Corrosion of Ticode-12 in A Simulated Waste Isolation Pilot Project (Wipp) Brine

1982 ◽  
Vol 15 ◽  
Author(s):  
T. M. Ahn ◽  
B. S. Lee ◽  
J. Woodward ◽  
R. L. Sabatini ◽  
P. Soo
Keyword(s):  
Corrosion Rate ◽  
Pilot Project ◽  
Intensity Level ◽  
Uniform Corrosion ◽  
Static Loads ◽  
Waste Container ◽  
Simulated Waste ◽  
High Level Nuclear Waste ◽  
Acidic Conditions ◽  
High Level

ABSTRACTThe corrosion behavior of TiCode-12 (Ti-0.3 Mo-0.8 Ni) high level nuclear waste container alloy has been studied for a simulated WIPP brine at a temperature of 150°C or below. Crevice corrosion was identified as a potentially important failure mode for this material. Within a mechanical crevice, a thick oxide film was found and shown to be the rutile form of TiO2, with a trace of lower oxide also present. Acidic conditions were found to cause a breakdown of the passive oxide layer. Solution aeration and increased acidity accelerate the corrosion rate. In hydrogen embrittlement studies, it was found that hydrogen causes a significant decrease in the apparent stress intensity level in fracture mechanics samples. Hydride formation is thought to be responsible for crack initiation. Stress corrosion cracking under static loads was not observed. Attention has also been given to methods for extrapolating short term uniform corrosion rate data to extended times.

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.

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.

scholarly journals Carbon-14 release and speciation from carbon steel in highly alkaline conditions

Radiocarbon ◽  
2018 ◽  
Vol 60 (6) ◽  
pp. 1683-1690
Author(s):  
Frank Druyts ◽  
Sébastien Caes ◽  
Peter Thomas
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Nuclear Power ◽  
Power Plants ◽  
Carbon 14 ◽  
Alkaline Conditions ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Reactor Pressure ◽  
Static Corrosion

ABSTRACTThe release and the speciation of carbon species from irradiated JRQ carbon steel samples, representative of the reactor pressure vessel of Belgian nuclear power plants, were studied in a saturated portlandite aqueous solution, relevant for the Belgian Supercontainer design, as perceived for the geological disposal of high-level nuclear waste. To achieve this, we performed simple immersion and potentiostatic corrosion tests. In addition, the corrosion rate (which determines the 14C release) was estimated by measuring the release of 60Co. Gas chromatography showed that during the static corrosion test, the carbonaceous species methane, carbon dioxide, ethene, and ethane were produced. Under the hypothesis that all the carbon released from the JRQ steel was transformed into carbon-base gaseous compounds, this corresponds to a corrosion rate of approximately 100 nm/yr, which is in good agreement with literature data.

Corrosion Processes Affecting the Performance of Alloy 22 as a High-Level Radioactive Waste Container Material

2000 ◽  
Vol 663 ◽  
Author(s):  
G.A. Cragnolino ◽  
D.S. Dunn ◽  
Y.-M. Pan ◽  
O. Pensado
Keyword(s):  
Radioactive Waste ◽  
Electrochemical Techniques ◽  
Department Of Energy ◽  
Localized Corrosion ◽  
Dissolution Behavior ◽  
Uniform Corrosion ◽  
High Level Radioactive Waste ◽  
Waste Container ◽  
Alloy 22 ◽  
High Level

ABSTRACTAlloy 22 is the material preferred by the U.S. Department of Energy for the waste package outer container for geological disposal of high-level radioactive waste at the proposed site in Yucca Mountain, Nevada. Alloy 22 is considered to be extremely resistant to various modes of aqueous corrosion over broad ranges of temperature, pH, and concentration of anionic and oxidizing species. Uniform corrosion under passive dissolution conditions, localized corrosion in the form of crevice corrosion, and stress corrosion cracking are discussed on the basis of experimental results obtained with mill annealed, thermally treated, and welded specimens using electrochemical techniques. The approach developed for long-term performance prediction, including the use of empirically derived parameters for assessing localized corrosion and the modeling of the passive dissolution behavior, is described.

scholarly journals Laser Photoacoustic Spectroscopy for Trace Level Detection of Actinides in Groundwater

1986 ◽  
Vol 84 ◽  
Author(s):  
Mark M. Doxtader ◽  
Victor A. Maroni ◽  
James V. Beitz ◽  
Michael Heaven
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Near Field ◽  
Trace Level ◽  
Field Environment ◽  
Waste Container ◽  
Laser Photoacoustic Spectroscopy ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Radionuclide Release

The Basalt Waste Isolation Project (Rockwell Hanford Operations- BWIP) is investigating the feasibility of building a repository in the Columbia River Basalts for the permanent disposal of high-level nuclear waste. One aspect of this effort is to develop an understanding of the chemical behavior of radionuclides in the near-field environment of the waste container. Such information is needed to determine radionuclide release rates from the waste package and to make long-term projections of repository performance. To accomplish this task, ultrasensitive laser- based techniques, such as laser photoacoustic spectroscopy (LPAS) and laser induced fluorescence (LIF), are being developed as analytical methods for the trace-level detection and speciation of actinides in solutions typical of those encountered in groundwaters near the BWIP repository.

Long-Term Thermal Stability of Alloy 825 as a High-Level Nuclear Waste Container Material

1995 ◽  
Vol 412 ◽  
Author(s):  
D. S. Dunn ◽  
Y.-M. Pan ◽  
G. A. Cragnolino ◽  
N. Sridhar
Keyword(s):  
Grain Boundary ◽  
Nuclear Waste ◽  
Elevated Temperatures ◽  
Thermal Exposure ◽  
Boundary Region ◽  
Waste Container ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Welding Processes ◽  
Container Material

AbstractThe thermal exposure of Fe-Cr-Ni-Mo materials to certain temperature regimes often results in the formation of grain boundary carbides and the associated depletion of alloying elements. This phenomenon, termed sensitization, is frequently the result of welding processes or in service exposure to elevated temperatures. In this investigation, alloy 825, a candidate high-level nuclear waste (HLW) container material, was thermally exposed to temperatures in the range of 550 to 800 °C for periods of up to 1,000 hr. Sensitization of the material was evaluated by corrosion tests and grain boundary analyses using an analytical electron microscope. The sensitized microstructure was found to contain M23C6-type carbides as well as a Cr-depleted region in the vicinity of the grain boundaries. The degree of sensitization was correlated to the extent of Cr depletion in the grain boundary region.

scholarly journals Characterization of the Resistance of Alloy 22 to Stress Corrosion Cracking

2002 ◽  
Author(s):  
Kenneth J. King ◽  
John C. Estill ◽  
Rau´l B. Rebak
Keyword(s):  
Slow Strain Rate Test ◽  
Environmentally Assisted Cracking ◽  
Waste Container ◽  
Alloy 22 ◽  
Aqueous Environments ◽  
Current Design ◽  
Rate Test ◽  
High Level Nuclear Waste ◽  
High Level

In its current design, the high-level nuclear waste container includes an external layer of Alloy 22 (Ni-22Cr-13Mo-3W-3Fe). Since the containers may be exposed to multi-ionic aqueous environments over their lifetime, a potential degradation mode of the outer layer could be environmentally assisted cracking (EAC). The objective of the current research is to characterize the effect of applied potential and temperature on the susceptibility of Alloy 22 to EAC in simulated concentrated water (SCW) using the slow strain rate test (SSRT). Results show that Alloy 22 may suffer EAC at applied potentials approximately 400 mV more anodic than the corrosion potential (Ecorr).

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