Numerical Analysis of Thermal Stratification in the Reactor Upper Plenum of MONJU with 1/3 Sector and Full Sector Models

Abstract

Three-dimensional analysis of thermal stratification phenomenon in the upper plenum of MONJU is conducted using FLUENT ver.12.1. This paper discusses the influence generated by upper core structure, which affects the flow structure near the core outlet region, and evaluates the thermal stratification phenomenon by the mean of comparing the full sector model built by the porous media approach with 1/3 sector model built by as-built geometry. Although there is a difference of the flow pattern from the core outlet between two models, the thermal stratification interface of 1/3 sector model shows the same trend with that of the full sector model.