Integrated molecular profiling to explore the microbiology of deep geological repository components for storage of used nuclear fuel

核废料管理组织(NWMO)由《核燃料废物法》于2002年成立，负责加拿大所有使用过的核燃料的长期管理。根据国际科学共识，这需要建设一个采用多屏障系统的深层地质储存库(DGR)。拟建的DGR将建在地下约500米的稳定低渗透性围岩中，并将用过的燃料密封在镀铜碳钢旧燃料容器(UFC)内，其中碳钢提供强度，铜提供腐蚀保护。UFC将被放置在高度压实的膨润土(HCB)盒中，并储存在地下安置室。膨润土是一种低渗透性粘土，在饱和地下水时会膨胀，因此是一种很好的密封材料。为了长期稳定，对于DGR的工程和天然屏障组件来说，将地质时间范围内的微生物生长和活动降至最低是至关重要的。NSERC联盟的这项提案将涉及协调采样和分析工作，以产生对DGR组件的微生物学、可能的宿主地点以及此类系统的自然发生的地质类似物的新见解。这项拟议的研究将使用尖端微生物学和生物地球化学分析技术，从地下岩石和地下水样本中探索微生物剖面和相关的天然有机物(NOM)剖面，这是为潜在的DGR地点建立安全案例的重要一步。用于工程屏障组件中的膨润土粘土的实验工作将有助于识别微生物在预期条件下的生存能力和持久性特征。还将研究与地质储存库模拟系统有关的天然岩石和水样的微生物和NOM剖面，以更好地预测微生物的稳定性和活性。总体而言，这里提出的研究和交付成果将是建立安全案例的关键，有助于有信心地设计和实施用于永久储存加拿大高水平核废料的DGR。

Established in 2002 by the Nuclear Fuel Waste Act, the Nuclear Waste Management Organization (NWMO) is responsible for the long-term management of all of Canada's used nuclear fuel. In accordance with international scientific consensus, this requires the construction of a deep geological repository (DGR) that employs a multi-barrier system. The proposed DGR will be constructed ~500 m below ground in a stable low-permeability host rock and will seal used fuel inside copper-coated carbon steel used fuel containers (UFCs) where carbon steel provides strength and copper confers corrosion protection. The UFCs will be placed within highly compacted bentonite (HCB) boxes and stored in underground emplacement rooms. Bentonite is a low permeability clay that swells when saturated with groundwater, making it an excellent sealing material. For long-term stability, it will be critical for both the engineered and natural barrier components of a DGR to minimize microbial growth and activity over geological timeframes. This NSERC Alliance proposal will involve coordinated sampling and analysis efforts to generate new insight into the microbiology of components of a DGR, possible host sites, and naturally occurring geological analogues for such systems. The proposed research will use cutting-edge microbiology and biogeochemical analytical techniques to explore microbial profiles and associated natural organic matter (NOM) profiles from subsurface rock and groundwater samples, which is an important step toward building a safety case for a potential DGR site. Experimental work with bentonite clay that is intended for use within the engineered barrier components will help identify signatures of microbial viability and persistence under the expected conditions. Microbial and NOM profiles from naturally occurring rock and water samples associated with geological repository analogue systems will also be studied to better predict the stability and activity of microorganisms. Overall, the research and deliverables proposed here will be essential for building a safety case that help with confident design and implementation of a DGR for permanent storage of Canada's high-level nuclear waste.