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article imageSan Onofre nuclear power plant — Reasons for shutdown reported

By Anne Sewell     Jun 19, 2012 in Environment
Los Angeles - The San Onofre power station was shut down in January this year due to a scare, when the plant released trace amounts of radiation. Now a report explains what actually happened, and it could have been so very much worse.
The San Onofre Nuclear Generating Station is located 70 miles south of Los Angeles, and has been on temporary shut down since January 2012. At the time, Unit 2 of the San Onofre facility was shut down for routine maintenance and upgrades, when the plant’s crew was forced to halt operations of Unit 3 upon discovering a leak.
After months of meticulous investigation, Federal regulators have now published a report on the incident, and have told AP that design flaws have caused the tubing carrying radioactive water throughout the plant to be worn down extensively.
While it was initially thought that the release of trace amounts of radiation was a fluke, it now seems that this could have been very much worse.
Nuclear Regulatory Commission Regional Administrator, Elmo Collins told AP over the weekend that the design of the heavily modified generators at San Onofre was to blame for the rapid deterioration of the tubing in the facility.
"Eight tubes did not have structural integrity. We've never seen that before in the industry. No more than one had ever happened. I think the extent of the tube to tube interaction we saw also has not been seen in the industry, so this is a significant and serious safety issue," said Collins.
Apparently only one other nuclear plant in the U.S. uses the same generators as those at San Onofre, but that plant has not experienced tube decay anywhere near that evident at San Onofre.
Collins suggests that this is because the San Onofre plant produces "a remarkable output of power."
On the website for the owners of the facility, Edison International, the plant is described as being able to create 2,200 megawatts of electricity - which is “enough power to meet the needs of 1.4 million average Southern California homes at a point in time.”
Collins added, "The phenomenon that we think causes this tube-to-tube interaction is definitely proportional to the power. At least in some theoretical sense, that might be part of the answer."
While regulators believe they have pin-pointed the problem at San Onofre, correcting this problem will be difficult. Of particular concern is the age of the components believed to be behind the leak. The plant’s current steam generators were installed as replacements in 2009 and 2010 at a cost of $670 million.
The NRC adds in their report that of the 129 steam generator tubes tested in March of this year, eight had failed completely, “indicating that they could rupture during some operating conditions.”
The report adds, “The integrity of steam-generator tubes is important because the tubes provide an additional barrier inside the containment building to prevent a radioactive steam release.”
"It's not too hard to frame up the problem," Collins says. "The answers are very difficult, or they already would have emerged."
"These are significant technical issues. They are not resolved yet,” he added.
On Monday night a meeting was held to discuss the specifics of the report. The groups Residents United for a Safe Environment and San Clemente Green both released a statement saying, "the crippled San Onofre nuclear power plant has posed an unnecessary risk to our environment and our communities. It has also left Southern California Edison ratepayers footing a $670.8 million bill for critically flawed steam-generator equipment."
Donna Gilmore, spokesperson for the Friends of the Earth, said, "It's insane for anyone in California to have to live with this risk - for nothing. The only advantage of that plant is it makes millions for Edison every day it's running."
However, Southern California Edison say they are in no hurry to restart the plant.
Jennifer Manfre, spokesperson for California Edison states, "We are always putting safety as our top priority in how we design and in the specifications that we made when we were creating these new steam generators. That was really about being safe. We're here to discover what went wrong, and what that process is to make it absolutely safe."
While regulators are still working on the situation, it seems that California barely missed being a second "Fukushima."
More about San Onofre, Nuclear plant, Power, Electricity, Tubes
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