To contribute to the clarifying of the mechanisms and establishing of the countermeasure on SCC of pressure boundary materials for PWRs, collaborative research programs are conducting with Japanese PWR utilities on the stress corrosion cracking initiation and propagation characteristics for the laboratory experiments and actual experiences in commercial PWR plants, and studying on the evaluation of the materials and stresses by the high resolution analytical instruments from the view point of high nano-technology.

To improve the reliability, safety and economy of the current nuclear power plants, BWR and PWR, cooperative research programs are promoted with worldwide participation of organizations and specialists. One of the stem activities is to develop innovative new materials that are highly reliable in practical applications. The main feature of the approach is to apply modern “nano-meter level” technologies to the clarification of complicated materials degradation mechanisms specific to the reactor environment. Specific attention has been paid to the analyses of crystal grain structure and stresses.

Developing the highly SCC resistant and high temperature weld cracking resistant new structural materials that meet to current material standards are conducting based upon the publications of the above essential mechanistic studies and fundamental scientific principles.

To develop the high resistant nickel based alloys to weld hot cracking, the fundamental studies are performing on the effect of fundamental characteristics and metallurgical factors on weld hot cracking for laboratory melted nickel based testing alloys.