プラズマ・核融合学会誌
Print ISSN : 0918-7928
78 巻 , 11 号
選択された号の論文の12件中1~12を表示しています
Rapid Communications
解説
  • 多田 栄介, 羽田 一彦, 丸尾 毅, 安全評価グループ
    2002 年 78 巻 11 号 p. 1145-1156
    発行日: 2002年
    公開日: 2005/12/08
    ジャーナル フリー
    Following the Engineering Design Activity of ITER, joint implementation towards construction has been made among the international partners. To this end, in Japan, efforts have been made to develop a fundamental approach for ensuring safety and establishing associated codes and standards for structural and seismic integrity in licensing preparation. This paper gives an outline of a safety approach and presents an outline of technical codes for the integrity of unique ITER components.
  • 小西 哲之
    2002 年 78 巻 11 号 p. 1157-1164
    発行日: 2002年
    公開日: 2005/12/08
    ジャーナル フリー
    Based on the fundamental approach for safety of ITER, a possible extension of it to assure the safety of fusion power plant was considered. Although the entire an alysis and licensing preparation are specific for ITER, its methodology which takes full advantage of the inherent features of fusion is expected to be applied to the fundamental logic of fusion power plants. Both energy and radioactive source terms that could be potential hazards are typically operative for a number of days rather than for a year, as in the case of fission. The major differences from the test reactor ITER were identified as the power blanket, coolant loop, and a generator train that will hold high temperature and a considerable amount of tritium. It is anticipated that the tritium inventory and most of the tritium plant would essentially be same as those for ITER, tritium recovery and removal from the blanket loop will dominate the fusion power plant tritium systems. Such a tritium system will actively remove tritium at a daily throughput of the order of plant inventory. This feature suggests that no dedicated off-normal systems are needed to assure the safety of the fusion plant in terms of environmental tritium release.
小特集 「核融合炉の経済性と環境負荷 -その解析と今後の課題-」
研究論文
  • Satoshi NISHIO, Kenji TOBITA, Kenkichi USHIGUSA, Satoshi KONISHI, Rea ...
    2002 年 78 巻 11 号 p. 1218-1230
    発行日: 2002年
    公開日: 2005/12/08
    ジャーナル フリー
    Based on the last decade of JAERI reactor design studies, an advanced commercial reactor concept (A-SSTR2) that meets both economical and environmental requirements has been proposed. The A-SSTR2 is a compact power reactor (Rp = 6.2 m, ap = 1.5 m, Ip = 12 MA) with a high fusion power (Pf = 4 GW) and a net thermal efficiency of 51%. The machine configuration is simplified by eliminating the center solenoid (CS) coil system. An SiC/SiC composite for the blanket structure material, helium gas cooling with a pressure of 10 MPa and an outlet temperature of 900°C, and TiH2 for the bulk shield material are introduced. For the toroidal field (TF) coil, a high temperature (TC) superconducting wire made of bismuth with a maximum field of 23 T and a critical current density of 1,000 A/mm2 at a temperature of 20 K is applied. In spite of the CS-less configuration, a computer simulation gives satisfactory plasma equilibria, plasma initiation process, and current ramp-up scenario. The current rampup time is about 22 hours. The MHD stabilities for the ballooning mode and the ideal low n kink-modes are confirmed. The stabilization of n = 1 and n = 2 kink modes requires a shell position closer than 1.4 times and 1.2 times the plasma minor radius, respectively. With regard to the divertor thermal condition, it was found that a neon gas-seeded divertor plasma with a fraction of ˜ 2.5% gives a thermal load reduction at the divertor plate from 460 MW to 100 MW and a plasma temperature drop at the divertor plate from 200 eV to 20 ˜ 30 eV. By increasing the shield thickness by about 15 cm, the total radwaste is dramatically reduced. The radwaste percentage relative to the total waste is reduced from 92 wt.% to 17 wt.%.
  • 近藤 克己, 水内 亨, 長崎 百伸, 岡田 浩之, 佐野 史道, 別生 榮, 設楽 弘之, 真鍋 義人, 洪 遠齢, 川染 勇人, 高宮 ...
    2002 年 78 巻 11 号 p. 1231-1238
    発行日: 2002年
    公開日: 2005/12/08
    ジャーナル フリー
    Recently magnetic confinement theories in helical systems have been developed, and various magnetic configurations have been proposed. Heliotron J was constructed to optimize the helical-axis heliotron concept by introducing bumpiness in the magnetic spectra. The ECH system with 53.2 GHz and 70 GHz gyrotrons in Heliotron J produced a plasma with Te= 1 keV and ne=1.5×1018 m-3, which is in the rare collisional regime. Preliminary estimation of the global energy confinement time is close to that expected from ISS95-scaling. Impurity behavior in the Heliotron J plasmas is also reported.
  • Kameo ISHII, Akiyosi ITAKURA, Makoto ICHIMURA, Isao KATANUMA, Eiichiro ...
    2002 年 78 巻 11 号 p. 1239-1250
    発行日: 2002年
    公開日: 2005/12/08
    ジャーナル フリー
    Loss regions in the plasma particles' velocity space are decreased by the electrostatic potentials created on both sides of the plasma, which results in the improvement of the axial confinement in the tandem mirror. We found experimentally that the ion loss region was in contact mainly with both a plug potential bounce region and the outer mirror throat bounce region in which ions were bounced near the outer mirror throat of the plug/barrier cell. These bounce ions play an important role in tandem mirror confinement. The outer mirror throat bounce region is caused by the relatively high potential in the neighborhood of the outer mirror throat. The core plasma's radial potential profile was controlled by changing the potential of coaxially separated end plates, and it was found that control of the radial potential profile was useful for retardation of the radial loss of the bounce ions. We observed a hump structure on the energy distribution function of the end-loss ions, and found that the enhancement of the end-loss ions was caused by ion flow from the trapped region to the loss region due to Alfvn Ion Cyclotron (AIC) fluctuations. Although the ion diffusion due to the fluctuations enhances the axial ion loss, the axial loss can be reduced by creation of a higher confining potential.
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