Is a 10 percent chance of disaster too high for a nuclear power station?

[bananas]

http://blogs.reuters.com/the-deep-end/2011/03/29/is-a-10-percent-chance-of-disaster-too-high-for-a-nuclear-power-station/

Is a 10 percent chance of disaster too high for a nuclear power station?
Mar 29, 2011 17:25 EDT

JAPAN-QUAKE/Kevin Krolicki has another alarming special report from Japan today challenging the assertion that the disaster facing Fukushima Daiichi nuclear plant was beyond expections.

The report quotes Tokyo Electric’s own researchers who did a study in 2007 on the risk of tsunamis:

The research paper concluded that there was a roughly 10 percent chance that a tsunami could test or overrun the defenses of the Fukushima Daiichi nuclear power plant within a 50-year span based on the most conservative assumptions.

But Tokyo Electric did nothing to change its safety planning based on that study, which was presented at a nuclear engineering conference in Miami in July 2007.

Read the full special report in PDF format here.

From the first link in that article:

http://www.reuters.com/article/2011/03/29/us-japa-nuclear-risks-idUSTRE72S2UA20110329

Special Report: Japan engineers knew tsunami could overrun plant
By Kevin Krolicki, Scott DiSavino and Taro Fuse
TOKYO | Tue Mar 29, 2011 2:00pm EDT

TOKYO (Reuters) - Over the past two weeks, Japanese government officials and Tokyo Electric Power executives have repeatedly described the deadly combination of the most powerful quake in Japan's history and the massive tsunami that followed as "soteigai," or beyond expectations.

When Tokyo Electric President Masataka Shimizu apologized to the people of Japan for the continuing crisis at the Fukushima Daiichi nuclear plant he called the double disaster "marvels of nature that we have never experienced before".

But a review of company and regulatory records shows that Japan and its largest utility repeatedly downplayed dangers and ignored warnings -- including a 2007 tsunami study from Tokyo Electric Power Co's senior safety engineer.

"We still have the possibilities that the tsunami height exceeds the determined design height due to the uncertainties regarding the tsunami phenomenon," Tokyo Electric researchers said in a report reviewed by Reuters.

The research paper concluded that there was a roughly 10 percent chance that a tsunami could test or overrun the defenses of the Fukushima Daiichi nuclear power plant within a 50-year span based on the most conservative assumptions.

<snip>

[aquart]

1. DUH. Here's a better question: Can you stop it once it starts?

[kristopher]

2. This demonstrates the same hubris that exists everywhere within the fission industry.

There is no such thing as a corporate conscience, nor an independently regulated nuclear industry.

[geckosfeet]

3. 1% is too high

I might accept .000001% if proper precautions are taken.

[bvar22]

4. Fukushima has taught us that...

...if we continue to use Nuclear Plants,
It WILL happen again!

The false claim the Nuclear Plants are SAFE
because they have been have been "engineered to withstand natural disasters"
has been completely DEBUNKED.

It WILL happen again.
Its only a matter of time.


Man has NEVER produced even a simple machine that is Fail Safe.

[madokie]

6. Even a pair of pliers can break

I've had it happen to me before so yes man can never build a simple machine that is fail safe.

[flamingdem]

5. In the flurry of WSJ articles about hesitations on nuke construction

there was an article, one I posted I think, that says the US is counting on exporting nuclear technology to other countries.

It hits me that we're really in trouble if that happens, it will happen to some extent but will slow down due to Fukushima fears, because other countries cannot afford a nuclear nightmare. On top of that they will not have the same resources Japan has in terms of trained and experienced engineers.

How many of those can we afford globally?

Tepco is looking at bankruptcy and admitting the disaster will cost them 200 billion or more! So a trillion when you think of the lost exports and long term consequences for tourism, etc.....

Who will bail out these countries?

[Nihil]

7. That's a very good point ...

> ... other countries cannot afford a nuclear nightmare.
> On top of that they will not have the same resources Japan
> has in terms of trained and experienced engineers.

... and, in conjunction with the OP point - that even though their
own highly trained engineers determined that the risk of such a tsunami
was approaching 10%, they were over-ruled - is indeed a major concern.
What chance does a less-trained/less-experienced professional have
of avoiding the same fate when the decision makers are even more
corrupt and less likely to heed advice?

K&R for yet another example of where greed & politics over-ruled the
engineers & scientists.

