Fault tolerant shunt regulator for a spacecraft thermionic nuclear reactor

The paper describes the details of a majority voted fault tolerant shunt regulator for a 6 kW thermionic nuclear reactor. The shunt regulator compensates for spacecraft load changes to maintain a constant load on the reactor. Power not used by the loads or to recharge the spacecraft battery is dissipated in externally mounted resistors. The excess power control is done by sequentially switching the shunt resistors for coarse control. The fine adjustment of the excess power is done using a multistage linear sequential shunt. The shunt regulator is designed to handle multi‐kilowatt load transients and is tolerant to any single failure in the control electronics. The power handling capability can be increased by increasing the number of the digital switched shunts. The breadboard test and analysis results are presented.