Is an Exclusion Zone Needed for a Small Modular Reactor?

Abstract

The exclusion zone radius for CANDU reactors is typically one kilometer. The aim of this zone is to dilute any radioactive releases during an accident, before reaching the public, to meet the dose acceptance criteria with consideration of other factors, such as evacuation land usage, security, etc. This paper presents a simple method for determining the whole-body dose from a hypothetical severe reactor accident at various distances and power levels. The method estimates the activity of released nuclides and models their dispersion in a plume. The results are verified against those of more complex models for a typical CANDU reactor’s generic large release. The exclusion zone radius is then estimated for a Small Modular Reactor (SMR) so that the dose in a severe accident does not exceed the dose permitted at the boundary of the exclusion zone, following a generic large release.