Scaling analysis of PMR200 reactor cavity cooling system

The reactor cavity cooling system (RCCS) of the PMR200, a demonstration plant of very high temperature reator (VHTR), removes the residual heat, which amounts to 0.3–0.6% of the reactor full power, at both high and low pressure modes, by means of radiation and natural convection. Its operation has to be passive to eliminate any accidents associated with human errors. Prior to the experimental performance verification of the RCCS, a scaling analysis has been performed. In the present study, the scaling was based on the cavity radiation number. Based on it, the scaling laws between the model and prototype were derived, and applied to the RCCS down-scaling.