Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation

Petri Kinnunen, Martin Bojinov, Jarmo Lehikoinen, Klas Lundgren

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

Abstract

The ultimate goal of this work is to develop a deterministic model for activity build-up and to increase the theoretical understanding of the oxide film build-up and breakdown, controlling the localised corrosion of structural materials in Light Water Reactors. The first step of the overall reaction of activity build-up in oxidised structural material surfaces in primary LWR circuits is the interaction of activated ionic species from the coolant with the oxide layers, involving surface complexation and redeposition stages. An experimental investigation of the interaction of the LWR oxides with coolant-originating species was performed to assess the thermodynamics of these stages. A series of high-temperature titrations at 280oC was performed, in which the competitive adsorptivity of Zn, Co and Ni cations onto iron oxide surfaces has been studied. The experiments provided the necessary information concerning the reactions at outer oxide / coolant interface. The obtained results were quantitatively interpreted using the diffuse layer and non-electrical surface complexation models and the extracted stability constants of the surface complexes were found to be in agreement with extrapolations of room-temperature data. The determination of the kinetic and transport parameters for the subsequent incorporation of Zn in the inner oxide layer on stainless steels and nickel alloys is based on the fitting of experimental depth profiles of these elements to the diffusion-migration equations for the non-steady state transport. The obtained parameter values are discussed in terms of the dynamics of the oxides on the structural materials.
Original languageEnglish
Title of host publicationSAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006
Subtitle of host publicationFinal Report
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages115-126
ISBN (Electronic)951-38-6887-7
ISBN (Print)951-38-6886-9
Publication statusPublished - 2006
MoE publication typeNot Eligible

Publication series

NameVTT Tiedotteita - Research Notes
PublisherVTT
Number2363
ISSN (Print)1235-0605
ISSN (Electronic)1455-0865

Fingerprint

oxide films
coolants
conduction
oxides
adsorptivity
light water reactors
nickel alloys
iron oxides
titration
extrapolation
stainless steels
surface layers
corrosion
breakdown
interactions
cations
thermodynamics
kinetics
room temperature
profiles

Cite this

Kinnunen, P., Bojinov, M., Lehikoinen, J., & Lundgren, K. (2006). Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation. In SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006: Final Report (pp. 115-126). Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Research Notes, No. 2363
Kinnunen, Petri ; Bojinov, Martin ; Lehikoinen, Jarmo ; Lundgren, Klas. / Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation. SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006: Final Report. Espoo : VTT Technical Research Centre of Finland, 2006. pp. 115-126 (VTT Tiedotteita - Research Notes; No. 2363).
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Kinnunen, P, Bojinov, M, Lehikoinen, J & Lundgren, K 2006, Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation. in SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006: Final Report. VTT Technical Research Centre of Finland, Espoo, VTT Tiedotteita - Research Notes, no. 2363, pp. 115-126.

Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation. / Kinnunen, Petri; Bojinov, Martin; Lehikoinen, Jarmo; Lundgren, Klas.

SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006: Final Report. Espoo : VTT Technical Research Centre of Finland, 2006. p. 115-126 (VTT Tiedotteita - Research Notes; No. 2363).

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

TY - CHAP

T1 - Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation

AU - Kinnunen, Petri

AU - Bojinov, Martin

AU - Lehikoinen, Jarmo

AU - Lundgren, Klas

PY - 2006

Y1 - 2006

N2 - The ultimate goal of this work is to develop a deterministic model for activity build-up and to increase the theoretical understanding of the oxide film build-up and breakdown, controlling the localised corrosion of structural materials in Light Water Reactors. The first step of the overall reaction of activity build-up in oxidised structural material surfaces in primary LWR circuits is the interaction of activated ionic species from the coolant with the oxide layers, involving surface complexation and redeposition stages. An experimental investigation of the interaction of the LWR oxides with coolant-originating species was performed to assess the thermodynamics of these stages. A series of high-temperature titrations at 280oC was performed, in which the competitive adsorptivity of Zn, Co and Ni cations onto iron oxide surfaces has been studied. The experiments provided the necessary information concerning the reactions at outer oxide / coolant interface. The obtained results were quantitatively interpreted using the diffuse layer and non-electrical surface complexation models and the extracted stability constants of the surface complexes were found to be in agreement with extrapolations of room-temperature data. The determination of the kinetic and transport parameters for the subsequent incorporation of Zn in the inner oxide layer on stainless steels and nickel alloys is based on the fitting of experimental depth profiles of these elements to the diffusion-migration equations for the non-steady state transport. The obtained parameter values are discussed in terms of the dynamics of the oxides on the structural materials.

AB - The ultimate goal of this work is to develop a deterministic model for activity build-up and to increase the theoretical understanding of the oxide film build-up and breakdown, controlling the localised corrosion of structural materials in Light Water Reactors. The first step of the overall reaction of activity build-up in oxidised structural material surfaces in primary LWR circuits is the interaction of activated ionic species from the coolant with the oxide layers, involving surface complexation and redeposition stages. An experimental investigation of the interaction of the LWR oxides with coolant-originating species was performed to assess the thermodynamics of these stages. A series of high-temperature titrations at 280oC was performed, in which the competitive adsorptivity of Zn, Co and Ni cations onto iron oxide surfaces has been studied. The experiments provided the necessary information concerning the reactions at outer oxide / coolant interface. The obtained results were quantitatively interpreted using the diffuse layer and non-electrical surface complexation models and the extracted stability constants of the surface complexes were found to be in agreement with extrapolations of room-temperature data. The determination of the kinetic and transport parameters for the subsequent incorporation of Zn in the inner oxide layer on stainless steels and nickel alloys is based on the fitting of experimental depth profiles of these elements to the diffusion-migration equations for the non-steady state transport. The obtained parameter values are discussed in terms of the dynamics of the oxides on the structural materials.

M3 - Chapter or book article

SN - 951-38-6886-9

T3 - VTT Tiedotteita - Research Notes

SP - 115

EP - 126

BT - SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kinnunen P, Bojinov M, Lehikoinen J, Lundgren K. Further development of the Mixed-Conduction Model of oxide films in LWRs emphasising surface complexationand reprecipitation. In SAFIR: The Finnish Research Programme on Nuclear Power Plant Safety 2003-2006: Final Report. Espoo: VTT Technical Research Centre of Finland. 2006. p. 115-126. (VTT Tiedotteita - Research Notes; No. 2363).