The use of natural and archeological analogues for understanding the long-term behavior of nuclear glasses

The knowledge of the long-term behavior of nuclear waste in anticipation of ultimatedisposal in a deep geological formation is of prime importance in a waste managementstrategy. If phenomenological models have been developed to predict the long-termbehavior of these materials, validating these models remains a challenge, whenconsidering the time scale of radioactive decay of radionuclides of environmentalconcern, typically 104 –10 5 yrs. Here we show how natural or archaeological analoguesprovide critical constraints not only on the phenomenology of glass alteration and themechanisms involved, but also on the ability of experimental short-term data to predictlong-term alteration in complex environments.La connaissance du comportement a` long terme des de´ chets nucle´ aires dans les conditionsd’un stockage ge´ ologique profond est un point capital de la strate´ gie de la gestion desde´ chets. Meˆme si des mode` les phe´ nome´ nologiques permettent de pre´ dire le comporte-ment a` long terme de ces mate´ riaux, leur validation reste toujours un challenge devant ladure´ e de la radioactivite´ , typiquement de l’ordre de 104 –10 5 ans. Dans cet article, nousmontrons comment les analogues naturels et arche´ ologiques peuvent aider a` de´ finir, nonseulement la phe´ nome´ nologie et les me´ canismes implique´ s lors de l’alte´ ration des verres,mais e´ galement la capacite´ des expe´ riences de laboratoire pour pre´ dire l’alte´ ration sur lelong terme dans des environnements complexes