Effect of high-temperature water environment on the fracture behaviour of low-alloy RPV steels

The structural integrity of the reactor pressure vessel (RPV) of light water reactors (LWR) is of utmost importance regarding operation safety and lifetime. The fracture behaviour of low-alloy RPV steels with different DSA (dynamic strain aging) & EAC (environmental assisted cracking) susceptibilities and microstructures (base metal, simulated weld coarse grain heat affected zone) in simulated LWR environments was evaluated by elastic plastic fracture mechanics (EPFM) tests with different strain rates and by metallo- and fractographic post-test observations. These tests revealed some evidences of high-temperature water and hydrogen effects on the fracture behaviour and potential synergies with DSA and EAC