Recommendations on an Integrated Approach for Modelling Nearfield Atmospheric Dispersion for a Prototypical SMR Site

This paper presents recommendations on integrated computational fluid dynamics (CFD) and Gaussian plume modeling of near-field atmospheric dispersion using wind tunnel experiments and field data. The aim of the larger study is to support the development of emergency planning zones for small modular reactor facilities that may be co-located near urban centers. The specific topics addressed in this paper are the generation of high-fidelity domain information, as well as cross comparisons between open domain (i.e., full scale) and closed domain (i.e., wind tunnel) simulations and experimental measurements. Aerial photogrammetry measurements were taken of a real reactor facility, demonstrating how that type of measurement can be incorporated into the workflow of generating both the CFD simulation domain and 3D printed geometries used in wind tunnel experiments. Then, a comparison took place between dispersion predictions from open-field CFD, preliminary wind tunnel experiments of the scaled domain, CFD simulations of the scaled wind tunnel experiments, and Gaussian Plume Model (GPM) simulations. This allows for a number of practical limitations to be identified in the wind tunnel and open-field configuration comparisons, including geometric and boundary constraints inherent to each. Plume spread predictions are also evaluated against NUREG standards to assess consistency of the model to the present regulatory standards.