ROSEMEAD (CBS/AP) – A consumer advocate division of the California Public Utilities Commission doesn’t believe utility customers should have to deal with the massive costs related to the shutdown of the San Onofre Nuclear Generating Station.

In a motion filed Tuesday, the Division of Ratepayer Advocates requested the state direct Southern California Edison to give up about $600 million in rates and San Diego Gas & Electric Co. to chop about $185 million.

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Some of the funds, however, could be retained for safety and security expenses.

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On June 7, Edison announced it would close the plant for good.

San Onofre hasn’t produced power since January 2012, after a small radiation leak led to the discovery of unusual damage to hundreds of virtually new tubes that carry radioactive water in the plant’s steam generators.

For months, the commission has been looking at costs tied to the faulty generators and who should pay the bill, customers or ratepayers. That review could take years to complete.

In a statement, SDG&E spokeswoman Stephanie Donovan said the company didn’t expect the commission to make an immediate decision and would work “with all of the parties in this proceeding to determine what’s in the best interest of customers.” SCE spokeswoman Maureen Brown said in a statement the motion was premature and its conclusions “unfounded.”

The commission “has set rates beginning in January 2012 as ‘subject to refund,’ so no party is disadvantaged by permitting the commission’s reviews to run their course,” Brown said.

It was estimated that the San Onofre closure cost about $400 million.

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