Optimizing the local-scale turbulence-induced dispersion of LAPMOD at a Chinese nuclear power plant with heterogeneous topography and irregular building layouts

Abstract

This study proposes a composite correction scheme to address the inadequate turbulence-induced dispersion of the Lagrangian Particle Model (LAPMOD) at a nuclear power plant site with complex terrains and irregular buildings. The proposed scheme combines both background and local optimization of the turbulence intensity, which are overall lower bound settings and local correction in building zones. The feasibility of the correction is comprehensively assessed by comparing multiple LAPMOD's simulations with measurements from two wind tunnel experiments of a Chinese nuclear power plant. Furthermore, a comprehensive sensitivity analysis is conducted to optimize the mixing length parameterization in the surface layer of the proposed scheme. The results show that the correction scheme significantly enhances the agreement between simulations and measurements, with respect to both spatial plume coverage and quantitative metrics. It effectively mitigates long-range overestimations in the plume center, reduces deviations at axial sites, and accurately reproduces the vertical concentration profile at the main mountain and building-area boundary. The quantitative metrics confirm the excellent performance of the correction scheme, achieving the acceptance criteria of all four quantitative statistical metrics. The sensitivity analysis reveals that the optimal mixing length is the ensemble mean of two classic schemes, enhancing applicability of the proposed scheme in practice.