> People don't understand the fundamental problem of fusion. It's a problem of energy loss. Of enormous energy losses.
I'm not sure that's even true, because if you manage to crack that, you still have the problem that your sustainable reaction is pumping out most of its energy in the form of very fast neutrons, which are (a) very hard to harvest energy from and (b) extremely bad for people and materials if you don't. You could have a self-sustaining reaction that you can't actually use!
It requires much higher temperatures, and thus suffers much higher Bremsstrahlung. You can sniff out BS quickly with anyone claiming a steady state aneutronic reactor. A working aneutronic design would necessarily be pulsed. Not that it can't be done, but you'd first need to pass through DT and DD performance metrics and then go another order of magnitude. No one's done that yet.
High energy neutrons leave the system. They cause damage to the container (ie neutron embrittlement) and that's a separate problem. But the real problem is the energy loss from the system.
Charged particles can be contained. Personally I think there are limits to even that because a high-temperature plasma is turbulent [1]. Containing that is just a hugely difficult problem.
I'm not convinced that nuclear fusion will ever be commercially viable.
Also, the fusion reactors will inevitably have poor volumetric power density, due to limits on power/area through the first wall and the square-cube law.
Engineering studies of stellarators found they tend to be larger and have worse economics than tokamaks.
We need a liquid with high heat capacity, large hydrogen content (for high neutron interaction rate) and a solid 300 year engineering history in heat engine applications. Better if it is nontoxic and environmentally friendly as well.
I'm not sure that's even true, because if you manage to crack that, you still have the problem that your sustainable reaction is pumping out most of its energy in the form of very fast neutrons, which are (a) very hard to harvest energy from and (b) extremely bad for people and materials if you don't. You could have a self-sustaining reaction that you can't actually use!