Fabian Margit, Czompoly Otto, Tolnai Istvan, De Windt Laurent
Centre for Energy Research, Konkoly Thege st 29-33, 1121, Budapest, Hungary.
Centre for Geosciences and Geoengineering, Mines Paris, PSL University, 77300, Fontainebleau, France.
Sci Rep. 2023 Sep 16;13(1):15372. doi: 10.1038/s41598-023-42645-6.
Deep geological repository is widely considered as the preferred solution for the final disposal of high-level radioactive waste. Investigation representative of the Hungarian disposal concept was conducted using mock-up diffusion cells to study the chemical changes of S235JR carbon steel canister and CEM II/B concrete of the Public Limited Company for Radioactive Waste Management under anerobic and water saturated conditions at 80 °C. Micro-Raman, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, fluid and potentiometric analysis were performed over a period of 12 months. The analysis was supported by thermodynamic and reactive transport modeling using the HYTEC code. The findings revealed that a uniform corrosion process occurred, leading to rapid passivation of the C-steel with magnetite as the primary corrosion product. Modeling demonstrated that the increase in temperature to 80 °C and the chemical evolution of the concrete did not significantly affect the corrosion passivation process. Although the formation of Fe-siliceous hydrogarnets is thermodynamically possible at 80 °C, it did not jeopardize magnetite passivation. The results show that the passivation of the containers occurred under the test conditions and this is a promising result for further investigations.
深层地质处置库被广泛认为是高放废物最终处置的首选方案。采用模拟扩散池对匈牙利处置概念的代表性样本进行了研究，以考察放射性废物管理股份有限公司的S235JR碳钢罐和CEM II/B混凝土在80°C厌氧和水饱和条件下的化学变化。在12个月的时间里进行了显微拉曼光谱、扫描电子显微镜-能量色散X射线光谱、流体和电位分析。该分析得到了使用HYTEC代码进行的热力学和反应输运建模的支持。研究结果表明，发生了均匀腐蚀过程，导致碳钢迅速钝化，主要腐蚀产物为磁铁矿。建模表明，温度升高到80°C以及混凝土的化学演化对腐蚀钝化过程没有显著影响。虽然在80°C下热力学上可能形成铁硅质水石榴石，但这并没有危及磁铁矿的钝化。结果表明，在试验条件下容器发生了钝化，这对于进一步研究来说是一个很有前景的结果。
