• Garcia, D.
• Henocq, P.
• Altmaier, Marcus
• Vandenborre, J.
• Missana, T.
• Mace, N.
• Ricard, D.

Abstract

The CORI (Cement-Organic-Radionuclide-Interactions) Workpackage integrated into EURAD (EURAD – European Joint Programme on Radioactive Waste Management, https://www.ejp-eurad.eu) performs research to improve the knowledge on the organic release issues which can accelerate the radionuclide migration in the context of the post closure phase of geological repositories for ILW and LLW/VLLW including surface/shallow disposal. The R&D in CORI extends the current state-of-the-art and will contribute to optimize disposal solutions and consider questions of regulatory concern. CORI results will help member states to further develop their national R&D programs and support programs at an early implementation stage.CORI research addresses topics in the context of cement-organics-radionuclides-interactions. Organic materials are present in some nuclear waste and as admixtures in cement-based materials and can potentially influence the performance of a geological disposal system, especially in the context of low and intermediate level waste disposal. The potential effect of organic molecules is related to the formation of complexes in solution with some radionuclides of interest (actinides + lanthanides) which can (i) increase radionuclide solubility and (ii) decrease radionuclide sorption. Organic substances require special attention since a significant quantity exists in the waste and in the cementitious materials, with a large degree of chemical diversity. Cement-based materials will be degraded with time, leading to specific alkaline pH conditions under which the organics can degrade, thus increasing their impact on repository performance. CORI has prepared a State-of-the-Art document which gives an introduction to the main research topics targeted in CORI (available at: https://www.ejp-eurad.eu/publications/eurad-deliverable-31-cori-sota-cement-organic-radionuclide-interactions-content-lilw).The three R&D Tasks in CORI shortly summarized in this contribution are:Organic Degradation. Focus is on the characterization of soluble organic species generated by radio-lytic and hydrolytic degradation of selected organics (PVC, cellulose, resins, superplasticizers). Stud-ies also include the analysis of degradation and stability of small organic molecules such as carboxylic acids and the determination of degradation rates.Organic-Cement-Interactions. Studies focus on investigating the mobility of selected organic mole-cules in cement-based materials. Mobility of organic molecules includes sorption and transport proper-ties. Organics will also include small 14C bearing molecules as identified in the EC EURATOM project CAST. Both retention on individual cement phases and cementitious systems are investigated.Radionuclide-Organic-Cement-Interactions. Radionuclide migration processes are studied in the ternary system. The role of organic molecules on the transfer properties of radionuclides are investigated through sorption and transport experiments. Selected radionuclides cover a range of chemical characteristics and redox states relevant for conditions in L/ILW disposal.This contribution will provide information on how and where to get more detailed technical information on the work performed in EURAD-CORI as well as integrated summary information on main results, and announce forthcoming dissemination activities organized in EURAD-CORI.Acknowledgments: The EURAD-CORI project leading to this application has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 847593.

Topics

• impedance spectroscopy
• surface
• phase
• mobility
• experiment
• cement
• cellulose
• resin
• Lanthanide
• carboxylic acid
• infrared emission spectroscopy
• Actinide