Thermal and Mechanical Design Aspects of the LIFE Engine

Fusion-Fission Blanket Options for the LIFE Engine

“…7,8 Similarly, flow conditions across the Be layer, fuel bed and graphite reflector for spherical geometry with similar radial dimensions have been shown to provide adequate cooling. 6 These results are currently being verified for the modular design. The nuclear fuel for LIFE hybrid blankets is proposed to be a TRISO-based fuel kernel surrounded by additional porous and structural carbon-based layers contained in slow moving graphite pebbles.…”

“…Neutronics and burnup simulations employ a control scheme that uses 6 Li enrichment in the coolant to control thermal power and tritium breeding ratio (TBR). 9 The requirement to operate at constant thermal power is such that early in the cycle excess tritium is produced (TBR > 1) and stored for later use when TBR falls below 1.…”

“…10 We also use a modified version of Monteburns 2.0, which in turn utilizes ORIGEN2.2 to perform isotopic depletion. 11,12 These models are coupled and controlled via custom software developed at LLNL to adjust the 6 Li enrichment in the coolants and track TBR, thermal power and various reaction rates of interest. The transport calculations use ENDF/B-VII.0 nuclear data Doppler broadened to 600°C or 900°C according to the material temperature and scattering kernels are added when applicable.…”

“…We employ a methodology using 6 Li 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.…”

“…The LIFE hybrid design was originally proposed as a spherically symmetric system using oxide-dispersion strengthened (ODS) ferritic steel for the 1 st wall and all blanket components. 6 Recent work has focused on the operability and maintainability of the power plant and this has led to the adoption of a modular design for the 1 st wall and blanket. Such a design simplifies the process for replacing life-limited components, and thus increases overall plant availability.…”