I would imagine the 20-50km zone is just-in-case so people can't come back later and say they didn't do enough, should something major happen. From everything I've been able to get my hands on, right now it's a race to absorb as many neutrons to temper the reactions as possible.(hence the boron) From what I've read LWRs don't "melt down" like you think of a 80s-era cold-war soviet meltdown occurring. Pending a nuclear blast, I'm buying tomorrow.
I love how people are talking about what happened on here, as if they suddenly became nuclear power experts overnight from reading a few things on the internet. I have an idea - how about if you don't have significant experience as a nuclear power engineer, you keep your mouth shut? A better use of time would be to make trading plans for the various contingencies, and look at how you can best position yourself in each case. "Whereof one cannot speak, thereof one should remain silent." - Ludwig Wittgenstein, Tractatus Logico-Philosophicus
Many years ago in a past life I worked in the nuclear industry on the scientific end and I do have some knowledge of nuclear power plants, but I am not an expert, not now anyway. I do want to reiterate what I said earlier, and that is that in my opinion it is somewhat more likely that the outcome of this extremely serious situation in Japan will be to show the world that nuclear energy is just as safe, if not safer than alternatives. If anything kills off fission reactors it is most likely to be cost. Not just the cost of building and operating them, but also the cost of cleanup after disasters, such as Chernobyl and what is happening now in Japan. I don't want to equate the situation in Chernobyl in any way with the situation in Japan, however. They are as different as night and day, both from a design standpoint and the competency of the personnel involved. It is almost impossible to tell from mainstream press reports exactly what is going on, however it does seem that in at least one case there was some intentional venting from one of the containment structures. That is a concern but not a reason to overreact. So far the release of radioactive material seems manageable and not of significant danger to anyone except perhaps those on the scene. If you are interested in early reactor history in the US including a core meltdown event you will find the following link factual and interesting. http://www.osti.gov/bridge/purl.cov...40B388839446?purl=/195702-qNe0Sk/webviewable/
People of Hawaii should stop listening to "everything is under control" and arm themselves with giger caunters
I should have added to my post directly above that still another, and perhaps the hardest to overcome, challenge for the nuclear reactor industry is irrational public opinion. Perhaps the nuclear industry should do what the medical hardware industry did and change the terminology. When Nuclear magnetic resonance imaging was adopted in medicine the name was changed to MRI or magnetic resonance imaging to get rid of the scary word "nuclear". Perhaps Nuclear reactor power stations can become EFPS, "environmentally friendly power stations".
Since no trader is an expert in everything, a lot of research is finding out as much relevant material as possible as quickly as possible, then getting in a position to capitalize. Nothing wrong with some internet conjecture.
Well according to the article I just read, "Japanâs nuclear safety agency said 1,450 workers were at the Dai-ichi plant on Sunday, its usual staffing. The workers were in protective gear and were taking shorter turns than usual in units 1 and 3 to limit their exposure, agency spokesman Yoshihiro Sugiyama said." So that answers one of my questions...a lot more workers than I was expecting! Still not clear how they all survived the tsunami whilst the tsunami took out the water cooling pumps. http://www.japantoday.com/mobile/view/180000-evacuated-as-nuclear-plant-crisis-intensifies
No, of course not. Right now it is rational to be concerned about the specific situation in Japan. I am hoping, and I think it will turn out to be true, that in this worst case scenario we will learn that these plants, are safe for the general public. We will never ever eliminate the dangers posed by human error and greed, and we might as well get used to our reality that we can never be absolutely safe until the day we die. added in edit: I should have said "worst case natural scenario". There can always be something worse caused by humans themselves. The Chernobyl disaster, or the fire bombing of Tokyo would be examples.