Recent advances in understanding ruthenium behaviour under air-ingress conditions during a PWR severe accident

Air oxidation of Zircaloy-4 in the 600–1000°C temperature range: Modeling for ASTEC code application

“…Air ingress is typically associated with poor heat transfer; the combined effect of these factors can give rise to an increased rate of assemblies degradation. Furthermore, the exposure of UO 2 to air at elevated temperatures can lead to increased release of some fission products, notably the highly-radiotoxic ruthenium [4,5] while the effect of air is likely to further weaken the oxidized cladding as a barrier against fission product release. These considerations have taken IRSN to launch a research program consisting of experimental investigations and development of an accurate modeling of air oxidation in the ASTEC safety code.…”

High-resolution infrared spectroscopy and analysis of the ν2/ν4 bending dyad of ruthenium tetroxide

“…RuO 4 is quite reactive at room temperature and decomposes readily to produce RuO 2 films, which is used in the semiconductor industry [3]. Ru is also a fission product of uranium and can be created, under its volatile form RuO 4 , after an air inlet in the nuclear containment and can be used as a marker of air ingress in the reactor during a severe nuclear accident [4][5][6]. For this reason, the possible remote sensing of this compound in the atmosphere has gained technological importance and motivated recent spectroscopic studies [7].…”

Joint Raman spectroscopic and quantum chemical analysis of the vibrational features of Cs2RuO4

“…Much attention has been devoted to the study of the behavior of the ruthenium fission product in nuclear reactor accidents …”