Development of Divinylbenzene Foam Shells for Use as Inertial Fusion Energy Reactor Targets

An overview of the present status of development of a hollow foam shell designed to produce high yields when used in a krypton fluoride inertial fusion energy (IFE) reactor is presented. Prototype shells have been produced from a 100 mg/cm³ density CH foam with an ~4-mm diameter and 300 m wall thickness. A triple-orifice droplet generator was used to form the shells using solutions of an internal water phase, an oil phase (divinylbenzene monomer, dibutyl phthalate solvent, and a radical initiator), and an external water phase. The lowest percent of nonconcentricity measured for a completed shell was 3%, and the lowest average percent of nonconcentricity for a batch of shells was 7%. A technique to overcoat the shells with a 1- to 5-m-thick full-density polymer layer using an interfacial polycondensation reaction is being developed. Methods to further optimize dimensions to produce shells that meet IFE specifications are also discussed.