Properties of heavy section steel plates and forgings for nuclear vessels produced in Japan—Part 2. Fracture toughness

Abstract Large research efforts have been made to characterize the fracture toughness of reactor vessel steels and extensive fracture toughness databases have been determined. Among such investigations, the HSST program in the United States is the typical study in which the basis of the reference temperature-fracture toughness curve approach (ASME K IR concept) was established for production heats of nuclear pressure vessel steels. However, recent analytical and experimental progress shows the limitation of this concept, and a number of new methods to evaluate fracture toughness are being explored for possible standardization. The present paper reports on a study which sought to establish the procedures to obtain fracture toughness values and provides a comprehensive statement on the toughness of nuclear pressure vessel steels and weldments produced in Japan. Static, dynamic and crack arrest toughness tests were performed. Approximately 3000 fracture toughness data were obtained and compared by test types to the ASME K IR curve.