Effects of Environment on Localized Corrosion of Copper-Based, High-Level Waste Container Materials

CORROSION ◽  
1993 ◽  
Vol 49 (12) ◽  
pp. 967-976 ◽  
Author(s):  
N. Sridhar ◽  
G. A. Cragnolino
Keyword(s):  
Localized Corrosion ◽  
High Level Waste ◽  
Waste Container ◽  
High Level

The Use of Repassivation Potential in Predicting The Performance of High-Level Nuclear Waste Container Materials

1994 ◽  
Vol 353 ◽  
Author(s):  
Narasi Sridhar ◽  
Darrell Dunn ◽  
Gustavo Cragnolino
Keyword(s):  
Field Tests ◽  
Localized Corrosion ◽  
High Level Waste ◽  
Repassivation Potential ◽  
Waste Container ◽  
Highly Sensitive ◽  
Plant Equipment ◽  
Robust Parameter ◽  
High Level Nuclear Waste ◽  
High Level

AbstractLocalized corrosion in aqueous environments forms an important bounding condition for the performance assessment of high-level waste (HLW) container materials. A predictive methodology using repassivation potential is examined in this paper. It is shown, based on long-term (continuing for over 11 months) testing of alloy 825, that repassivation potential of deep pits or crevices is a conservative and robust parameter for the prediction of localized corrosion. In contrast, initiation potentials measured by short-term tests are non-conservative and highly sensitive to several surface and environmental factors. Corrosion data from various field tests and plant equipment performance are analyzed in terms of the applicability of repassivation potential. The applicability of repassivation potential for predicting the occurrence of stress corrosion cracking (SCC) and intergranular corrosion in chloride containing environments is also examined.

An Approach to Analysis of High Level waste Container Performance in an Unsaturated Repository Environment

1993 ◽  
Vol 333 ◽  
Author(s):  
John C. Walton ◽  
Narasi Sridhar ◽  
Gustavo Cragnolino ◽  
Tony Torng ◽  
Prasad Nair
Keyword(s):  
Dominant Role ◽  
Near Field ◽  
Temperature Fields ◽  
Localized Corrosion ◽  
High Level Waste ◽  
Quantitative Methodology ◽  
Waste Container ◽  
Wide Range ◽  
Engineered Barrier ◽  
High Level

ABSTRACTOne of the requirements for the performance of waste packages prescribed in 10CFR 60.113 is that the high level waste must be “substantially completely” contained for a minimum period of 300 to 1000 years. During this period, the radiation and thermal conditions in the engineered barrier system and the near-field environment are dominated by fission product decay. In the present U.S design of the engineered barrier system, the outer container plays a dominant role in maintaining radionuclide containment. A quantitative methodology for analyzing the performance of the container is described in this paper. This methodology enables prediction of the evolution of the waste package environment in terms of temperature fields, stability of liquid water on the container surface, and concentration of aggressive ions such as chloride. The initiation and propagation of localized corrosion is determined by the corrosion potential of the container material and critical potentials for localized corrosion. The coiTOsion potential is estimated from the kinetics of the anodic and cathodic reactions including oxygen diffusion through scale layers formed on the container surface. The methodology described is applicable to a wide range of metals, alloys and environmental conditions.

Environmental Effects on Localized Corrosion of a High-Level Nuclear Waste Container Material

1990 ◽  
Vol 212 ◽  
Author(s):  
N. Sridhar ◽  
G. Cragnolino ◽  
W. Machowski
Keyword(s):  
Localized Corrosion ◽  
A Value ◽  
Waste Container ◽  
Electrochemical Parameters ◽  
Cyclic Potentiodynamic Polarization ◽  
High Level Nuclear Waste ◽  
Full Factorial Experimental Design ◽  
High Level ◽  
Full Factorial ◽  
High Chloride

ABSTRACTThe effect of environmental variables on the localized corrosion behavior of alloy 825 is examined in this paper. Cyclic, potentiodynamic polarization tests based on a two-level, full factorial experimental design were conducted. An index incorporating both the visual and scanning electron microscope examinations of localized corrosion and the electrochemical parameters was used for the statistical analysis. The analysis showed that chloride is the single most important promoter of localized corrosion, while nitrate was the single most important inhibitor. Fluoride was a weak inhibitor, especially at low chloride levels. Sulfate was a weak promoter, especially at high chloride levels. Temperature did not have a significant effect within the chloride levels examined. Separate experiments indicated that silicon, added as metasilicate, did not have any significant effect on localized corrosion. The adverse effect of chloride was observed at concentrations as low as 100 ppm. Addition of H2O2 increased the corrosion potential of alloy 825 to a value above the repassivation potential observed in the 300 ppm chloride solution.

Modeling of the oxic stage in a HLW disposal cell in an argillaceous host rock

2012 ◽  
Vol 1475 ◽  
Author(s):  
François Marsal ◽  
Laurent De Windt ◽  
Delphine Pellegrini
Keyword(s):  
Reactive Transport ◽  
Near Field ◽  
Pyrite Oxidation ◽  
Gas Diffusion ◽  
Radioactive Waste Disposal ◽  
Localized Corrosion ◽  
High Level Waste ◽  
Perfect Contact ◽  
High Level ◽  
Water Saturated

ABSTRACTDetermining the redox conditions in the near field of deep underground radioactive waste disposal cells is a key question regarding the performance of metallic components (e.g. waste overpack), which may undergo drastic corrosion processes in oxic conditions. This oxic transient is supposed to be short due notably to the oxygen consumption by corrosion and pyrite oxidation. However, the observed precipitation of Fe(III)-minerals as well as localized corrosion patterns on steel coupons placed during 6 years in a borehole drilled in the Toarcian argillite of Tournemire (France) may suggest that in-situ oxic conditions lasted several years, which is not consistent with reactive transport simulations performed with usual hypotheses (perfect contact between materials, high pyrite accessibility, water saturated conditions). Multicomponent reactive transport simulations considering gas diffusion were performed with the code HYTEC and reproduce correctly the observations made in Tournemire while considering imperfect interfaces and resaturation processes. The model was then applied to a disposal cell for high-level waste (HLW) representative of the design developed in France, putting into evidence the possibility of a redox contrast between the front and back of a disposal cell in an argillaceous medium, as well as a duration of the oxic stage within the cell as long as the ventilation of handling drifts is maintained.

Investigation on Corrosion Behavior of High-Level Waste Container Materials

PRICM ◽  
2013 ◽  
pp. 167-179
Author(s):  
Qiufa Xu ◽  
Wei Wang ◽  
Xiaolu Pang ◽  
Quanlin Liu ◽  
Kewei Gao
Keyword(s):  
Corrosion Behavior ◽  
High Level Waste ◽  
Waste Container ◽  
High Level
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