Units 2 and 3 of the San Onofre Nuclear Generating Station -- a major producer of electricity for Southern California for about 40 years -- were idled more than a year ago after a series of water leaks were discovered in the steam-generating system of the northern San Diego County plant.
Edison said in a written statement the company's inability to come up with a restart plan that would satisfy the Nuclear Regulatory Commission was causing too much uncertainty.
"We have concluded that the continuing uncertainty about when or if SONGS 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," said Ted Craver, chairman and chief executive officer of Edison International, SCE's parent company.
The plant powered about 1.4 million households in Southern California before the outage, the Los Angeles Times said.
Edison said it would probably require another year to come up with an acceptable restart plan, and its time and resources would be better spent finding new sources of generation to replace San Onofre's 2,200 megawatts of capacity.
Unit 1 at the plant was retired in 1992.
Edison said it would cut the workforce at San Onofre from approximately 1,500 to 400 in the coming months.
Southern California Edison estimates that it will record a charge in the second quarter of between $450 million and $650 million before taxes, or between $300 million and $425 million after taxes, in accordance with accounting requirements.
"Looking ahead," SCE President Ron Litzinger said, "we think that our decision to retire the units will eliminate uncertainty and facilitate orderly planning for California's energy future."