Divertor design study on compact DEMO reactor for handling of huge exhaust power

Conceptual designing of the divertor system is required for DEMO reactor next to ITER for the handling of huge exhaust power. For the divertor design study using SOLDOR/NEUT2D code in the compact DEMO reactor, Slim CS, we find out a prospective divertor design to hold the detached divertor condition within allowable heat load for the first time. Although the heating power on Slim CS increases ∼ 6 times larger than that for ITER, the tolerable heat load on divertor target is restricted to 10 MW/m², which is less by half than that for ITER. Assuming the heating power of 500 MW and ion out flux of ∼ 1 x 10²³ s^-1 with a low-aspect ratio plasmas and vertical divertor target, the peak heat load is estimated to be 50 MW/m² on the outer target with attached condition. This value exceeds significantly the allowable limit of 10 MW/m². By installing the V-shaped corner in bottom of the outer divertor target and introducing argon impurity, the detached condition with higher particle recycling and radiation loss conditions is obtained, and the peak heat load is successfully reduced to 7.2 MW/m². (author)