A mid-1960’s concept from General Electric showing a Manned orbital Laboratory-type space lab with two docked Gemini capsules and one nuclear reactor for power. Derived from the SNAP-10a system, this powerplant featured a small reactor at the apex of the cone; the cone itself is the radiator for the system. The SNAP-10a was not a spectacularly efficient system… it produced around 30 kilowatts of thermal energy, of which only 500 were converted to electricity. The system shown below would have been a larger, more powerful and hopefully more efficient system.
The small compact and busy-looking item on the far left of the image would have been the reactor itself. Between that and the structural truss work connected to the large radiator was a thick radiation shield, composed of something like tungsten. Even with this massive chunk in the way, the reactor was still segregated far away from the crew.