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San Onofre: Design Caused Decay

Evening Edition

Alison St. John, a KPBS News reporter, and Murray Jennex, a professor at San Diego State University and former consultant to San Onofre, talk to KPBS.

Aired 6/19/12 on KPBS Midday Edition.

Guests: Alison St. John, KPBS News

Murray Jennex, San Diego State University

Arnie Gundersen, Fairewinds


People gather at a community meeting in San Juan Capistrano on June 18, 2012.
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Above: People gather at a community meeting in San Juan Capistrano on June 18, 2012.

This week, the federal Nuclear Regulatory Commission (NRC) released its determination that the excessive wear and decay in tubes which carry radioactive water in the San Onofre Nuclear Generating Station was caused by modifications to the plant's design.

At a community meeting Monday evening in San Juan Capistrano, NRC officials stunned the large audience with the news that generator manufacturer Mitubishi's computer codes to simulate how the generators would work were "off" by a factor of three or four.

NRC inspectors also considered other culprits -- such as flaws in fabrication or installation of the 400 additional tubes and their V-shaped supports. They concluded that "thermal velocities" were much higher than predicted, causing the tubes to vibrate against each other and against the support structure, causing premature wear.

San Onofre, which is owned by Southern California Edison, has been idle since January, when a broken tube in one of the four steam generators released a small amount of radiation.

NRC investigators soon discovered some tubes were so badly corroded that they could fail and possibly release more radiation. The findings were shocking, as the generators had been extensively overhauled in 2009 and 2010, and the equipment was virtually new.

Environmental groups such as Friends of the Earth contend that the NRC let Edison avoid public review of its large-scale changes to the design of the plant, instead allowing the changes to qualify as "in-kind," or essentially identical to the old equipment.

Friends of the Earth is now calling on the NRC not to allow the operator, Southern California Edison, to restart the plant without going through a licensing amendment and public review.

Dave Freeman and Arnie Gunderson, advisors to Friends of the Earth, hold a pr...
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Above: Dave Freeman and Arnie Gunderson, advisors to Friends of the Earth, hold a press conference outside the NRC's public meeting, to call for more stringent oversight of both the NRC and Southern California Edison. June 18th 2012

The overhaul of San Onofre cost $670 million.

About 7.4 million Southern Californians live within 50 miles of San Onofre.

NRC Regional administrator Elmo Collins was clear the plant operator, Southern California Edison, still has multiple questions to answer before it can even apply to restart.

"So far," he said, "these issue are not resolved to the NRC’s satisfaction."

The plant provided approximately 20 percent of the region's electricity.

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Avatar for user 'WhatsItAllAbout'

WhatsItAllAbout | June 19, 2012 at 11:25 p.m. ― 4 years, 9 months ago

It seems that they (NRC & Edison) are equally mystified.
They need more time and information and investigation.
So far, They are pointing the finger at a computer issue with Mitsubishi.
No one is man enough to stand up and take any responsibility.
Gee, those computers are really handy, aren't they.
Should we really trust SCEdison with a nuclear power plant if they are so
confused and mystified by this?
Can we trust the NRC to pay attention and regulate?

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Avatar for user 'RochelleBecker'

RochelleBecker | June 19, 2012 at 11:48 p.m. ― 4 years, 9 months ago

Time to talk about how much SCE is willing to spend to bring their steam generators back to life. The Energy Commission is jumpstarting the discussion at the CalTrans building in LA. For flier:

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Avatar for user 'AnneSilverstone'

AnneSilverstone | June 20, 2012 at 10:17 p.m. ― 4 years, 9 months ago

It wasn't a computer that decided to go ahead with the new design, so that excuse does not fly as far as I am concerned. At this point I have no trust in SCE or the NRC.

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Avatar for user 'crista1025'

crista1025 | June 20, 2012 at 11:25 p.m. ― 4 years, 9 months ago

It's always a "small amount of radiation" that "poses no threat". Do you really think they are going to admit "Ya, an incredible amount of radiation was released because we are incompetent. Get ready for some cancer!" Please. They just FINALLY told us the "amount" of radiation released at the meeting- because people were asking OVER AND OVER. 5.2 Milirems- although they have shown clearly that they are not to be trusted, so why should we believe that number? Why was it such a problem to tell us the number in the first place if it was no big deal? Why does it take a year for radiation readings from their monitors to be posted to the NRC website? Any one with a geiger counter can get the readings instantly. Some other facts released at the meeting: In Unit 3, 9% of the tubes showed wear of 10% or more. In Unit 2, 12% of the tubes showed wear of 10% or more. These tubes were supposed to last for 40 years. NRC also said that "damage during shipping" could have accounted for the difference in wear between Unit 2 and Unit 3. Don't they inspect these things before they install them? This is NOT a test site, we ARE people with families who live here! I bet no one in the NRC lives in the "50 Mile Zone" around San Onofre. Maybe if they did, they would have regulated a little more.

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