Abstract
This thesis is part of the issue of management of ultimate waste generated by the civil nuclear power industry. In the prospect of a deep geological disposal, this high level waste is confined in a borosilicate glass matrix in order to control and limit its impact on the environment. The main challenge is to predict the long-term behavior of these nuclear glasses to guarantee the safety of the disposal solution. For this purpose, two main factors must be considered: the complex self-irradiation of the glass resulting from the radioactive elements contained in the vitreous matrix and the interaction with the surrounding environment, in particular the water from the disposal site which should reach the glass canister after several thousand years. Recent studies on this subject have contributed to assess the respective effects of these solicitations. To go further in understanding the long-term behavior of nuclear glasses, in this work, nuclear glasses are represented by a glass having a simplified composition chosen by the international community, the ISG glass (for International Simple Glass). This glass is subjected to various external irradiation conditions simulating the main sources of irradiation of a real radioactive glass (alpha and beta decay doses, gamma transitions), then it is altered by water. In order to approach the real conditions of aging of nuclear glasses, this study takes into account the effects of synergies between the different contributions related to irradiation and the reactivity of the glass under water. To achieve this, the impact of pre-irradiation scenarios on the structure and properties of the ISG glass was first studied. Once these glasses were characterized, they were then altered under different conditions in order to study the alteration of these glasses in the first moments and over the long term. Then, glass alteration was monitored by analysing both the leachate and the altered samples in order to as sess the impact of these pre-irradiations on the glass alteration behavior.