![]() ![]() ![]() The glass alteration in the presence of clay leads to the formation of calcite and Mg-silicates at 50 ☌ in addition to apatite and powellite at 90 ☌. The glass dissolution rate up to 17 months tends towards 10⁻⁴ and 10⁻³ g m⁻² d⁻¹ at 50 and 90 ☌, respectively. Results showed that the presence of steel did not enhance the dissolution rate of the glass despite the retention of ²⁹Si released from the glass on the corrosion products. COx water was injected through the percolation cells at 120 bars (solution flow rate 0.05–0.38 mL d⁻¹). Tests were performed by using percolation cells containing glass and stainless steel sandwiched between two clay cores in two different combinations: glass/clay at 50 and 90 ☌, and glass/steel/clay/at 90 ☌. Experiments were carried out to understand the effect of near-field materials on the rate of glass dissolution and the migration of ²⁹Si in the claystone core. The leaching of ²⁹Si-doped SON68 French nuclear waste glass was investigated in Callovo-Oxfordian (COx) water in the presence of P235GH stainless steel and COx argillite. First numerical simulations performed to determine the ductile damage of a low alloy steel overpack subjected to both, general corrosion and localized mechanical loads are also presented. The mechanical studies focus on the behavior of a confined API5LX65MS steel casing (the disposal cell liner) submitted to general corrosion which governs the long term mechanical loading of the overpack. The following part of the paper is then focused on a description of the numerical simulations and corrosion tests (general corrosion, pitting and crevice corrosion, stress corrosion cracking with influence of the evolution of the water chemistry, temperature and radiolysis) performed in order to evaluate the mechanical behavior and durability of the disposal package. The design options and the manufacturing processes of the disposal package are then described in order to show how the best technologies have been selected to ensure that the leak and gas tightness of the overpack is maintained as long as possible (and at least 500 years). The horizontal steel cased disposal cell (0.7m ID micro-tunnel) inside which the disposal packages will be stored is also presented. After a brief description of HLW disposal package models, their main functions are presented (handling purposes, containment of radioactive substances, criticality hazard control, delaying water contact with vitrified matrix, etc.). In this work, the kinetics of the rust growth is discussed, on the bases of the rate of mass increase and of the composition of the rust, as a function of the climatic parameters and the oxygen content of the atmosphere.Īndra, the French national radioactive waste management agency, is in charge of studying the disposal of high-level and long-lived intermediate-level waste (HLW and ILW-LL) in a deep geological repository (aka Cigéo). Ex situ Raman spectrometric analyses indicate the formation of magnetite, maghemite and oxyhydroxides species in the 298–363 K temperature range, and for oxygen contents above 1 vol.%, whereas only Fe3O4 and γ-Fe2O3 are detected at 363 K. The experiments showed that, in the temperature under study (298–363 K), the mass increase due to the formation of oxide/hydroxide rose sharply above 70% RH, as is commonly observed at room temperatures, indicating that the phenomenon remains electrochemical in nature. The work was performed using iron samples deposited as thin films on a quartz crystal microbalance (QCM) and disposed in a climatic chamber. The purpose of this study is to examine the risks of atmospheric corrosion of steel waste canisters following their deep geological disposal in the temperature range from 303 to 363 K. ![]()
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