Effect of V shape notch on stress analysis of nuclear graphite component for liquid molten salt reactor

Background: Nuclear graphite has served as neutron moderator, reflector and structural material in the liquid molten salt reactor (MSR) due to its excellent irradiation performance and mechanical properties at high temperature. During the life time of reactors, the properties of nuclear graphite will be changed due to the irradiation damage. Purpose: The aim is to study the effect of V-shape notch on stress analysis of nuclear graphite component for liquid MSR.Methods: A user-defined material model (UMAT) was used to model the irradiation behavior of nuclear graphite component. The finite element method was used to develop numerical models for the stress analysis of nuclear graphite component. Results and Conclusion: The stress of nuclear graphite component increases as the irradiation gradient. What's more, the stress results of nuclear graphite component without crack and with V-shape crack are different. In the absence of a V-shape crack, the fracture position of the square-shaped graphite component may occur at the center of the structure. In the case of having a V-shape crack, the crack propagation may occur near the crack tip of the nuclear graphite component, which may cause fracture failure of the component.