Quote from GTS:
Remember that Chernobyl violently exploded after going critical so there is a big difference. If this thing doesn't explode and they can just get it to the point that they can entomb it with concrete I don't think it would result in a large uninhabitable area.... of course this isn't over yet.
Quoting from the Chernobyl Wiki page
Let's hope the Japanese can do something to contain the disaster from growing bigger. Perhaps we may also watch the markets and get some clue.