Fast efficient modelling of hydride reorientation

点击翻译按钮获取中文摘要

A mechanistic understanding of hydrogen diffusion and hydride precipitation underpins the prediction of delayed hydride cracking (DHC) in zirconium alloy nuclear fuel cladding. DHC presents a problem to service life of nuclear fuel pins and integrity of pins in waste storage. This project builds upon a study by a previous student to use analytical stress fields, in combination with discrete dislocations, to model a millimetre scale area but with single micron accuracy, including grain orientation effects, but in seconds rather than hours (as per state-of-the-art phase field models). The new modelling approach is being examined by Rolls-Royce for incorporation into their research strategy and has gained significant interest in the US via the Department of Energy (DOE) and Electric Power Research Institute (EPRI). Whilst showing potential, the model captures only some of the relevant phenomena. This project, will couple to the existing framework, other crucial aspects of DHC, including grain boundary compatibility stresses, intergranular versus transgranular hydride precipitation; further enhancement of the coupling of atomic hydrogen diffusion to microscale hydride precipitation (to enable cooling effects to be modelled, especially thermal cycles known as ratchetting) and finally to develop visualization/image analysis tools to characterize the resultant microstructures for reorientation of hydrides producing a probabilistic model that can be used by industry.