In this scenario people are in a constant war on an infinite flat world with the geography of Antarctica's interior (but with no liquid water or hydrocarbons). Notably this world has an abundance of deposits of radioactive ore and the people are decades ahead of us in some areas like nuclear tech, as well as having shadow magic that can create very effective shielding and cheaply separate isotopes. This world experiences a universal 1 G acceleration, but while other physics are the same there's no "true" gravity. This also means that gravitational sensors can't work.
The scale of conflict means that people need to build a lot of transport vehicles as cheaply as possible and having to set up a new settlement and move isn't uncommon so it should ideally be as easy as possible to set up new factories. Not having the transport vehicle compete with military vehicles for minerals or rare components is also strongly desired here where possible.
What sort of nuclear based transportation would be best suited to cheaply transporting large amount of cargo at decent speed over Antarctic geography, if radiation weren't a concern?
For these purposes something like the Antarctic Snow Cruiser doesn't remotely cut it, the people here want way more carrying capacity and speed.
Importantly people in this world don't really need to worry about any radiation that wouldn't rapidly kill them: Due to a combination of biotech, and using shadow magic to shield against radiation and separate radioisotopes.
Shadow magic wards can also be used to shield mechanical components against radiation, but this gets costlier the better the absorption needs to be (so you're not blocking a direct nuclear strike with this).
In order to not let radiation reveal one's activity/position, people deliberately set off large numbers of nukes and fly around drones that spray nuclear fallout behind them. In order obscure their location and activities (like them using nukes for tunneling).
Propulsion options I've considered but can't decide between include:
- Nuclear saltwater rockets (I strongly suspect they may not be practical for this application).
- Nuclear thermal rockets (seem like a better option than the saltwater rocket, but it is still a rocket so idk, also seems worse than a ramjet because of the propellant's weight).
- Nuclear reactor power source for electric propulsion like jet engines.
- Ramjets which directly use nuclear material to heat up air generating thrust like Project Pluto. This option seems like it might be the most promising since I've heard ramjets are simpler than regular jet engines.
- Nuclear steam-craft are an idea I had where a vehicle sucks up snow with a fan/scoop and then flies around over the ground on jets of steam (I have no idea how viable this would be). I guess this might technically count as a type of NTR as well.