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High-Temperature Superconducting Coil Option for the LHD-Type Fusion Energy Reactor FFHR

Gourab BANSAL, Nagato YANAGI¹⁾, Tsutomu HEMMI²⁾, Kazuya TAKAHATA¹⁾, Toshiyuki MITO¹⁾ and Akio SAGARA¹⁾

The Graduate University for Advanced Studies, Toki, Gifu 509-5292, Japan

1)

National Institute for Fusion Science, Toki, Gifu 509-5292, Japan

2)

Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193, Japan

(Received 17 November 2007 / Accepted 23 February 2008 / Published 5 August 2008)

Abstract

Large-current-capacity high-temperature superconducting (HTS) conductors using YBCO tapes are being considered as an option for the LHD-type fusion energy reactor FFHR. The typical operating current, magnetic field, and temperature of such conductors in FFHR are 100 kA, 13 T, and 20 K, respectively. A preliminary design of the HTS conductor has been proposed for the FFHR helical coils. Analyses have been performed on the proposed HTS conductor regarding thermal properties, mechanical structures, AC losses, and quench detection and protection. It is suggested that stainless steel might be a better choice for the outer jacket of the HTS conductor compared to aluminum alloy. Due to increased specific heats of conductor materials at 20 K, HTS magnets are supposed to be operated more stably compared to low-temperature superconducting (LTS) magnets operated at ∼4 K. The required refrigeration power is also reduced. Therefore, using HTS conductors, it is considered to be viable to assemble the continuous helical coils in segments with joints of conductors, as additional heat generation at the joints can be taken care by utilizing the surplus refrigeration power. According to these analyses, HTS conductors seem to be promising for the FFHR coils.

Copyright (c) 2008 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

LHD, FFHR, fusion reactor, HTS, YBCO, BSCCO, superconductor, stability

DOI: 10.1585/pfr.3.S1049

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This paper may be cited as follows:

Gourab BANSAL, Nagato YANAGI, Tsutomu HEMMI, Kazuya TAKAHATA, Toshiyuki MITO and Akio SAGARA, Plasma Fusion Res. 3, S1049 (2008).