Studies of impurity seeding and divertor power handling in fusion reactor

Hoshino, Kazuo; Asakura, Nobuyuki; Shimizu, Katsuhiro; Tokunaga, Shinsuke

The power handling in the divertor is the most crucial issues for a fusion reactor design. In the previous study of development of the power handling scenario for a compact DEMO reactor, further reduction of the target heat load was required even in the case where more than 90% of the exhausted power from the core plasma was radiated by the argon impurity. In this study, the impact of the impurity seeding and the machine specifications on the divertor power handling has been investigated by using the SONIC code. With decreasing the fusion power, the divertor plasma detachment is extended and the target heat load decreases. The SONIC simulation showed the target heat load less than 6 MW/m for a tungsten mono-block divertor with a ferritic steel water-cooling pipe, at the fusion power less than 2 GW. It is also showed that the impurity radiation fraction on the exhausted power can be reduced to 80% at the fusion power of 2 GW for a copper-alloy water-cooling tube.