Thanks
Strangely (though I know I'm not the only one) I've become much more pro-nuclear power during this awful saga. Education is good.
This is mediocrity at its best. Your main line or argument is comparing nuclear power with coal/oil/gas power. Which are basically three century old solutions from the beginning of the industrial age.
You will always excel if you compare yourself with the loser in the class. Rather than compare it archaic technologies, compare it with itself and see what could have been improved.
There are plenty of recorded tsunamis of greater hight recorded in Japan's history prior to the building of the plan. Secondly they should have contemplated the scenario in which the wall is not enough. On the following lines
a) we have a wall to contain tsunamis and it will contain waves up to X height
b) what are our options if the wall is compromised or not high enough for the incoming wave?
Unfortunately b was not answered. While it is true that there could be many events and natural disasters, there is one important outcome to consider : vast quantities of water get in. You don't need to think of all the possible events, just one important outcome : water in the plant perimeter. Why not seal the generator in concrete buildings that don't allow water to get in? Why not put some generators up hill, far from the waterline?
Thinking all possible scenarios is not all that complex. For each backup system you have to think about a) being ok or b) failing. Since there was powerline, generator and battery as options you really don't have that many decision points. Now you may rant all you want about reasons for that to fail, a tree falling, an airplane crash, an earthquake, etc etc etc. But the bottom line is just this: what do we do when backup X fails?
Why not the option of having an external jack to plug a trailer loaded generator? Why not auxiliary water connections to put in an external cooling unit for the pools? Why no containment dome on the pools themselves!!??
The main concern right now is the fuel in the pools. Nobody cared to ask what if all three backups fail. It is pretty clear to anybody in the industry that those pools would dry up. Ironically the fuel from the shutdown reactor is one of the ones posing the greatest threat right now. And no one ever though of putting tubes to the outside of a the building to connect some water hydrants?
How expensive can it be to put an external connector to water sprinklers? How hard was it to think of a safer pool? Particularly when it is clear that power failure would lead to its overheating.
So to address your point about worse case scenarios. No they are not designed to consider worse case scenarios because clearly we are living through a worse case scenario that wasn't considered. Once again I don't believe "that every possible natural disaster is predictable and there can't be an unseen event." To do so is impossible, but it is possible to consider the failure of all the systems and all backup systems we implement. Because those are finite and set by us and thus predictable. And then ask us what do we do then.
However, Japan has a coastline approximately 29,000km long. Therefore, to affect this 1km of coastline where the reactors are located is a;
((1/6.73) x (1/10) x (1/29,000) x 40) chance.
Do you think there will be radioactive snow as far as Mongolia?
Do you think there will be radioactive snow as far as Mongolia?
...just an aside, sir.....
'toke'....great name..
....does is have the same meaning in danish as in english?
Not really, but it has a lot of desert.Why not? Mongolia is close to Japan.
That comes to around 0.000002049 or 1 in 487925.
Now multiply that times what's at stake. Just the cleanup has been placed in this thread at 100 billion. Plus the new plant themselves, plus public image impact, plus stock loss, plus lost revenue, plus human impact, etc.
Lets just talk material costs at 120 billion? 0.000002049 * 120B = 245880
If an insurance company were to pay out 1 in every 487925 possible outcomes it would have to charge you $245,880 for coverage so to speak. You can cover the generators with that money can't you?
There's also the issue that your calculation is slightly flawed. A tsunami can easily cover more than 1km of area. So the 1/29000 isn't very accurate. For example the quake in the Indian ocean easily affected all of Sri Lanka.
As you can see from the image here it is quite a large area:
http://www.disasterscharter.org/image/journal/article.jpg?img_id=96235&t=1300352325135
Maybe 1/20 of the costal area? Moving 1/29000 to 1/20 or 1/30 greatly increases the odds.
BTW, how much are the generators themselves valued at? How much is it worth constructing around them to further protect them?
Look at these costs: http://www.hardydiesel.com/detroit-diesel-generators/
Building sized generators are running up to half a million. Why do you think they'd put half a million Dollar generators in place? It is sheer negligence to spend so much money on that and then fail secure them in a water tight building. How much would such building add? $100,000?? Not much more than that even for the over priced nuclear industry.
And now they're going to need to do it now anyway, and they have the lack of power from the shutdown reactors, and they're in the middle of a crisis, and bleeding money on other things, and on top of that they'll have the cleanup bill. Suddenly Java Man's 5% tax increase begins to sound like a drop in a bucket compared to all this.
Prevention is usually cheaper than correction. Ever heard of insurance policies? It's the stuff you pay with the intent on not using it.
That comes to around 0.000002049 or 1 in 487925.
Which is the starting point. Now if we add System X (automatic shutdown) to protect from the hazard, what is the chance that this too fails. And now add Safety System Y (containment), and System Z (back-up cooling), etc., etc. At some point the probability that ALL those additional systems fail simultaneously probably does become negligible. At that point why add more and more redundancy?
As others have said, it comes down to a risk assessment.
Besides, an earthquake occuring in Tokyo may produce a 9.0 'quake in Fukushima, but due to its location it wouldn't necessarily produce a tsunami. Quakes seem to be the more common threat.
Very quick and dirty risk assessment (it's a Sunday);
Based on Wiki-p there have been 195 tsunamis in Japan in a 1300 year period. Therefore there is approximately 1 tsunami hitting Japan every 6.73 years. Of these about 1 in 10 are listed (let's say they are the 'notable' ones). However, Japan has a coastline approximately 29,000km long. Therefore, to affect this 1km of coastline where the reactors are located is a;
((1/6.73) x (1/10) x (1/29,000) x 40) chance.
Of course, the outcome of a nuclear incident varies, therefore I'll let the reader suggest what value should be ascribed to the severity of this risk. But the point is the engineers will have done this calculation and presumably factored in the probabilities of multiple failures of the safety systems over the 40 year working life of the plant, and the figures they got were again, presumably, below the threshold for requiring any additional systems.
And there has to be a threshold, to everything up to and including nuclear facilities, otherwise we'll end up designing all our infrastructure to withstand meteor impacts.
Which is the starting point. Now if we add System X (automatic shutdown) to protect from the hazard, what is the chance that this too fails. And now add Safety System Y (containment), and System Z (back-up cooling), etc., etc. At some point the probability that ALL those additional systems fail simultaneously probably does become negligible. At that point why add more and more redundancy?
There are two power sources to run the cooling. If one fails, the external AC power, you have a very large increase in the probability that another will fail due to tsunami, the generators. That is, tsumais that wrecked the generators are associated with the quake that killed the external AC. If one happens, then the other will also likely happen.
Can we protect against a 5 m tall wave? Yes An 8 m tall wave? No. What do we do then. Asking if we can protect against a 9, 10, 11 m etc wave is pointless beyond that.
Japan Times has an article on scare-mongering international media.
http://search.japantimes.co.jp/cgi-bin/nn20110321f1.html
The article cites a "Wall of Shame" that collects the most egregious articles on the tsunami/quake/nuclear problem:
http://jpquake.wikispaces.com/Journalist+Wall+of+Shame