Diffusion of corrosion agents through an engineered barrier system

腐蚀剂通过工程屏障系统扩散

• 批准号: 514187-2017
• 负责人: Krol, Magdalena
• 金额: $ 6.74万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=618173
• 关键词: Diffusion; corrosion; agents; through; engineered

Many countries are studying long-term solutions for safe storage of used nuclear fuel. One such solution,selected by the Canadian Nuclear Waste Management Organization (NWMO), is the use of deep geologicalrepositories (DGRs) that would be located several hundred metres below ground level. DGRs would store usedfuel canisters (UFCs) surrounded by an engineered barrier system (EBS), composed of copper coatings to act asa corrosion barrier and highly compacted bentonite (HCB) that surrounds the UFC. HCB swells upon contactwith water and can therefore seal gaps within the repository and provide a moderately thermally conductivemedium. It can also slow groundwater infiltration and retard the movement of radionuclides in the event of aUFC breach. In addition, the HCB can suppress microbial activity near the container by restricting space andwater availability to microbes that may be present. However, diffusion of sulphide can result in microbiallyinfluenced corrosion (MIC), potentially causing early failure of the barrier. The proposed research willinvestigate the factors that can affect sulfide diffusion to the UFC surface. The project will include diffusionexperiments performed under a range of potential repository conditions, based on current Canadian designspecifications and predictions for DGR conditions. The results of the experimental studies will be used tofurther expand and validate a three-dimensional computer model. The resulting model will be capable ofparametric studies to refine and optimize the design of the Canadian DGR. The results of this study willidentify key parameters that may result in higher corrosion rates, leading to a refinement of NWMO's EBSdesign and providing Canadians with a safe and sustainable method of used nuclear fuel disposal. This studywill address significant scientific questions regarding diffusion of corrosive species through the engineeredbarrier system in sub-surface environments, and will also enhance predictive modelling capabilities tostrengthen the sponsoring agency's long-term DGR design/performance criteria.

许多国家正在研究安全储存废核燃料的长期解决方案。加拿大核废物管理组织（NWMO）选择的解决方案之一是使用位于地面以下数百米的深层地质处置库（DGR）。 DGR 将存储用过的燃料罐 (UFC)，周围环绕着工程屏障系统 (EBS)，该系统由充当腐蚀屏障的铜涂层和围绕 UFC 的高度压实膨润土 (HCB) 组成。 HCB 与水接触后会膨胀，因此可以密封储存库内的间隙并提供适度的导热介质。它还可以减缓地下水渗透，并在 UFC 破裂时延缓放射性核素的移动。此外，HCB 还可以通过限制可能存在的微生物的空间和水的可用性来抑制容器附近的微生物活动。然而，硫化物的扩散会导致微生物影响的腐蚀（MIC），可能导致屏障的早期失效。拟议的研究将调查影响硫化物扩散到 UFC 表面的因素。该项目将包括根据当前加拿大设计规范和 DGR 条件预测，在一系列潜在储存库条件下进行的扩散实验。实验研究的结果将用于进一步扩展和验证三维计算机模型。由此产生的模型将能够进行参数研究，以完善和优化加拿大 DGR 的设计。这项研究的结果将确定可能导致更高腐蚀率的关键参数，从而改进 NWMO 的 EBS 设计，并为加拿大人提供一种安全且可持续的废核燃料处置方法。这项研究将解决有关腐蚀性物质通过地下环境中工程屏障系统扩散的重大科学问题，还将增强预测建模能力，以加强赞助机构的长期 DGR 设计/性能标准。