Committee Wants Answers to Powering Down Nukes

By Published On: February 15, 2013

Squaring state marine resource protection with the approved use of nearly 5 billion gallons/day of seawater to cool the state’s two nuclear power plants was the focus of a state committee that met Feb. 11. Members asked for answers to the feasibility of powering down the two nuclear generating plants to reduce the amount of seawater traditionally used to cool the facilities and reduce marine life impacts. Other front-burner issues at the Review Committee for Nuclear Fueled Power Plants meeting early this week included setting confidentiality parameters on redesigns of the cooling technology at the power plants being developed by Bechtel for Pacific Gas & Electric and Southern California Edison. In 2010, the State Water Resources Control Board adopted a mandated phase-out of once-through cooling at coastal power plants because of the impacts to the seals, fish, larvae and other sea life. Diablo Canyon is permitted to consume 2.5 billion gallons/day. The currently shuttered San Onofre Nuclear Generating Station is allowed by the state to consume 2.4 billion gallons/day of seawater. With San Onofre off line, it is estimated to use less than half its permitted allocation. The nuke still has to keep circulating water to keep spent fuel and other highly radioactive components from melting down. To what degree the units at Diablo Canyon and the San Onofre station can be “derated” or powered down “to reduce marine impacts is a piece of information that is not there. It deserves to be there,” said Melissa Jones, California Energy Commission staff and former agency executive officer. She and other committee members noted the degree of derating, how long it can be maintained, and the corresponding reduction in sea life mortality is surely known because plant manager and majority owner of San Onfore, Southern California Edison, hopes to run one of the units at 70 percent for a trial five months (story page 7). The Southern California nuke has been off-line since January 2012 because of unprecedented wear in the steam generators. PG&E environmental operations staff member Bryan Cunningham said Diablo is powered down to 56 percent of its capacity during routine maintenance, including this month. The entrainment of the marine critters is reduced, although the decrease in the amount of harm varies by the season and year. “It is not a one size fits all,” said Dominic Gregorio, State Water Resources Control Board ocean unit chief, about the amount of sea life saved by reducing the amount of ocean water used for once-through cooling. The committee, made up of representatives from PG&E, Edison, Bechtel, state agencies, and anti-nuclear and environmental advocates, is working its way through a huge number of technical and financial issues involved in modernizing the two nuclear plants to reduce their water use. Upgrading the plants cooling technology is a highly complex and expensive undertaking. In addition, the expense of meeting marine protection standards at San Onofre--including possibly installing cooling towers--is getting more scrutiny because of its closure following the leak and discovery of wear in its steam generators.

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