Savannah's nuclear reactor is located in the containment vessel accessed through this airlock.
The containment vessel, 35 feet in diameter and 50.5 feet long, is located in the reactor space. It houses the Savannah's entire reactor plant and primary cooling system. It was designed to contain all the water and steam released in the event of a mechanical failure of the pressurized water loops (maximum credible accident) and to support the lead and polyethylene shielding covering the upper half of the containment vessel under a 30° roll.
The containment vessel was continuously air-conditioned to maintain a temperature of 120°F.