Thermoelectric nuclear power systems

The design of nuclear power plants with thermoelectric energy conversion systems was underway in the 1960s in many countries (the Russian Federation, the USA, the United Kingdom, and France). These plants were intended as power sources for space and oceanic research. 

The AEG sponsored research ia the program known as Systems for Nuclear AuxiHary Power (SNAP) as early as the 1950s. Most of the systems developed iavolved the radioisotope plutonium-238 as a heat source for a thermoelectric generator. Such electrical suppHes permitted radio transmission to earth from spacecraft such as Pioneer and l qyager. 

Radioisotopes provide excellent low-power, long life energy sources. The device SNAP-7B (System for Nuclear Auxiliary Power) powers an unattended lighthouse. It uses thermoelectric conversion the hot junctions are clustered around the strontium-90 titanate source, which produced 0.45 watt/g. 

Space exploration relies heavily on solar energy when the spacecraft is in the inner solar system. However, solar power is insufficient for spacecraft that have to journey to the outer planets. Chemical energy sources, typically batteries, tend to be relatively heavy and have rather short lifetimes for missions that are to last many years. The solution adopted to date is to combine a radioactive solid with a thermoelectric generator (see Section 15.2.3). The advantages of this solution are that there are no liquids to spill and no moving parts to wear, and a nuclear isotope with a long half-life will continue to provide power over the lifetime of the craft. 

Passive or active power conversion devices can be used to convert the heat generated by the nuclear core into electricity. Passive systems, such as thermoelectric or thermophotovoltaic, are solid state and have no moving components. The lack of moving components can lead to high reliability, but these devices presently have thermal power conversion efficiencies less than 10%. Active systems convert thermal power first into shaft power and then into electrical power. Active systems typically have thermal... 

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