PAssive Systems: Simulating the Thermal-hydraulics with ExperimentaL Studies (PASTELS)

PASTELS aims to significantly increase the knowledge within Europe of
innovative passive systems, namely SACOs and CWCs, and the ability of several
European system and CFD computational codes to be able to accurately model key
phenomena such as natural circulation loops and condensation. This is very
challenging due to their very specific properties, i.e. small driving forces
working against high resistive forces which are specific to the concept of
these technologies. Given the growing use of the SACO and CWC technologies in
non-European NPPs, it is essential, especially with the foreseen future use of
Small Medium Reactors (SMR) that the European nuclear community is able to
adapt its current numerical tools to this promising technology. Extensive experimental
testing (SET, CET and integral experiments) with representative operating
conditions on semi-industrial full scale test facilities (PKL facility [DE] and
PASI facility [FI]) will provide essential data to support the improvement of
the numerical activities. Existing data from PERSEO and HERO-2 facilities will
also be used. The numerical and experimental activities will be conducted in an
integrated step-by-step approach. PASTELS will investigate improvements to
models, novel methodologies for the coupling of system and CFD codes working at
different scales. Additionally, important knowledge on the behaviour of the
SACO and CWC will be captured through the observation of their behavior during
the test campaigns. Different and similar computational codes will be used by
the partners in order to be able to benchmark and compare the different results
obtained, understand the causes and propose strategies to improve them. All
project results will feed into extensive methodology guidelines and a roadmap
to achieving licensing and implementation of these innovative passive system
technologies in future European NPPs.