>>13996349that's the easy part.
>>13996360closed cycle heat engines exist.
>>13996342the issue is that basically all nuclear reactors we know of produce deathly amounts of neutron radiation. Neutrons are difficult to shield, so while the reactor can be quite small, the shielding cannot. As an example of how small reactors can get, see the demon core, although something like the SNAP 8 reactor is more realistic. It would be better just to have electric cars recharged by a nuke plant or nuclear powered power to gas.
>>13996382the ford nucleon was designed by artists instead of engineers