Radiation service life of the vessel metal in operating VVÉR reactors

The current status of the prediction of radiation embrittlement of the vessel material in first- and second-generation VVER reactors is analyzed. The radiation service life of the vessel of each type of reactor is determined by factors due to the special features of the operating regime of the reactor and the chemical composition of the vessel metal. A method of monitoring the state of the material of first-generation reactor vessels is examined. The method is based on extracting and studying samples of a metal from the inner surface of the sample. The main problems of monitoring the state of the metal in VVER-440/213 and VVER-1000 vessels are analyzed. It is indicated that adjustments must be made in the normative relations which are currently used for predicting radiation embrittlement of vessel material. The most important questions concerning reactor dosimetry for VVER vessel material are illuminated.