Concrete long-term behaviour in the context of nuclear waste management: Experimental and modelling research strategy

This paper draws the main lines of the scientific strategy adopted by CEA for its R&D programme dedicated to the study of the long-term behaviour of cement-based materials in relationship with cemented nuclear waste management. In the framework of the safety assessment analysis, the long-term stability of waste package confinement and mechanical properties is required. This analysis was achieved considering the different environmental conditions - atmospheric and water saturated environments - which could affect the waste package. As far as the unsaturated phase (storage) is concerned, corrosion and air carbonation of reinforced concrete were identified as the two main phenomena which could jeopardize the waste package long-term performances. During the disposal phase, underground water leaching may significantly contribute to the chemical degradation of concrete. The understanding and modelling of phenomena and mechanisms responsible of such degradation are therefore essential to make relevant and robust long-term predictions. With this aim, CEA has developed an extended research programme to assess the long-term degradation of concrete through a chemistry-transport and mechanical coupled approach. The relevancy and validity of such a programme are discussed here.