:-(

[madokie]

8. Greed and stupidity

are mostly what screws things up :hi:

[kristopher]

9. You can't engineer out greed or stupidity either; it is always with you. nt

[One_Life_To_Give]

10. 1 Event every 500 years or 0.2%/year or 2000ppm/yr

With 440 operating reactors worldwide that would yield an incident every 13 months, on average. Looking over recent history if we assume a nominal rate of 1 major incident every 23 years. That equates to 10^-4, 1 in 10,000 operating years or 100ppm/yr.

Thats not a bad failure rate if we were talking about just a loss of the plant. But when as in these cases the loss of land use, evacuations, loss of life and/or health is this still acceptable?

[SpoonFed]

11. WTF

Your numerical analysis of the risk makes absolutely no sense.

Does ppm in your post refer to parts per million?
An assumption of 1 major accident every 23 years is a gross underestimation giving my understanding of history.
Can you relate your definition of major accident to the INES scale for me please?

[One_Life_To_Give]

12. ppm or Parts per million is for my quality friends who put field failures into that

I was counting the events at Fukushima, Chernobyl and TMI. Although I am not sure the later really qualifies.
My views of these events is shaped by IEC61511, 61508 and ISA SP84.
A major event would have a threshold of either killing minimum 1-10 people beyond the fence-line directly.
Or leading to/being significant contributor to the death or permanent injury of min. 10-100 people beyond the fence-line.
Loss of use/rendering unfit for human habitation of multiple (over20?) residential structures for periods of more than 1 month.

Previously I would of expected Civilian Nuclear to compare favorably to the Chemical Industry. But I don't see where my numbers support that.

[SpoonFed]

15. Okay.

I guess I have some issues.

I see an inherent flaw in using the methodological framework of safety evaluation for instrumented systems in determining the risk of a serious nuclear event, when it is under the circumstances of such an event in which those very same safety systems have failed to prevent and/or caused the event to occur. Not to mention that radioactive nuclides and their health effects are terribly different scope of interest than electronics and electrical control systems from my understanding of physics and engineering.

Furthermore, I think using ppm in the context of nuclear safety and recent discussions about radiologic nuclide emmision and their health effects adds confusion. At first glance, it appeared to me that your use of ppm as a unit and stating a measurment or calculation of 100ppm was an attempt at obfusicating the health effects of radiation, as most people would read that number 100ppm and immediately think "small" or "insignificant". I'm going to assume this wasn't your motive.

I have a differing view about what constitutes a major event.

Previously I would of expected Civilian Nuclear to compare favorably to the Chemical Industry. But I don't see where my numbers support that.

Sorry, I don't follow your aside. Can you elaborate?

[One_Life_To_Give]

16. Chem Industry seems to use higher standards than Nuke

When I hear Chemical Process industry numbers for events such as 500,000gal gas leak into residential neighborhood. Figures of 10^-4 failures per year of a tank wall. Plus a dike for an additional reduction of 10^-4 for dike failure. And perhaps a farm of say 10 tanks. Gives a probability of failure putting product into the neighboring residential neighborhood of 10^-7 events per year.

It appears to me that an equivalent event a a nuclear plant does not have the same degree of risk reduction. Meaning that it's a more probable event for the same impact to the general public. I used to assume that the Nuke Industry would of been paranoid and maintained a much higher or atleast the same level of risk reduction overall as the Chem Industry. But I have changed my mind. The trouble as you point out, with little numbers is they add up.

I do think you can apply the Safety Lifecycle Analysis process to most anything. In the end it's just a process used to identify risks so they can be addressed. Wether it is Mechanical, Electrical or Radiological.

[Fledermaus]

13. Ring of Fire + Nuclear Power = Fail!

Probably any nuclear power plant on the sea is a bad idea. According to Wikipedia, "Asteroids with diameters of 5 to 10 m (16 to 33 ft) enter the Earth's atmosphere approximately once per year, with as much energy as Little Boy, the atomic bomb dropped on Hiroshima, approximately 15 kilotonnes of TNT. These ordinarily explode in the upper atmosphere, and most or all of the solids are vaporized.<3> Objects with diameters over 50 m (164 ft) strike the Earth approximately once every thousand years, producing explosions comparable to the one known to have detonated above Tunguska in 1908.<4>"

[pscot]

14. If the disaster is Fukushima

a .00001 chance is too high.