World Is Ignoring Most Important Lesson From Fukushima

mdsolar writes "Kenichi Ohmae, an MIT-trained nuclear engineer also widely regarded as Japan's top management guru, is dean of Business Breakthrough University. In the CSM he writes: 'Fukushima's most important lesson is this: Probability theory (that disaster is unlikely) failed us. If you have made assumptions, you are not prepared. Nuclear power plants should have multiple, reliable ways to cool reactors. Any nuclear plant that doesn't heed this lesson is inviting disaster.'"

Comments

Error in translation?

[ceoyoyo]

Either there's an error in translation or the MIT trained nuclear engineer has forgotten what probability theory is.

Having multiple means of cooling a reactor sounds like a good idea, but that will only reduce the probability of disaster.

Re:Error in translation?

[RightwingNutjob]

Too many people learn risk management like this:

The probability of a widget failing is 0.001. The cost of a widget failing for us is $1000. Therefore, we should budget $1 per widget to cover the expected failures.

Trouble is, this only makes sense if you make 10000 widgets. Then you expect 0.001 x 10000 x 1000= 1000x(10 +/- sqrt(10)) failures (assuming widget failures are independent and uncorrelated events, which means the expected number of failures follow a Poisson distribution), so if yo budget
$20000 = 1000 x (~10 + 3*sqrt(10)), you'll be covered 99% of the time.

Note that "99% of the time" means that if you make 100 production runs of 10000 widgets, and budget $20000 for covering failures on each run, you'll be good for 99 of those 100 runs, and you might be over budget on the 100th.

When you make exactly one widget, and it costs you $1000 if it fails, and you estimate that the probability of failure is 0.001, and you budget exactly $1 to cover failures, what you've done is you've wasted $1, and you're still not covered, because if your one widget fails, you don't have the budget to cover it.

There was exactly one Fukushima plant, and when you talk about risk analysis for something like that, anything that is remotely likely to cause a catastrophic failure needs to be fully accounted for, because there is no such thing as an amortized catastrophic failure. It either works or it blows up in your face, not a small percentage of your face.

Reckless!

[Anonymous Coward]

That's just the kind of reckless thinking that caused the failure in the first place. We must provide for EVERY contingency, no matter how unlikely!

For the children!

Re:Reckless!

[lgw]

From what I understand pebble-bed reactors don't even count on gravity-fed cooling. The reaction simply stops if it gets too hot, effectively setting a maximum temp that won't burn through concrete.

Of course, pebble-bed was more about demonstrating idiot-proof safety than practical power generation, but it would actually work just fine (if not as cheaply as more sophisticated designs).

Or use a different type of reactor....

[blunttrauma]

Or use a different type of reactor that doesn't rely on electricity for cooling. See any of Kirk Sorensen's liquid-fluoride thorium reactor talks on YouTube. His talk at Ted is a good 10,000 overview and only 10 minutes long: http://www.youtube.com/watch?v=N2vzotsvvkw

Re:Correct

[Mitchell314]

Right. Everybody's percolating coffee machines wouldn't work. Death would be a welcome reprieve should this horrible reality come into being.

Re:Correct

[ArhcAngel]

Nuke em...It's the only way to be sure.

Wrongheaded....

[NoKaOi]

Modern reactors already do the things this guy is suggesting. This guy is decades late to the party. I'm sure there will be 100 comments saying this by the time I hit submit, but the real lesson should be to build new plants with modern reactors, so that once built the old ones can be decommissioned *after* the new ones are built. The kind of attitude this guy has (I'm sure his real motivation is just to get attention) obviously scares people into not wanting new nuke plants built.

On the other hand, he's not very specific in the TFA. Perhaps is real life he has suggested a specific way to retrofit existing reactors with backup generators? Or is he just regurgitating crap that we were reading the day after the tsunami?

And Business Breakthrough University? SERIOUSLY? WTF is that? It reminds me of all those high priced fat loss pills that were developed by places like the "fat loss institute." Apparently anyone can file a DBA with the word institute or university in it. Does anybody really regard this clown as Japan's top management guru? Or am I wrong and this guy is actually dean of an accredited university?

Re:Correct

[Troggie87]

For those who don't follow reactor tech and don't know whats being talked about, liquid sodium reactors use literally a vat of salts and radioactive material in a magma-like sludge. There is a plug at the bottom of the vat with a melting point that is well above operating spec, but well within reach if the reactor lost cooling. If all other failsafes are disabled, the plug melts and all the molten sludge runs into 2-3 smaller tanks. The reaction then stops being self sustaining, and you just have to recover the containment units and repair the reactor. Its literally idiot proof barring a fault line opening a chasm beneath the plant or a direct asteroid impact.

