4 ms·

Sort of, but it's a vast oversimplification. Fission is very safe relative to something like coal because all of the pollution is concentrated in barrels instea

Sort of, but it's a vast oversimplification. Fission is very safe relative to something like coal because all of the pollution is concentrated in barrels instead of pushed into the atmosphere, but has the risk of meltdown. To be fair lots of other non-nuclear plants have had disasters that released toxic gasses around the globe too. Fusion in theory has no pollution at all, but that's theoretical until large scale fusion plants are built.

jeffbee 5y ago
Fusion reactors don't create fission products, obviously, but why wouldn't fusion create radioactive waste via neutron activation? Materials exposed to neutron flux, in any kind of device, may be activated into radioactive isotopes.
- willis936 5y ago
  Yes, but first wall materials are chosen to have a high melting point and short half life when activated. Close the building off for 100 years then scrap it. It's a far cry from the myriad of nightmare scenarios fission plants need active control against.
  - slipframe 5y ago
    Closing the building off for 100 years might work fine, but that can't be the solution to every problem, it wouldn't be economically viable. Ostensibly simple matters like routine maintenance are very complicated propositions for fusion reactors; you can turn the reactor off but it will still be too radioactive for anybody to work inside. So you either need some sophisticated robotics to repair anything that might ever need repairing, or you have to consider the entire reactor to be disposable. Of course, repairing things inside a fission reactor is no less nasty, but fission reactors are comparably much simpler and much smaller. Swapping a fission reactor out with a new one is comparably much easier than with a fusion reactor.
    - DennisP 5y ago
      For General Fusion, about the only part exposed would be the central column, which I suspect they'll design to be easily replaced; pull out from the top and drop in a new one. Aside from that, the burning plasma is just surrounded by liquid lead/lithium. MIT's Commonwealth uses an inner wall that's 3D-printed and designed to be replaced annually. They've tested joints in their superconducting tape, which will let them open up the coils on hinges so they can drop in a new inner wall. They'll surround that with liquid beryllium/lithium as coolant and breeding blanket.
rcpt 5y ago
Another byproduct of fission is "long-time nuclear waste warning booty shorts" https://twitter.com/mochasucculent/status/1256386154653380608?s=21 https://twitter.com/mochasucculent/status/125638615465338060...

jeffbee 5y ago

Fusion reactors don't create fission products, obviously, but why wouldn't fusion create radioactive waste via neutron activation? Materials exposed to neutron flux, in any kind of device, may be activated into radioactive isotopes.

willis936 5y ago
Yes, but first wall materials are chosen to have a high melting point and short half life when activated. Close the building off for 100 years then scrap it. It's a far cry from the myriad of nightmare scenarios fission plants need active control against.
- slipframe 5y ago
  Closing the building off for 100 years might work fine, but that can't be the solution to every problem, it wouldn't be economically viable. Ostensibly simple matters like routine maintenance are very complicated propositions for fusion reactors; you can turn the reactor off but it will still be too radioactive for anybody to work inside. So you either need some sophisticated robotics to repair anything that might ever need repairing, or you have to consider the entire reactor to be disposable. Of course, repairing things inside a fission reactor is no less nasty, but fission reactors are comparably much simpler and much smaller. Swapping a fission reactor out with a new one is comparably much easier than with a fusion reactor.
  - DennisP 5y ago
    For General Fusion, about the only part exposed would be the central column, which I suspect they'll design to be easily replaced; pull out from the top and drop in a new one. Aside from that, the burning plasma is just surrounded by liquid lead/lithium. MIT's Commonwealth uses an inner wall that's 3D-printed and designed to be replaced annually. They've tested joints in their superconducting tape, which will let them open up the coils on hinges so they can drop in a new inner wall. They'll surround that with liquid beryllium/lithium as coolant and breeding blanket.

rcpt 5y ago

Another byproduct of fission is "long-time nuclear waste warning booty shorts" https://twitter.com/mochasucculent/status/1256386154653380608?s=21 https://twitter.com/mochasucculent/status/125638615465338060...