Diversity and potential activity of microorganisms present in natural clay and bentonite: Key components of deep geological repositories for used nuclear fuel

天然粘土和膨润土中存在的微生物的多样性和潜在活性：废核燃料深层地质处置库的关键组成部分

• 批准号: 446702-2012
• 负责人: Korber, Darren
• 金额: $ 10.2万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=597062
• 关键词: Diversity; potential; activity; microorganisms; present

Agencies responsible for used nuclear fuel management have selected deep underground storage in engineered repositories in either crystalline or sedimentary rock formations as a safe, long-term solution (100,000 to 1,000,000 years) to the growing used fuel inventory. Over such long time frames, potential exists for the metabolic activities of either indigenous or introduced microbes to impact the repository integrity (e.g., by corroding fuel canisters via sulphide production, or by producing gases that could pressurize the repository and cause fractures in the clay barrier). As well, recent studies examining the suitability of 170 million year-old sedimentary deposits at Mont Terri, Switzerland, as a host rock formation revealed the presence of very low numbers of a variety of microbes, including those with potential sulphate reducing capabilities, and when a source of electron donors was provided, these numbers increased significantly. The significance of these findings is not yet certain; however, technology-transfers applicable to the Canadian deep geological repositories (DGR) concept are anticipated. The proposed research will investigate various scenarios whereby microorganisms may impact key components of DGR for used nuclear fuel, including the applied and evolutionary significance of microbial populations harboured in ancient clays like the Mont Terri formation, as well as transformation of the repository atmosphere from an oxidizing to reducing state. Model systems simulating repository conditions will help to evaluate the performance of engineered processes and conditions in terms of the growth and activity of key microorganisms, and in particular, the extent to which corrosive and metabolic intermediates are formed. The potential for interfaces between the various engineered barrier system components to provide refuges for biofilm formation with enhanced metabolic activity is also a key goal. Such knowledge is important to ensure that Canadian DGRs are engineered to mitigate microbial effects that may occur over the expected repository life cycle, and to aid in the development of predictive computer models that strengthen Canada's long-term DGR design and performance criteria.

负责乏核燃料管理的机构已选择在结晶岩层或沉积岩层中的工程处置库中进行深层地下储存，作为对不断增长的乏燃料库存的安全、长期（10万至100万年）解决办法。在如此长的时间范围内，土著或引入的微生物的代谢活动有可能影响储存库的完整性（例如，通过产生硫化物腐蚀燃料罐，或通过产生可能给处置库加压并导致粘土屏障破裂的气体）。此外，最近的研究检查了瑞士Mont Terri的1.7亿年沉积矿床作为宿主岩层的适用性，发现存在非常低数量的各种微生物，包括具有潜在硫酸盐还原能力的微生物，当提供电子供体来源时，这些数量显着增加。这些发现的重要性尚不确定，但预计将进行适用于加拿大深层地质处置库概念的技术转让。拟议的研究将调查微生物可能影响用过核燃料的DGR关键成分的各种情况，包括Mont Terri地层等古老粘土中所含微生物种群的应用和进化意义，以及储存库气氛从氧化状态向还原状态的转变。模拟储存库条件的模型系统将有助于评估工程工艺和条件在关键微生物的生长和活动方面的性能，特别是腐蚀性和代谢中间体形成的程度。各种工程化屏障系统组件之间的界面为生物膜形成提供具有增强的代谢活性的避难所的潜力也是一个关键目标。这些知识对于确保加拿大的发电厂经过设计，以减轻在预期的处置库生命周期内可能发生的微生物影响，以及帮助开发预测性计算机模型，加强加拿大的长期发电厂设计和性能标准，都是非常重要的。