On: A new heat engine with no moving parts is as efficient as a steam turbine

[worldsayshi]

Could this maybe be used as part of a fusion reactor?

[short_sells_poo → worldsayshi]

I think the problem isn't that we can't achieve 2000 degrees with fission, but the entire design would need to be re-thought to handle such temperatures.

You need a completely different sort of materials and need to consider new types of risks for a reactor that's supposed to operate at such temperatures.