Excavators work on demolishing what was the control building at San Onofre Nuclear Generating Station on Aug. 1. (Nelvin C. Cepeda / The San Diego Union-Tribune)
The Nuclear Regulatory Commission popped in for a regular look-see at San Onofre Nuclear Generating Station in June, concluding that decommissioning work was pretty much on schedule and radiological work areas were “adequately controlled.”
Two dings, however.
Southern California Edison self-reported two low-level violations: The first involving a “failure to ensure a package for shipment was leakproof and properly closed and sealed to prevent release of radioactive content as required by U.S. Department of Transportation regulations,” and the second involving a “failure to ensure, by examination or appropriate tests, that the packaging for the Unit 2 pressurizer (main function: to keep reactor’s coolant below boiling) was proper for the contents being shipped as required by DOT regulations.”
The NRC said those were low-level violations — Severity Level IV (less serious but of more-than-minor concern; Levels I and II can be considered the bad boys). Since Edison and its decommissioning contractor placed the two deficiencies into a “corrective action program,” and since the safety significance was low, and since the violations “were non-repetitive and not willful,” Edison was not cited, according to the inspection report.
What happened?
A Unit 2 pressurizer leaked water at a railyard in San Bernardino County while being shipped offsite for disposal, Edison spokesman Jeff Monford said.
Demolition work continues at San Onofre Nuclear Generating Station. (Image courtesy Southern California Edison)
It leaked about one drop every two minutes, was stopped and sealed, and the deck of the rail car was cleaned. Radiological surveys found no detectable radioactivity above background levels on or around the component, and there was no threat to public health or the environment, Monford said.
The second component, the pressurizer from Unit 3, did not leak; it was stationed at the same railyard while en route to the offsite disposal facility. Both components were returned to San Onofre on July 4 and will remain on site “while an evaluation is being conducted to learn from this event and avoid recurrence with similar components.”
There’s no date for wrapping up that evaluation just yet.
Bluff surveys
Rail cars pull into the San Onofre Nuclear Generating Station to be loaded with non-contaminated debris to be hauled to a landfill in 2022. (Nelvin C. Cepeda / The San Diego Union-Tribune)
The NRC inspectors reviewed the plant’s radioactive waste treatment, effluent and environmental monitoring; remedial and final surveys; fire protection program; and solid radioactive waste management in addition to the transportation of radioactive materials.
It was a routine, announced inspection, and Edison et al. “were found to be conducting activities in accordance with site procedures, license requirements, and applicable NRC regulations” with those two exceptions.
Cleanup of the reactor cavities was slightly behind the original schedule, but “commensurate with the challenges encountered.” Non-radioactive buildings were being demolished during the inspection, and “inspectors observed that good industrial safety controls were in place including use of water cannons to suppress the dust created by demolition activities.”
Of interest: Procedural and radiological controls for the environmental monitoring program, including the planned drain down of the Unit 3 reactor cavity, were in place, and “good health physics and operational preplanning controls were in place to support the drain down,” the NRC said. (The release of wastewater from the plant, happening regularly for decades, remains a concern for some.)
Trucks are loaded with noncontaminated demolition debris for transport to an offsite waste or recycling facility at San Onofre Nuclear Generating Station. (Nelvin C. Cepeda / The San Diego Union-Tribune)
Edison is also doing ongoing radiological surveys of the north and south ocean-sidebluffs, which hadn’t been included in the historical site assessment, “to demonstrate that the areas had not been impacted by previous plant operations.” Surface scans for gamma radiation and soil sampling for radionuclides were done properly and found no detectable plant-related radionuclides, the report and Monford said.
Those results support Edison’s classification of the bluffs as a “non-impacted area” in its complex License Termination Plan.
Edison reviewed the NRC’s findings with its decommissioning contractor and workers, “and we remain committed, in our oversight role, to ensuring safety and adherence to all regulatory requirements,” Monford said.
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