The San Onofre Nuclear Generating Station, which generates enough electricity to power 1.4 million homes, will stay offline indefinitely until inspectors decipher and correct unusual wear in the steam generator tubes, according to the chairman of the Nuclear Regulatory Commission, who toured the plant Friday.
The problem was discovered Jan. 31, leading to an immediate shutdown of that unit at the plant located about 70 miles south of Los Angeles.
"They have to demonstrate to us that they understand the causes and ultimately they have a plan to address those causes that will ensure public health and safety," said Chairman Gregory Jaczko.
Jaczko toured the plant with Democratic Sen. Dianne Feinstein and Republican Rep. Darrell Issa. The tour included a first-hand look at the facility's sea wall.
An advocacy group conducted a protest on a bluff just north of the plant. The group callled for a closure of the plant. One of the demonstrators held a sign that read, "No Fukushima Here," a reference to the site of last year's meltdown that followed a tsunami.
"We demand that the NRC not allow this plant to open until there's been some testing done to make sure that those tubes will be safe when they're turned on," said one demonstrator.
The plant operates two units, and each unit has thousands of the steam generator tubes. They act as barriers between the radioactive and non-radioactive sides of the plant, which will remain offline until inspectors determine what's behind the erosion.
Unit 3 was taken offline in January because of excessive wear in the tubes. Unit 2 was taken offline for planned maintenance Jan. 9 and remains offline.
Unit 1 has not been in operation since the early 1990s.
San Onofre generations about 2,200 megawatts of electricity, 10 percent of SoCal Edison's service area.
Since January, the Edison system has been able to get by without San Onofre's power by repowering AES generating stations in Huntington Beach and Long Beach.
But with summer on the way, the utility is looking at other ways to supplement the loss, including conservation methods, effeciency methods and bringing up additional transition lines.
Regulators outlined in a letter the steps that must be taken before the reactors can go back online.
Officials have said there is no danger to workers or plant neighbors.