from the conferences organized by TANGER Ltd.
The material in nuclear reactors of the VVER 440 type and their main circulation pipes is exposed to temperatures in the range of 100-300 °C during the operating conditions, but in some nodes can be this range of temperatures exceeded. These temperature conditions are suitable for low-temperature sensitization and the microstructure sensitized in this way may be susceptible to inter-granular corrosion during long-term operation. The material 08CH18N10T that was subjected to observation was obtained from a real operation, where it was exposed to operating conditions for a long time. The microstructure of this material was compared with the microstructure of a new material of the same type that was exposed to operating temperatures in laboratory conditions. The new main circulation pipeline material is currently replacing the old one in real operation. The microstructure was evaluated based on the results from optical and transmission electron microscopy and for the identity of the secondary phases was used the selective electron diffraction. The specimens were subjected to a non-destructive corrosion test ASTM A262 method A, on the basis of which a statistical method was used to compare the percentage of attacked grain boundaries of the observed materials.
Keywords: Austenitic stainless steel, corrosion, precipitation, sensitization© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.