Environmental effects on irradiation creep behavior of highly purified V–4Cr–4Ti alloys (NIFS-Heats) irradiated by neutrons

In order to investigate the effect of the environment on the irradiation creep properties of highly purified V–4Cr–4Ti alloys, neutron irradiation experiments with sodium-enclosed irradiation capsules in Joyo and lithium-enclosed irradiation capsules in HFIR-17J were carried out using pressurized creep tubes (PCTs). It was found that the creep strain rate exhibited a linear relationship with the effective stress up to 150 MPa at 458 and 598 °C in the Joyo irradiation experiments. For HFIR-17J irradiation at 425 °C, the creep strain rate also exhibited a linear relationship with the effective stress up to 150 MPa. The activation energy of the irradiation creep and irradiation creep stress factor were estimated to be 46 kJ/mol K and 1–2, respectively. No significant difference in the irradiation creep behavior between liquid-sodium and liquid-lithium environments could be seen.