Abstract
Modern society relies heavily on the fossil fuels that lead to the carbon dioxide emissions. The development of 700℃ class advanced ultra super critical plant is one of the solutions for the reduction of carbon dioxide emissions. The technology developments of the 700℃ class USC plant are being evaluated in Europe and the United States. In Japan, the 700℃ class USC technology was chosen as one of the national projects last year. This paper describes the development issues and progress of the turbine material and the structures for 700℃ class USC. It especially introduces the progresses in development of two kinds of unique Ni base alloys.