Evaluation of Particle Recycling and Impurity Generation from the First Wall for JT-60 Superconducting Modification
S. Sakurai, Y. Miyo, K. Yokoyama, K. Sato, H. Takenaga, K. Tsuchiya, K. Shimizu, J. Yagyu, K. Ezato, K. Masaki, Y. Kudo, H. Tamai, A. Sakasai, M. Matsukawa and S. Ishida
Japan Atomic Energy Research Institute, Naka Fusion Research Establishment, Mukouyama 801-1, Naka-machi, Naka-gun, Ibaraki, JAPAN 311-0193
Abstract.
Particle flux onto the wall and energy dependence on erosion was evaluated for the design of the first wall of JT-60 superconducting modification (JT-60SC). Since the particle flux density at the outer baffle is mainly originated in divertor neutral source and about 1/100 of that at the outer divertor in JT-60U. The reduction of backflow by strong divertor pumping with vertical targets and long legs in JT-60SC is effective for the control of main plasma density even in wall saturation. No erosion was observed at less than the threshold incident energy density in the disruption heat load test of reduce activation ferritic steel F82H. No tungsten contained 2 wt% in bulk was observed in a deposited layer by vaporization due to its high boiling point. The protection of carbon guard limiters should be designed to reduce the heat load during disruptions < 2 MJ/m2.