1. Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama 708-0698, Japan
2. Faculty of Agriculture, Tottori University, 4-101 Koyamacho-Minami, Tottori 680-8551, Japan
3. Prototype Fast Breeder Reactor Monju, Japan Atomic Energy Agency, 2-1 Shiraki, Tsuruga-shi, Fukui 919-1279, Japan