I think one of the critics of ITER points out there’s not enough beryllium production on the planet currently to supply more than a few fusion power plants. And

I think one of the critics of ITER points out there’s not enough beryllium production on the planet currently to supply more than a few fusion power plants. And it’s rare enough that maybe it couldn’t be ramped very high. By the ITER design they use beryllium to multiply neutrons to make their supply of Helium 3. Also https://en.wikipedia.org/wiki/Berylliosis https://en.wikipedia.org/wiki/Berylliosis does not sound fun.