SP-100 Thermoelectric Converter Technology Development

As part of the SP-100 Space Reactor Power System Program being undertaken for the U. S. Department of Energy, GE is developing a thermoelectric (T/E) power converter which utilizes reactor delivered heat and transforms it into usable electric power by purely static means. This converter is based to GE's product line of successful thermoelectric space power systems. The SP-100 power converter embodies the next generation improvement over the type of T/E converter successfully flown on the six U. S. space missions. That is, conduction coupling of T/E cell to both the heat source and the heat rejection elements. The current technology utilizes radiation coupling in these areas. The conduction coupling technique offers significant improvements in system specific power since it avoids the losses associated with parasitic ΔT's across the radiation gap between the heat source and the hot junction of the thermoelectric (T/E) cell. However, this advantage brings with it the associated challenges of (1) electrically isolating the voltage developed by a string of T/E cells and spacecraft ground (at which potential the hot side heat exchanger will be running) and (2) compensating for the thermally induced deformations of the T/E cell elements and the elements to which they are attached, caused by the nearly 500C° temperature difference across the T/E cell assembly. Both of these challenges have been successfully met and fabrication/test accomplishments have proven the viability of the necessary enabling technology. The paper discusses how these challenges have been met.