Numerical investigation on ultimate pressure capacity of a SMR containment vessel

The containment structure is a vital component ensuring the safety of nuclear power plants by preventing the release of radioactive materials under severe accident-induced conditions. As small modular reactors (SMRs) have been developing globally, steel containment vessels (CVs) have replaced conventional containment buildings and new assessment method should be established with regard to safety. In this study, ultimate pressure capacity (UPC) was assessed for the Innovative SMR (i-SMR) steel CV by using the finite element analysis software ABAQUS. Free-field areas were proposed with equations, through comparisons of UPCs at different locations. By using maximum principal, hoop, and membrane strain, the most appropriate strain parameter was suggested. Furthermore, temperature effect under the postulated severe accident-induced condition and buckling initiation pressure were assessed. The findings provide a comprehensive methodology for assessing the UPC of not only for the i-SMR but also for the advanced reactors utilizing steel CV.