Head, Structural Materials Laboratory, Studsvik, Nyköping
Pages: 36 Published: Jan 1967
Tension and impact specimens of several Swedish and U.S. pressure vessel steels have been irradiated to doses between 2 x 1018 and 3 x 1019 neutrons (n)/cm2 (>1 Mev) at temperatures between 40 and 550 C (105 to 1020 F). A saturation effect with respect to dose is obtained in some, but not all, steels at higher irradiation temperatures. Similar steels and even different heats of the same steel in some cases behave differently after irradiation. An attempt has been made to correlate the difference observed when irradiations were made in two different neutron spectra with calculated differences between the two spectra. A method for estimating the brittle-fracture tendency of pressure vessels is described. The crackpropagation transition temperature is used as a criterion of safety. An estimate of this transition temperature at the end of the reactor's lifetime must take effects due to fabrication, welding, geometry, aging, and irradiation into account. The magnitudes of the different factors influencing the final transition temperature are discussed, and the data for the Marviken reactor's pressure vessel are presented.
irradiation, pressure vessels, steels, radiation effects, tension test, impact test, neutrons, embrittlement
Paper ID: STP41325S