from the conferences organized by TANGER Ltd.
The long-term global trend in energy consumption indicates that the gradual shutdown of nuclear power units after reaching their planned service life may increase the risk of power outages. One effective way to mitigate this risk is to extend the operation of nuclear units beyond their originally designed lifetime. A crucial prerequisite for reliable long-term operation is a detailed understanding of degradation processes occurring in structural materials, particularly microstructural changes induced by prolonged thermal exposure and the associated changes in the mechanical and physical properties of nuclear power plant materials. The present study focuses on the analysis of secondary phase precipitation processes in austenitic steel 08CH18N10T, which has been exposed to real operating conditions for 28 years. The results were systematically compared with those obtained for a reference, non-operated material in order to identify possible differences in the extent and character of precipitation. Experimental observations performed using transmission electron microscopy (TEM) were complemented by quantitative statistical analysis of microstructural parameters. The obtained results indicate a high degree of microstructural stability of the investigated steel even after prolonged thermal exposure. No significant differences in either the nature or the amount of precipitates were observed between the operated and reference materials, confirming the material’s good resistance to long-term thermal ageing and supporting its suitability for extended operation of nuclear facilities.
Keywords: Austenitic steel 08CH18N10T, Nuclear power plant materials, Long-term thermal ageing, Secondary phase precipitation© 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.