Abstract
The Argentine Atomic Energy Commission (CNEA) is responsible for developing a nuclear waste disposal program. This program contemplates the design and construction of a facility for the final disposal of medium level radioactive waste. The waste management objective is to ensure protection to people and the environment for a period of 300 years. In order to achieve this objective, the criteria applied is the use of multiple independent and redundant barriers. The barriers that will be used in the near surface repository include, waste forms, metallic disposal containers, backfill and buffer materials, reinforced concrete vault, cover and geological medium. Since the vault and cover are major components of the engineered barriers, the durability of these concrete structures is an important aspect for the facilities integrity. In the present work, the rebar corrosion behavior of a high quality concrete prepared with sulfate resistant cement is analyzed. The influence of chloride and sulfate ions as well as concrete carbonation on the rebar corrosion process was evaluated. The purpose of the study was to evaluate the durability of reinforced concrete containers built for the final disposal of intermediate- level radioactive nuclear waste. Electrochemical non-destructive tests were performed over a period of 1000 days on concrete specimens containing rebar segments, in order to monitor the main corrosion parameters used to characterize the rebar corrosion process. The results show that the concrete under study provides a protective environment to the reinforcing steel showing low corrosion rates, and a low diffusion coefficient for both, chloride ions and carbon dioxide.
