1. Japan Atomic Energy Research Institute Thermohydraulic Safety Engineering Laboratory, Department of Reactor Safety Research Tokai, Ibaraki, 319-11 Japan
2. Nagoya University Department of Energy Engineering and Science Furo-cho, Chikusa-ku, Nagoya, 464-8603 Japan
3. Idaho National Engineering and Environmental Laboratory Department of Nuclear Engineering, P.O. Box 1625, Idaho Falls, Idaho 83415