It's described in the article I linked in the comment two above, I'll link it again here. A steam explosion spreading orders of magnitude more radiation than Chernobyl had already (which was prevented by people entering the reactor in the days immediately after the first explosion).
Incidentally, nuclear detonations can happen, and there is some belief that very small ones did happen in Chernobyl, but the type of the explosion is really besides the point.
>Incidentally, nuclear detonations can happen, and there is some belief that very small ones did happen in Chernobyl, but the type of the explosion is really besides the point.
If you're going to make the claim that this is possible, we need a source.
Lol, I just dug up the first article I could find, admittedly didn't check the news source.
But that source isn't for the claim you're quoting... that's for the (well known) claim that Chernobyl could have gone much worse if not for remdiation efforts, it shouldn't be hard to find alternate sources for that claim.
For the claim you're quoting, see the paper cited in the sibling comment to mine.
https://www.thetrumpet.com/14007-three-men-who-saved-million...
Incidentally, nuclear detonations can happen, and there is some belief that very small ones did happen in Chernobyl, but the type of the explosion is really besides the point.