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San Onofre’s Steam Generators Worse Off Than Other U.S. Nuclear Plants

San Onofre's Nuclear Generating Station's new steam generators are the most troublesome in the country and tube damage is more extensive than Southern California Edison has admitted publicly, according to a new report based in part on a leaked Edison document.

San Onofre has repaired four times as many tubes as the combined total of repaired tubes at all other U.S. nuclear power plants.

San Onofre was shut down in January after tubes wore too thin inside newly installed steam generators. A tube break could cause radioactive water to leak. A report commissioned by Friends of the Earth finds that San Onofre has repaired about 1,300 generator tubes -- four times as many as the combined total of repaired tubes at all other U.S. nuclear power plants. That conclusion was based on the Nuclear Regulatory Commission's own numbers.

Nuclear consultant Arne Gundersen wrote the report for the environmental group. He said the NRC and majority owner Edison have not been straight with the public.

"They portrayed this as San Onofre has tubes that are plugged but so does the rest of the industry,” Gundersen said. “What the NRC didn't say and what Edison didn't say is compared to the rest of the industry, the damage at San Onofre is extraordinary."

NRC spokesman Victor Dricks challenged the report's findings that hundreds more tubes than those already repaired are damaged. He said the bulk of the additional tubes cited by Gunderson are below the 35 percent wear threshold that would require a tube to be taken out of service and repaired or plugged.

Gundersen also criticized Edison for suggesting that running one of the two reactors at lower power might reduce or eliminate the tube wear problem.

"They both need to shut down until extensive repairs are made. Running them until repairs are made, I don't think is in the public's best safety interest,” he said.

The NRC's Dricks said San Onofre can only start back up if the agency is reassured it can be operated safely. Edison did not reply to a request for comment by deadline.

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