Waste Zone Conceptual Model Effect on Predicted Radionuclide Flux from Near Surface Repository

This paper presents an investigation into how a waste zone conceptualization approach might affect the evaluated radionuclide concentration beneath a repository. The analysed system represents a concrete vault of a near surface repository where two types of waste packages (concrete containers with cemented radioactive waste) are disposed of. Three waste zone conceptual models of different levels of complexity were developed: homogeneous, layered and detailed. The investigation revealed that the highest influence is on short-lived non-sorbed radionuclides. The homogeneous conceptual model in this case is the most conservative. For long-lived radionuclides, the developed conceptual models do not make a significant difference in the predicted radionuclide release. (author)