Superconducting magnet radiation limit considerations for fusion reactors

The radiation limits for fusion reactor magnets have a direct impact on the cost of electricity. For example, reducing the inboard shield by 1 cm saves up to $3 million in the Tokamak Fusion Core Experiment cost. The magnet components most sensitive to radiation damage are the superconductor, stabilizer, and insulators. Nuclear heating in the magnet affects the design and also impacts the economic performance of the reactor through increased refrigeration costs. The radiation effects in the different components of the magnet are related, as all of them are determined by the flux level in the magnet. Hence, in efforts to push radiation limits, these effects should be considered simultaneously. Furthermore, the levels of radiation effects that correspond to the optimum nuclear heating determined from economic trade-off analysis will be useful in specifying the fluence, dose, and stabilization limit goals for the magnet development program. In this paper, we review the available irradiation data and assess the need for achieving higher irradiation levels