OT: Batteries for the grid - cost

No, it's power. Which would tend to melt everything. But there was still the cooling water, which flashed to steam.

Exactly. the only way you can get an explosion in a reactor is with steam or hydrogen.

The problem with trying to detonate a nuclear weapon is to smash a critical mass hard enough together for long enough for the chain reaction to consume a large part of the fissionable material.

Nuclear reactors aren't full of TNT and shaped fissionable elements...if they go critical, they just melt.

And when they melt, there isn't enough material to stay critical

If it had been a nuclear explosion like Hiroshima or Nagasaki, they wouldn't have needed the containment building - there would have been nothing left to contain.

It just got very hot, very fast, ruptured the cooling pipes and allowed water and steam onto the red-hot core - kerboom!

I was in the US in 1979 and when TMI happened, couldn't believe the number of ignorant twerps who though that if a reactor core melted, it formed a sphere that would just melt its way all the way down to China. They seem unable to apply their own experience to the situation. Perhaps they also thought that if you pour out a glass of water, when it hits the floor the water stays in a glass-shaped lump, like a blancmange.

Let alone melting its way down to the centre of the earth and then back out the other side against gravity!

more a kerpop. The real damage was done by the fire

Was TMI befre or after 'the china syndrome' film? That was in 1979...

"The China Syndrome premiered at the 1979 Cannes Film Festival, where it competed for the Palme d'Or while Lemmon received the Best Actor Prize.[3] It was theatrically released on March 16, 1979, twelve days before the Three Mile Island nuclear accident"

Well there ya go.

Yes well quite. The universe of ignorant twerps evidently extends to the film industry - who could have imagined that, eh?

What's even more witty was that the China Syndrome trailer (or mebbe TV ad, I forget) consisted of them imagining this sphere of molten uranium hurtling through the Earth's crust on its way to China. But the film isn't about that at all. It's about a crooked set of construction people who faked most of the X-ray photos of the welds in the reactor's pipework. They took one such x-ray photo, and then made 500 copies. Our hero and Jane Fonda spot this and try to get the site closed.

Yeah, its utter crap really. Like most propaganda

"hydrogen contains no carbon" ... you don't say ...

"so when burnt only produces heat and water" ...don't they know that water vapour is a powerful greenhouse gas? :-)

At least Teeside is a long way from my part of the world, so I'll be OK if TNP's worst fears are realised and it goes bang.

No a prompt critical reactor power spike can be quick enough that expansion via core melting would not be quick enough to stop it. The uranium core itself could vaporize explosively. The neutron density would be doubling in tenths of seconds, due to the very short prompt critical mean neutron generation time. This would not happen in a normal, non prompt critical, meltdown, where the small proportion of delayed neutrons increases the mean neutron generation time, in this instance melting is quick enough to slow the chain reaction.

The explosion wouldn't be that big, but it would be an explosion. Indeed the maximum potential explosive yield of a uranium fission reactor is theoretically quite low, I can't be bothered to look it up. Low, but still in the tons of TNT range.

Explosions and detonations are slightly different. An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases.

The problem with a nuclear bomb is not to get an explosion but to get a high yield.

No, see above.

I dont believe you.