Modelling the transport in the porous layer of oxide films formed on material surfaces in nuclear power plants: Model extension to more general conditions

Jarmo Lehikoinen, Markus Olin

    Research output: Book/ReportReport

    Abstract

    In this study, the role of the porous oxide film, deposited on top of the primary passive (compact) film, to control activity incorporation on the primary circuit surfaces of nuclear power plants (NPPs) is investigated. To serve this purpose, a computerized steady-state transport model, previously developed for a simplified BWR case, has been extended to take into consideration more general high-temperature aqueous and oxide compositions. In practical terms, computationally laborious multi-species reactions for ions, aqueous complexes, precipitates and dissolved gases as well as three types of boundary conditions at the compact film/porous film interface can now be included in the revised model. The model is rendered flexible enough to enable comparison of the effects of various NPP operating conditions, including those prevailing in PWRs. In this report, results calculated with the revised transport model for a BWR system are presented and discussed. The results allow, among other things, a qualitative evaluation of the fate of soluble, radioactive minority species within the pore fluid of the porous film à priori. A further elaboration of this system was highly warranted in that it serves as a template when moving to computationally more demanding PWR conditions. An outline of a technique to incorporate adsorption by way of mechanistic surface complexation into the transport model is also given.
    Original languageEnglish
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Number of pages24
    ISBN (Print)951-38-5955-X
    Publication statusPublished - 2002
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesVTT Tiedotteita - Meddelanden - Research Notes
    Number2131
    ISSN1235-0605

    Keywords

    • nuclear power plants
    • iron
    • corrosion
    • oxide films
    • high temperature
    • adsorption
    • complex formation
    • transport modelling
    • water chemistry
    • hematite

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  • Cite this

    Lehikoinen, J., & Olin, M. (2002). Modelling the transport in the porous layer of oxide films formed on material surfaces in nuclear power plants: Model extension to more general conditions. VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 2131