The logic behind thick liquid-walled fusion concepts

It may be possible to surround the region where fusion reactions are taking place with an neutronically thick liquid blanket which has penetrations that allow only a few tenths of a percent of the neutrons to leak out. This paper will discuss the logic of such designs and describe their evolution with examples applied to both magnetic and inertial fusion (HYLIFE-II). Theses designs are robust to pulsed loading and have a number of advantages over the usual designs with solid first walls. For example, solid components will last the life-of-the-plant, and therefore the capacity factor is expected to be 10% or so higher than for the non-liquid walled blankets, because no blanket replacement shutdowns are required. The component replacement, operations, and maintenance costs might be half the usual value because no blanket change-out costs or accommodating facilities are required. These savings might lower the cost of electricity by 20%. The components might not have to be of nuclear-grade construction, partly because the liquid attenuates neutrons and results in less activation of materials. Upon decommissioning, the reactor materials might qualify for disposal by shallow burial even when constructed of ordinary 304 stainless steel. The need for a high-intensity 14-MeV neutron test facility to develop first-wall materials is greatly reduced. Flowing molten Li, molten salt (Li2BeF4, called Flibe), and molten Li17Pb83 have been considered. An advantage of molten salt is that it will not burn and has a low tritium solubility and a low tritium inventory, but it has 300 MCi of 2-hr half-life 18F