Ultra-High-Performance Concrete Containments for Safer Small Modular Reactors

小型模块化反应堆(SMR)提供了更多负担得起的核能，对加拿大的低碳能源未来至关重要。然而，正如加拿大核安全委员会所强调的那样，由于缺乏SMR的经验，它们的保障和安全构成了一个重大挑战。该项目涉及与混凝土安全壳结构有关的SMR保障措施和安全措施。传统上，混凝土安全壳结构要么是预应力混凝土，要么是钢衬钢筋混凝土。然而，鉴于加拿大恶劣的天气条件，由于冻融循环或钢筋和预应力筋腐蚀而导致混凝土退化的风险增加，传统混凝土安全壳结构的安全可能受到威胁。SMR的高温和高内部压力可能会进一步加剧这些风险，特别是在事故期间。本项目提出了一种基于超高性能混凝土的新型混凝土安全壳结构。超高性能混凝土的强度超过传统混凝土的四倍，同时提供了本质上致密的微结构、非凡的韧性和对劣化剂的几乎不渗透。这些特点有利于提高混凝土安全壳结构的耐久性、辐射屏蔽性和防渗性。将开发一种优化超高性能混凝土混合料设计的新工具，同时对国内材料(钢渣和磁铁矿砂)进行定价化，以生产具有高能量吸收能力的重质、高辐射屏蔽超高性能混凝土，以抵御高内压，特别是在事故中。这项研究的预期广泛影响包括支持作为传统选择的替代方案的新型混凝土安全壳结构(具有更高的安全功能)的监管决策；促进SMR设施工作人员、环境和公众的安全；改善SMR核设施的纵深防御，以及培养加拿大在核能领域的全球领先地位。

Offering more affordable nuclear energy, small modular reactors (SMRs) are critical to Canada's low-carbon energy future. However, given the lack of experience with SMRs, their safeguards and security pose a major challenge, as emphasized by the Canadian Nuclear Safety Commission. This project addresses SMR safeguards and security pertaining to concrete containment structures. Traditionally, concrete containment structures are either pre-stressed concrete or reinforced-concrete with steel liners. However, given Canada's hostile weather conditions, the safety of conventional concrete containment structures can be jeopardized by an increased risk of concrete degradation due to freeze-and-thawing cycles or corrosion of reinforcing bars and prestressing tendons. These risks can be further exacerbated by the SMR's elevated temperatures and high internal pressure, particularly during accidents. This project proposes a new type of concrete containment structures based on ultra-high performance concrete (UHPC). UHPC exhibits a strength exceeding four times that of conventional concrete while providing an intrinsically dense microstructure, remarkable toughness, and almost impermeability to deteriorating agents. These features are advantageous for improving the robustness, radiation shielding, and leak-tightness of concrete containment structures. A new tool for optimizing UHPC mixture design will be developed while valorizing domestic materials (steel slag and magnetite sand) to produce heavy-weight, high-radiation shielding UHPC featuring high energy absorption capacity needed to resist high internal pressure, particularly during accidents. The expected pervasive impacts of this research include supporting regulatory decision making on novel concrete containment structures (with higher safety functions) as an alternative to traditional options; propelling the safety of SMR facility workers, the environment, and the public; improving the Defense-in-Depth of SMR nuclear facilities, and fostering Canada's far-front global leadership in the nuclear energy sector.