Monday, 23 July 2012

Good News 2: Recycling nuclear waste

Nuclear waste is nasty. It's poisonous and very long-lived. There isn't a whole lot of it compared, say, to spoil from coal mines, but it's a lot nastier. And there will be more, even if we build no more nuclear power stations.

Discussions so far have concentrated on surface storage followed, eventually, by disposal underground. There's an unsurprising reluctance by most people to have it stored under their ground. But is that the best we can do? Can it be reused or recycled?

Turns out we can do better - and there are several ways.
  1. We can bombard the waste with high-speed neutrons from a particle accelerator. This causes the radioactive nuclei in the waste to split (fission) creating much shorter-lived elements. These are easier to deal with since we only have to store them safely for centuries, not millenia.
  2. We can add Thorium to the waste before bombardment. The mix will then generate power much as a Uranium reactor does except that it will consume waste and will probably be safer.
  3. We can design the reactor to create its own fast neutrons and omit the accelerator top get a new design of power-generating reactor.
Though the basic physics is well understood the engineering is not and it will take at least a decade, maybe two, to fix that. Perhaps they will never work.

But to know this we need research. The first accelerator-driven research reactor was commissioned in Tokyo in 2009 whilst Europe's own reactor, Guinevere, went live in Paris last January. Let's hope the problems can be solved. We badly need nuclear reactors that don't leave us with long-lived radioactive waste if we're to break our addiction to fossil fuels.

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