Uranium deposits: Natural analogues for radioactive waste repositories

在世界范围内，到2030年将有大约500个核反应堆运行，这将导致全球核能发电量增加66%。为了在竞争日益激烈的采矿和能源勘探市场中保持领先地位，加拿大及其工业需要在制定核废料处理战略方面采取领导地位。大多数使用过核燃料的国家都认为，最安全的方法是将这种废物处置在一个深层地质处置库（DGR）中，而安全处置高放核废料需要在DGR中封存至少100万年。长期安全评估模式所要求的很长的时间框架（例如100万年）是在长期安全评估模式中处置自然资源所涉及的比较困难的概念之一。这远远超出了在实验环境中可以考虑的任何事情。铀矿床可以提供关于放射性废物形式和放射性废物贮存库性能的重要资料，因为铀矿（UO2+X）是大多数铀矿床中最丰富的含铀矿物，在许多方面与UNF中的UO2相似。我们建议研究承载特定矿床的地质环境，这些矿床可以作为重要的自然实验室，在非常大的空间（纳米到公里）和时间尺度（数千到数百万年）上研究铀和其他放射性核素。这项拟议的研究汇集了来自马尼托巴大学、加拿大核安全委员会（CNSC）和Cameco公司的地球科学家。这项工作将为三名博士生和几名本科生研究助理提供培训。这种伙伴关系的主要潜在结果和影响将是表明自然类似物（例如铀矿床）可以补充DGR性能的数值模拟数据。我们将使用在地质时间尺度上形成的系统的定量数据，这些系统在数百万到数十亿年的时间里保持稳定，从而为DGR概念的安全性提供更多的信心。

Worldwide, there will be ~500 nuclear reactors operating by 2030, which will result in a 66% increase in global nuclear power generation. To remain at the forefront of an ever-competitive mining and energy exploration market, Canada and its industries need to adopt a leadership position in the development of strategies for nuclear waste disposal. Most countries with used nuclear fuel (UNF) agree that the safest way is to dispose of this waste in a deep geological repository (DGR) and that safe disposal of high-level nuclear waste (HLNW) requires containment in the DGR for at least 1 million years. One of the more difficult concepts involved in the disposal of UNF in DGRs are the very long time frames (e.g., 1 million years) required by the long-term safety assessment models. This is well beyond anything that can be considered in an experimental setting. Uranium deposits can provide important information on the performance of radioactive waste forms and radioactive waste repositories because uraninite (UO2+X), the most abundant uranium-bearing mineral in most uranium deposits, is similar in many ways to the UO2 in UNF. We propose to study the geological environments that host specific deposits, which can serve as important natural laboratories in which to study uranium and other radionuclides over very large spatial (nanometers to kilometers) and temporal scales (thousands to millions of years). The proposed research brings together geoscientists from the University of Manitoba, the Canadian Nuclear Safety Commission (CNSC) and Cameco Corp. This work will provide training for three PhD students and several undergraduate research assistants. The major potential outcome and impact of this partnership will be to show that natural analogues (e.g., uranium deposits) can complement numerical modeling data for DGR performance. We will use quantitative data from systems that formed over geological time-scales, and that have remained stable for millions to billions of years, thus providing more confidence in the safety case for the DGR concept.