Impact of Rainfall Patterns on a Near-Surface Radioactive Waste Disposal Facility: Climate Change and Long-Term Perspectives

With an emphasis on climate change and long-term perspectives, this study discusses the impact of rainfall patterns on the safety and integrity of near-surface radioactive waste disposal facilities in South Korea. Future rainfall and infiltration scenarios are prepared by using historical rainfall data from the Ulsan district, and the impact of rainfall patterns is modeled with COMSOL Multiphysics and GoldSim. Infiltration patterns do not significantly affect the total annual dose. However, they do have a minor impact on the total annual dose from¹²⁹I and⁹⁰Sr, contributing a smaller dose during the 1,000-year simulation period. Radionuclides such as³H,⁹⁹Tc, and¹⁴C are the primary contributors to the total annual dose, which results from the radionuclide concentrations in the saturated rock zone, regardless of the assumed cases of inputs such as waste zone permeability and saturated zone groundwater flow rate. This study provides essential insights and recommendations for the safe management and design of multi-layered cover system in radioactive waste disposal facilities, considering the evolution of long-term climatic conditions.