Study of microstructure and mechanical properties of steel 08CR18NI10T irradiated in the core of reactor VVER-1000

Control-rod channel (steel 08Cr18Ni10T) of absorbing element of fuel assembly of reactor VVER-1000 irradiated at temperatures 284...322 degree C in the damage doses range 1...9 dpa is investigated. On microstructure study the vacancy pores were revealed at temperatures 308..310 degree C and at damaging doses of 8 and 4.5 dpa respectively. The dose dependence of steel 08Cr18Ni10Ti mechanical properties at testing temperatures 20,300 and 450 degree C are obtained. The steel hardening and the ductility decrease are observed at all testing temperatures. The comparison of obtained results with the results of steel 08Cr18Ni10Ti irradiated in fast-neutron reactors was carried out.It was revealed that the temperature boundary of vacancy porosity was approximately equal for the irradiated in different reactors steels and constituted 305-310 degree C. Hardening if steel, irradiated in the fast neutron reactor is higher than that for the steel irradiated in thermal reactor at similar irradiation conditions (280...300 degree, 7...9 dpa)