[Table of Contents]

Plasma and Fusion Research

Volume 6, 2405083 (2011)

Regular Articles

A Robust Design Window for the Heliotron DEMO Reactors
Takuya GOTO, Junichi MIYAZAWA, Teruya TANAKA, Nagato YANAGI and Akio SAGARA
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan
(Received 23 December 2010 / Accepted 21 March 2011 / Published 12 July 2011)


According to the achievements in the Large Helical Device (LHD) experiments, a design of a DEMO reactor with a LHD-type heliotron system is foreseeable. On the other hand, a DEMO is the next step reactor and high reliability and feasibility are demanded in its design. In this study, a robust design window, i.e., the design window that is not sensitive to a change in uncertain physics parameters, was surveyed through parametric scans using a system design code. It was found that a difference in main design parameters (major radius, magnetic field strength, fusion output) gives only a small change in a dependence of physics requirements on the physics conditions. Therefore, it is important to find the design window with a lower requirement on the confinement improvement to assure the design robustness. In this respect, a reduction in the minimum inboard blanket space, one of the key parameters in a LHD-type heliotron reactor design, can effectively expand the design window and contributes to the design robustness. An acceptance of higher neutron wall load and an achievement of further high confinement improvement are also expected to make both a DEMO and a commercial reactor to be more feasible and economically attractive.


heliotron system, DEMO reactor, design window analysis, system design code, blanket space

DOI: 10.1585/pfr.6.2405083


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This paper may be cited as follows:

Takuya GOTO, Junichi MIYAZAWA, Teruya TANAKA, Nagato YANAGI and Akio SAGARA, Plasma Fusion Res. 6, 2405083 (2011).