Seminarium KMMF "Teoria Dwoistości"

Nuclear power provides ~17% of UK electricity. Seven out of the eight civil nuclear power stations in the UK are the Advanced Gas-cooled Reactor (AGR) design. Each reactor core is 10m high with a diameter of 10m contained within a concrete pressure vessel. A reactor comprises ~3,000 cylindrical graphite bricks that are connected and stacked vertically into 250 channels. Uranium fuel is inserted into these channels. The core provides structural integrity for housing the fuel and acts as the neutron moderator. The graphite undergoes neutron damage in the reactor’s aggressive environment, compromising reactor structural integrity. Assessment and prediction of integrity are critical to safety and planning reactor lifespan. The condition of the graphite reactor core is the major life-limiting factor for nuclear power stations. Routine inspections of the oldest AGR cores have shown significant cracks in the graphite bricks. Numerical models give EDF Energy the ability to predict if these cracks are life-limiting.Brittle crack propagation is an inherently unstable and highly nonlinear process that continues to be the subject of significant scientific attention despite decades of study. We established a new methodology and computational framework for simulating this phenomenon in the complex environment of a nuclear reactor. The research exploits Configurational Mechanics to describe crack propagation mathematically. This led to theoretical advances and new numerical methods integrated into MoFEM – an open-source finite element analysis software developed at the University of Glasgow, incorporating many of the latest advances in scientific computing.In the talk, after a brief introduction, I will focus on the Configurational (Eshelbian) Mechanics framework to model topology evolution due to crack propagation. From the first laws, I derive what is understood by the equilibrium of the crack front. Using Griffith criterion and the principle of maximal dissipation, I will derive kinematic constraints for crack area growth. The second part of the talk focus on the numerical aspect. I will conclude with some real-life examples. To attend our online seminar, please use the Zoom identificator: https://us02web.zoom.us/j/8145917621?pwd=bVVKend0SHFKNUNyUUQ4cWNRK3laZz09