Geometry effects on the pressure-temperature limit curve of small modular reactor vessel

The reactor vessel (RV), recognized as a critical component that ensures the safety of nuclear power plants, is designed and manufactured with sufficient margins in strength and fracture toughness. With the development of small modular reactors (SMRs), RVs include transition regions characterized by geometric discontinuities that limit the application of existing evaluation methods. This study proposes adequate modeling and numerical analysis techniques tailored to assess the different geometries and better understand their impact. A suitable modeling scheme was introduced to consider specific features when evaluating postulated cracks in the RV. Fracture mechanics evaluations using the finite element method were also conducted to examine accurately the cracks and their associated risks. The results from each finite element analysis were utilized to develop pressure-temperature limit curves, providing insight into the operational range of a developing SMR. This framework addresses the unique challenges in RV design and enhances the safety and reliability of SMR operations.