Abstract: Improved efficiency process for preparing or breeding tritium gas from dense molten lithium alloy by bombardment of the alloy as a target material using a linear accelerator emitting a high energy proton beam to generate a neutron flux. The invention involves using a dense eutectic molten lead lithium alloy as the target material, directing the impact area within the body of molten target material, such as to a depth of about 2 meters of the target material, and continuously circulating the molten alloy past the impact area to dissipate the heat of reaction to provide a substantial lead source for maximum neutron production and to provide an effective lithium source to absorb the neutrons, to produce the highest possible amount of tritium per proton applied by the high energy proton beam. The formed tritium gas is insoluble in and separates from the molten alloy.