Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants

Pekka Stén, Eini Puhakka, Ermo Ikävalko, Jarmo Lehikoinen, Markus Olin, Pekka Sirkiä, Petri Kinnunen, Timo Laitinen

    Research output: Book/ReportReport

    Abstract

    The construction materials used in coolant systems in nuclear power plants become covered with oxide films as a result of exposure to the aqueous coolant. The present work belongs to a research program on the properties of such films and especially on the transport of inorganic species through the films. The focus is on the incorporation of the highly energetic long-lived cobalt isotope 60Co in the films causing build-up of radiation fields in the out-of-core system. The present report concentrates on experimental adsorption studies both in ambient conditions and in high-temperature (573 K and 507 K), high-pressure conditions closely resembling those prevailing in the cooling circuits of nuclear power plants. In addition to cobalt adsorption, adsorption of zinc and nickel were studied, as a novel method to decrease the activity incorporation due to 60Co is injection of zinc into the primary coolant. Potentiometric acid-base titrations of hematite suspensions were conducted in the presence and absence of adsorbing metal cations (Zn2+, Co2+, Ni2+). Qualitatively the effect of adsorbed metal cation is noticed as a shift in the potentiometric titration curve, at a given pH more base is consumed due to the metal adsorption. Adsorption of inorganic solutes on oxide surfaces is nowadays most frequently modelled by employing the surface complexation approach, which was succesfully used also in this study to explain the results of the room-temperature experiments. However, it was found that a simple surface complexation model was not accurate enough to reproduce the high-temperature titration data in the presence of a metal cation. A reasonable fit of the high-temperature experimental data was obtained by extending the surface complexation model to take into account surface precipitation. The tentative equilibrium constants of the adsorption reactions, extracted by FITEQL version 4.0 modelling software, were used to calculate high-temperature adsorption edges. Although there seems to be practically no difference in the high-temperature adsorption affinities between zinc and cobalt, it is easy to understand that zinc can, however, be used to retard cobalt adsorption provided that zinc concentration in the solution is considerable higher than cobalt concentration.
    Original languageEnglish
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Number of pages41
    ISBN (Electronic)951-38-6178-3
    ISBN (Print)951-38-6177-5
    Publication statusPublished - 2003
    MoE publication typeNot Eligible

    Publication series

    SeriesVTT Tiedotteita - Meddelanden - Research Notes
    Number2182
    ISSN1235-0605

    Fingerprint

    Nuclear power plants
    Oxide films
    Adsorption
    Zinc
    Cobalt
    Complexation
    Metals
    Titration
    Coolants
    Cations
    Cobalt Isotopes
    Temperature
    ferric oxide
    Equilibrium constants
    Nickel
    Oxides
    Suspensions
    Cooling
    Radiation
    Acids

    Keywords

    • iron oxide
    • adsorption
    • nuclear power plants
    • NPP
    • high temperature
    • surface properties
    • surface precipitation
    • oxide films
    • hematite
    • cobalt
    • zinc
    • nickel

    Cite this

    Stén, P., Puhakka, E., Ikävalko, E., Lehikoinen, J., Olin, M., Sirkiä, P., ... Laitinen, T. (2003). Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 2182
    Stén, Pekka ; Puhakka, Eini ; Ikävalko, Ermo ; Lehikoinen, Jarmo ; Olin, Markus ; Sirkiä, Pekka ; Kinnunen, Petri ; Laitinen, Timo. / Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants. Espoo : VTT Technical Research Centre of Finland, 2003. 41 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 2182).
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    abstract = "The construction materials used in coolant systems in nuclear power plants become covered with oxide films as a result of exposure to the aqueous coolant. The present work belongs to a research program on the properties of such films and especially on the transport of inorganic species through the films. The focus is on the incorporation of the highly energetic long-lived cobalt isotope 60Co in the films causing build-up of radiation fields in the out-of-core system. The present report concentrates on experimental adsorption studies both in ambient conditions and in high-temperature (573 K and 507 K), high-pressure conditions closely resembling those prevailing in the cooling circuits of nuclear power plants. In addition to cobalt adsorption, adsorption of zinc and nickel were studied, as a novel method to decrease the activity incorporation due to 60Co is injection of zinc into the primary coolant. Potentiometric acid-base titrations of hematite suspensions were conducted in the presence and absence of adsorbing metal cations (Zn2+, Co2+, Ni2+). Qualitatively the effect of adsorbed metal cation is noticed as a shift in the potentiometric titration curve, at a given pH more base is consumed due to the metal adsorption. Adsorption of inorganic solutes on oxide surfaces is nowadays most frequently modelled by employing the surface complexation approach, which was succesfully used also in this study to explain the results of the room-temperature experiments. However, it was found that a simple surface complexation model was not accurate enough to reproduce the high-temperature titration data in the presence of a metal cation. A reasonable fit of the high-temperature experimental data was obtained by extending the surface complexation model to take into account surface precipitation. The tentative equilibrium constants of the adsorption reactions, extracted by FITEQL version 4.0 modelling software, were used to calculate high-temperature adsorption edges. Although there seems to be practically no difference in the high-temperature adsorption affinities between zinc and cobalt, it is easy to understand that zinc can, however, be used to retard cobalt adsorption provided that zinc concentration in the solution is considerable higher than cobalt concentration.",
    keywords = "iron oxide, adsorption, nuclear power plants, NPP, high temperature, surface properties, surface precipitation, oxide films, hematite, cobalt, zinc, nickel",
    author = "Pekka St{\'e}n and Eini Puhakka and Ermo Ik{\"a}valko and Jarmo Lehikoinen and Markus Olin and Pekka Sirki{\"a} and Petri Kinnunen and Timo Laitinen",
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    Stén, P, Puhakka, E, Ikävalko, E, Lehikoinen, J, Olin, M, Sirkiä, P, Kinnunen, P & Laitinen, T 2003, Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants. VTT Tiedotteita - Meddelanden - Research Notes, no. 2182, VTT Technical Research Centre of Finland, Espoo.

    Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants. / Stén, Pekka; Puhakka, Eini; Ikävalko, Ermo; Lehikoinen, Jarmo; Olin, Markus; Sirkiä, Pekka; Kinnunen, Petri; Laitinen, Timo.

    Espoo : VTT Technical Research Centre of Finland, 2003. 41 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 2182).

    Research output: Book/ReportReport

    TY - BOOK

    T1 - Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants

    AU - Stén, Pekka

    AU - Puhakka, Eini

    AU - Ikävalko, Ermo

    AU - Lehikoinen, Jarmo

    AU - Olin, Markus

    AU - Sirkiä, Pekka

    AU - Kinnunen, Petri

    AU - Laitinen, Timo

    N1 - Project code: D2SU00092

    PY - 2003

    Y1 - 2003

    N2 - The construction materials used in coolant systems in nuclear power plants become covered with oxide films as a result of exposure to the aqueous coolant. The present work belongs to a research program on the properties of such films and especially on the transport of inorganic species through the films. The focus is on the incorporation of the highly energetic long-lived cobalt isotope 60Co in the films causing build-up of radiation fields in the out-of-core system. The present report concentrates on experimental adsorption studies both in ambient conditions and in high-temperature (573 K and 507 K), high-pressure conditions closely resembling those prevailing in the cooling circuits of nuclear power plants. In addition to cobalt adsorption, adsorption of zinc and nickel were studied, as a novel method to decrease the activity incorporation due to 60Co is injection of zinc into the primary coolant. Potentiometric acid-base titrations of hematite suspensions were conducted in the presence and absence of adsorbing metal cations (Zn2+, Co2+, Ni2+). Qualitatively the effect of adsorbed metal cation is noticed as a shift in the potentiometric titration curve, at a given pH more base is consumed due to the metal adsorption. Adsorption of inorganic solutes on oxide surfaces is nowadays most frequently modelled by employing the surface complexation approach, which was succesfully used also in this study to explain the results of the room-temperature experiments. However, it was found that a simple surface complexation model was not accurate enough to reproduce the high-temperature titration data in the presence of a metal cation. A reasonable fit of the high-temperature experimental data was obtained by extending the surface complexation model to take into account surface precipitation. The tentative equilibrium constants of the adsorption reactions, extracted by FITEQL version 4.0 modelling software, were used to calculate high-temperature adsorption edges. Although there seems to be practically no difference in the high-temperature adsorption affinities between zinc and cobalt, it is easy to understand that zinc can, however, be used to retard cobalt adsorption provided that zinc concentration in the solution is considerable higher than cobalt concentration.

    AB - The construction materials used in coolant systems in nuclear power plants become covered with oxide films as a result of exposure to the aqueous coolant. The present work belongs to a research program on the properties of such films and especially on the transport of inorganic species through the films. The focus is on the incorporation of the highly energetic long-lived cobalt isotope 60Co in the films causing build-up of radiation fields in the out-of-core system. The present report concentrates on experimental adsorption studies both in ambient conditions and in high-temperature (573 K and 507 K), high-pressure conditions closely resembling those prevailing in the cooling circuits of nuclear power plants. In addition to cobalt adsorption, adsorption of zinc and nickel were studied, as a novel method to decrease the activity incorporation due to 60Co is injection of zinc into the primary coolant. Potentiometric acid-base titrations of hematite suspensions were conducted in the presence and absence of adsorbing metal cations (Zn2+, Co2+, Ni2+). Qualitatively the effect of adsorbed metal cation is noticed as a shift in the potentiometric titration curve, at a given pH more base is consumed due to the metal adsorption. Adsorption of inorganic solutes on oxide surfaces is nowadays most frequently modelled by employing the surface complexation approach, which was succesfully used also in this study to explain the results of the room-temperature experiments. However, it was found that a simple surface complexation model was not accurate enough to reproduce the high-temperature titration data in the presence of a metal cation. A reasonable fit of the high-temperature experimental data was obtained by extending the surface complexation model to take into account surface precipitation. The tentative equilibrium constants of the adsorption reactions, extracted by FITEQL version 4.0 modelling software, were used to calculate high-temperature adsorption edges. Although there seems to be practically no difference in the high-temperature adsorption affinities between zinc and cobalt, it is easy to understand that zinc can, however, be used to retard cobalt adsorption provided that zinc concentration in the solution is considerable higher than cobalt concentration.

    KW - iron oxide

    KW - adsorption

    KW - nuclear power plants

    KW - NPP

    KW - high temperature

    KW - surface properties

    KW - surface precipitation

    KW - oxide films

    KW - hematite

    KW - cobalt

    KW - zinc

    KW - nickel

    M3 - Report

    SN - 951-38-6177-5

    T3 - VTT Tiedotteita - Meddelanden - Research Notes

    BT - Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants

    PB - VTT Technical Research Centre of Finland

    CY - Espoo

    ER -

    Stén P, Puhakka E, Ikävalko E, Lehikoinen J, Olin M, Sirkiä P et al. Adsorption studies on iron oxides with reference to the oxide films formed on material surfaces in nuclear power plants. Espoo: VTT Technical Research Centre of Finland, 2003. 41 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 2182).