JumpCrisscross 6 hours ago

> thorium cycle is generally neutron negative

Source for the fuel cycle?

Thorium 232 -> 233 is neutron negative. But after that you get all kinds of nonsense.

  • lazide 5 hours ago

    Thorium 232 is the thorium in the cycle yes. And all kinds of nonsense is correct for the daughter products. But in general, to actually use do anything with thorium you need excess neutrons.

    Even the daughter uranium 233 only produces on average 2.48 neutrons per fission, so it’s very difficult even in a combined lifecycle process to have enough - thorium doesn’t produce uranium 233 immediately (takes almost 30 days), neutron capture with that low a ratio requires a LOT of thorium, which is going to mostly just suck up all neutrons and you won’t have any extra for addition uranium 233 fissions, etc.

    It’s quite difficult (impossible?)to have actually work without a source of a large amount of additional neutrons.

    • JumpCrisscross 4 hours ago

      > to actually use do anything with thorium you need excess neutrons

      Unless 100% of those neutrons is being absorbed by the thorium, this means you'll have neutron flux at the boundary. Which, for a liquid moderator, means all the pipes and tanks and pumps.

      • lazide 3 hours ago

        It’s almost like there is a reason why it’s not commonly used despite all the hype.