Study on irradiation embrittlement of nuclear pressure vessel steels

From the standpoint of economy and design, mono block large forgings have become in use for nuclear steam supply system components and the minimization of weld seams has been encouraged. The SA508, C1.3 Steel is the standard material for these forgings at present and have almost the same or superior properties compared to conventional SA533, Gr. B steel plate. Until now, however, the neutron irradiation embrittlement susceptibility of this material has not been clear because of the lack of irradiation test data. In this paper, the neutron irradiation embrittlement susceptibility of SA508, Cl.3 steel are reported on the several accelerated test data using the material of actual SA508, Cl.3 large forging and compared to the susceptibility of SA533, Gr.B steel. It is proved that the neutron irradiation embrittlement susceptibility of SA508, Cl.3 steel is almost the same as that of SA533, Gr.B steel. (author)