Fusion-Fission Blanket Options for the LIFE Engine

Abstract The Laser Inertial Fusion Energy (LIFE) concept is being developed to operate as either a pure fusion or hybrid fusion-fission system. The hybrid version is designed to generate power and burn both fertile and fissile nuclear fuel. The fuel blanket is composed of TRISO-based fuel cooled by a molten salt. Low-yield (˜25-40 MJ) targets and a repetition rate of ˜10-15 Hz produce a 300-500 MW fusion source. When this fusion power is coupled to a compact (2-4 m diameter) target chamber, a 14 MeV neutron flux of ˜2 × 1014 n/cm2-s drives fissile production and destruction in the fuel blanket providing an additional energy gain of 4-8, depending on the fuel and design objective. We employ a methodology using 6Li as a neutron absorber to generate self-sustaining tritium production for fusion and to maintain constant power over the lifetime of the engine. In a single pass, fertile LIFE blankets achieve uranium and thorium utilization beyond 80% without chemical reprocessing or isotopic enrichment. Fissile blankets destroy more than 90% of the initial load of weapons grade plutonium or highly enriched uranium.