High-value, low-volume, safety-critical metallic components in nuclear plants almost invariably contain welds. Welding is an aggressive process that causes microstructural changes in the weld and adjacent heat affected zone, develops residual stresses and structural distortion, and changes the material properties. Premature degradation in-service and unexpected failures are usually associated with welds.
Both current and next-generation nuclear plants are expected to stay in service for in excess of 60 years, and there is strong downward pressure on fabrication costs.
Multi-scale modelling has an important role to play in both optimising the state of welds on service entry, and predicting their long-term behaviour. However, such modelling requires accompanying multi-scale characterisation, mechanistic understanding, and experimental validation.
This project examines the response of a low alloy pressure vessel steel to both current arc-welding, and next-generation high-energy beam welding. It makes use of advanced microscopy, sophisticated materials testing, and residual stress measurement techniques to develop and, crucially, validate continuum and meso-scale models of the welding process in a low alloy pressure vessel steel used in the nuclear industry.
CDT name: GREENCDT
The programme is funded by EPSRC, industrial partners and participating institutions