With the recent deregulation of electric power supply, "maintenance optimization" has become important as a means of increasing economic efficiency while maintaining safety and reliability in nuclear power plants in Japan. Draw- ing upon an excellent track record of more than thirty years experience in activities ranging from the construction to maintenance of nuclear power plants, Mitsubishi Heavy Industries, Ltd. (MHI) makes every effort to provide ad vanced comprehensive engineering and highly reliable equipment, facilities, and on-site work, while positively carrying out various activities to meet customer needs from every perspective. Such service activities are supported by timely servicing through customer support and a wide range of support systems, and are expanded as activities of advancement developed in close cooperation with customers.