Feds: Design flaws at Calif. nuke plant behind leak

The San Onofre nuclear power plant in Southern California, shown in a 2004 file photo. / Getty Images

(AP) CAPISTRANO BEACH, Calif. - After months of investigation, federal regulators have determined that design flaws appear to be the cause of excessive wear in tubing that carries radioactive water through California's troubled San Onofre nuclear power plant, a top federal regulator said.

The twin-reactor plant between Los Angeles and San Diego has been idle since January, after a tube break in one of four, massive steam generators released traces of radiation. A team of federal investigators was dispatched to the plant in March after the discovery that some tubes were so badly corroded that they could fail and possibly release radiation, a stunning finding inside the virtually new equipment.

Flaws in fabrication or installation were considered as possible sources of the rapid tube decay but "it looks primarily we are pointed toward the design" of the heavily modified generators, Nuclear Regulatory Commission Regional Administrator Elmo Collins told The Associated Press in an interview Sunday.

Collins couldn't rule out that one or more of the generators, installed in a $670 million overhaul in 2009 and 2010, might have to be replaced.

Eight tubes failed during earlier pressure tests in the Unit 3 reactor and "we have not seen that in the industry before," Collins said.

"It's these four steam generators that either have, or are susceptible to, this type of problem," Collins said, referring to the unusual damage caused when alloy tubes vibrate and rattle against each other or brackets that hold them in place.

So far, a fix has remained elusive.

"It's not too hard to frame up the problem," he added. "The answers are very difficult, or they already would have emerged."

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The disclosure will rivet new attention on a series of alterations to the equipment design, including the decision to add 400 tubes to each generator and installing V-shaped supports that were intended to minimize tube wear and vibration.

It's possible operator Southern California Edison could face penalties stemming from the federal investigation, Collins said.

The generators were designed to meet a federal test to qualify as "in-kind," or essentially identical, replacements for the original generators, which would allow them to be installed without prior approval from federal regulators.

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[Ulgnud]

It is a technical problem with a machine. Stop running around in a panic and fix it. The wackos in California want light, then do what it takes to produce it or buy up candles.

[skeezix06]

One question. Did they get the parts or the material to make the parts from China?

[gbreadmann]

The fix is very simple; like many other power companies that ignored this exact same problem over the decades and let their steam generator tubes rot, you'll have to ship four brand new steam generators to the plant on flatbed rail cars.

This is not a "new" problem; it's a "management cutting corners and ignoring the engineers' advice" problem.

[John782011]

As someone who has had a career in nuclear power, I can say for a fact that the errosion of steam generating pipes in a two to three year time span is neither common nor typical. Nor is doing steam generator tube isolations an easy task since one has to operate from inside the contaminated primary side of the SG vessel.

[hypnotoad72]

Profiteering hurts everyone in the end. Only those that think they are not being hurt don't even realize it. :(

But it's all about money, which is a fabricated concept that - compared to hyped drug-induced songs from the 1960s - really has become a monster.

[mryoubrian]

Such a crying shame.

Here you have an aging nuclear facility, long past its prime, within about 100 miles of a fault line, next to the ocean..... and all this after Japans nightmare.

Yet the Dutch, Ireland, and England have already drawn up the plans, approved permits, installed, tested, and put on line several tidal energy plants that are off shore producing electricity 24/7/365, rain or shine, and this plant is within spitting distance of the fix ( the ocean).

We chose to spend the same amount of time arguing about alternative energy. Even if we could go online tomorrow, we would be in 4th place already. But it has been 4 years and we are 8 years behind everyone else. I hope we don't have a big leak of radioactivity.

At least with the 2 new geothermal plants in Oregon, the biggest thing that can leak is steam. Also Oregon has been going all out to install wind turbines for several years now. I hope they don't have a massive leak of ......wind?

Americans- fat, stubborn as all hell, greedy and deaf.

P.S. We also spent sooooo much time arguing about high speed rail ... that we are now so far behind the rest of the world, even our grandchildren will never get to see it unless they visit Germany, England, France, Japan or China.

[hypnotoad72]

Actually, some say the same thing about European countries, while blindly hyping up China...

There's no perfect system, and many reasons behind each of the individual qualifiers you pin on Americans (which are not universal truths either, much less stereotypes...)

[cubscout09]

This "modification" involved cutting open the reinforced concrete containment vessel, replacing the turbines, and patching the huge hole. The original designer never intended that this happen. The reactors have already exceeded their designed time in service.

The $670 million dollars borrowed to perform the "modification" has a Department of Energy loan guarantee. In addition, if the reactors must be retired, it is estimated that another $110 million must be borrowed, again with a DOE loan guarantee.

When the "modification" was performed, radioactive water was spilled from a tanker truck with a stuck valve "God knows where" on the highway between San Onfre and truck stop, somewhere in the Southwest. Recently, a worker trying to inspect the damaged turbines slipped, fell and was completely immersed in a holding pool of mildly radioactive water. The LA Times has 5 pages of links to similar stories.

http://articles.latimes.com/keyword/san-onofre-nuclear-power-plant

Make up your own mind regarding nuclear power, but, try to be as informed as possible.

[pnut134]

Arnie Gunderson predicted this a year ago, as well as warning about other dangerous nuclear exposures facing America and the world.

http://fairewinds.com/

[John782011]

That failure is very alarming in such a short time.