fission stops if you no longer have enough material to sustain a chain decay reaction.

( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 13:54, 2 replies, latest was 13 years ago)

Why are you talking dirty to me?

(Bicycle Repairman "you're also a bit of a wanker", Thu 18 Oct 2012, 13:56, Reply)

because it's science chat and I fancy you.

( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 13:57, Reply)

But that happens a long time after you're dead and charcoally.
with fusion all that happens is it stops and you are left with a big pile of water.
(Bazongaloid, Thu 18 Oct 2012, 13:58, Reply)

I definitely don't know this, so it's just a straight-up question
given the "issue" with fission is that the reaction becomes a chain until it runs out of fuel, and the fusion could do the same, how is fusion safer? I get that you could control the fuel feed in a fusion system which you obviously can't in a fission one because of the whole critical mass thing, but theoretically anything smaller than iron can fuse and release energy. If we build a fucking big one, isn't there a risk assoicated with things other than the fuel fusing? and what if a fuel supply cutoff fails?
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 14:02, Reply)

Fusion doesn't chain reaction in the same way.
You need to keep the pressure and temperature incredibly high to make teh reaction happen. When it does you end up with a net increase in energy, but if it goes tits up and say your reacion chamber broke, there would be an instantaneous drop in pressure. Now there might be a big fire, but the reaction would stop straight away and therfore not continue fusing.

Plus, the product of fusion is helium, so rather than blowing highly radioactive shit everywhere, you have a bit of a fire and everyone talking in squeaky voices. No harm no foul.
(Bazongaloid, Thu 18 Oct 2012, 14:07, Reply)

I totally get the by-products being safer.
assuming it's just and H to He fusion.

I'm still not convinced at large scale there isn't a serious risk - I guess it depends how interchangable temperature and pressure are as reaction conditions.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 14:10, Reply)

There is a risk, it could explode and kill all the people in the factory
but what it won't do, what it physically cannot do, is keep burning and reacting and melting the core so it sinks through the Earth's crust, all the while spewing out deadly toxins and irradiating a wide area around the plant, and some of Wales.

So from that point of view, it's immeasurably safer.
(Bazongaloid, Thu 18 Oct 2012, 14:12, Reply)

You have a similar level of risk...
...if you drop a freshly baked McDonald's apple pie onto the pavement.

They're the hottest substance known to science.
(Bicycle Repairman "you're also a bit of a wanker", Thu 18 Oct 2012, 14:17, Reply)

My labs are only class 2
we can't have McDonalds apple pies in them, the safety handling systems aren't up to it. So I am unable to confirm or deny this.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 14:22, Reply)

I see that.
I just wonder, for a large reactor, just how big a bang it would be. I mean the explosion might well wipe out a whole city rather than just the factory.

Still, I appreciate, better than a massive radiation leak. Unless, of course, it's in Wales.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 14:19, Reply)

The answer is therefore obvious!
We build the fucker in Runcorn.
(Bicycle Repairman "you're also a bit of a wanker", Thu 18 Oct 2012, 14:20, Reply)

Possibly as big as a fission reactor
You wouldn't build it in the city centre, that would be retarded.

You're such a retard.
(Bazongaloid, Thu 18 Oct 2012, 14:20, Reply)

yeah, well, it takes one to know one
and you know perfectly well what I meant.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 18 Oct 2012, 14:22, Reply)

That depends which city centre you have in mind.
I can think of a few which would be made more desirable with the addition of an explodey, hydrogen hot-hot thing.
(Bicycle Repairman "you're also a bit of a wanker", Thu 18 Oct 2012, 14:25, Reply)