someone else said we will need some kind of nuclear power for future space exploration

And I was one of those someone else’s, but in the context of calling out that there’s likely little in common.

• a power plant on earth needs to be scaled up, assembled on site to meet the needs, can depend on gravity and open air. It needs repair ability and refuel ability, and can’t pollute ground water. It is well staffed and call in more as needed
• a power plant off planet is likely much smaller, it has t be completely assembled ahead of time to fit on a rocket, and can not count on gravity, water, air, or even air pressure. It’s critical that it move mostly hands off: there’s no staff, no repairs, no spare parts.

biomass shouldn’t be installed as it destroys too many native forests.

That’s a choice: too many less developed countries still clear native forest for agriculture, so expanding agriculture has a downside . ITs something those countries need to take care of regardless, just to feed their people.

This is a failure of policy and governance, not technology