San Onofre: Expert testimony shows how Edisons failures led to nuclear crisis

San Onofre: Expert testimony shows how Edisons failures led to nuclear crisis

Friends of the Earth tells NRC utility should have sought license review

ROCKVILLE, Md. — Southern California Edison made critical and fundamental errors in the design of the replacement steam generators for the San Onofre nuclear reactors, according to expert testimony from Friends of the Earth at a Nuclear Regulatory Commission hearing today.

The testimony, which will be presented to the NRC Petitions Review Board, is the first step in a process resulting from the NRC commissioners’ unanimous vote to require staff to weigh the past licensing issue raised in Friends of the Earth’s June 18 petition. The evidence presented clearly showed that Southern California Edison should have been required to go through a license amendment process before installing new steam generators in 2009 and 2010.

Arnie Gundersen, an internationally renowned nuclear engineer, and consultant to Friends of the Earth, explained to the NRC’s Petition Review Board that the design changes proposed by Edison for the replacement generators created a dangerously high level of steam (known as a “high void fraction”) at the top of all four replacement steam generators. These major changes, made to the design of the original generators that lasted for nearly three decades, created conditions causing vibration that led to severe damage to the thousands of thin, tightly-packed tubes inside the steam generators in both San Onofre reactors.

“Nearly a decade ago, when Edison was designing these defective steam generators, it should have been obvious to them that this combination of radical changes required a license review,” said Gundersen. “If Edison had assessed the design changes correctly at that time, the flaws in the design and their consequences, including high void fraction and fluid elastic instability, would have been discovered.”

Edison installed the new steam generators at an expected cost to ratepayers of $670 million. The radically redesigned steam generators should have operated for decades, but they have rapidly deteriorated in less than two years as thousands of tubes were worn and damaged by rattling and clashing with each other and support structures.

The Friends of the Earth evidence also detailed how Edison failed to conduct a correct analysis of the changes being made to the steam generators, as required by the NRC.

“Edison played fast and loose by making radical design changes and ducking the rules,” said Kendra Ulrich, nuclear campaigner with Friends of the Earth. “The result was the most rapid breakdown of such replacement steam generators in the history of the U.S. nuclear industry. If Edison had followed the rules, an NRC license review would have found these glaring defects, and the lives and livelihoods of millions of people would not have been put at risk nor would hundreds of millions of dollars have been squandered. “
In a separate proceeding — the second component of the NRC commissioners’ decision on the Friends of the Earth petition — a judicial panel of the NRC’s Atomic Safety and Licensing Board is evaluating whether the restart process should also require a license amendment. Friends of the Earth filed the opening brief and affidavits from expert nuclear consultants with the ASLB on Friday, January 11.

The meeting of the NRC’s Petitions Review Board begins at 12:30 p.m. Eastern time today. At that time, slides from Gundersen’s presentation will be available at The meeting is expected to conclude by 2:30 p.m., and Gundersen will be available for questions at (802) 238-4452.


Kendra Ulrich, Friends of the Earth: (216) 571-7340
Bill Walker: (510) 759-9911
Arnie Gundersen: (802) 238-4452

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