Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A coupled model for oxidative dissolution of spent fuel and transport of radionuclides from an initially defective canister
KTH, Superseded Departments, Chemical Engineering and Technology.ORCID iD: 0000-0001-6801-9208
KTH, Superseded Departments, Chemical Engineering and Technology.
2001 (English)In: Nuclear Technology, ISSN 0029-5450, E-ISSN 1943-7471, Vol. 135, 273-285 p.Article in journal (Refereed) Published
Abstract [en]

An earlier model for oxidative dissolution of spent fuel was developed by including the release behavior of actinides from the fuel surface and the barrier effect of Zircaloy claddings. The aim here is to explore the possibility and consequences of precipitation in the water film around the fuel pellets due to solubility, and transport limitations of nuclides. The model has been applied in the performance assessment of a damaged canister under natural repository conditions, by coupling to a redox-front-based model for transport of nuclides. The simulation results identify? that the time of penetration of the canister, the size of the damage, and the initial free volume of the fuel rods are important factors that dominate the dissolution behavior of the fuel matrix and thus the transport behavior of actinides in the nearfield of a repository.

Place, publisher, year, edition, pages
2001. Vol. 135, 273-285 p.
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:kth:diva-12972OAI: oai:DiVA.org:kth-12972DiVA: diva2:320016
Note
QC 20100521Available from: 2010-05-21 Created: 2010-05-20 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Oxidative Dissolution of Spent Fuel and Release of Nuclides from a Copper/Iron Canister: Model Developments and Applications
Open this publication in new window or tab >>Oxidative Dissolution of Spent Fuel and Release of Nuclides from a Copper/Iron Canister: Model Developments and Applications
2001 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Three models have been developed and applied in the performance assessment of a final repository. They are based on accepted theories and experimental results for known and possible mechanisms that may dominate in the oxidative dissolution of spent fuel and the release of nuclides from a canister. Assuming that the canister is breached at an early stage after disposal, the three models describe three sub-systems in the near field of the repository, in which the governing processes and mechanisms are quite different.

In the model for the oxidative dissolution of the fuel matrix, a set of kinetic descriptions is provided that describes the oxidative dissolution of the fuel matrix and the release of the embedded nuclides. In particular, the effect of autocatalytic reduction of hexavalent uranium by dissolved H2, using UO2 (s) on the fuel pellets as a catalyst, is taken into account. The simulation results suggest that most of the radiolytic oxidants will be consumed by the oxidation of the fuel matrix, and that much less will be depleted by dissolved ferrous iron. Most of the radiolytically produced hexavalent uranium will be reduced by the autocatalytic reaction with H2 on the fuel surface. It will reprecipitate as UO2 (s) on the fuel surface, and thus very little net oxidation of the fuel will take place.

In the reactive transport model, the interactions of multiple processes within a defective canister are described, in which numerous redox reactions take place as multiple species diffuse. The effect of corrosion of the cast iron insert of the canister and the reduction of dissolved hexavalent uranium by ferrous iron sorbed onto iron corrosion products and by dissolved H2 are particularly included. Scoping calculations suggest that corrosion of the iron insert will occur primarily under anaerobic conditions. The escaping oxidants from the fuel rods will migrate toward the iron insert. Much of these oxidants will, however, be consumed by ferrous iron that comes from the corrosion of iron. The nonscavenged hexavalent uranium will be reduced by ferrous iron sorbed onto the iron corrosion products and by dissolved hydrogen.

In the transport resistance network model, the transport of reactive actinides in the near field is simulated. The model describes the transport resistance in terms of coupled resistors by a coarse compartmentalisation of the repository, based on the concept that various ligands first come into the canister and then diffuse out to the surroundings in the form of nuclide complexes. The simulation results suggest that carbonate accelerates the oxidative dissolution of the fuel matrix by stabilizing uranyl ions, and that phosphate and silicate tend to limit the dissolution by the formation of insoluble secondary phases.

The three models provide powerful tools to evaluate "what if" situations and alternative scenarios involving various interpretations of the repository system. They can be used to predict the rate of release of actinides from the fuel, to test alternative hypotheses and to study the response of the system to various parameters and conditions imposed upon it.

Place, publisher, year, edition, pages
Stockholm: KTH, 2001. viii, 68 p.
Series
Trita-KET, ISSN 1104-3466 ; 154
Keyword
model, oxidative dissolution, spent fuel, radiolysis, release, mass transport, radionuclide, hydrogen, corrosion, canister, near field, repository
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-3292 (URN)ISBN 91-7283-220-7 (ISBN)
Public defence
2002-02-01, 00:00 (English)
Note
QC 20100521Available from: 2002-01-22 Created: 2002-01-22 Last updated: 2010-05-21Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Liu, LongchengNeretnieks, Ivars
By organisation
Chemical Engineering and Technology
In the same journal
Nuclear Technology
Chemical Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 43 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf