Integrity analysis of a reactor pressure vessel subjected to pressurized thermal shocks by considering constraint effect

• Linear elastic analysis leads to a more conservative result.
• Both deep and surface points of the crack tip should be considered in the analysis.
• During the MLOCA transient, constraint loss occurs for the shallow crack.
• Safety margin of the RPV is increased based on the K–T approach.

The integrity analysis of a reactor pressure vessel subjected to pressurized thermal shocks is performed. Linear elastic analysis leads to a more conservative result than the elastic–plastic analysis if the warm prestressing effect is not considered. The stress intensity factor for the deepest point of a surface crack front is not always larger than that for a surface point, indicating that both the deepest and surface points of the crack front should be considered. The safety margin of the reactor pressure vessel is larger based on the K–T approach than that only based on a K approach.