1. Department of Nuclear System Safety Engineering, Graduate School of Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka-machi, Nagaoka-shi, Niigata 940-2188, Japan
2. Department of Industrial Products and Packaging Quality, Institute of Quality Science, Poznań University of Economics and Business, Niepodległości 10, Poznań 61-875, Republic of Poland
3. National Institute for Fusion Science, 322-6, Oroshi-cho, Toki-shi, Gifu 509-5292, Japan