3-LAYER (PELLET, GAS-GAP AND CLAD) 'SIMPLIFIED' FUEL ROD THERMALLYEQUIVALENT TO 4-LAYER (WITHOUT GAS-GAP) HEATER SIMULATOR

摘要

Method of formulating 'simplified' 3-layer rod model(representing fuel pellet, gas-gap and clad) thermally equivalentto 4-layer heater simulator (materials in contact, without gas-gap)is presented. Such thermally equivalent and through inputparameters easy to specify rod model is defined. Validationagainst measured data for cladding surface temperatures in bothpre- and post-CHF regimes proved applicability of thisapproach in transients. The rod model is qualified for furtheruse in COBRA 3–CP and COBRA/TF codes for their validationon experiments using the particular heater simulator design.