Fission power plants in space

[farmerben]

The kilopower is the leading design with vaporized sodium sterling engines.  I can clearly see the simplicity compared to water and steam turbines in space applications even if the sterling cycle is inherently less efficient.  What other ways of generating electricity would work in space?

What about the the idea of a smaller subcritical core of HEU, or the same size of low enriched uranium plus a neutron source.  

Regarding neutron sources which is better a pulsed fusion design (neurister or farnsworth fusor)  or a beryllium-plutonium source?  Considering weight, could a neutron source replace reflector and control rod material to advantage?

What about the idea of a subcritical reactor which captures protons.  This is done by setting the core at a negative voltage compared to the end of a long antenna and flying through the radiation belts such as around Earth and Jupiter.   With this high energy protons strike on or near the core itself creating spallation neutrons.

Edited September 24, 2023 by farmerben

[DDE]

I find it notable that separate neutron sources are unheard of outside of nuclear munitions and special "nuclear water burner" fusion plants. They're probably a needless complication.

[farmerben]

Chernobyl style reactors have alpha- beryllium neutron sources, that why they were able to run on natural uranium and light water, something no western power plant does.

[magnemoe]

56 minutes ago, DDE said:

I find it notable that separate neutron sources are unheard of outside of nuclear munitions and special "nuclear water burner" fusion plants. They're probably a needless complication.

Yes, note that the main issue with nuclear power plants is that their nuclear pile is so large you need to cool it after shutting it down simply because all the heat in the pile. Yes you also have radiation after shutting down to. 
Smaller reactors like the ones used in submarines has much smaller piles so  you can just stop them. Yes they will be warm but you will not get issues like in Fukuyama there the steam broke down into hydrogen and oxygen who then exploded.
So an separate neutron source has no safety benefit.
It has been some ideas of using neutron radiation to run an reactor on nuclear waste, here you need neutrons to get the wast to be more radioactive so you get more heat.  

[DDE]

8 hours ago, farmerben said:

Chernobyl style reactors have alpha- beryllium neutron sources, that why they were able to run on natural uranium and light water, something no western power plant does.

RMBKs started off running on uranium that was about as twice enriched and then the fraction was doubled even further. The two real benefits chasing them seemed to be the lack of need for a monolithic steel pressure vessel (a production bottleneck and cost factor) and online refueling capability that allows plutonium harvesting (never actually used).

[kerbiloid]

11 hours ago, magnemoe said:

like in Fukuyama

A philosopher's reactor.

Burns from nothing and ignites everyone.

2 hours ago, DDE said:

that allows plutonium harvesting (never actually used).

At least, after 2022...