Abstract
Containments of German light water reactors (LWR) are equipped with passive auto-catalytic recombiners (PAR) for the removal of hydrogen released during a severe accident. The exothermal reaction of hydrogen and oxygen on the catalyst sheets inside the PAR provides a mitigation of the threat of a detonation. A research project 'Studies for the advancement of the safety assessment methods for PAR in NPP containments during severe accidents' is presently conducted at the RWTH Aachen University, Chair for Reactor Safety and Reactor Technology (LRST), in collaboration with the Institute for Safety Research and Reactor Technology (ISR) at the Forschungszentrum Juelich GmbH (FZJ) and funded by the German Federal Ministry of Economics and Technology (BMWi). The project aims at the achievement of a profound understanding of recombiner phenomena in order to develop advanced models for the PAR assessment in severe accident analysis. The work programme includes several experimental studies at different test facilities used in cooperation with FZJ. Aspects to be considered are e.g. the starting behaviour, the inerting effect of steam and the effect of different geometries of the catalyst elements. A medium scale facility for studies under natural flow conditions is currently under construction. The experimental results obtained will be used for code development and validation.
