Transport of ruthenium in primary circuit conditions during a severe NPP accident

Autor: N. Davidovich, Teemu Kärkelä, N. Vér, Jouni Pyykönen, Tim Haste, Laurent Cantrel
Přispěvatelé: Davidovich, N., Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), VTT Technical Research Centre of Finland (VTT), SARNET2
Jazyk: angličtina
Rok vydání: 2014
Předmět:
Zdroj: Kärkelä, T, Vér, N, Haste, T, Davidovich, N, Pyykönen, J & Cantrel, L 2014, ' Transport of ruthenium in primary circuit conditions during a severe NPP accident ', Annals of Nuclear Energy, vol. 74, pp. 173-183 . https://doi.org/10.1016/j.anucene.2014.07.010
Annals of Nuclear Energy
Annals of Nuclear Energy, Elsevier Masson, 2014, 74 (C), pp.173-183. ⟨10.1016/j.anucene.2014.07.010⟩
ISSN: 1873-2100
0306-4549
DOI: 10.1016/j.anucene.2014.07.010
Popis: International audience; Ruthenium species, volatilized from damaged fuel during a severe accident in a nuclear power plant, are radiotoxic and can be transported to the containment atmosphere in gaseous form. To limit the possible source term to the environment, it is of interest to understand the behaviour of Ru after it has been released from fuel and the phenomena taking place within the decreasing temperature section of the reactor coolant system. This was investigated in the framework of EC SARNET and SARNET2 projects, as a part of the Source Term work package, with several separate-effect tests on the transport and speciation of Ru in primary circuit conditions considering the influence of other fission products as well. The source of Ru was metallic Ru, RuO2 powder or gaseous RuO4. The large-scale integral tests of the Phébus FP program were conducted with real irradiated fuel, and more realistic analysis on the release and transport of Ru could be performed. Experimental studies proved that the transport of ruthenium to the containment atmosphere took mainly place as RuO2 particles when Ru source was oxidized above 1250 °C. The fraction of Ru transported in gaseous form was at its highest when ruthenium was oxidized at approx. 1000-1100 °C. A major part of the released Ru was deposited at the decreasing temperature area of the circuit as RuO2. Revaporisation of the deposited Ru at low temperature was a significant source of gaseous ruthenium. In order to understand the behaviour of ruthenium in these tests, the analysis work was extensive and several simulations were carried out. As an outcome, the observed transport and deposition of ruthenium was explained. The simulation studies gave also an insight into the performance of the ASTEC code and some model improvements for Ru transport through the reactor coolant system have been identified. © 2014 Elsevier Masson SAS.
Databáze: OpenAIRE