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Officials: Small Radiation Leak Possible At San Onofre Nuclear Plant

San Onofre Nuclear Generating Station
Nuclear Regulatory Commission
San Onofre Nuclear Generating Station
Possible leak in a steam generator at the San Onofre Nuclear Reactor
Guest: Gil Alexander, media relations spokesperson, Southern California Edison

CAVANAUGH: I'm Maureen Cavanaugh. It's Wednesday, February 1st. Our top story on KPBS Midday Edition, a leak in the shell of unit -- No. 3 reactor at San Onofre caused a shutdown late yesterday. Officials now say a small increase in radio activity has been detected but is still within acceptable levels. Of joining us to explain what went wrong and how it's being fixed is my guest, Gill Alexander, media spokes person for Southern California Edison. Welcome to the show. ALEXANDER: It's good to be with you. CAVANAUGH: The nuclear regulatory commission came out half an hour ago saying a small amount of radioactive gas could have escaped, but it would not have posed a safety risk. Is that generally what Southern California Edison has been telling the media? ALEXANDER: Well, no, we generally don't talk about what might be or could or possibly might happen. What I can tell you is what is happening. And let me respond first of all. There is not a leak in the shell or in the dome that people see when they drive past the two reactors on I-5. What we detected yesterday afternoon late in the day was a leak was water that's fully contained, a very small amount of water, inside the southern dome. And so as a precautionary measure, we shut down the unit to go inside and inspect and repair. To put it in context, US nuclear power plants classify emergencies in four ways from the least severe to the most severe. This doesn't even rate the lowest rating. CAVANAUGH: Now, you have been quoted as saying you detected a slight increase in radioactivity, but it's still within acceptable levels. How small is that increase? How would is that compare, let's say, to the amount of radiation in an X-ray? ALEXANDER: Well, Southern California Edison I don't believe has been quoted as saying that. I think you may be picking up on comments made by the nuclear regulatory commission. The most important thing I can tell you is that the plant is covered with sensitive detectors. And we have detected no significant or measurable increase in radiation. There is the technical possibility in an event such as this, the precise leak of water inside containment. There's the technical possibility of an external release that would raise radio activity levels, but we're not finding that in this situation. CAVANAUGH: Well, you were quoted as saying in an article in the San Diego reader. But let's move on. What's happening now at San Onofre? Is it too soon for crews to get in to find out what is happening with the leak? ALEXANDER: Well, we're beginning that process. We shut the reactor down at 5:30 yesterday. That takes place fairly quickly. But we do then need to wait for the whole system to cool down. We boil water and make steam to win a turbine, to spin a generator. When you've got boiling water and hot steam, you need to wait for the thing to cool down. We are currently planning on an approach to analyzing this small water leak. We'll probably have crews inside the southern dome by tomorrow morning, then we'll see where the leak is, what the nature of the leak is, plan the repairs and provide. CAVANAUGH: How concerned are you over a steam generator that was just installed last year that now has this leak? ALEXANDER: Well, your point is well taken that this is a 2-year-old component that you would not expect to see any leak. Even though this one is extremely small. But the truth is, we won't know what we're dealing with. Is it a weld? Is it a piece of pipe? What is it and how could it have happened? We just won't know that until we get crews inside. CAVANAUGH: Now, some critics of San Onofre have said if this new generator can't take ordinary daily use, how will it stand up to an earthquake? Do you feel there's any merit in a concern like that? ALEXANDER: No, there's no merit whatsoever. That would be -- that would just be fear mongering to try to connect dots that just don't connect. In terms of earthquake readiness, all safety sensitive systems, and that includes the steam generators are rated to with stand up to what's called .67 G for gravity of motion. You may recall the great California shakeout drill, earthquake drill last September. That was based on the big one hitting the San Andreas fault. Our plant can with stand ground motion five times greater than that. And that includes the steam generators. CAVANAUGH: I understand this shutdown leaves San Onofre not producing any power. Why is that? ALEXANDER: Well, we had planned for some time one of our regular technology upgrades and maintenance outages for the northern dome. So early in the year, in January, we removed it from service. We're now going through two months of planned maintenance. That happens every 22 months upon yesterday's incident in the southern dome certainly was unplanned. CAVANAUGH: When do you think unit three might be back online? ALEXANDER: Well, are we won't have any idea until crews get in and assess the leak. It's a little like taking your car in for a major tune-up and demanding to know exactly how long the mechanic needs. We need to see the leak and assess how difficult or easy it might be to repair, and only then will we know how many days we'll be offline. CAVANAUGH: Is the manufacturer, Mitsubishi, are they going to come over and help with these repairs, do you think? ALEXANDER: We're not only conferring with Mitsubishi heavy industries that built the steam generators, but also with other US plants. San Onofre was fortunate to be one of the last in the US to have to replace its steam generators. The original components worked really well. So there's a lot of experience in the industry with steam generator performance, and we're gathering lessons learned today. CAVANAUGH: How much money do you think you're losing with the San Onofre power plant down? ALEXANDER: It's impossible to say because the replacement power comes from the marketplace. And it's the old principle of supply and demand. Fortunately, this is the winter time and if you can imagine, Southern California Edison customers use twice as much power on a July or August afternoon as on a February afternoon. So I suppose if you're going to have a mechanical problem with a power plant, this is the time to have it. CAVANAUGH: I've been speaking with gill Alexander, he is media relations spokes person for Southern California California Edison. Gill, thank you very much. ALEXANDER: My pleasure.

Southern California Edison News Release
Southern California Edison (SCE), operator of the San Onofre Nuclear Generating Station, has begun a precautionary shutdown of Unit 3 because sensors installed for this purpose detected a possible leak in one of the unit’s steam generator tubes.
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A nuclear reactor at San Onofre Nuclear Generating Station remained off-line today due to an equipment problem that sent a small, non-hazardous amount of radioactive gas into an auxiliary building and possibly into the atmosphere, authorities said.


The leak in a steam-generator tube in Unit 3 at the power plant just north of Camp Pendleton was detected about 6 p.m. Tuesday, according to the U.S. Nuclear Regulatory Commission.

An alarm alerted station personnel to the presence of radioactivity in the ancillary structure, and they immediately began shutting down the reactor, NRC spokesman Victor Dricks said.

Since the equipment-housing building into which the gas leaked is not airtight, it is possible a "very, very low level'' of radioactivity escaped into the environment, according to Dricks, who said those traces would be "barely measurable against (existing) background levels'' and would pose no danger to the public.

SONGS crews will fully evaluate the cause of the mishap and the steps required to repair it before resuming operations, according to Southern California Edison, which operates the facility.

Once the problem is resolved, it will likely take several days for the reactor to be restarted, the Rosemead-based utility advised.


At the time of the accident, the other reactor at the plant already was powered down for routine maintenance, refueling and technology upgrades. Still, the utility had ample reserve power to meet customer needs, according to SCE officials.

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