety” and whether SCE was required to report the mishap to the NRC within 24 hours — meaning no later than Aug. 4.
According to a 2015 NRC memo, the relevant-to-this-incident definition of an “important-to-safety” mishap is whether it could threaten harm to workers or the off-site public. The same memo said there is fuzziness in laying out the exact criteria to officially declare an incident or flaw as “important-to-safety.”
The public did not become aware of the incident until a SONGS safety employee brought it up in a public hearing by the San Onofre Community Engagement Panel on Aug. 9.
The delays in notifying the NRC and the public prompted criticisms from the San Clemente City Council and the San Diego-area-based Public Watchdogs organization. Both wanted to have representatives observe last week’s inspection by three NRC experts, but agency policy forbids outside observers on such inspections.
Southern California Edison closed SONGS reactor Units 2 and 3 in 2013 and rather than replace faulty steam generators. Preliminary decommissioning operations are underway by an AECOM-EnergySolutions team. Reactor Unit 1 at the plant shut down in 1992 and has already been decommissioned, with its fuel moved to an on-site dry storage pad. The pad has been expanded to hold the used fuel from the remaining two reactors.
Holtec began transferring the fuel from Units 2 and 3 to dry storage early this year and is due to complete the work by the middle of 2019. However, the work has been suspended pending the outcome of the NRC inspection and recovery efforts by SCE and Holtec.
To date, 29 canisters of fuel assemblies have been transferred, with 44 to go. The radioactive material would then remain on the storage pad until an off-site location for temporary storage or permanent disposal is ready. The NRC inspection is not expected to affect SONGS’ goal of finishing the spent fuel transfer by mid-2019, said SCE spokeswoman Liese Mosher.
