Starlight, a stationary inertial-confinement-fusion reactor with nonvaporizing walls

The Starlight concept for an inertial-confinement-fusion (ICF) reactor utilizes a softball-sized solid-lithium X-ray and debris shield that surrounds each pellet as it is injected into the reactor. The shield is sacrificial and vaporizes as it absorbs X-ray and ion-debris energy emanating from the fusion reactions in the fuel pellet. However, the energy deposition time at the surface of the first wall is lengthened by four orders of magnitude (to >100 μs), which allows the energy to be conducted into the wall fast enough to prevent vaporization. Starlight operates at 5 Hz with 300-MJ-yield fuel pellets. It features a stationary, nonvaporizing first wall that eliminates erosion and shock waves which can destroy the wall; also, it allows arbitrary fuel pellet illumination geometries so that efficient coupling of either laser or heavy-ion-beam driver energy to the fuel pellet can be achieved. When neutrons penetrate the shield, the wall experiences neutron damage that limits its lifetime. Hence, wall materials that have an economic lifetime must be chosen. The general concept and a specific design for laser drivers using a 6-m-radius, 2 1/4 Cr 1 Mo steel first wall are described. Heat-transfer calculations used to establish the radius and a structural analysis that shows stresses are within allowable limits are included. A wall lifetime of over six years is predicted