18th IAEA Fusion Energy Conference

Conceptual Design of Advanced Steady-State Tokamak Reactor (A-SSTR2)
- Compact and Safety Oriented Commercial Power Plant -

S. NISHIO¹⁾, K. USHIGUSA¹⁾, S. UEDA¹⁾, A. POLEVOI²⁾, K. TOBITA¹⁾, R. KURIHARA¹⁾, I. AOKI¹⁾, H. OKADA¹⁾, G. HU³⁾ , S. KONISHI¹⁾, I. SENDA¹⁾, Y. MURAKAMI¹⁾, T. ANDO¹⁾, Y. OHARA¹⁾, M. NISHI¹⁾, S. JITSUKAWA¹⁾, R. YAMADA¹⁾, H. KAWAMURA¹⁾, S. ISHIYAMA¹⁾ , K. OKANO⁴⁾, T. SASAKI⁵⁾, G. KURITA¹⁾, M. KURIYAMA¹⁾, Y. SEKI¹⁾, M. KIKUCHI¹⁾
1) Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, Naka-machi, Naka-gun, Ibaraki-ken, 311-0193 Japan
2) STA fellow, Kurchatov Institute, RF,
3) STA scientist exchange program, SWIP, P.R.China,
4) Central Research Institute of Electric Power Industry, Japan,
5) Mitsubishi Fusion Center, Japan

Abstract.
Basing the last decade JAERI reactor design studies, the advanced commercial reactor concept (A-SSTR2) which meets both economical and environmental requirements has been proposed. The A-SSTR2 is a compact power reactor (R_p=6.2m, a_p=1.5m, I_p=12MA) with a high fusion power (P_f =4GW) and a net thermal efficiency of 51%. The machine configuration is simplified by eliminating a center solenoid (CS) coil system. SiC/SiC composite for blanket structure material, helium gas cooling with pressure of 10Mpa and outlet temperature of 900・/FONT>C, and TiH2 for bulk shield material are introduced. For the toroidal field (TF) coil, a high temperature (T_C) superconducting wire made of bismuth with the maximum field of 23Tand the critical current density of 1000A/mm² at a temperature of 20K is applied. The supporting structure for the large electromagnetic force on the TF coil is arranged by eliminating the CS coil system. In spite of the CS-less configuration, the plasma equilibrium conditions, plasma break down and plasma current ramp up scenario were successfully simulated. The current ramp up time is about 22 hours. The MHD stabilities for the ballooning mode and the ideal low n kink-modes are confirmed. The n=1 and n=2 kink modes stabilization require the shell position closer than 1.4 times of the plasma minor radius and 1.2 times, respectively. As to the divertor thermal condition, it was found that 2.2 % Ar seeding or 0.5 % Kr seeding into the divertor plasma region could reduce the divertor plate thermal load from 460 MW to 100 MW and the plasma temperature from 200 eV to 20~30 eV.