Nordic Collaboration: Impact of Ag and NOx Compounds on the Transport of Ruthenium in the Primary Circuit of NPP in a Severe Accident

Paper in proceeding, 2016

When ruthenium is released from the fuel as ruthenium oxides to the environment in a severe NPP accident, ruthenium isotopes Ru-103 and Ru-106 cause a radiotoxic risk to the population both in a short and long term. As the previous international studies on the transport of ruthenium in the reactor coolant system (RCS) have mainly been conducted in pure air-steam atmospheres, the current study was dedicated to air ingress conditions with representative airborne air radiolysis (NOx) and control rod (Ag) species which were mixed with vaporized Ru oxides. The aim was to study the impact of these additives on the transport of ruthenium as gas and particles through the primary circuit of nuclear power plant in a severe accident. As a main outcome, the transport of gaseous ruthenium through the facility increased significantly when the oxidizing NO2 gas was fed into the atmosphere.