Thermal Behavior of Long-Lived Intermediate-Level Radioactive Waste in ICEDA Storage Unit

Activated Long-Lived Intermediate-Level metallic radioactive Waste (LL-ILW) from dismantled or in operation French nuclear power plants are conditioned since 2021 in a new EDF facility named ICEDA.After conditioning, packages with LL-ILW are transferred to large halls to be stored during decades before ultimate 500 m underground geological disposal.To control the risk of Delayed Ettringite Formation (DEF) in the packages, core temperature of the packages must stay below 65C under normal storage conditions.This paper focuses on numerical studies which evaluate the maximum temperature evolution within the packages over time, considering conduction, radiation and convection.Computations show that the core temperature in packages always stays below 65C, even during the remarkable heatwave that occurred in 2003.