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

提供更实惠的核能，小型模块化反应堆（smr）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，由于缺乏小型反应堆的经验，它们的保障和安全构成了重大挑战。该项目涉及SMR的保障措施和与混凝土安全壳结构有关的安全问题。传统上，混凝土安全壳结构要么是预应力混凝土，要么是带钢衬垫的钢筋混凝土。然而，考虑到加拿大恶劣的天气条件，由于冻融循环或钢筋和预应力筋的腐蚀，混凝土退化的风险增加，可能会危及传统混凝土围护结构的安全性。SMR的高温和高压会进一步加剧这些风险，特别是在事故发生时。本项目提出了一种基于超高性能混凝土（UHPC）的新型混凝土围护结构。UHPC的强度是传统混凝土的四倍，同时具有致密的微观结构、非凡的韧性和对变质剂几乎不渗透的特性。这些特点有利于提高混凝土安全壳结构的坚固性、辐射屏蔽性和密封性。在对国产材料（钢渣和磁铁矿砂）进行优化设计的同时，将开发一种新的优化UHPC混合料设计工具，以生产出具有高能量吸收能力的轻质、高辐射屏蔽的UHPC，该UHPC具有抵抗高内压（特别是事故期间）所需的高能量吸收能力。这项研究的预期普遍影响包括支持对新型混凝土安全壳结构（具有更高的安全功能）作为传统选择的替代方案的监管决策；促进小堆设施工作人员、环境和公众的安全；改善小型堆核设施的纵深防御，促进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.