Seismic demand assessment for SMRs considering local geotechnical characteristics and permafrost through large-scale computing and hybrid simulations

小型模块化反应堆（SMR）的功率容量从10 MW（e）到300 MW（e）。它们旨在为建造大容量核电站或电力传输的基础设施有限的偏远社区提供服务。SMR的重要部件在工厂制造，并在现场运输和安装。与大型核电厂不同的是，核电厂的选址可以根据各种地质灾害仔细选择，SMR可能需要安装在不利的地点，因为它们的设计是为传输网络有限的小型偏远社区提供服务。考虑到潜在的不利场地条件，近场土壤的非线性建模是不可避免的，以准确预测SMR设备的地震需求。本研究项目旨在开发能够实际评估SMR设备抗震要求的方法。提出了三个主要的研究任务。首先，将开发一种模拟方法，其中SMR场地的远场土壤可以使用钻孔日志数据以半自动方式建模。远场土壤将在超级计算机中进行分析。近场土壤，这可能会表现在一个非线性范围内，由于土壤-结构相互作用，将在一个专门的开源程序建模。将开发一种数值分析方法，以同时整合两个域模型。其次，将进行参数研究，以调查非线性近场土壤和冻融多年冻土的影响。第三，将开发一种先进的混合（实验-数值）模拟方法，该方法可以模拟部分嵌入式SMR与近场土壤的相互作用。混合模拟方法可以扩大规模进行大规模测试。 通过该项目，至少有三名HQP将接受培训，深入了解非线性土-结构相互作用，这是SMR设计和评估的重要研究领域。研究结果将使加拿大核工业处于SMR设计和部署的最前沿。

Small modular reactors (SMRs) have power capacities from 10 MW(e) up to 300 MW(e). They are designed to serve remote communities where the infrastructure for constructing large-capacity nuclear power plants (NPPs) or electric power transmission is limited. Significant parts of SMRs are manufactured at a facility and shipped and installed on a site. Unlike the large-scale NPPs for which the sites can be carefully selected considering various geotechnical hazards, the SMRs may need to be installed on unfavourable sites as they are designed to serve small remote communities with limited transmission networks. Considering the potentially unfavourable site conditions, nonlinear modelling of near-field soil is inevitable for accurately predicting seismic demands to SMR equipment. This research project is to develop methods with which the seismic demands on the equipment of SMRs can be realistically assessed. Three main research tasks are proposed. Firstly, a simulation method will be developed where the far-field soil of an SMR site can be modelled in a semi-automatic manner using borehole log data. The far-field soil will be analyzed in a supercomputer. The near-field soil, which might behave in a nonlinear range due to soil-structure interaction, will be modelled in a dedicated open-source program. A numerical analysis method will be developed to integrate the two domain models concurrently. Secondly, a parametric study will be carried out to investigate the impact of nonlinear near-field soil and the freeze and thaw of permafrost. Thirdly, an advanced hybrid (experimental-numerical) simulation method will be developed, which can model the interaction of a partially embedded SMR with nearfield soil. The hybrid simulation method can be scaled up for large-scale testing. Through the project, at least three HQPs will be trained with an in-depth understanding of nonlinear soil-structure interaction, which is an essential research area for the design and assessment of SMRs. The research results will put the Canadian nuclear industry at the forefront of SMR design and deployment.