Analysis of a full-scale integral test in PERSEO facility by using TRACE code

Over the last decades a lot of experimental researches have been done to increase the reliability of passive decay heat removal systems implementing in-pool immersed heat exchanger. In this framework, a domestic research program on innovative safety systems was carried out leading the design and the development of the PERSEO facility at the SIET laboratories. The configuration of the system consists of an heat exchanger contained in a small pool which is connected both at the bottom and at the top to a large water reservoir pool. Within the frame of a national research program funded by the Italian minister of economic development, the DEIM department of the University of Palermo in cooperation with ENEA has developed a computational model of the PERSEO facility in order to simulate its behaviour during an integrated test. The analysis here presented has been performed by using the best-estimate TRACE code and - in order to highlight the capabilities and limits of the TRACE model in reproducing qualitatively and quantitatively the experimental trends - the main results have been compared with the experimental data. The comparison shows that the model is able to predict the overall behaviour of the plant during the meaningful phases of the transient analysed. Nevertheless, some improvements in the modelling of certain components in which take place complex three-dimensional phenomena are suggested in order to reduce some discrepancies observed between code results and test measurements.