Assessment of fracture toughness of heavy section steels for nuclear pressure vessels

Fracture toughness tests were conducted on three heats of nuclear pressure vessel steel plate (SA533B C1.1), a submerged arc welding joint of one of the same plates, and three heats of forged steel for nuclear pressure vessels (SA508 C1.3) to evaluate the static fracture toughness K sub(IC), dynamic fracture toughness K sub(Id) and crack arrest toughness K sub(Ia). These test results showed that the lower boundaries of K sub(IC), K sub(Ia) and all the fracture toughness data points lay above the K sub(IC), K sub(Ia) and K sub(IR) curves given by ASME Boiler and Pressure Vessel Code, respectively. Further discussion was made on these three fracture toughness parameters. (author)