Comparison of free surface flow measurements and smoothed particle hydrodynamic simulation for potential nuclear power plant flooding simulation

Abstract

Flooding is a potential concern for Nuclear Power Plants (NPPs) and, as demonstrated at Fukushima Japan in 2011, can cause extensive damage. Given the flooding concern in NPPs, research is underway to better characterize plant vulnerabilities and the associated risk. Improved NPP flooding risk characterization starts with improving the realism of scenarios by using physics-based flooding simulations. Smoothed Particle Hydrodynamics (SPH) is one method for modeling fluid flow and is being investigated for NPP flooding event simulation. However, for flooding scenarios to be effectively represented, SPH results need to be validated with physical (experimental) results to determine the accuracy of the simulation code. This paper provides a comparison of SPH results with experimental results associated with steady-state flow over an ogee spillway. The SPH code used for this validation activity is the developmental code Neutrino. The goal of this comparison is to determine Neutrino’s ability to model free surface flow for incorporation into NPP flooding scenario simulations. A Neutrino model was constructed and optimized by conducting parametric studies on model width and SPH-particle diameter. The results using a model width of 4 m and a particle diameter of 0.35 m provided relative percent errors from 1.5% to 11.7% for ten different flow measurements. Results from this SPH comparison provide sufficient basis for further investigation of applying SPH for NPP flooding simulations. The comparison results also demonstrate the need for development of model optimization guidance.