Nuclear Plant Has Flaw Undetected for 19 Years

[Carmalita]

PHOENIX, Oct. 13 (AP) - A potential problem with the emergency reactor core cooling system at the nation's largest nuclear power plant went undetected from 1986, when the plant began producing electricity, until last week, the Nuclear Regulatory Commission and the plant operator confirmed Thursday.

The issue, a design flaw, was identified when engineers at the plant, the Palo Verde Nuclear Generating Station, did an analysis after commission overseers raised questions at a detailed inspection early last week. The analysis showed that the emergency cooling system might not operate as expected to provide water to reactor cores after a small leak in the reactor cooling lines, said a commission spokesman, Victor Dricks.

The worst-case result of an emergency cooling system failure is a meltdown of the reactor core and release of radioactivity into the atmosphere. Plants have redundant systems, however, and many other failures would have to occur before that happened, nuclear experts say.

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[tlatchaw]

Zoinks!

I'm glad that they found that. I'm sure that particular fault will be very carefully checked at every other plant in the country now too. It stinks that it went undetected 16 years, but I'm glad that a review caught it. Maybe they really are checking things the way that they're supposed to.

 

[Carmalita]

Zoinks!

I'm glad that they found that. I'm sure that particular fault will be very carefully checked at every other plant in the country now too. It stinks that it went undetected 16 years, but I'm glad that a review caught it. Maybe they really are checking things the way that they're supposed to.

The check system worked but, like you I have concern that it took so many years to work.

 

[dustin]

I think the same thing happened in Russia...what like 15 years ago? (when the emergency cooling failed)...or maybe that was a chemcial plant...

 

[Ken King]

I think the same thing happened in Russia...what like 15 years ago? (when the emergency cooling failed)...or maybe that was a chemcial plant...

Man, it's hard to believe that Chernobyl is coming up on its 20th anniversary already (accident was in April 1986). I think the detected design flaw in this story is a little different then what happened at Chernobyl. The Ukraine exlposion came about while they were doing a test at the plant and the automatic shutdown mechanisms had been intentionally (and mistakenly) disabled which halted the cooling flow at a critical moment. From what I remember reading it was more operator error then anything else, though the unit design has always been considered unstable under certain operating conditions.

 

[Carmalita]

I have heard that the design of that reactor was a different design than those used in America. Is this so?

 

[Ken King]

I have heard that the design of that reactor was a different design than those used in America. Is this so?

That is my understanding too, though I don't now a darn thing about nuclear power plants except that if something goes seriously wrong with one it won't be pretty.

 

[dustin]

Man, it's hard to believe that Chernobyl is coming up on its 20th anniversary already (accident was in April 1986). I think the detected design flaw in this story is a little different then what happened at Chernobyl. The Ukraine exlposion came about while they were doing a test at the plant and the automatic shutdown mechanisms had been intentionally (and mistakenly) disabled which halted the cooling flow at a critical moment. From what I remember reading it was more operator error then anything else, though the unit design has always been considered unstable under certain operating conditions.

That's right...Chernobyl...



Yeah I've heard that the design of the it was not as robust as those in the states and europe.

 

[Carmalita]

That is my understanding too, though I don't now a darn thing about nuclear power plants except that if something goes seriously wrong with one it won't be pretty.

I also have no knowledge of these things but I believe that I recall reading that the design was not used in America because it was considered unsafe by our engineers.

 

[AK-74me]

I think the same thing happened in Russia...what like 15 years ago? (when the emergency cooling failed)...or maybe that was a chemcial plant...

Yeah but this is not even comparable the thing that made Chernobyl a disaster is that they had no containment building the way Nuke plants in the U.S. have, so really even if the core did melt down, which still would be a huge deal, there would still, theorically, not be a part 100 release.

 

[itsbob]

That's right...Chernobyl...



Yeah I've heard that the design of the it was not as robust as those in the states and europe.

Not even close to being the same animal... Russian Reactors are bulit as cheap as possible, on a concrete slab.. they melt down there is nothing that can be done, the reactor sits on the top of the slab and releases radiation.. ours are built in their own protective sarcophagus' below ground or if they do "melt down' they fall into their own crypts.. where as in Russia, people had to sacrifice their lives flying through the radioctive clouds dropping chemicals and building a crypt around it.. Chernobyl is still highly radioactive and people still rish their lives daily walking through the site and flying over it to test the radioactive releases, and to see if the crypt they built for it develops a leak.

 

[sleuth]

The check system worked but, like you I have concern that it took so many years to work.

As much as we'd like to be, engineers ain't perfect.
We design things to the best of our understanding, but in complex systems such as these, it's easy to miss something. No one person can get their minds around this large of a system. That's the reasons for the extensive review processes.

