Time-dependent fatigue reliability of main vessel steel structural components in sodium cooled fast breeder reactors

• Published in: Nuclear engineering and design 2025-03, Vol.433, p.113820, Article 113820
• Main Authors: Ghosh, Sourangshu, Kumawat, Komal, Sajish, S.D., Arul, John, Bhattacharya, Baidurya
• Format: Article
• Language: English
• Subjects: Fatigue reliability; Multiaxial loading; Seismic; Temperature dependence; Thermal transients
• ISSN: 0029-5493
• DOI: 10.1016/j.nucengdes.2024.113820

•Pool type fast breeder reactors (FBRs) have unique design features.•Components and joints in core support structure and shell are critical for safety.•These components are subjected to multiaxial fatigue loads by earthquakes and thermal transients.•Fatigue crack growth rate parameters are experimentally determined.•A time dependent fatigue reliability model is developed. Sodium cooled Fast Breeder Reactor (FBR) technology is an important constituent of India’s self-sufficiency program in power generation. The FBR designed by the Indira Gandhi Centre for Atomic Research is a pool type reactor, where the entire primary system is contained within a large main vessel supported from the top. The structural integrity of weld joints and other components that transfer the core load to the main vessel supports are important for the safety of the reactor. Apart from gravity loads, these structures are subject to random dynamic (thermal transients and seismic) loads and a harsh operating environment throughout the plant service life. This paper develops a time-dependent fatigue reliability model of components subjected to elevated temperature multiaxial loading histories expected in typical Indian FBRs. The methodology is demonstrated on a generic 316 LN stainless steel component. Experimentally determined crack growth parameters are used. A parametric study for identifying key factors affecting the reliability is conducted.