Simulation Study of Large Power Handling in the Divertor for CFETR Phase II

Abstract

The Chinese Fusion Engineering Testing Reactor (CFETR) is a next fusion device proposed in China. The ability to exhaust the plasma power loss is a critical issue for the successful production of a fusion power reactor. For Phase II of CFETR with fusion power ~1 GW, the extremely large divertor heat load would be a severe challenge to achieve steady-state operation. In this paper, we have simulated the divertor performance by using SOLPS5.0 (B2.5-EIRENE) code package for a lower single null divertor configuration based on a core self-consistent steady-state scenario with Ar seeding. The core self-consistent steady-state scenario is calculated by a 1.5-D modeling workflow utilizing the One Modeling Framework for Integrated Tasks (OMFIT) framework. The modeling shows that Ar puffing from the lower divertor region together with D2 puffing from upstream is highly effective in mitigation of the divertor peak heat flux and temperature for the whole outer target and near strike point on the inner divertor target, however, electron and ion temperature ( $T_{e}$ and $T_{i})$ at far scrape-off layer on inner divertor is still higher than the erosion mitigation. In addition, comparison simulation of different divertor geometries has been performed in this paper. Further work on self-consistent core-edge coupling to estimate the effect of impurity seeding on core performance as well as the optimization of divertor geometry and operations will be studied.