A Study on the Turbulence Models for Full-Scale Analysis of Reactor Vessel Internals

Since there are complex thermal-hydraulic phenomena inside a reactor, understanding of the flow characteristics in the Reactor vessel internals (RVIs) is an important factor when designing nuclear power plants (NPPs). Many studies have been conducted to analyze the flow characteristics of the RVIs in the steady states. The rapid flow transients may cause water hammering, so that the characteristics of reactor coolant flow have great effect on the safety of NPPs. In this paper, a numerical study was performed to analyze coolant flow distribution in RVIs of optimized power reactor (OPR-1000). An analysis method was established to evaluate operating transient conditions. This study was to examine two representative turbulence models for full-scale analysis of RVIs. Thereby, the following key findings were observed. (1) Fluid velocity and pressure distributions obtained from DES model were lower than those obtained from SST model. (2) Temperature profiles calculated from both turbulence models were the same.