BR 2 bundle mockup heat transfer experiments

Heat transfer calibration tests on helium cooled bundles of 12 artificially roughened rods have been performed, with the purpose of obtaining information for the thermo-hydraulic design of the 12-rod bundle fuel element to be irradiated in BR2. The rods were electrically heated. Altogether 50 isothermal and 110 non-isothermal runs were performed. The maximum achieved rod linear power was 460 W/cm, the maximum measured wall temperature was 7900C. The code SAGAPO was developed to predict the thermodynamic performance of such clusters. This paper describes the measurements performed, the experimental set-up and the fundamentals of the SAGAPO code. The main results of the calculations performed with SAGAPO for the BR2 irradiation experiment are also given. (Auth.)