FEBEX In-Situ Test: Preliminary Results of the Geochemical Characterization of the Metal/Bentonite Interface
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- 作者：Elena Torres ; elena.torres@ciemat.es ; Marí ; a J. Turrero ; Daniel Moreno ; Lorenzo Sá ; nchez ; Antonio Garraló ; n
- 关键词：radioactive waste disposal ; in situ test ; dismantling ; bentonite alteration ; iron ; geochemical gradients
- 刊名：Procedia Earth and Planetary Science
- 出版年：2017
- 出版时间：2017
- 年：2017
- 卷：17
- 期：Complete
- 页码：802-805
- 全文大小：380 K
- 卷排序：17
文摘
The in situ Full-scale Engineered Barrier Experiment (FEBEX) in Grimsel (Switzerland) has been dismantled after 18 years of operation. The test was designed to demonstrate the feasibility of manufacturing and assembling the engineered barriers and to monitor the performance of a real-scale Engineered Barrier System (EBS) in the long-term. Samples of bentonite in contact with different metallic components were collected during dismantling activities to examine the alteration processes induced in the bentonite by the corrosion of metals. The samples cover different positions of the bentonite barrier to check the effect of saturation and hydration on the geochemical processes observed. This paper presents the results on the soluble ions, exchangeable cations, CEC, adsorbed iron and mineralogy in three samples of bentonite located at the vicinity of the heater and another one near the contact of the bentonite with the granite. According to results obtained, temperature and hydration seems to have a significant effect on the geochemical evolution of the interface and, therefore, in the initialization of corrosion processes. Lack of available water in the surroundings of the heater seems to constrain the Fe-related alteration processes.