LWR oxide model for improved understanding of activity build-up and corrosion phenomena (LWROXI), 2004-2006

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LWR oxide model for improved understanding of
activity build-up and corrosion phenomena
(LWROXI), 2004-2006

• Kinetics of the growth and restructuring of the
  oxide layer on stainless steel in a light water
  reactor coolant
• Martin Bojinov, Petri Kinnunen
• VTT Industrial Systems
• SAFIR-puoliväliseminaari 20.-21.1.2005

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What the project is about?
Modelling approaches for steps I-III were
separately developed in the former FINNUS
research program
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What the project is about?

• The goals of the project are
• to develop a predictive model for activity
  build-up in nuclear power plants
• to increase the understanding and develop a
  phenomenological model of the oxide film build-up
  and break-down, controlling the stress corrosion
  cracking.
• This work is performed in co-operation with ALARA
  Engineering (Sweden) and Advanced Nuclear
  Technology (ANT, Sweden), who have long
  experience of BWR type water chemistries in
  Sweden and Finland.
• The work is funded by VYR, Statens
  kärnkraftinspektion (SKI, Sweden) and Statens
  strålskyddsinstitut (SSI, Sweden)

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Tasks of the project (1/3)

• Stage I. State-of-the-art and refinement of the
  model for oxide films in LWRs (2004).
• 1. Literature review of oxide growth and
  restructuring
• 2. Description of the current state of the model
  for oxide films on stainless steels and nickel
  base alloys in LWRs.
• 3. Refinement of the model for oxide films on
  stainless steels and nickel base alloys in LWRs.
• Results presented in
• Characterisation and modelling of oxide films on
  stainless steels and nickel alloys in light water
  reactors (Bojinov, Martin Kinnunen, Petri
  Lundgren, Klas Wikmark, Gunnar, 2004, VTT
  Industrial Systems, Espoo. 142 s. Research report
  No. BTUO 73-041285

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Tasks of the project (2/3)

• Stage II. Further development and quantification
  of the Mixed-Conduction Model (2005).
• 4. Further development and quantification of the
  surface complexation / deposition model at the
  oxide / coolant interface.
• To experimentally produce high temperature data
  to be used in estimating surface complexation
  constants for adsorption reactions of different
  cations. This data is needed in establishing a
  foundation for item 7. Equipment produced in
  SAFIR/INTELI -project in 2004.
• 5. Further development and quantification of the
  Mixed-Conduction Model for the inner compact
  layer of the oxide film.
• The information obtained during 2004 on the
  compact film and that obtained in item 4 will be
  combined in order to cover all the possible paths
  for transport and incorporation of minor species
  in the oxide. This information is needed for item
  7.
• 6. Critical analysis and evaluation of LWR data
  on water chemistry and activity build-up to be
  used in integrating the modelling approach to
  real process conditions.
• This information is needed for item 7.

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Tasks of the project (3/3)

• Stage III. Benchmarking and development of an
  integrated model (2006).
• 7. Benchmarking by comparison of plant data and
  model predictions.
• The benchmarking will be made on basis of the
  previous performed plant data analysis, and the
  parallel performed development of an integrated
  activity build-up model, i.e. in an iterative
  process. )
• 8. Development of an integrated activity build-up
  model.
• Development of an integrated activity build-up
  model includes the data, insights and sub-models
  gained in steps 1 to 6. The integrated model will
  be used to predict a few typical scenarios
  planned for already operating or new BWR or PWR
  plants, in order to demonstrate and establish the
  applicability of the model.
• 9. Reporting.

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Oxidation of stainless steels in high temperature
electrolytes