Effects of the Environmental Pressure in the Corrosion Potential of the Copper that Will Be Used as Container of High Level Radioactive Waste

2003 ◽  
Vol 807 ◽  
Author(s):  
I. Escobar ◽  
E Silva ◽  
C. Lamas ◽  
C. Silva ◽  
L. Werme
Keyword(s):  
Radioactive Waste ◽  
Metal Ion ◽  
Corrosion Potential ◽  
Electrochemical Cell ◽  
Copper Surface ◽  
Copper Corrosion ◽  
Deep Groundwater ◽  
Beneficial Effects ◽  
High Level ◽  
Work Up

ABSTRACTThe SKB project of Sweden has considered copper as the most appropriate metal to be used as container for high activity radioactive waste. However, it is still necessary to carry out some studies that can assure that their chemical, physical, mechanical properties, etc. do not loose stability in a period so long as 100.000 years.In this work we show using anodic polarization, the corrosion potential (Ecorr) behaviour in different pressurized environment. The copper surface was characterized using optical microscopy. The electrochemical cell was mounted in a high pressure chamber that allowed to work up to 40 atm. The electrolyte solution simulates the deep groundwater, being the composition reported in literature [1].The experimental results in solutions without bentonite show only slightly changes of the corrosion potential to cathodic values. At pressures of 40 atm, products of corrosion are observed, covering micropitting, that can be induced because of a bigger interaction metal/ ion at these pressures.In the other case, bentonite presence produces beneficial effects in the resistance of the copper corrosion, since it is observed that the corrosion potential is displaced to more anodics values. This effects could be explained due to that this clay is able to retain ions that are aggressives for copper, such as chloride, sulphide, etc., and it liberates others that don't produce deterioration, such as sodium, that is in concordance with others authors[15].

A Modeling Study of General Corrosion of Copper Overpack for Geological Isolation of High-Level Radioactive Waste

1999 ◽  
Vol 556 ◽  
Author(s):  
A. Honda ◽  
N Taniguchi ◽  
H. Ishikawa ◽  
M. Kawasaki
Keyword(s):  
Radioactive Waste ◽  
Rotating Disk ◽  
Copper Surface ◽  
Rotating Disk Electrode ◽  
General Corrosion ◽  
Reaction Products ◽  
High Level Radioactive Waste ◽  
Solution Layer ◽  
High Level ◽  
Modeling Study

AbstractThis paper describes a modeling study for general corrosion of copper which is a candidate material for high-level radioactive waste overpacks. The model is a mixed-potential model combined with diffusive transport of reactants and reaction products. The rest potential and corrosion rate of copper in aerated solution were measured while controlling the thickness of a diffusive solution layer on the copper surface using a rotating-disk electrode. Experimental data were used for validation of the model.

scholarly journals Graded Dietary Resistant Starch Concentrations on Apparent Total Tract Macronutrient Digestibility and Fecal Fermentative End-Products and Microbial Populations of Healthy Adult Dogs

2020 ◽  
Author(s):  
Alison N Beloshapka ◽  
Tzu-Wen L Cross ◽  
Kelly S Swanson
Keyword(s):  
Resistant Starch ◽  
Healthy Adult ◽  
Latin Square ◽  
Basal Diet ◽  
Gastrointestinal Health ◽  
Beneficial Effects ◽  
Gross Energy ◽  
Quadratic Effects ◽  
Fecal Ph ◽  
High Level

