Simon has a background in nuclear fuel materials and materials behaviour in extreme environments. Much of his work has focused on understanding materials by combining the use of predictive modelling techniques and experiment.

Simon has grown a team of simulators and experimental scientists at Bangor University, predicting materials behaviour whilst coupling it with experimental analysis and synthesis relevant to the nuclear and space industries. He is a principal investigator in the National Nuclear User Facility (2a) program at the university to build a nuclear materials user facility and lead a team of researchers performing research to reduce uncertainties in the nuclear industry - eMEANSS.