You laid it out pretty clearly, but one detail ought to be corrected -- Voyagers etc. use Radioisotope Thermoelectric Generators rather than reactors. The diff

You laid it out pretty clearly, but one detail ought to be corrected -- Voyagers etc. use Radioisotope Thermoelectric Generators rather than reactors. The difference is, there is no chain reaction in RTGs; the natural spontaneous fission is relied on. The construction (lack of neutron moderator) prevents chain reaction for safety reasons -- no chance of runaway reaction. On the other hand, it means the thermal output cannot be regulated at all, and drops steadily in parallel to the half-decay time. The RTGs are so safe they even used miniature ones in some heart pacemakers implanted years ago; they are still going [1]. -- [1] http://duckduckgo.com/?q=nuclear+pacemaker&v= http://duckduckgo.com/?q=nuclear+pacemaker&v=