Environment & Science

So Cal Edison: Both reactors at San Onofre nuclear plant have problems with tube wear

A shot of the San Onofre Nuclear Power Plant.
A shot of the San Onofre Nuclear Power Plant.
David McNew/Getty Images

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The operators of the San Onofre nuclear power plant now say they’re seeing the same type of unusual wear in both reactor units. The plant has been closed since January while the company continues to dig for the cause of the problems.

Southern California Edison says water tubes in the steam generators of Unit 2 appear to have the same problem as tubes in Unit 3.

“We did indeed find the same characteristic of wear that we had seen in Unit 3," said Jennifer Manfre of Southern California Edison. "We’ve found it now in Unit 2 in a very limited area.”

The unusual wear was discovered on two of those tubes. The reactor has nearly 20,000.

Environmental groups have said they want an independent analysis of the faulty steam generator tubes. The groups also claim the San Onofre plant has one of the worst safety records of the nation’s nuclear plants.

A second report, commissioned by the group Friends of the Earth, asserts that substantial changes made in the design and fabrication of key components is causing the problems with tube wear at the nuclear plant.

The study by Arnie Gundersen and Fairewinds Associates has said the design changes to the San Onofre Nuclear Generating Station reactors, made by SoCal Edison, “likely led to the equipment degradation and failure that has forced the reactors offline.”

The tubes are a primary barrier preventing radiation from escaping into the atmosphere.

Meanwhile, SoCal Edison says additional inspection and analysis of the Unit 2 steam generators is continuing and the company will report those findings to the Nuclear Regulatory Commission.

Their representative, Jennifer Manfre, said there’s no timeline for restarting the plant.

“It’s really about ‘let’s look at the safety issues,’" according to Manfre. "That’s where we are aligned with the NRC (Nuclear Regulatory Commission) and we’re all looking at the safety protocols and understanding the cause."

Problems with the tubes in Unit 3 forced that reactor offline Jan. 31.

Meanwhile, Manfre says the company is looking at contingency plans, including buying energy supply on the open market, in case the plant remains offline when the summer power demand increases.

The other reactor, Unit 2, was already shut down for maintenance. Inspections later found tubes in that reactor were banging against each other and support structures, something SoCal Edison still can’t explain.

The Nuclear Regulatory Commission says the plant will remain in shutdown mode until the exact cause is understood. NRC Chairman Gregory Jaczko added that when that report is completed, the federal agency will schedule a public meeting to talk about the findings.