In a special meeting of the Diablo Canyon Independent Safety Committee, members announced that they’d like to see further review and analysis of the current proposal to convert cooling systems at the Diablo Canyon nuclear power plant.
Committee members raised questions about the potential safety impacts to the plant from both the construction phase and potential for increased salt content that could impact offsite power. Committee member Bob Budnitz said one of the concerns is that the offsite backup power systems could be impacted by salt buildup from the proposed cooling towers “in a way we don’t like.”
On Aug. 8, the committee held a special meeting outside of its normal quarterly meeting schedule. The committee, tasked with reviewing issues that might impact safety at the plant, revealed its draft evaluation based on the Bechtel report: a Bechtel Power Corporation technical evaluation of various possibilities to update the plant’s cooling system.
Under a state mandate on all coastal power plants, Diablo Canyon is reviewing options to switch from its current once-through cooling method. Based on an approximately two-week review of the report, the committee highlighted an initial evaluation.
“Our review concludes that both southern siting and seawater evaporative cooling would impact the operability and performance of several safety-related systems,” the draft report states.
Without a more detailed analysis of the sites and systems outlined in the Bechtel report, the draft evaluation points to the potential that backup power could fail due to salt corrosion, security threats from changes to post-9/11 security infrastructure, and impacts from design changes to the emergency diesel generator fuel tanks and auxiliary saltwater system.
Overall, the draft evaluation concluded that none of the proposed cooling systems outlined by the Bechtel report would “pose a significant safety problem at Diablo Canyon.” However, committee members said they wanted more review of the potential impacts, including a probabilistic analysis. Additionally, they stressed that a new cooling system—such as some outlined in the seven options of the Bechtel report—would require a license amendment request with the Nuclear Regulatory Commission. Such a request would be a years-long process that is not outlined in the proposed 6 1/2-year construction timeline in the Bechtel report.
And that report has yet to go public. The committee’s draft review was only made public one day before its Aug. 8 meeting, while the Bechtel report is scheduled for a full open review in September. The three committee members unanimously agreed to withhold adopting their draft evaluation and decided to revisit the issue at their next regular meeting in October, when the public will have more time to review the Bechtel report as well as their draft evaluation.
“That’s when you, the public, will have your shot at this report,” Budnitz told attendees at the Aug. 8 meeting. “But of course, if they change things, we’re going to take another shot at it too, at that time.”