Los Angeles, Jun 8 (IANS/EFE): California's San Onofre nuclear power plant, which has been offline since April 2012, is to be shut down permanently, Southern California Edison (SCE) said Friday.

Regulators ordered SCE to suspend operations at the plant after a leak in one of the two reactors led to the discovery of cracks in a new steam generator system installed in 2010.

Subsequent inspections detected additional problems.

Last month, the US Nuclear Regulatory Commission's Atomic Safety and Licensing Board turned down SCE's bid to restart one of the San Onofre reactors at 70 percent of capacity.

The NRC panel concluded that Edison would have to submit to a lengthier process to amend the plant's operating license.

Seeking approval to amend the licenses would involve unacceptable delays, Ted Craver, CEO of SCE parent company Edison International, said Friday.

"Looking ahead, we think that our decision to retire the units will eliminate uncertainty and facilitate orderly planning for California's energy future," SCE President Ron Litzinger said in a statement.

San Onofre has a history of problems and environmental groups and residents of the surrounding area have long sought its closure.

The plant is located is an earthquake-prone region and safety concerns escalated after the temblor and subsequent tsunami of March 11, 2011, that caused catastrophic damage at the Fukushima nuclear plant in Japan.

"I am greatly relieved," California Sen. Barbara Boxer, who chairs the Senate Environment and Public Works Committee, said on learning of Edison's decision.

"This nuclear plant had a defective redesign," the Democrat said in a statement.

"Modifications to the San Onofre nuclear plant were unsafe and posed a danger to the 8 million people living within 50 miles of the plant."