Microstructural examination of reactor pressure vessel steels by positron annihilation point of view

This paper presents a comparison of commercially used German and Russian reactor pressure vessel steels from the positron annihilation spectroscopy (PAS) point of view, having in mind knowledge obtained also from other techniques from the last decades.The second generations of Russian RPV steels seems to be fully comparable with German steels and their quality enables prolongation of NPP operating lifetime over projected 40 years. The embrittlement of CrMoV steel is very low due to the dynamic recovery of radiation-induced defects at reactor operating temperatures.

► We compared several commercially used German and Russian reactor pressure vessel steels from the positron annihilation spectroscopy (PAS) point of view.
► The embrittlement of Russian type of CrMoV steel is very low due to the dynamic recovery of radiation-induced defects at reactor operating temperatures.
► The second generation of WWER-440 RPV materials with low content of impurities has proven very high stability to radiation damage at least up to a neutron dose of 2 dpa.