Compact DEMO, SlimCS; Design progress and issues

Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; Hayashi, Takumi; Asakura, Nobuyuki; Sakurai, Shinji; Nishitani, Takeo; Ozeki, Takahisa; Ando, Masami; Ezato, Koichiro; Hamamatsu, Kiyotaka; Hirose, Takanori; Hoshino, Tsuyoshi; Ide, Shunsuke; Inoue, Takashi; Isono, Takaaki; Liu, C.; Kakudate, Satoshi; Kawamura, Yoshinori; Mori, Seiji; Nakamichi, Masaru; Nishi, Hiroshi; Nozawa, Takashi; Ochiai, Kentaro; Ogiwara, Hiroyuki; Oyama, Naoyuki; Sakamoto, Keishi; Sakamoto, Yoshiteru; Seki, Yohji; Shibama, Yusuke; Shimizu, Katsuhiro; Suzuki, Satoshi; Takahashi, Koji; Tanigawa, Hisashi; Tsuru, Daigo; Yamanishi, Toshihiko; Yoshida, Toru

Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).