The D2G nuclear reactor was found on all US nuclear cruisers with the exception of the USS Long Beach (CGN-9).
- D = Destroyer-sized reactor
- 2 = 2nd generation
- G = General-Electric built.
It was rated for a max 150 megawatt output.
It was designed to last for 15 years with normal usage.
US nuclear cruisers were outfitted with two reactors per vessel, with the ability to cross-connect the steam and feed water plants to power both engine rooms from a single reactor.
With both reactors running, steam plants split, the average cruiser could reach 32 knots. With one reactor running, steam plants cross-connected, it would reach 25-27 knots. With one reactor running, steam plants split, on one shaft, they could only reach 15 knots.
These reactors were boron-doped vertically for longer core life, and axially for even power distribution without hot spots. They employ 12 H-shaped control rods driven by DC-powered movable armature reluctance motors.
Three main loops driven by three reactor coolant pumps supplied three steam generators with super-heated water, which, in turn, supplied saturated steam to the engine room. All US nuclear cruisers have been decommissioned. Most US aircraft carriers and all attack and ballistic missile submarines are nuclear powered.