Zhang Qichao, Zheng Min, Huang Yanliang, Kunte Hans Joerg, Wang Xiutong, Liu Yuemiao, Zheng Chuanbo
Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2019 Mar 1;9(1):3195. doi: 10.1038/s41598-019-39751-9.
The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers. The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 10 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel.
对于处于深层地质处置中的高放废物（HLRW）容器，需要回填材料作为高放废物的第二道防线，通常选用高度压实的膨润土。随着时间的推移，地下水会渗入回填材料，在形成的电解质中导致容器建造材料的腐蚀。碳钢、钛及其合金是制造高放废物容器的潜在候选材料。当前的研究旨在评估高放废物容器在深层地质处置中数十万年的安全性，并通过电化学方法，包括开路电位（OCP）、电化学阻抗谱（EIS）和动电位极化曲线（PC）测量，估计它们在不同温度下一系列含水量的压实膨润土中的腐蚀行为，从而为未来容器制造的材料选择提供便利。分别估计了碳钢、纯钛和钛合金在中国北山地区模拟地下水渗入的高庙子压实膨润土中长达10年的预期处置期内的腐蚀速率，结果表明钛及其合金是比碳钢更可靠的用于建造高放废物容器的材料。
