CANDU 6 fuel channel thermal hydraulics analysis: comparison between CANFLEX bundle and 37-element bundle

The paper describes a thermal-hydraulics analysis of a CANDU 6 fuel channel for two different cases: the channel is fueled with the 37 elements bundle and the channel is fuelled with the CANFLEX bundle. The analysis is performed using the RELAP5/SCADAP mod3.4 code. For each case pressure and temperature at inlet header, pressure and temperature at outlet header and channel power represent the boundary conditions. The RELAP 5 model consists in an inlet feeder modeled as a pipe component with 20 volumes, inlet end fitting, fuel channel modeled as a pipe component with 12 volumes, outlet end fitting and outlet feeder modeled as a pipe component with 21 volumes. The paper presents results obtained for transients representative for loss of coolant accident. (authors)