One-dimensional numerical simulations are presented of the compression and thermonuclear burn of a radiation-driven, reactor-size inertial fusion target that uses a substantially reduced tritium level. A parameter study of thermonuclear energy output is carried out in which the tritium content of the target is systematically reduced. The energy output is found not to be sensitive to a reduction in the tritium content of the target by up to 50%, which means that the tritium inventory in the reactor system could be substantially reduced. Moreover, the tritium fractional burn in low tritium targets is found to be much higher compared with equimolar deuterium-tritium targets. Therefore, the process of evacuation of the target debris from the reactor chamber after each shot will be much cleaner in the former case compared with the latter. These results can have very important implications for the safety and environmental acceptability of future inertial fusion reactor systems.