Abstract Resistant starch (RS) is fermentable by gut microbiota and effectively modulates fecal short-chain fatty acid concentrations in pigs, mice, and humans. RS may have similar beneficial effects on the canine gut, but has not been well studied. The objective of this study was to evaluate the effects of 0, 1, 2, 3, and 4% dietary RS (Hi-maize 260) on apparent total tract macronutrient digestibility, and fecal characteristics, fermentative end-product concentrations, and microbiota of healthy adult dogs. An incomplete 5 x 5 Latin square design with 7 dogs and 5 experimental periods was used, with each treatment period lasting 21 d (d 0-17 adaptation; d 18-21 fresh and total fecal collection) and each dog serving as its own control. Seven dogs (mean age = 5.3 yr; mean BW = 20 kg) were randomly allotted to one of five treatments formulated to be iso-energetic and consisting of graded amounts of 100% amylopectin cornstarch, RS, and cellulose, and fed as a top dressing on the food each day. All dogs were fed the same amount of a basal diet throughout the study and fresh water was offered ad libitum. The basal diet contained 6.25% RS (DM basis), contributing approximately 18.3 g of RS/d based on their daily food intake (292.5 g DM/d). Data were evaluated for linear and quadratic effects using SAS. The treatments included 0%, 1%, 2%, 3%, and 4% of an additional RS source. Because Hi-maize 260 is approximately 40% digestible and 60% indigestible starch, the dogs received the following amounts of RS daily: 0% = 18.3 g (18.3 g + 0 g); 1% = 20.1 g (18.3 g + 1.8 g); 2% = 21.9 g (18.3 g + 3.6 g); 3% = 23.7 g (18.3 g + 5.4 g); and 4% = 25.5 g (18.3 g + 7.2 g). Apparent total tract dry matter, organic matter, crude protein, fat, and gross energy digestibilities and fecal pH were linearly decreased (P < 0.05) with increased RS consumption. Fecal output was linearly increased (P < 0.05) with increased RS consumption. Fecal scores and fecal fermentative end-product concentrations were not affected by RS consumption. Although most fecal microbial taxa were not altered, Faecalibacterium were increased (P < 0.05) with increased RS consumption. The decrease in fecal pH and increase in fecal Faecalibacterium would be viewed as being beneficial to gastrointestinal health. Although our results seem to indicate that RS is poorly and/or slowly fermentable in dogs, the lack of observed change may have been due to the rather high level of RS contained in the basal diet.

New extractant for selective recovery of palladium from high level radioactive waste

1994 ◽  
Vol 187 (1) ◽  
pp. 19-24 ◽  
Author(s):  
V. Guyon ◽  
A. Guy ◽  
J. Foos ◽  
R. Chomel ◽  
T. Moutarde ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Selective Recovery ◽  
High Level Radioactive Waste ◽  
High Level

Chloride-Induced Localized Corrosion of Fe3Al-Type Iron Aluminides: Beneficial Effects of Cr And Mo Additions

1990 ◽  
Vol 213 ◽  
Author(s):  
R. A. Buchanan ◽  
J. G. Kim
Keyword(s):  
Corrosion Potential ◽  
Open Circuit ◽  
Iron Aluminides ◽  
Localized Corrosion ◽  
Aqueous Corrosion ◽  
Pitting Potential ◽  
Beneficial Effects ◽  
Protection Potential ◽  
Cr Concentration ◽  
Mo Additions

ABSTRACTIn this study, an acid-chloride electrolyte at pH = 4 (H2SO4) and containing 200 ppm Cl- was used to define the effects of Cr concentration (0–6 at.%) and Mo additions (0–2 at.%) on the aqueous corrosion behavior of iron aluminides containing 28 at.% Al. For the Fe-28Al composition, cyclic-anodic-polarization testing indicated passivation, but with a relatively low breakdown potential for pitting corrosion, and a protection potential lower than the open-circuit corrosion potential. Cr additions alone proved beneficial by continuously increasing the pitting potential. However, even at the highest Cr level, 6%, the protection potential was still lower than the corrosion potential, indicating that pitting could initiate after an incubation period. Mo additions were found to raise the protection potential, such that at 1 and 2% Mo levels (4 % Cr), it was higher than the corrosion potential, indicating significantly improved resistance to the initiation of localized corrosion. Immersion testing showed that the latter compositions remained passivated with no localized corrosion for a period of four months, at which point the tests were terminated. The overall results indicated that for satisfactory resistance to chlorideinduced localized corrosion, both higher Cr levels (4–6 at.%) and Mo additions (1–2 at.%) are desirable.

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