The Equivalent Cylinder Models for the Homogenization of Pebble Bed Reactor Cores

摘要

The double heterogeneity involved in thernhomogenization of the spherical pebbles has been one of thernmain concerns in the analysis of pebble bed reactors.rnHowever, many codes do not support a doublyrnheterogeneous spherical geometry. Therefore, an equivalentrncylindrical cell has been used as an approximation. Thernvalidity of this approximation has been tested for thernLEUPRO-1 UO2 fuel in reference 1. They showed that arnspherical pebble can be transformed to a 1-D cylindricalrnmodel with an acceptable accuracy by conserving the meanrnchord length of the fuel zone. Recently, Kim et al. proposedrnthe reactivity equivalent physical transform (RPT) methodrnfor the treatment of the double heterogeneity. In RPTrnmethod, the doubly heterogeneous problem is transformedrnto an equivalent singly heterogeneous problem.