Experimental results for RVK-500 recombiner tested in conditions typical for pressurized water NPP severe accidents

Abstract

Severe accidents at NPPs with light water coolant can lead to situations when large quantities of hydrogen are released due to zirconium-steam reaction. To avoid explosion consequences, they started to install hydrogen passive autocatalytic recombiners (PARs) at NPPs. Calculating simulation based on PAR models is used to predict and justify the needed quantity of PARs and the chosen place of their location inside the NPP. To validate PAR computational models, experimental data are need. Within the scope of this work, the integrated tests of the RVK-500 type recombiner, which included 20 experiments, were conducted to obtain large body of data on PAR operation in different modes and conditions that can be realized in case of hypothetical accident at NPP. For this purpose, a facility equipped with a measuring set able to work at high pressures, temperatures, and humidity was constructed. The tests were conducted in accord with thepredevopled PAR testing procedure and program to describe PAR characteristics, such as its start-up, H2 recombination rate, efficiency, and ignition limit. In addition, a small-scale facility was used to study the potential of particles separated from the catalytic elements to induce combustion.