Establishing an open, systems level technical basis in determining the SMR emergency planning zone (EPZ)

小型模块化反应堆(SMR)的应急规划区(EPZ)可以比目前在加拿大和全球运行的传统大型反应堆设计更小(在规模上)。SMR的出口加工区在技术上取决于其“设计中的安全”；也就是说，集成的被动和固有安全功能预计将减少意外事故的可能性，这些事故越来越小或通过设计消除。SMR也有能力减轻设计扩展条件带来的后果。与现有的遗留设计相比，人们期望有技术基础来证实出口加工区，而不是由主题专家定义的原始建议(具有足够的安全边际)。这项拟议的研究在系统层面上调查了具有被动和固有设计特征(包括深度防御)的参考SMR的设计中的安全性，使得对其放射性库存的非现场释放--所谓的源项--的评估很小，并构成了确定其非现场释放机制的基础。这为出口加工区奠定了技术基础。在这样做的过程中，需要一个参考SMR，因为许多初创企业的设计都受到商业保护(详细)。然而，小概率事件的时间演化预计将取决于设计。此外，由于SMR将用于非常规和/或偏远地点，因此非常规威胁(外部、电力损失等)的范围。需要重新评估。也就是说，相对于新的申请，现有出口加工区和相关疏散计划中嵌入的保守主义也需要审查。经修订的界定出口加工区的技术基础有助于加拿大和全球核知识库，并有助于统一监管。最后，通过传统出版物和现有社交媒体平台，对所有包容性利益攸关方进行知识分享和培训，促进核能的发展，并提高对核能和辐射科学观念的接受和理解程度。

The emergency planning zone (EPZ) of a Small Modular Reactor (SMR) can be smaller (in size) than traditional larger, reactor designs that are currently operating in Canada and globally. The EPZ of SMR technically depends on its "safety-in-design"; that is, integrated passive and inherent safety features are expected to reduce the probability of unanticipated accidents to be increasingly small or eliminated by design. The SMR's ability to mitigate consequences from design extension conditions is also expected. Compared to existing legacy designs, one expects a technical basis to substantiate the EPZ, rather than original recommendations (with sufficient safety margins), defined by subject matter experts. The proposed research investigates at the system level, safety-in-design of a reference SMR with passive and inherent design features (defense in depth included) such that assessment of off-site release of its radioactive inventory - the so-called source term is small, and forms the basis of defining its off-site release mechanism. This establishes the technical basis of the EPZ. In so doing, there is a need for a reference SMR, since many start-up designs are commercially protected (in detail). Yet the time evolution of low probability events is expected to be design-dependent. Further, since SMR will be utilized in unconventional and/or remote locations, the spectrum of unconventional threats (external, loss of electrical power etc.) needs re-evaluation. That is, the conservatism embedded in existing EPZ and linked evacuation plans also need review, relative to new applications. A revised, technical basis of defining the EPZ contributes to the Canadian and global nuclear knowledge base and contributes to regulatory harmonization. Finally, knowledge sharing and training of all inclusive stakeholders, via both traditional publications and existing social media platforms, advance nuclear energy, and enhance the level of acceptance and understanding of perceptions regarding nuclear energy and radiation science.