Estimation of radionuclide activity release from near surface disposal repository for a hypothetical research reactor in Saudi Arabia

Abstract

Objectives: The purpose of this study is to estimate the activity release from near surface disposal repository for a hypothetical open pool light-water research reactor (OP-LWR) in the Riyadh region, Saudi Arabia. Methods: mathematical model was used to model six cement barriers near surface disposal repository. Water infiltration into the repository and into the radioactive waste is assumed to be the main cause of activity release into the environment. The hydraulic conductivity, specific mass, the porosity of the cement, and the local geosphere were considered, as well as the expected radioactive waste inventory produced by this reactor. Results: The results show that there is a direct proportionality between distribution coefficient, retardation factor, and the mean time to collapse (MTTC). Also, the results show that nickel has the highest mean time to collapse among all the other radionuclides in the proposed model. The highest activity release in the biosphere was found to be 1.1×104 Bq for Tc-99 after 1300 years. Conclusions: The impact of the radiological behavior of each selected radionuclide enabled finding the effect on the repository performance.

Keywords

• Radioactive waste
• Near surface disposal
• Safety assessment