A cost-based criterion for implementing data-driven disruption predictors

Plasma disruptions are a serious impediment to tokamak operations, and accordingly there has been a lot of attention given to the topic of predicting disruptions in order to avoid or more effectively mitigate them. While existing prediction goals are based on a combination of engineering constraints and desired operating outcomes, it does not follow that a predictor must meet these strict requirements to offer a benefit. Rather, a cost-based criterion should provide the necessary justification to implement a disruption predictor. A general model for such a cost-based criterion is derived here. This model is used to demonstrate that, with realistic assumptions about the cost of disruptions compared to the cost of unnecessary discharge terminations, existing disruption prediction techniques already meet the minimum criterion to reduce operating costs.