| Abstract [eng] |
Radioactive waste is generated due to modern human activities mainly from the energy sector and various medical applications. As such, this dangerous class of waste must be properly managed and disposed of. One of the most common methods of radioactive waste conditioning is cementation in a concrete matrix and disposal in repositories with appropriate engineered barrier system to prevent radionuclide leaching into the surrounding environment. Naturally, concrete slowly degrades as it is exposed to various environmental conditions such an agressive chemical environment and water flow through the material. This requires for a thorough investigation on the potential effects of concrete degradation on the capability to keep the radionuclides retained in the concrete. This work is going to investigate how different environmental conditions could affect concrete alteration and consequently radionuclide release from the repository. To achieve this, 3 seperate cases of different water (rainwater, rainwater with additional CO2 partial pressure and groundwater) flow through the engineered barriers and waste matrix, and it‘s impact on the capability of the bottom concrete barrier to retain radionuclides and prevent their leaching out into the environmet are investigated. Addtionally, a case was modelled when the sorption value was selected regardless of the chemical evolution in the local environment. This was done to create a benchmark case for comparison. Relative radionuclide flux out of the bottom barrier into the environment was compared between each case, it was found, that the highest radionuclide flux was in the case with groundwater flow causing degradation of concrete barriers. |
