LOS ANGELES (AP) — The mounting bill tied to the shuttered San Onofre nuclear power plant in California jumped to more than $400 million through December, as the company that runs it contends with costly repairs and a host of questions about its future, regulatory filings and officials said Tuesday.

The seaside plant between Los Angeles and San Diego was sidelined in January 2012 after a tiny radiation leak led to the discovery of unusual damage to hundreds of tubes that carry radioactive water inside its steam generators.

Edison International, the parent of operator Southern California Edison, said replacement power cost reached $300 million through Dec. 31, while repairs and inspections hit $102 million.