If we want a nuclear power plant in space with a capacity similar to that of a conventional water boiling turbine nuclear power plant on Earth today, what kinds of fundamental design changes would have to be made? The largest reactor in operation delivers about 6-7 GW. How could that be replicated in space, either free floating or on a surface?
How do thermionic emission reactors, like the Russian TOPAZ, scale up to Gigawatts? I suppose that radio thermal generators are out of the question on that scale, if for no other reasons the cost of creating and handling plutonium-238. Is water boiling the big future for nuclear power also in space?
I want to emphasize operations in space, not manufacturing. Assume manufacturing on Earth and launched, at most piecemeal for simple docking assembly. I want to ask about what kind of BIG nuclear reactor actually would work in space, rather than how it would get there.
To clarify, I am not asking about nuclear thermal propulsion systems, but reactors optimized for the production of electric power.