Similar to Chernobyl. They use the ice wall there also. (or did anyway).
If you EVER want to read something scary, read the Wikipedia article on the Chernobyl event.
Lots of Brave people died there.
That's true and they went in knowing it was a death sentence.
Called "the Elephant's foot," it is a congealed slab of reactor core, called "corium." The Russians say it's pretty radioactive.
As for the 800,000 gallons of radioactive water, the solution is obvious but everyone will go nuts over it. Just dump it in the ocean. Seriously, 800,000 gallons is literally a "drop in the ocean." In fact, ocean water is a really good way of cleansing radioactivity. Look at the sunken warships at Bikini Atoll that were "expended" in the A-bomb tests. Scuba divers can go dive them now, the radioactivity has been "washed away" by the seawater. Of course, I know that the radioactive particles are still out there, but the point is that they have been so dispersed by the ocean that they are no longer noticeable.
Read up on the Fire Dept. that responded. They immediately realized what was going on and that they could only slow the progression of the disaster. They stood, fought and died. No retreat no surrender.