Abstract:
The criteria and implications for successful design, licensing and power plant operation
are assessed, and imposed constraints and limitations are examined. The design of a reliable
fusion power plant is dependent on the availability of licensed nuclear materials and the
structural–thermal loading conditions during normal and abnormal events. Various conditions
in a tokamak lead to structural damage and possible failure. Taking into consideration all the
possible structural failure mechanisms, the most likely are combinations of fatigue and creep.
Issues encountered in the fusion environment are the significant amount of irradiation creep,
the large ratio of helium production to displacement damage, and the degradation of fatigue
strength and ductility, effects which are even encountered at low temperatures. Design codes
distinguish between failure criteria under steady and transient loads, and lay down rules for
failure prediction under combined creep–fatigue conditions. Currently, there are no established
fusion specific licensing processes or component design codes. Any limits imposed on designs
or performance are taken from existing design codes developed by the fission industry. There
is a need to initiate the process of defining and developing tools for the design and licensing of
fusion components and facilities to ensure nuclear safety.
