A steam explosion is not a nuclear explosion. A steam explosion is just water vapor being compressed so much that it explodes through the material housing it. That is not the same as a nuclear explosion, and it is no where near as devastating. A steam explosion will take out a building, a nuclear explosion will take out city blocks and above. Remember, I said it will not cause a nuclear explosion. Yes the heat from the rods in meltdown can cause the water vapor (steam) to explode.
It's still an explosion though, which you seem to rule out completely, earlier, neither did you mention a steam explosion was possible:
Nuclear power plants do not explode, they meltdown. A meltdown will contaminate the soil, air, and water around the plant, but a nuclear explosion will not occur.
Hermetic, 42 minutes ago
Hermetic, 42 minutes ago