This is now the second time you've accused me of not knowing what I'm talking about and yet your only difference of opinion is my terminology as to whether it's a meltdown or whether the process of "oh shit, dump water on it" is controlled or not. In fact, most of the information I have on this topic was from spending most of Sunday re-reading Wikipedia on nuclear reactors, but thanks for assuming I watch or read ANY mainstream news.
QUOTE: "A meltdown occurs when a severe failure of a nuclear power plant system prevents proper cooling of the reactor core, to the extent that the nuclear fuel assemblies overheat and melt, either partially or completely"
That has occurred. That's not in dispute, unless I'm just completely 100% off base here. A quick Google search reveals that fuel rods in both reactors were not only uncovered by water at various points, but were also "exposed" which I presume to be through a containment failure, AND there are numerous reports that the parts of the rods have in fact melted.
As I said earlier, this constitutes a meltdown and greatly increases the severity and danger of the problem at hand. It's not a total meltdown, I already "disclaimered" that repeatedly. Those rods melting pose a large risk to containment efforts. If they melt, they can escape much more easily and that means radiation exposure on a much greater level, even if only for workers at the plant.
I don't mean to sound patronising or rude, if that is what came across sorry.
Whilst mostly you're correct, there are some fundamental problems with what you are saying.
It's definitely stretching the definition of a meltdown to refer to this event as such. It's still pretty much unknown if any melting has occurred, and to what extent it has done. Generally a meltdown is as I described it; where the situation is unrecoverable with the standard cooling and you are facing the situation of simple containment.
I suppose technically this could be seen as a partial meltdown; but the truth is that this situation is at the very edge of the margin for such a problem. A meltdown is not a binary thing, but in this case it is not really a meltdown, and that was my main point.
Right now it is absolutely recoverable, and based on the latest data #1 and #3 reactors will be fine from this point on. Certainly if they survive the next couple of days it will all be fine.
but were also "exposed" which I presume to be through a containment failure
No. If this were the case there would be a much serious issue :) It simply means the coolant level dropped so far that they were exposed to the air inside the container.
If they melt, they can escape much more easily and that means radiation exposure on a much greater level, even if only for workers at the plant.
Potentially... but bear in mind that radiation expulsion so far is relatively unrelated to the core; the radiation released so far is included in the steam that is being vented (and then the explosions push it right out). In a proper meltdown situation the risk is that an explosion releases actual core material into the wild, that would be a magnitude worse than the current situation.
At the moment I don't believe the rods are melting, they are being successfully cooled (and for the most part have been).
I don't know, maybe you're right but I continue to see, more and more, evidence that they did melt. I continue to see more and more people placing this between TMI and Chernobyl in severity...
QUOTE: "A meltdown occurs when a severe failure of a nuclear power plant system prevents proper cooling of the reactor core, to the extent that the nuclear fuel assemblies overheat and melt, either partially or completely"
That has occurred. That's not in dispute, unless I'm just completely 100% off base here. A quick Google search reveals that fuel rods in both reactors were not only uncovered by water at various points, but were also "exposed" which I presume to be through a containment failure, AND there are numerous reports that the parts of the rods have in fact melted.
As I said earlier, this constitutes a meltdown and greatly increases the severity and danger of the problem at hand. It's not a total meltdown, I already "disclaimered" that repeatedly. Those rods melting pose a large risk to containment efforts. If they melt, they can escape much more easily and that means radiation exposure on a much greater level, even if only for workers at the plant.