Description
In addition to the familiar functions of capturing neutron energy, breeding tritium and providing a coolant for heat extraction, inertial dt fusion reactors must typically also manage the shockwave driven by the pulsed energy delivery. In this work we show how the reactor in our FLARE concept (Fusion Via Low-Power Assembly and Rapid Excitation) uses a natural lithium blanket to perform these multiple simultaneous roles. A thick (2m), in-vessel, natural lithium blanket - made possible by ambient pressure operation - almost completely surrounds the neutron source, providing lithium first-wall, tritium breeding, energy capture, energy gain, coolant and shock mitigation functions. Transient structuring of the lithium is shown to reduce the shock intensity to manageable levels through expansion, reflection, scattering and absorption of the shock energy. The lithium is in its natural Li6/Li7 isotopic mix without neutron multipliers or Li6 enrichment. The combination of high solid-angle coverage by a thick lithium blanket and the availability to the lithium of the un-moderated native fusion neutron spectrum leads to high neutron energy capture (> 99.9%) and in turn to a TBR (Tritium Breeding Ratio) of 1.8. with low vessel neutron damage and consequently long vessel lifetimes ((> 60yrs). Fusion reactor designs with an overall TBR greater than the engineering threshold for tritium self-sufficiency, expected to lie between 1.05 and 1.2, may complement break-even or simpler zero-TBR reactors in the future fusion economy.