See no mention of radiation shielding. Waste heat totally absorbed by the heat engine? Even if not much load on the engine?
Was told that the reactor on our SSN nuke subs is about the size of an older floor standing Xerox machine, but the cooling and other plumbing adds enormously to the system size.
I don’t know.
Well, -89
Maybe they are using sodium? I’m sure the fuel assembly is quite small and only contains a few fuel pellets
Another guess could be at -89f maybe it’s air cooled like my Harley. /s