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来源，可以帮助实现加拿大的气候变化目标。由于其发达的核科学和技术部门，加拿大可以成为发展和部署SMR的领先者。SMRS的安全设计依赖于创新的被动冷却系统，以应对假设的事故情景。这种新的冷却系统的设计与以前的反应堆不同，因为SMR的规模和设计与CANDU反应堆相比更小。然而，对被动冷却系统在强凝结和气溶胶沉积方面的事故情景运行了解不足。由于温度和空气浓度的变化，强凝结和气溶胶颗粒的传输预计在SMR中比在以前的反应堆设计中更重要。在安全分析中对这些现象的不正确处理可能会导致设计在事故场景中不能根据需要保留裂变产物。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开发和测试计算流体力学模型，该模型描述了密封式腔室中的流体流动、热量和质量传输以及气溶胶传输。该模型将是含有气溶胶颗粒的蒸汽和空气的三维流动计算，包括在垂直壁上的凝结。模型的结果将与今年在安大略省Chalk River的加拿大核实验室(CNL)进行的实验进行比较。新模型将为SMR安全分析提供一个重要的新软件工具，并使CNL能够支持SMR的发展。加拿大在这一高科技领域的成功将带来就业和知识产权，并能够兑现气候变化承诺。

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.