Improved methods for prediction of creep-fatigue in next generation conventional and nuclear plant

Materials technology poses a major challenge in the design and construction of next generation super critical/ultra super critical power plant (SC/USC) and Generation IV (GenIV) nuclear plant. New plant is expected to have in the order of a 60 year life-time, imposing complex design difficulties in areas of creep rupture and creep fatigue damage. For SC/USC plant, the main goal is the enhancement of performance by raising the steam pressure and temperatures. In order to achieve these goals materials with acceptable creep rupture strength at design temperatures and pressures must be used. In GenIV designs, the issue is more complex, with both low and high tempera-ture designs. A key requirement in the majority of the designs, however, will be acceptable resistance to creep rupture, fatigue cracking, creep fatigue interactions, with the additional effects of void swelling and irradiation creep. The accumulation of creep fatigue damage over time in both SC/USC and GenIV plant will be one of the principal damage mechanisms. This will eventually lead to crack initiation in critical high temperature equipment. Hence, improved knowledge of creep and fatigue interactions is a necessary development as components in power-generating plants move to operate at high temperature under cyclic conditions. The key to safe, reliable operation of these high-energy plants will depend on understanding the factors that affect damage initiation and propagation, as well as developing and validating technologies to predict the accumulation of damage in systems and components.