This is a report on the effects of relatively low intensities of nuclear radiation on various organic dielectrics in capacitors, where a particular sensitivity to such radiation was noted. The purpose of the study was to select a suitable dielectric for high voltage capacitors that are to withstand a minimum dosage of 2 megarads, but preferably 20–40 megarads (40 year's life). These capacitors are to be located in the containment vessels of nuclear power facilities where they are to protect the primary coolant motors (6600 volts, 3 phase) from overvoltage surges. This requires units with a rated voltage of 3810 volts, line to ground.