Given that Small Modular Reactors (SMRs) are emerging as a key innovation in nuclear energy due to their compact design, modular fabrication, and enhanced safety features, they offer the potential to reduce radionuclide inventories and, consequently, to justify smaller Emergency Planning Zones (EPZs) compared to conventional nuclear reactors. The present study addresses the assessment of off-site radiological consequences from postulated accidents in SMRs. The main objective of this thesis is to determine potential radiological doses. This is performed considering site-specific conditions representative of the Belgian Nuclear Research Centre (SCK CEN) in Mol, Belgium. This work focuses on two representative SMR designs: a reference Pressurized Water Reactor (PWR), the NuScale Power Module, and a Lead-cooled Fast Reactor (LFR), ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator).