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[deleted] t1_j0qjeuy wrote

Reply to comment by BlueSkyToday in Nuclear fusion breakthrough: What does it mean for space exploration? by Gari_305

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BlueSkyToday t1_j0uqwjb wrote

I was thinking laser fusion when I wrote that.

Unfortunately, I'm pretty dubious about fusion in general. We had a second fusion project at the Lab, MFE (Magnetic Fusion Energy). That was defunded in the 80's IIRC.

I don't understand projects like ITER. The machine is huge, and it uses a Beryllium jacket to increase the neutron flux because most of the energy in the fusion reaction is carried away by the neutron, but the neutrons get used up in the reaction, which means that they're not available to boil the water for the steam plant.

I've heard it said that ITER's jacket will use one year's worth of the World's production of beryllium. And beryllium is nasty to work with.

There are other groups working on alternative designs, some of them are very interesting but I don't know enough about them to make definitive comparisons.

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ItsAConspiracy t1_j0z4vx4 wrote

The kinetic energy doesn't disappear just because the neutron interacts with a nucleus. Any more than it disappears when a bullet hits a block of clay: the bullet mostly stops, but the clay moves and heats, because momentum is conserved. In the same way, ITERs breeding blanket is going to heat up plenty. Run water pipes through it and you're good.

The beryllium supply is a real issue though. CFS is working on a tokamak a tenth the size that should do the same thing as ITER, because it uses much better superconductors, but even that uses a lot of beryllium.

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