Characterization of Ceramic Assemblies for Radioactive Waste Storage: Mechanical and Physico-Chemical Approach

The host laboratory is the LGP – Production Engineering Laboratory which is a multidisciplinary laboratory under the supervision of UTTOP,

LGP covers the fields of Engineering Sciences (SI) and Information and Communication Science and Technology (STIC), is organized into 2 scientific departments and 10 research groups,

Disciplines: materials, mechanics, industrial engineering, control engineering, computer science, electrical engineering, robotics, and production science and technology.

Andra, the French national agency for radioactive waste management, is responsible for finding long-term disposal solutions for various categories of radioactive waste. For the most hazardous high-level, long-lived waste, the current approach involves vitrification and storage. The long-term solution, both in France and worldwide, is deep geological disposal at a depth of 500 meters, as planned in the Cigéo project (QR code shown in attached file). Vitrified waste is placed in a stainless-steel container, which should then be inserted into a carbon steel disposal container designed to protect the waste for 500 years. However, under disposal conditions, low-carbon steel corrodes and releases hydrogen gas, complicating long-term management. Andra is therefore exploring alternative solutions, including the feasibility of manufacturing storage containers from ceramics .A 1:6 mock-up container, manufactured by Galtenco company is shown on attached file. Achieving a reliable, 500-year watertight sealing between the ceramic container body and lid requires: optimized surface design and structuring, an appropriate sealing material, and a heating system to melt this material. Understanding the physico-chemical adhesion mechanisms and evaluating mechanical performance are critical to optimizing the assembly. 

Internship Tasks:

• Literature review: Surface treatments, sealing materials, and adhesion tests applicable to dense oxide ceramics.
• Experimental studies: Evaluate parameters for optimized adhesion, including surface topology and surface reactivity, physico-chemical characterization of sealing materials, and mechanical testing using a compression shear test adapted for ceramics.
• Development of adhesion tests: Create or adapt tests to monitor interfacial cracking at the substrate/sealing material interface, as a relevant tool to study the effects of processing and water exposure. This will be coupled with modeling studies at ISAE SUPAERO.

Master’s-level student or engineer with a generalist background in Materials Science. The internship offers the opportunity to develop expertise in adhesion and surface treatments, and to gain hands-on experience with a wide range of characterization techniques, both in physico-chemistry (DSC, AFM, SEM, etc.) and mechanics.