Effectiveness of Thermal Annealing in Recovery of Tensile Properties of Compositionally Tailored PWR Model Steels Irradiated in LYRA-10

Understanding the mechanical behaviour of reactor pressure vessel (RPV) steels at high fluences has become an important topic in regard to Long-Term Operations (LTO) existing nuclear power plants (NPP). The effectiveness thermal annealing treatments recover properties compositionally tailored pressurised water (PWR) model irradiated neutron fluences, up 1.22 × 1020 n·cm?2, is analysed this study. Tensile testing four different PWR RPV was performed after irradiation and subsequent recovery treatment 450 °C for 40 h. Irradiation-induced hardening have been assessed by comparing strength ductility subsequently annealed samples with unirradiated reference all steel. resulted a significant yield (~75–89%) ultimate tensile (~78–96%) steels. This study proves that substantial irradiation-induced (up ~389 MPa) observed containing Ni Mn contents can still be recovered using treatment. No influence on Microscopy analyses these understand underlying damage mechanisms are planned near future.