First wall and limiter lifetime in pulsed tokamak reactors

This study concentrates on the structural integrity of certain reactor subsystems under cyclic operation to answer the question: ''How long a burn pulse is needed to achieve the benefits of steady-state operation''. Component lifetime in the steady-state is limited by three effects: radiation damage, disruptions, and sputtering erosion. Cyclic operation modifies one of these (the number of disruptions may increase with the number of burn cycles) and introduces a fourth life limit, thermal fatigue. The design strategy is to determine the structure and coating thicknesses which maximize component lifetime against all life limitations. After calculating disruption damage (vaporization, melting) for candidate materials the authors present the lifetime analysis for different structures