Influence of post-radiation annealings on the microstructure and 12Cr18Ni9Ti steel mechanical properties in the WWR-K reactor up to 5 cna

Purpose of this work is study of influence both neutron irradiation and following annealings on the microstructure and strength characteristics of stainless austenitic steel irradiated in the WWR-K reactor up to damage dose ∼5 cna. It is expected, that structure evolution in such conditions, when velocity of radiation defects build up is insignificant, and it will be considerably differs from the structure evolution observed in the fast reactors at commensurable integral doses. The 12Cr18Ni9Ti steel serves in the capacity of examination object - the material of the automatic regulation rod operated in the research reactor core more than 20 years. Sum fluence makes up 1.3·1022 n/cm2 (E>0.1 MeV). Characterization of microhardness and mechanical properties of steel after irradiation and following prolonged (∼13 years) natural ageing is carried out. A cycle of post-radiation isochronous annealing within temperature range 200-1050 deg. C is worked out