There are also gravity-fed means of cooling conventional reactors, but I wouldn't call any of them fool proof. Liquid sodium seems like the best bet to me from a safety standpoint, at least as far as using up existing nuclear material. Thorium reactors show promise as well, but since we have a ton of reusable nuclear material liquid sodium would be my choice from a practicality standpoint.

One MIT Engineer to Another

[Anonymous Coward]

I am an MIT trained nuclear engineer than specializes in Probabilistic Risk Assessment. The first thing we should note is the PRA has had many benefits for the nuclear industry. Once you calculate the risk, and understand the contributors, you understand how to make things safer.

http://mydocs.epri.com/docs/CorporateDocuments/SectorPages/Portfolio/Nuclear/Safety_and_Operational_Benefits_1016308.pdf

The thesis of this article has a few problems, though the conclusion isn't horribly off base. The first problem is that he believe probability theory was applied to ignore the risk of the tsunami. The opposite is true. In fact, probabilistic hazard assessment of the tsunami showed the site to be horribly under prepared in 2006 (10% chance of exceeding the design basis in 50 years or about 1 in 500 per year [which is high for nuclear reactors]). There were even more studies in later years before the tsunami hit. This was just plain bad management and shows what may happen when you ignore updated risk information.

http://enformable.com/2011/10/new-exposed-scandal-shows-tepco-calculations-in-2006-showed-probability-of-worst-case-tsunami-dramatically-increased-10-over-50-years-utility-took-no-countermeasures/

The main point though, that no matter how unlikely a single event is (in this case a tsunami), you ought to have some countermeasures, is not bad. That is why PRA is used in combination with deterministic defense-in-depth measures at well designed, operated, and managed nuclear reactors. Mobile emergency diesels should be available to all reactors and are in the United States. This is a feature that Fukushima did not have. At the end of the day though, ceoyoyo is right. Even with multiple methods of cooling a reactor, you can not eliminate the possibility of core melt and release of radionuclides to the public. You can only ensure the release is acceptably infrequent. This brings us full circle to the fact that using probability theory to focus on the high risk stuff is good and that Fukushima failed to do this.

That being said, even in the case of passively cooled reactors such as fast reactors, massive earthquakes (1 in 1,000,000 per year or less), could destroy the water tank or piping required for passive cooling to take place. I would argue that while one should not ignore earthquakes and other rare external events below a certain probability. The burden would be onerous to use events below 1 in 100,000 per year as a design basis. This is in line with previous regulatory safety goal and can be seen in use in debate over the transition break size rule. A plug for my journal article is below. If you are wondering which author I am, the hint is that I am not the NRC commissioner.

http://www.sciencedirect.com/science/article/pii/S0029549311008284

Re:What the hell?

[mlts]

Where the rubber meets the road is deaths per terawatt hours. Even with the disaster, nuclear remains well lower (0.04) than any of the other mainstream energy sources (coal's world average is 161, oil is 36).

With nuclear having 900 times fewer deaths than oil, this shows that something is being done right.

The problem is that with all the fear around nuclear reactors, no new, safe ones are built, so we are left with maintaining venerable designs designed barely after WWII with far fewer safety features.

The insanity of this shows when one compares this with other industries. It would be ridiculous to claim that aircraft are fundamentally unsafe and banning any new design to be made, only allowing biplanes from WWI to keep in the skies. Or saying how pathetic an automobile is while barring anything newer than a steam engine.

Re:Correct

[NeutronCowboy]

Molten salt reactors introduce a new problem though: the material is highly corrosive, and there are few materials that have even been tested that could provide a proper lifespan to the reactor. Furthermore, maintenance on the entire primary loop is like maintenance on the containment vessel for water cooled reactors: you just don't do it. This means that while the system is safer from a human fuck-up perspective, it presents brand-new engineering, construction and maintenance challenges.

Found a perfect place for a nuclear reactor...

[slew]

Unforutnatly, it doesn't meet all of your criteria...

* only 8 light minutes from earth (closer than 1 light year)
* actually engages in nuclear reactions (although you didn't specify fusion vs fision)
* doesn't use current nuclear infrastructure (check!)
* produces lots of waste (e.g., low energy cosmic rays)
* is actually "nuclear" in the fusion sense (but not fission sense)
* uses techology that has billions of years of hardcore reliability testing (check!)
* generally doesn't offend anyone's delicate sensibility (other than basement dwellers and vampires)

For now, I'll keep this perfect place a secret, because as soon as people find out about it, people are gonna protest and want to have it shut it down...