1. Oak Ridge National Laboratory, Computational Sciences and Engineering Division, Mail Stop 6085, Oak Ridge, Tennessee 37831
2. Kyushu University, Research Institute for Applied Mechanics, Kasuga, Fukuoka 816-8580, Japan
3. Osaka University, Graduate School of Engineering, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
4. Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, Tennessee 37831
5. Massachusetts Institute of Technology, Nuclear Reactor Laboratory, 138 Albany Street, Cambridge, Massachusetts 02139