A servo amplifier was designed to meet the nuclear radiation environment expected in the nuclear ramjet missile. An extensive search of radiation effects data was made to Judiciously select radiation resistant components and materials. The resulting design used RCA nuvistor tubes for voltage amplification, and power amplification was achieved with G. E. ceramic tubes. The amplifier was instrumented to evaluate individual stage performance. Irradiation testing was conducted over a 130 hour period and the unit was subjected to an integrated fast neutron flux of 2.0 Ã 1017 neutrons/cm2 (E>0.3 Mev) and an associated gamma dose of 2.5 Ã 1011 ergs/gm-(C). The servo amplifier operated throughout the test with negligible changes in amplifier characteristics.