demagogue on 15/3/2011 at 02:21
Because it's exactly when people get emotional that they push through bad policy as a knee-jerk reaction without debate and without fully understanding the situation.
There were explosions from the hydrogen build-up by superheated water, but that's a separate thing from the risk of radioactive release. There are things you can do for better regulation -- The US has more safety checks to deal with power-cuts because of the terrorist risk. But these things were designed to deal with these kinds of problems.
Anyway, reason the experts are being cautiously optimistic in this situation: (
http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/)
Quote Posted by "@the end of the article"
Now, where does that leave us?
* The plant is safe now and will stay safe.
* Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.
* Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.
* There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage.
* The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the “main” nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago. This further reduces the activation. The bottom line is that there will be some low level of activation of the seawater, which will also be removed by the treatment facilities.
* The seawater will then be replaced over time with the “normal” cooling water
* The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.
* Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.
* The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)
* I believe the most significant problem will be a prolonged power shortage. About half of Japan’s nuclear reactors will probably have to be inspected, reducing the nation’s power generating capacity by 15%. This will probably be covered by running gas power plants that are usually only used for peak loads to cover some of the base load as well. That will increase your electricity bill, as well as lead to potential power shortages during peak demand, in Japan.
baeuchlein on 15/3/2011 at 04:14
The situation may have changed. Apparently, there has been another explosion, and this time reports speak of damage to the inner parts of reactor 2, not just to the concrete roofs, as with the previous two explosions.
Anyway, there are some things about this explanation you cited which may not be right.
Quote:
* The plant is safe now and will stay safe.
Depends on what the last explosion did, and whether the article's author was right about all these things he wrote.
Quote:
* The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the main nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago.
The uranium
chain reaction was stopped, yes, but not the uranium
decay. That one
cannot be stopped. It is not very dangerous (compared to a nuclear chain reaction), however, as long as the uranium is kept away from people and from itself, to a degree - we're talking about the "critical mass" here; if there's more than than in a single spot, the decay will turn into a chain reaction again unless you have some other materials in between. That's what control rods and other "moderators" are for.
On the other hand, even if uranium decays without a chain reaction, it
will still produce Cesium and Iodine. This is part of the process of decaying and
cannot be stopped. The question is: how much will be produced?
If Iodine and Cesium are produced only in small quantitys over time, Iodine-131 and Cesium may be largely gone by the time the author refers to, because of their half-lifle values. Iodine-131's half-life time is some days. However, I do not know what happens after these materials have decayed. They will, however, decay to another decaying material, which would then send out radiation. I don't know how long the chain of decay is in these cases, but I remember that there are four possible ends of such a chain, three of them ending with some isotope of lead. So, there
will be more decay (which in turn will produce more radiation) even after that. Whether it will be dangerous or not I cannot say.
And there's something else the author ignores:
Some Cesium has already been found
outside the plant days ago. Since this Cesium must have been produced in the reactor core (if the author described it right), there has already been a way from the reactor core to the environment. The question is: What way is that?
I think it might have been transported out of the core when they released steam (depending on where their cooling water was converted to steam), and then the hydrogen-fueled explosion set it free. Maybe it was not much. Or maybe it was.
Anyway, it was certainly better to try to release steam, even if it was radioactive or carried radioactive materials, than to let the containment(s) burst because of pressure builtup.
Quote:
* The seawater will then be replaced over time with the normal
cooling water
* The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.
If the damage to the plant really is as low as the author says, he may be right.
Quote:
* Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.
I don't think so. There have been several reports here saying that the reactors there would have been turned off
forever (end-of-life) this month anyway, so the rods will be almost completely depleted and the plant turned off anyway. No one will then spend a lot of money to make any of this stuff usable again. Unless, of course, all these reports were wrong - which I cannot rule out completely.
Quote:
* The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)
this is possible, maybe. And
if Japan can pay it. And it will take time.
If we ignore the last explosion for the moment (since reports from it might very well be preliminary), things still do not look as bad as some people put it. But we're getting closer and closer to a disaster, and for
me, it's still far from certain that we can avoid it.
Therefore, I am less optimistic than the author of this text.
