Effects of proton irradiation on Chinese domestic RPV steels by variable energy positron annihilation spectroscopy

The effects of proton irradiation on Chinese domestic reactor pressure vessel (RPV) A508-3 steels have been investigated by variable energy positron annihilation spectroscopy. The samples were irradiated using 110 keV protons at doses ranging from 0.2 to 2.0 ×10¹⁷ cm⁻² at room temperature. Defect profiles were analyzed by measuring the S parameter as a function of incident positron energy from 0.25 to 26keV, corresponding to mean depths of up to ~940nm. It is interesting to note that the S-parameter increases rapidly with increasing dose, which implies that matrix damage has a direct relation to dose-dependent effects in microstructural evolution.