Structural integrity assessment of nuclear power plants, particularly regarding fatigue and fracture mechanics of metallic components, is essential for lifetime extension. To address these challenges, new methods and tools are needed.
The environmental impact on fatigue life is widely recognized and requires an environmental correction factor, in addition to classical parameters such as mean stress, temperature, cold work, and surface finish. A better understanding of these environmental effects, supported by consolidated experimental data, is necessary to improve assessment accuracy.
Vibration fatigue is a recurring issue in nuclear power plants, and more precise calculation methods are needed to better assess and prevent related failures.
What is FRACTIGUE?
The FRACTIGUE project aims to support new fatigue codification by integrating environmental effects for austenitic stainless steels and developing advanced fracture analysis tools.
Key goals include:
- validating fatigue rules through experiments and statistical analysis
- improving vibrational fatigue evaluation for small bore pipes
- assessing crack growth codification, especially under PWR conditions and extended plasticity
- validating ductile fracture methods through testing
- developing numerical methods for fatigue assessment
These efforts will strengthen safety and reliability in nuclear plant component evaluations.
The project will provide MAI members with experimental fatigue databases on vibrational fatigue and environmental effects on crack initiation and propagation. This will help to:
- Improve understanding of fatigue phenomena
- Develop new predictive models
- Strengthen existing codified rules
Regarding fracture assessment, the main benefit for end-users is gaining safety margins, allowing justification of larger defects or defects under more severe loading conditions.