Well, Japan has sent for one of the two largest concrete pumps in the world. It will be trucked to Atlanta from South Carolina and flown to Fukushima ASAP. It won't be coming back home.
So it's the Chernobyl option, I guess, after all. Why did they let some workers risk their lives if this was ever contemplated?
Because the concrete plan is not a good option. You will have no control whatsoever once the concrete is on there, one possible result being that it gets even hotter and who knows what might happen. Besides, the concrete of chernobyl is starting to wear down and they're expecting radioactivity to come free in a few years again.