Exactly, a real China syndrome has never happened before.. No real world data.. We are getting it all now.

The forecast for the corium blast that was prevented at Chernobyl was 3-5 megatons.. This has more cores, and more fuel involved. But I think that the worst that could occur would be an ELE from fission products in the environment, not a super sized supercritical blast.. The super blast would almost be preferred in my book as it would distribute the corium far apart as to not allow for continued melting and reaction and movement.. (But epic pollution) As a large blob it's very dangerous and as said before, we have no data for prediction, just theory.

Weapons in the megaton range use different physics, they are thermonuclear, as in they use a atomic bomb to start a fire to burn a fuel. This is worse, not from blast... But poison of all life on earth. This is slow, silent doom you have all been waiting for.

Start making your own plans to evacuate the northern hemisphere, I'm not kidding folks. And even that will only buy you a little more time.