SNAP-10A - Construction and Operation

Construction and Operation

The SNAP-10A has three major components — a compact nuclear reactor, the reactor reflector and control system, a heat transfer and power conversion system.

The reactor measured 39.62 cm (15.6 in) long, 22.4 cm (8.8 in) diameter and held 37 fuel rods containing 235U as uranium-zirconium-hydride fuel. The SNAP-10A reactor was designed for a thermal power output of 30 kW and unshielded weighed 650 lb (290 kg). The reactor can be identified at the top of the SNAP-10A unit.

Reflectors were arranged around the outside of the reactor to provide the means to control the reactor. The reflectors were composed of a layer of beryllium which would reflect neutrons thus allowing the reactor to begin and maintain the fission process. The reflectors were held in place by a retaining band anchored by an explosive bolt. When the reflector was ejected from the unit, the reactor could not sustain the nuclear fission reaction and the reactor permanently shut down.

The eutectic sodium-potassium (NaK) alloy was used as a coolant in the SNAP-10A. The NaK was circulated through the core and thermoelectric converters by a liquid metal direct current conduction-type pump. The thermoelectric converters (identified as the long white "apron") were doped silicon germanium materials thermally coupled but electrically isolated from the NaK heat transfer medium. The temperature difference between the NaK on one side of the thermoelectric converter and the cold of space on the other created an electric potential and usable electricity.