Meltdown

[G77]

I know its a few miles away like but this word 'meltdown' doesn't sound to good to me.

[cable man]

We are well out the way !!! But for some may be not be so far....

[brian]

At least it's beginning to make people ask proper questions about nuclear power again.

Too often you get hysterical objections that are easy to counter (it's all going to blow up!), and cold scientific assertions that are not (here is the data that proces it's safe), with the result that after they're built they continuously discharge "low level" and "safe" radiation.

Before we even get to the issue of "cancer hotspots", there are also a wide range of health issues, especially hormone-related, downstream of nuclear plants.

My g/friend's entire family all suddenly developed hypothyriodism within a year of each other. They live on the Isle of Man, just downstream of Sellafield. They say you know when its had a leak because the beaches get dead seals washed up.

[TheCoder]

Originally Posted by G77

I know its a few miles away like but this word 'meltdown' doesn't sound to good to me.

All meltdown situations are bad news but it doesn't mean that the problem can't be contained. The reactors in Japan are designed in such a way that a meltdown results in the fuel rods dropping down into a million gallon water tank which should be able to both dissipate the heat and moderate any further reaction. The problem with allowing this to happen is that it effectively writes off the reactor and presents you with one hell of a clean up bill, which is why its considered a last resort option. It appears at this time that the Japanese engineers believe they can still save the reactor if they can restore enough coolant to keep the temperatures down and fully moderate the reaction.

The reactors themselves are presently in a 'scram' state. All control moderators are fully inserted so most neutrons are absorbed rather than reactant. Under normal circumstances this would completely stop the reaction and shut the reactor down. Its only the leak of coolant which is causing a problem. This allows a heat build up from the residual reaction and can affect the primary containment vessel which, if unchecked, is your meltdown situation. Meltdown does not mean a nuclear explosion. It simply means that the primary reactor vessel gets so hot it melts !

Also, dont confuse this event with what happened at Chernobyl. In that case the primary problem was that one of the moderators was graphite which, unfortunatly, is combustible. The explosion in that case was basically caused by burning graphite increasing pressure in the containment vessel to the point where the reactor effectively blew its top resulting in core exposure to the outside atmosphere and thus a fairy large radiation leak.

[wasp11]

"one of the moderators was graphite which, unfortunatly, is combustible"
We have that problem in techwatch too.

[kegnkiwi]

i'm going via Korea in 3 weeks time its going to be a little closer than I really wanted to be.

[wasp11]

Originally Posted by kegnkiwi

i'm going via Korea in 3 weeks time its going to be a little closer than I really wanted to be.

You yorkshire men are thick skinned....... you,ll be fine mate