Model for the mechanical interaction between solid breeder and cladding materials

The use of solid breeders in the blanket components of fusion reactors is necessitated by the need for tritium breeding, with avoidance of problems arising from liquid-metal breeders such as excessive corrosion and magnetohydrodynamic pressure drops. To allow for tritium diffusion, solid breeders can be produced as porous square cylinders of dimensions on the order of 1 to 3 cm. Such cylinders, called pellets, are encapsulated in a structural cladding material that provides for a barrier to their interaction with the coolant. Mechanical interaction during power cycles determines the lifetime of breeder pins. The analysis presented in the paper gives a design tool for material choices and lifetime prediction for breeder pins of the UCLA solid breeder blanket. The design is evaluated, and operating conditions are suggested