San Onofre Nuke Shutting Down

Monday, June 10, 2013 @ 05:06 PM gHale


The beleaguered San Onofre nuclear power plant on the California coast is closing after an epic 16-month battle over whether the twin reactors could safely restart.

Operator Southern California Edison (SCE) said it will retire the twin reactors because of uncertainty about the future of the plant, which faced a tangle of regulatory hurdles, investigations and mounting political opposition. With the reactors idle, the company has spent more than $500 million on repairs and replacement power.

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San Onofre could power 1.4 million homes. California officials have said they would be able to make it through the summer without the plant but warned that wildfires or another disruption in distribution could cause power shortages.

It wasn’t clear how SCE would replace electrical production from the plant permanently. The California Public Utilities Commission said it will work with governments to ensure Southern California has enough electricity, which will require increased energy efficiency and conservation during peak usage, as well as upgrades to transmission and generation resources.

The plant between San Diego and Los Angeles hasn’t produced electricity since January 2012, after a small radiation leak led to the discovery of unusual damage to hundreds of tubes that carry radioactive water.

The plant “has served this region for over 40 years,” said Ted Craver, chairman of SCE parent Edison International. “But we have concluded that the continuing uncertainty about when or if (the plant) might return to service was not good for our customers, our investors or the need to plan for our region’s long-term electricity needs.”

SCE had been seeking permission from the Nuclear Regulatory Commission (NRC) to restart the Unit 2 reactor and run it at reduced power, in hopes of stopping vibration that had damaged the tubing.

“The Nuclear Regulatory Commission is aware of Southern California Edison’s plans to permanently shut down San Onofre, but we are waiting for formal notification of their decision,” said Victor Dricks, spokesman for NRC.

The problems center on steam generators installed during a $670 million overhaul in 2009 and 2010. After the plant shut down, tests found some generator tubes were so badly eroded they could fail and possibly release radiation, a stunning finding inside the nearly new equipment.

The four generators at San Onofre — two per reactor, each with 9,727 alloy tubes — function something like a car radiator, which controls heat in the vehicle’s engine. The generator tubes circulate hot, radioactive water from the reactors, which then heats a bath of non-radioactive water surrounding them. That makes steam, which then turns turbines to make electricity.

Edison has argued for months the Unit 2 plant could safely restart, but Craver raised the possibility of closing the plant because of lingering uncertainty about the future. The company had said little about the future of the heavily damaged Unit 3 reactor.

Questions arose over changes to the replacement generators — they were different than the originals, 23.6 tons heavier and hundreds of additional tubes ended up a part of design changes.

SCE, San Diego Gas & Electric and the city of Riverside own San Onofre. The Unit 1 reactor operated from 1968 to 1992, when officials shut it down and dismantled it.



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