1. Technical University Munich, Institute of Nuclear Engineering, Faculty of Mechanical Engineering, Boltzmannstrasse 15, 85748 Garching b. Muenchen, Germany
2. Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Mikata-gun, Fukui 919-1205, Japan
3. Kobe University, 1-1 Rokkodai, Nada-ku, Kobe-shi, Hyogo 657-8501, Japan