Q from a Non-Pysicist. Could Japan just pour cement on the reactors?

[Taverner]

Like they did in Chernobyl?

If they've decided they can't save the reactors, would dumping lead and cement on them do any good?

[buddysmellgood]

1. It has to be cooled first.

[Possumpoint]

2. Not Sure That It Would Be A Workable Solution

Putting a concrete cap on the reactors sounds like it would also cut off cooling water. If a core, especially #3 with the mox in it melts down it could do a "china syndrome" where it melts through the containment vessels and works its way down to the water table causing a steam explosion. Then you have a much worse situation.

[zipplewrath]

3. Ultimately, yes

At some point in the future I suspect that is functionally what will happen. Some sort of extremely thick walled "sarcophagus" will be built in/around them. Some amount of clean up/consolidation will occur first I'd imagine. And that's after they have had a chance to "cool off" much of the material to be buried.

[MineralMan]

4. Not immediately, and not until the extent of the damage

is known, which it is not so far. The other problem is that the outer containment structures have been destroyed in some cases. Before you can pour concrete, you have to have an enclosure to hold it. These are big structures. It's going to be a major engineering project. It won't happen soon, I'm afraid.

[PoliticAverse]

5. They didn't really "pour cement on the reactors" at Chernobyl...

The sarcophagus is more an outside container to keep radiation and dust/particles inside.
Even so the sarcophagus as originally constructed had large openings in it to prevent
excessive heat build up.

They also had to tunnel under the reactor to put in a thick concrete slab.

For more info see the video "Inside the Chernobyl Sarcophagus":
http://video.google.com/videoplay?docid=-5968506788418521112#

In Japan they still need to keep the fuel in the reactors and spent fuel pools
cool or the situation will worsen. They didn't have a spent fuel pool problem at
Chernobyl and the fuel there had already all melted into 'corium' ( see
http://en.wikipedia.org/wiki/Corium_%28nuclear_reactor%29. ).