Analysis of fuel centre temperatures with the TRANSURANUS code

At present a comprehensive verification of the fuel rod performance code TRANSURANUS is being performed using irradiation data from the International Fuel Performance Experiments (IFPE) Database and the OECD Halden Reactor Project. For this verification standard models and options are applied. Recent developments have concentrated on high-burn-up phenomena, such as the local thermal conductivity and the local porosity in the High Burn-up Structure (HBS). In this paper, fuel centre temperatures are calculated by the TRANSURANUS code with standard options and compared with measured temperatures, under steady-state conditions. More than 40 000 data points have been analyzed in total. They cover UO 2 fuel (both for Western-type LWR and for Russian-type VVER) and MOX fuel for LWR. It is shown that the vast majority of fuel centre temperatures predicted by the TRANSURANUS code deviates from the measured values by less than 10 %. For all standard fuel configurations the actual deviations are considerably smaller. The spread is of the same order of magnitude as the uncertainties in the measurements (due to power calibration and thermocouple calibration). The present analysis does not reveal any general bias. It can be concluded that under the studied conditions the TRANSURANUS code predictions of the fuel centre temperatures are very satisfactory.