Best Practices for Fracture Mechanics Based Testing for Environmentally Assisted Cracking in Advanced Reactor Applications

Abstract

Assessing environmentally assisted cracking (EAC) in advanced reactor environments offers challenges and opportunities relative to light water reactor practice. This paper presents the Kairos Power strategy to conduct fracture mechanics-based testing relevant to high temperature, molten salt cooled reactors. Key features of the Kairos Power testing strategy include: (1) test systems that capture key operating features of the reactor, (2) K-controlled, steady-state, single condition tests to help ensure characterization of the relevant crack driving force (e.g. the C*-integral), (3) conducting complementary tests in air to differentiate creep crack growth from EAC and (4) design features to ensure Operator safety. Initial results for 316H stainless steel at 650°C validate this approach and highlight some of the complications when testing in a regime where time dependent fracture mechanics applies.