Newly undertaken inspections for aged nuclear power plants

Some of Japan's oldest nuclear generation plants are now entering their 30th year, which is close to their designed lifespan. The rules on fitness-for-service for nuclear power plants undertaken by utilities are to extend the lifetime of plants to 60 years. Upon lifetime extension new rules must be applied and JSME (Japan Society of Mechanical Engineers) issued new rules in May 2000. These rules define allowable flaw sizes in operating plant components. In these circumstances, in-situ flaw sizing and repairs are urgently needed. Accordingly, laser inspections such as laser UT and laser holography are being developed.