Computational Fluid Dynamics Modelling Aerosol Removal in a Strongly Condensing Environment

小型模块化反应堆（SMR）已被确定为一种有吸引力的低碳清洁能源，可以帮助实现加拿大的气候变化目标。加拿大可以成为发展和部署小型反应堆的领导者，因为它的核科学和技术部门非常发达。smr的安全设计依赖于一个创新的被动冷却系统，以应对假想的事故场景。这种新型冷却系统的设计与以前的反应堆不同，因为与CANDU反应堆相比，SMR的规模和设计更小。然而，对于被动冷却系统在事故情景下的运行，对于强冷凝和气溶胶沉积的理解还不够充分。由于温度和空气浓度的变化而引起的强凝结和气溶胶粒子的输送，预计在小型反应堆中比在以前的反应堆设计中更为重要。在安全分析中对这些现象的错误处理可能导致设计中没有保留事故场景中所需的裂变产物。为了解决在安全分析中对这些现象进行建模的工具的需求，该项目将使用商业软件来开发和测试封闭型腔室中流体流动、传热、传质和气溶胶传输的计算流体动力学模型。该模型将是蒸汽和空气的三维流动计算，包括垂直壁上的凝结。该模型的结果将与今年在安大略省乔克河的加拿大核实验室（CNL）进行的实验进行比较。新模型将为SMR安全性分析提供重要的新软件工具，并使CNL能够支持SMR的开发。加拿大在这一高科技领域的成功将带来就业机会和知识产权，并能够履行气候变化承诺。

A small modular reactor (SMR) has been identified as an attractive source of low-carbon clean energy that can help to meet Canada's climate change goals. Canada can become a leader in the development and deployment of SMRs because of its well-developed nuclear science and technology sector. The safe design of SMRs relies on an innovative passive cooling system for postulated accident scenarios. The design of this new cooling system is different from previous reactors because of the smaller scale and design of the SMR compared to CANDU reactors. There is an inadequate understanding, however, of the accident-scenario operation of the passive cooling system with respect to strong condensation and aerosol deposition. Strong condensation and the transport of aerosol particles by changes in the temperature and air concentration are expected to be more important in the SMR than in previous reactor designs. Incorrect treatment of those phenomena in a safety analysis could lead to designs that don't retain fission products as needed in an accident scenario.To address the need for a tool to model those phenomena in a safety analysis, this project will use commercial software to develop and test a computational fluid dynamics model of the fluid flow, heat and mass transfer, and aerosol transport in a containment-type chamber. The model will be a three-dimensional flow computation of steam and air with aerosol particles including condensation on a vertical wall. The model results will be compared with experiments being conducted this year at Canadian Nuclear Laboratories (CNL) in Chalk River, Ontario.The new model will provide an important new software tool for SMR safety analysis and will enable CNL to support the development of SMRs. Success for Canada in this high-tech area will lead to jobs and intellectual property as well as being able to deliver on climate change commitments.