Japan earthquake/tsunami

[Van]

Originally Posted by Saltheart

Water is the coolant. However , its not going to cool the whole blob of fission material evenly. Some places are very hot , hot enough to first form steam , then the steam breaks down to H and O and then Boom. You have to take the risk of these H explosions (Actually are explosions) and steam explosions (too much water pressure in a sealed vessel and it bursts , what many would call an explosion too) because you have to try to keep everything cool as possible and try at all cost not to have molten uranium with no water on top of it because molten uranium without the water cover is going to be boiling off the most radioactive vapor aotms..

Good stuff.

And yes people think a plant can blowup like a nuclear bomb--NOT--.

In the case of the rods used in this older plant, they are coated with an alloy call zircalloy (sp?). This coating is supposed to help scavange hydrogen. Many plants that are this type (BWR) boiling water reactors have hydrogen problems ie. keeping it as low as possible and have various systems to midigate the gas.

But now that this reactor is superheating, the coating itself is breaking down, and oxidizing. That reaction creates even more hydrogen than breakdown of the cooling water. The explosion yesterday that blew the dome off was a hydrogen gas explosion.

Modern plants are (PWRs) pressurized water reactors. Much easier to control and less chance of environmental contamination as they are two separate systems, one for the reactor, one for the turbines.

I'm not sure yet, but I think they are calling this the worst nuclear disaster in history. If not yet they will......