Effect of chemical composition on irradiation creep of stainless steels irradiated in the BOR-60 reactor at 420 °C

The irradiation creep of six steels was investigated. For these steels, the Cr–Ni equivalents were calculated and the dependences of creep moduli on Ni equivalent were plotted. Pressurized tubes made from these steels were irradiated in different cells in row 6 of the BOR-60 reactor. The maximum damage doses achieved were about 60 and 100 dpa at irradiation temperature of 420 °C in various experiments. The levels of specified stresses changed from 0 to 320 MPa. The specimens were periodically removed from the reactor during refueling to measure their strain and then were returned to the reactor. The creep modulus B decreases with an increase of Ni equivalent over 16%. The dependence of creep modulus on Ni equivalent is similar to the dependence swelling on Ni.