NEUTION (Understanding transferability issues between ion and neutron-irradiated model materials – paving the way to a new generation of radiation resistant alloys) aims to: i) develop a reactor irradiation method using small-volume samples with residual radioactivity remaining below legal activity thresholds, eliminating the need for hot cells analysis; ii) apply this method to compare microstructural changes induced by neutron and ion irradiation; iii) investigate how sample thickness affects the formation and characteristics of radiation-induced defects; iv) interpret experimental results using advanced modelling techniques.