Diablo Canyon power plant produces about 10% of the state’s electricity. Going forward – the PG&E owned plant will be the only nuclear power plant operating in California as the industry has been beset by problems including fears of terrorism and earthquake fault zones. But now they have to worry about critters too.
Each power unit at the plant has a pressurized water reactor coupled with steam generators, feed water systems and cooling water systems. The seawater intake for the power plant is located within a cove that was built as part of the original plant construction.
The seawater enters the intake structure, passes through a series of bar racks and screens, and enters the plant where it is used to condense steam from the reactors.
In the past few years, there has been an increase in the population of salps, gelatinous ocean dwellers resembling small jellyfish, along the California Coast and in the vicinity of the DCPP Intake Cove.
Although individually innocuous, a large mass of many individuals can be problematic, clogging seawater intakes and damaging fishing nets. In April of 2012, PG&E was forced to shut down one of the nuclear reactors at the DCPP (the other had been previously shut down for scheduled maintenance) for several days when a massive salp population boom clogged the intake pipe.
In researching how to address this problem, PG&E found that the Ringhals Power Plant in Sweden installed a bubble curtain to divert salps from its intake pipes. Bubble curtains have also been recommended by the National Marine Fisheries Service (NMFS) as a safe and effective method to divert aquatic organisms away from underwater construction sites and decrease impacts associated with construction noise.
Now PG&E proposes to investigate the efficacy of this method by installing a temporary bubble curtain system in the DCPP Intake Cove for two years with installation of curtains in the next few months.
This month the California State Lands Commission offered their blessing on the project. The Coastal Commission already approved the plan earlier this spring.