LOMIR: Long-Term Monitoring of C-14 Compounds Released During Corrosion of Irradiated Metal
The LOng-term Monitoring of C-14 compounds released during corrosion of IRradiated metal (LOMIR) project is a IGD-TP project which supports the continuation of the corrosion experiment focused on irradiated steel in alkaline anoxic conditions at PSI initiated during the CAST project. The experimental outcomes will support the safety assessment for a geological repository of radioactive waste.
Project Dates: 1/01/2022 – 31/12/2024
Project Status: Ongoing
Project Website: N/A
Carbon-14 is a dose-determining radionuclide released during the corrosion of irradiated steel in a repository environment. Knowledge of the chemical forms of the 14C-bearing carbon compounds released during corrosion in highly alkaline anoxic conditions and the relation between the 14C release and steel corrosion rates is required to support safety assessments for a cement-based repository.
The CAST project addressed the release mechanisms of carbon-14 from radioactive waste materials under geological disposal facility conditions. The LOMIR project continues the steel corrosion experiment initiated in May 2016 by the Laboratory for Waste Management (LES) at the Paul Scherrer Institute (PSI) in the framework of the CAST project.
The corrosion experiment in question focuses on two activated ~1 g steel nut specimens provided by Gösgen nuclear power plant (KKG). The specimens are mounted in a gas-tight reactor and immersed in artificial cement porewater (pH = 12.5) and have a well characterised 14C inventory. The LOMIR project supports a continuation of the sampling campaign for this experiment over the three years of the project.
The overall objective of the LOMIR project is to extend the duration of the PSI irradiated steel corrosion experiment for a further three years to provide essential information on 14C speciation in support of safety assessments for deep geological repositories. The specific objectives of the project are:
- to test the hypothesis of an increase in the concentrations of 14C-bearing gaseous compounds driven by progressing corrosion of irradiated steel;
- to quantify the ratio between 14C carried by gaseous species and 14C carried by water-soluble organic and inorganic carbon compounds with time;
- to relate the release of 14C-containing carbon compounds to the corrosion process (production of H2), allowing in a longer term to determine the 14C production in the repository based on the corrosion rate of steels; and,
- to quantify the retention of 60Co during the corrosion of steel.