3. Conclusion

Operation-induced material ageing and degradation phenomena are important concerns for the safe long-term operation of LWRs. Ageing-related damage (e.g., the formation of cracks) directly impacts on plant availability and economics, e.g., due to stillstand periods and augmented periodic in-service inspections, component repairs and replacements, but may also affect plant safety and lifetime or lifetime extensions. Material ageing, lifetime management and maintenance programs were thus implemented in the last three decades and were crucial for lifetime extensions to 60 or even 80 years as well as for a high plant availability and cost effectiveness and were largely based on R&D efforts on material ageing.

The present article covered a few important materials and corrosion issues in the primary coolant circuit of BWRs like intergranular stress corrosion cracking...