Thermal-hydraulic code assessment activities of the Technical University of Catalonia

For the past 15 years, the Technical University of Catalonia (UPC) has been involved in analysis and support to exploitation tasks related to the thermal-hydraulic behavior of commercial nuclear power plants. There has been a close cooperation with 3 Catalan NPPs (Ascó-I and II and Vandellòs-II), all of them 3-loop PWRs of Westinghouse design. More recently, the research activities of the thermal-hydraulic group of the UPC have diversified, including subjects like advanced reactors passive safety and 3-D TH coupled neutronics. The UPC team analyzed (using RELAP5/Mod3.2) some PANDA experiments in relation to the TEPSS project (EU) and ISP-42. PANDA is an integral test facility to study, among other issues, the interaction between containment and primary system and the performance of passive safety features. One of the conclusions that came out from those benchmarks was that the mixing phenomena taking place in the containment couldn’t be simulated with a 1D model, but a system code like RELAP5 was necessary, considering the complex interaction between reactor and containment systems. Although som