Fracture propagation in nuclear graphite

Abstract

This paper presents an enhanced theoretical formulation and associated computational framework for brittle fracture in nuclear graphite within the context of configurational mechanics. A new condition for crack front equilibrium is exploited that leads to an implicit crack propagation formulation. This paper focuses on an extension of our previous work, whereby the complex internal stress state in a nuclear reactor is the primary driver for crack propagation in individual graphite bricks. The resulting crack path is resolved as a discrete displacement discontinuity, where the material displacements of the nodes on the crack front change continuously, without the need for enrichment techniques. Performance of the formulation is demonstrated by means of a representative numerical simulation, demonstrating both accuracy and robustness.