The objective of this thesis is to estimate the size of the exclusion zone around a small modular reactor (SMR). The aim of such zone is to provide an atmospheric space sufficient to dilute any radioactive releases during an accident, to a level below the safe regulated radiation dose for the public. A hypothetical severe accident is considered for a generic SMR, and the whole-body radiation dose associated with the accident was estimated at various distances and reactor power levels. The results were verified against those of a more complex model for a typical CANDU reactor. The obtained results were then employed to estimate the radius of the exclusion zone, by determining the distance at which the dose is at or slightly below the permitted dose to a member of the public. The method first estimates the quantity and type of radioactive materials available for release to the environment following a nuclear accident, known as the Source Term. This thesis employed a simplified approach for estimating the Source Term, utilizing the magnitude of the fission product yields, radionuclide release fractions, and reactor thermal power. The estimated Source Term values were then used as input to an atmospheric plume dispersion model, to determine the radiation dose at various distances after dilution. The HotSpot Health Physics code was employed to estimate the radiation dose, because it is a convenient and efficient tool for the many calculations associated with the numerous radionuclides that would be released during a postulated reactor accident. In addition to the effect of atmospheric dilution of radionuclides, the thesis also examined how the size of the exclusion zone is influenced by technical regulations and standards, reactor design and safety features, and by the presence of engineered barriers. Further, this thesis presents a survey of SMR designs currently in development and a review of their unique safety features.

A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Applied Science in Industrial Systems Engineering, University of Regina. ix, 50 p.