Partial Radiation Insulated Diode (PRID) for Space Nuclear Power Systems
The in-core thermionic nuclear reactor is a leading candidate for low power space systems requirements. The thermionic converters are static devices which convert heat directly to electricity in the form of high current, low voltage output power. The nuclear fuel cladding is used as the emitting electrode and is surrounded with close spacing by the collector electrode. The stability and lifetime of the system depend on the maintenance of the interelectrode gap established by the resulting coaxial geometry. Emitter distortion, therefore, can be a life-limiting factor. This is exacerbated by high emitter temperature and high fuel power density present in typical applications. In the particular case of low nuclear power level systems, the added complexity of a fast driver core section is necessary to ensure sufficient excess reactivity for power control.