DESIGN AND R&D ISSUES FOR THE JT-60 MODIFICATION TO A FULL SUPERCONDUCTING TOKAMAK
M. MATSUKAWA AND THE JT-60SC DESIGN TEAM
The JT-60SC Design TEAM:
M. Matsukawa, A. Sakasai, S. Ishida, N. Akino, T. Ando, T. Arai, K. Ezato, K. Hamada, N. Ichige, T. Isono, A. Kaminaga, T. Kato, M. Kikuchi, K. Kizu, N. Koizumi, Y. Kudo, G. Kurita, K. Masaki, K. Matsui, Y. M. Miura, N. Miya, Y. Miyo, A. Morioka, H. Nakajima, A. Oikawa, S. Sakurai, T. Sasajima, K. Satoh, K. Shimizu, S. Takeji, H. Tamai, M. Taniguchi, K. Tobita, K. Tsuchiya, K. Urata, J. Yagyu
Abstract.
This paper describes the modification program of JT-60 towards the tokamak fusion DEMO-reactor in support of ITER. The JT-60 is planned to be modified for the superconducting tokamak, JT-60SC, to establish steady-state operation at high beta and ensure plasma applicability of ferritic steel as reduced activation materials in a reactor-relevant regime with a break-even class plasma. Main parameters of the JT-60SC device are the plasma current of 4 MA, the toroidal field of 3.8 T, the major and minor radii of 2.8 and 0.85 m, respectively, the elongation and triangularity of 1.8 and 0.35, respectively, a current flattop duration of 100 s and the total heating power of 15 MW for 100 s. Nb3Al and Nb3Sn superconducting strands with a high Cu/non-Cu ratio and NbTi strands with ~10 mm diameter of filaments have been developed for the toroidal and poloidal superconducting coils requiring compactness and low AC losses. Full-scale cable-in-conduit cables were manufactured by automatic welding of SS316 conduits and jacketing the cables. An irradiation test for a mockup of the cost-effectively designed CFC divertor target plate has demonstrated the required high heat handling capability of ~10 MW/m2 on the JAERI Electron Beam Irradiation Stand.