On January 16th, Andra submitted the construction license application (DAC) of Cigeo, the French project for the deep geological disposal facility for the most highly radioactive waste. Over an operating period of about 100 years, this repository will receive about 10,000 m3 of vitrified long-lived high-level waste from the reprocessing of spent nuclear fuel, mainly from the “La Hague” plant. This is a crucial step marking both a culmination and a new start for the project. First and foremost, it is the result of 30 years of progressive development under regular evaluation and a process of iteration between knowledge acquisition, design and safety assessment. Over time, the scientific and technological aspects of the project have been refined into well‑defined design principles and a robust safety demonstration.

This presentation illustrates some key steps of this iterative process for the high-level vitrified waste disposal cells. It highlights the link between the evolution of environmental conditions in vitrified waste disposal cells (temperature, hydraulics, geochemistry, geomechanics…) and the long-term behavior of the vitrified waste. It specifies the remaining R&D topics to support the design of the disposal cell and to consolidate the robustness of the safety demonstration, drawing on the experience of performance and safety assessments.