scholarly journals Formation of Iron Sulfides on Carbon Steel in a Specific Cement Grout Designed for Radioactive Waste Repository and Associated Corrosion Mechanisms

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3563
Author(s):  
Mathieu Robineau ◽  
Valérie Deydier ◽  
Didier Crusset ◽  
Alexandre Bellefleur ◽  
Delphine Neff ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Radioactive Waste ◽  
Corrosion Product ◽  
Product Layer ◽  
Cement Grout ◽  
Radioactive Waste Disposal ◽  
Sulfide Concentration ◽  
Iron Sulfides ◽  
Corrosion Mechanisms ◽  
A Minor

Carbon steel coupons were buried in a specific low-pH cement grout designed for radioactive waste disposal and left 6 months in anoxic conditions at 80 °C. The corrosion product layers were analyzed by µ-Raman spectroscopy, XRD, and SEM. They proved to be mainly composed of iron sulfides, with magnetite as a minor phase, mixed with components of the grout. Average corrosion rates were estimated by weight loss measurements between 3 and 6 µm yr−1. Corrosion profiles revealed local degradations with a depth up to 10 µm. It is assumed that the heterogeneity of the corrosion product layer, mainly composed of conductive compounds (FeS, Fe3S4, and Fe3O4), promotes the persistence of corrosion cells that may lead to locally aggravated degradations of the metal. New cement grouts, characterized by a slightly higher pH and a lower sulfide concentration, should then be designed for the considered application.

scholarly journals Corrosion of Carbon Steel in Marine Environments: Role of the Corrosion Product Layer

2020 ◽  
Vol 1 (1) ◽  
pp. 198-218
Author(s):  
Philippe Refait ◽  
Anne-Marie Grolleau ◽  
Marc Jeannin ◽  
Celine Rémazeilles ◽  
René Sabot
Keyword(s):  
Carbon Steel ◽  
Corrosion Product ◽  
Metal Surface ◽  
Steel Surface ◽  
Solid Phase ◽  
Product Layer ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Uniform Corrosion ◽  
Corrosion Mechanisms

This article presents a synthesis of recent studies focused on the corrosion product layers forming on carbon steel in natural seawater and the link between the composition of these layers and the corrosion mechanisms. Additional new experimental results are also presented to enlighten some important points. First, the composition and stratification of the layers produced by uniform corrosion are described. A focus is made on the mechanism of formation of the sulfate green rust because this compound is the first solid phase to precipitate from the dissolved species produced by the corrosion of the steel surface. Secondly, localized corrosion processes are discussed. In any case, they involve galvanic couplings between anodic and cathodic zones of the metal surface and are often associated with heterogeneous corrosion product layers. The variations of the composition of these layers with the anodic/cathodic character of the underlying metal surface, and in particular the changes in magnetite content, are thoroughly described and analyzed to enlighten the self-sustaining ability of the process. Finally, corrosion product layers formed on permanently immersed steel surfaces were exposed to air. Their drying and oxidation induced the formation of akaganeite, a common product of marine atmospheric corrosion that was, however, not detected on the steel surface after the permanent immersion period.

Development of Mathematical Models for Long-Term Prediction of Corrosion Behaviour of Carbon Steel Overpacks for Radioactive Waste Disposal

1996 ◽  
Vol 465 ◽  
Author(s):  
A. R. Hoch ◽  
A. Honda ◽  
F. M. Porter ◽  
S. M. Sharland ◽  
N. Taniguchi
Keyword(s):  
Carbon Steel ◽  
Radioactive Waste ◽  
Mathematical Models ◽  
Waste Disposal ◽  
Corrosion Behaviour ◽  
Radioactive Waste Disposal ◽  
Cathodic Reaction ◽  
Term Prediction ◽  
Long Term Prediction

ABSTRACTMathematical models to enable long-term prediction of the corrosion behaviour of carbon steel overpacks for radioactive waste have been developed. An existing model of the growth of pits, implemented in the CAMLE software, has been extended and used to investigate the sensitivity of the predictions to input parameters, including cathodic reaction kinetics and the relative position of the anode and cathode. Predictions have also been made of the aeration period of the repository, during which localised corrosion is possible.

scholarly journals Evaluation Method for Corrosion Depth of Uncoated Carbon Steel and Its Time-Dependence Using Thickness of Corrosion Product Layer

2012 ◽  
Vol 61 (12) ◽  
pp. 483-494 ◽  
Author(s):  
Shigenobu Kainuma ◽  
Yuya Yamamoto ◽  
Yoshihiro Itoh ◽  
Hideyuki Hayashi ◽  
Wataru Oshikawa
Keyword(s):  
Carbon Steel ◽  
Time Dependence ◽  
Corrosion Product ◽  
Evaluation Method ◽  
Product Layer ◽  
Corrosion Depth ◽  
Corrosion Product Layer

Simulation of The State of Carbon Steel n Years After Disposal with n Years of Corrosion Product on its Surface in a Bentonite Environment

1994 ◽  
Vol 353 ◽  
Author(s):  
Yoichi Kojima ◽  
Toshinobu Hioki ◽  
Shigeo Tsujikawa
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Corrosion Product ◽  
Corrosion Behavior ◽  
Steel Corrosion ◽  
Product Layer ◽  
The State ◽  
Corrosion Product Layer ◽  
Time Frames

AbstractThe use of bentonite as buffer and carbon steel as overpack material for the geological disposal of nuclear waste is under investigation. To better assess the long term integrity of the carbon steel overpack, a quantitative analysis of the corrosion behavior on the steel surface for time frames beyond that of feasible empirical determination is required. The state n years after disposal, consisting of Carbon Steel / Corrosion Products + Bentonite / Water, was simulated and the corrosion behavior of the carbon steel in this state investigated. The following facts became apparent. Both the corrosion rate and the non-uniformity of it increased with increase in the corrosion product content in the compacted bentonite. When the corrosion product layer was formed between the carbon steel and the bentonite, it ennobled the corrosion potential and increased the corrosion rate.

Effects of Recrystallization on Time Variant Sorption of Radionuclides onto Steel Corrosion Products

1993 ◽  
Vol 333 ◽  
Author(s):  
Robert W. Smith ◽  
John C. Walton ◽  
Masudur Rahman
Keyword(s):  
Radioactive Waste ◽  
Surface Area ◽  
Corrosion Product ◽  
Waste Disposal ◽  
Complex Function ◽  
Steel Corrosion ◽  
Corrosion Products ◽  
Radioactive Waste Disposal ◽  
Geochemical Environment ◽  
The Impact

ABSTRACTCorrosion products resulting from the oxidation of steel containers and iron-containing waste can alter the local geochemical environment in radioactive waste disposal vaults and trenches. In addition, corrosion products can enhance the retention of radionuclides by providing a highly sorptive media. Initial hydrous corrosion products are poorly crystalline with large surface area, high sorption capacity, and large Kds. Over time, corrosion products recrystallize by step-wise dehydration to phases with significantly smaller surface areas. The decreased surface area results in decreased sorption and the potential for remobilization of previously sorbed radionuclides. The impact of time-dependent variation in sorption on radionuclide transport is a complex function of the rate of recrystallization and the radionuclide half-life.A mathematical model has been developed, which coupling mass transport with corrosion product recrystallization and equilibrium sorption of radionuclides. The model is applied release of radionuclides with a range of half-lives (year to 100,000s of years) from radioactive waste disposal facilities to illustrate the significance of corrosion product recrystallization on release.

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