Optimization activities on design studies of LHD-type reactor FFHR

A. Sagara, O. Mitarai, T. Tanaka, S. Imagawa, Y. Kozaki, M. Kobayashi, T. Morisaki, T. Watanabe, K. Takahata, H. Tamura, N. Yanagi, K. Nishimura, H. Chikaraishi, S. Yamada, S. Fukada, S. Masuzaki, A. Shishkin, Y. Igitkhanov, T. Goto, Y. OgawaT. Muroga, T. Mito, O. Motojima

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)


Recent activities on optimizing the base design of the large helical device (LHD)-type helical reactor FFHR (force free helical reactor) are presented. Three candidates to secure the blanket space are proposed with the aim of reactor size optimization without deteriorating α-heating efficiency and by taking cost analyses into account. In this way the key engineering aspects are investigated; from 3D blanket designs, it is demonstrated that the peaking factor of the neutron wall loading is 1.2-1.3 and a blanket covering ratio of over 90% is possible by proposing discrete pumping with a semi-closed shield (DPSS) concept. Helical blanket shaping along the divertor field lines is the next big issue. For large superconducting magnet systems under the maximum nuclear heating of 200 W/m3, cable-in-conduit conductor (CICC) and alternative conductor designs are proposed with a robust design of cryogenic support posts. For access to ignited plasmas, new methods are proposed, in which a long rise-up time over 300 s reduces the heating power to 30 MW and a new proportional-integration-derivative (PID) control of the fueling can handle the thermally unstable plasma at high-density operation. This paper focuses on FFHR2m1, which is a modified version of FFHR.

Original languageEnglish
Pages (from-to)1690-1695
Number of pages6
JournalFusion Engineering and Design
Issue number10-12
Publication statusPublished - Dec 2008

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • General Materials Science
  • Mechanical Engineering


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