The impact of rapid thermal loss events on the economics of stellarator and tokamak power plants

Toroidal magnetic fusion concepts are often considered leading candidates for near term fusion energy, but these devices are susceptible to rapid thermal losses, such as radiative collapses. The threat of “disruptions” in tokamaks, extremely fast thermal collapses followed by toroidal current quenches, have garnered serious attention but have received little treatment in economic studies of magnetic fusion energy. In this talk, we generalize a model presented in [1] to quantify the effect of thermal collapses on the cost of electricity produced by a magnetic fusion power plant and compare the challenges faced by tokamaks and stellarators. We outline the various ways rapid thermal collapses increase costs and decrease revenues, introduce metrics to quantify these effects, and add them to a Levelized Cost of Electricity model. We find that although current-free stellarator power plants face significantly fewer risks than tokamaks, rapid thermal collapses could still have a significant impact on the cost of electricity, especially for quasi-axisymmetric devices where important uncertainties remain regarding the expected thermal quench impacts and current quench forces.

[1] Maris et al. “The impact of disruptions on the economics of a tokamak power plant.” Accepted, Fusion Science & Technology (2023).