Couple that with the fact that engineers build their designs on loads of assumptions. 99.9% of the time, we'd like to think our assumptions are conservative. But sometimes, when we don't get all the information, when there's a bureaucratic error, when you have unexperienced engineers working, or even when you have an experienced engineer who doesn't fully understand the problem, these things happen.

It's analogous to the same reasons we have cracks in our airplanes where there shouldn't be any.

 

[Pete]

Good, I am glad they fixed it. Now they can build 150 more plants.

 

[Carmalita]

As much as we'd like to be, engineers ain't perfect.
We design things to the best of our understanding, but in complex systems such as these, it's easy to miss something. No one person can get their minds around this large of a system. That's the reasons for the extensive review processes.

Couple that with the fact that engineers build their designs on loads of assumptions. 99.9% of the time, we'd like to think our assumptions are conservative. But sometimes, when we don't get all the information, when there's a bureaucratic error, when you have unexperienced engineers working, or even when you have an experienced engineer who doesn't fully understand the problem, these things happen.

It's analogous to the same reasons we have cracks in our airplanes where there shouldn't be any.

I understand. The problem is that, in this case the consequences of failure are extreme. If an airplane crashes about one hundred fifty people die. Certainly, it is a tragedy and it is a complete tragedy to the people who die and their families and friends. But it is conceivable that hundreds of thousands of people could be impacted by a "worst case" failure of a nuclear power plant. The question then becomes, "Is the benefit worth the risk?" I do not say that it is not because I know little of the risk. But I feel that it is wise to ask the question continually.

 

[sleuth]

I understand. The problem is that, in this case the consequences of failure are extreme. If an airplane crashes about one hundred fifty people die. Certainly, it is a tragedy and it is a complete tragedy to the people who die and their families and friends. But it is conceivable that hundreds of thousands of people could be impacted by a "worst case" failure of a nuclear power plant. The question then becomes, "Is the benefit worth the risk?" I do not say that it is not because I know little of the risk. But I feel that it is wise to ask the question continually.

I don't remember what the risk matrix is for airplanes, but I believe the chances of failure on airplanes have to be less than 1/100,000 to get a flight clearance. And usually it's one in a million or less.

Even then, the failures often occur gradually and have multiple redundant systems to reduce the catastrophic effects.

I would venture a guess that nuclear power plants have to go through much of the same evaluations. The good thing is, they're on the ground, they're not under as much stress, they have fewer moving parts, and it is a much more controlled environment.

 

[itsbob]

I understand. The problem is that, in this case the consequences of failure are extreme. If an airplane crashes about one hundred fifty people die. Certainly, it is a tragedy and it is a complete tragedy to the people who die and their families and friends. But it is conceivable that hundreds of thousands of people could be impacted by a "worst case" failure of a nuclear power plant. The question then becomes, "Is the benefit worth the risk?" I do not say that it is not because I know little of the risk. But I feel that it is wise to ask the question continually.

Whats the worst case? And how do we come to the figure of "hundreds of thousands will die".. that sounds like a Clamshell Alliance statistic..

I would say Chernobyl was a worst case for THEIR designed nuke plant... I don't think that will happen here, but if it did the design of our systems would prevent a Chernobyl like calamity from happening.. it will be much more contained.

 

[Carmalita]

The good thing is, they're on the ground...

As are the hundreds of thousands of people that live near some of them.

they're not under as much stress...

I suppose that this is true if you do not consider extremely high temperature to be stress.

 

[Ken King]

I understand. The problem is that, in this case the consequences of failure are extreme. If an airplane crashes about one hundred fifty people die. Certainly, it is a tragedy and it is a complete tragedy to the people who die and their families and friends. But it is conceivable that hundreds of thousands of people could be impacted by a "worst case" failure of a nuclear power plant. The question then becomes, "Is the benefit worth the risk?" I do not say that it is not because I know little of the risk. But I feel that it is wise to ask the question continually.

That would depend on where the plane crashes. Into a city and you could have a hell of a lot more deaths, even thousands. I think that Chernobyl only had about 40 some deaths related to the radiation release. As to worse case scenario we had that at TMI back in the late 70s and the reactor designs were such that the melted core never got out of the vessel.

 

[Pete]

That would depend on where the plane crashes. Into a city and you could have a hell of a lot more deaths, even thousands. I think that Chernobyl only had about 40 some deaths related to the radiation release. As to worse case scenario we had that at TMI back in the late 70s and the reactor designs were such that the melted core never got out of the vessel.

I think it was much more than that.

 

[Ken King]

I think it was much more than that.

Yep, a few more

28 people died within four months from radiation or thermal burns, 19 have subsequently died, and there have been around nine deaths from thyroid cancer apparently due to the accident: total 56 fatalities as of 2004.

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