Corrosion Rates of Zircaloy-4 by Hydrogen Measurement under High pH, Low Oxygen and Low Temperature Conditions

2012 ◽  
Vol 1475 ◽  
Author(s):  
Tomofumi SAKURAGI ◽  
Hideaki MIYAKAWA ◽  
Tsutomu NISHIMURA ◽  
Tsuyoshi TATEISHI
Keyword(s):  
Corrosion Rate ◽  
Hydrogen Absorption ◽  
Gas Flow ◽  
Flow System ◽  
Low Oxygen ◽  
Solution Ph ◽  
Absorption Ratio ◽  
Naoh Solution ◽  
Image Position

ABSTRACTCorrosion tests of Zircaloy-4 were performed in a dilute NaOH solution (pH =12.5) at 303 K for 90 days using the gas flow system (oxygen; < 1 ppb) and a batch method (oxygen; < 0.1 ppm). The corrosion rate was determined by measuring gaseous hydrogen and the hydrogen absorbed into Zircaloy-4 assuming the following reaction:where x represents the Zircaloy-4 hydrogen absorption ratio. The initial hydrogen content in the Zircaloy-4 specimen was controlled to be below 10 ppm. The corrosion rate decreased with time (90-day values: 2.46×10-3 and 2.37×10-3 μm/y for the gas flow method and 6.72×10-2 μm/y for the batch test). The Zircaloy-4 hydrogen absorption ratio during corrosion was over 90%. The large amount of hydrogen absorbed in Zircaloy-4 will play an important role in the long-term safety for the disposal of irradiated Zircaloy materials.

Long-term Corrosion of Zircaloy-4 and Zircaloy-2 by Continuous Hydrogen Measurement under Repository Condition

2013 ◽  
Vol 1518 ◽  
pp. 173-178 ◽  
Author(s):  
Tomofumi Sakuragi ◽  
Hideaki Miyakawa ◽  
Tsutomu Nishimura ◽  
Tsuyoshi Tateishi
Keyword(s):  
Corrosion Behavior ◽  
Gas Flow ◽  
Hydrogen Generation ◽  
Tetragonal Zirconia ◽  
Solution Ph ◽  
Naoh Solution ◽  
The Difference ◽  
Process Controls ◽  
Kinetics Of

ABSTRACTCorrosion behavior is a key issue for the waste disposal of irradiated metals, such as hulls and endpieces, and is considered to be a leaching source of radionuclides including C-14. However, little information about Zircaloy corrosion in anticorrosive conditions has been provided.In the present study, long-term corrosion tests of Zircaloy-4 and Zircaloy-2 were performed in assumed disposal conditions (dilute NaOH solution, pH 12.5, 303 K) by using the gas flow system for 1500 days. The corrosion rate, which was determined by measuring gaseous hydrogen and the hydrogen absorbed in Zircaloy, decreased with immersion time and was lower than the value of 2×10−2 μm/y used in performance assessment (1500-day values: 5.84×10−3 and 5.66×10−3 μm/y for Zircaloy-4, 1000-day values: 8.81×10−3 μm/y for Zircaloy-2). The difference in corrosion behavior between Zircaloy 4 and Zircaloy-2 was negligible. The average values of the hydrogen absorption ratios for Zircaloy-4 and Zircaloy-2 during corrosion were 91% and 94%, respectively.The hydrogen generation kinetics of both gas evolution and absorption into metal can be shown by a parabolic curve. This result indicates that the diffusion process controls the Zircaloy corrosion in the early corrosion stage of the present study, and that the thickness of the oxide film in this stage is limited to approximately 25 nm and may therefore be in the form of dense tetragonal zirconia.

scholarly journals Identification of chemical form of stable carbon released from type 304L and 316L stainless-steel powders in alkaline and acidic solutions under low-oxygen conditions

Radiocarbon ◽  
2018 ◽  
Vol 60 (6) ◽  
pp. 1691-1710
Author(s):  
Ryo Nakabayashi ◽  
Tomonari Fujita
Keyword(s):  
Stainless Steel ◽  
Carboxylic Acids ◽  
Safety Assessment ◽  
Silicon Oxide ◽  
Chemical Form ◽  
Low Oxygen ◽  
Colloidal Carbon ◽  
Oxygen Conditions ◽  
Naoh Solution

ABSTRACTThe chemical form of14C released from irradiated stainless steel is a key parameter in the safety assessment of the subsurface disposal system in Japan. In this study, to identify the chemical form of the released carbon, unirradiated stainless-steel powders, which were found to be water-atomized powders with a silicon oxide film, were immersed in NaOH and HCl solutions under low-oxygen conditions for approximately 25 days. The results showed that the main chemical forms of the carbon were colloidal carbon in the NaOH solution and colloidal carbon and formic and acetic acids in the HCl solution. Almost no hydrocarbons were detected in both solution systems. Concerning the source of the colloidal carbon and carboxylic acids, the hypothesis that carbon in the oxide layer is released is considered to be reasonable. The very small amounts of hydrocarbons generated prevented us from discussing the source of the hydrocarbons. To validate the hypothesis and obtain further information on the hydrocarbons, additional experiments are necessary. In particular, for long-term safety assessment, it is important to determine whether the colloidal carbon, carboxylic acids and hydrocarbons are continuously released during the corrosion process. Therefore, information on the temporal evolution of the carbon should be obtained.

scholarly journals Evaluation of hydrogen gas flow system in DECY - 13 cyclotron

2021 ◽  
Vol 1825 (1) ◽  
pp. 012027
Author(s):  
F I Diah ◽  
Saminto ◽  
V A F Sari ◽  
K Wibowo ◽  
F S Permana
Keyword(s):  
Gas Flow ◽  
Flow System ◽  
Hydrogen Gas

scholarly journals Waterlogging-Stress-Responsive LncRNAs, Their Regulatory Relationships with MiRNAs and Target Genes in Cucumber (Cucumis sativus L.)

2021 ◽  
Vol 22 (15) ◽  
pp. 8197
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Adela Adamus ◽  
Małgorzata Czernicka
Keyword(s):  
Target Genes ◽  
Recovery Period ◽  
Sufficient Information ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Cucumis Sativus L ◽  
Waterlogging Stress ◽  
Non Coding Rna

Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber.

scholarly journals Synthesis of Ambient Cured GGBFS Based Alkali Activated Binder Using a Sole Alkaline Activator: A Feasibility Study

2021 ◽  
Vol 11 (13) ◽  
pp. 5887
Author(s):  
Thandiwe Sithole ◽  
Nelson Tsotetsi ◽  
Tebogo Mashifana
Keyword(s):  
Silicate Solution ◽  
Environmental Footprint ◽  
Ambient Temperatures ◽  
Granulated Blast Furnace Slag ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Porous Morphology ◽  
Furnace Slag ◽  
Alkali Activated

Utilisation of industrial waste-based material to develop a novel binding material as an alternative to Ordinary Portland Cement (OPC) has attracted growing attention recently to reduce or eliminate the environmental footprint associated with OPC. This paper presents an experimental study on the synthesis and evaluation of alkali activated Ground granulated blast furnace slag (GGBFS) composite using a NaOH solution as an alkaline activator without addition of silicate solution. Different NaOH concentrations were used to produce varied GGBFS based alkali activated composites that were evaluated for Uncofined Compressive Strength (UCS), durability, leachability, and microstructural performance. Alkali activated GGBFS composite prepared with 15 M NaOH solution at 15% L/S ratio achieved a UCS of 61.43 MPa cured for 90 days at ambient temperatures. The microstructural results revealed the formation of zeolites, with dense and non-porous morphology. Alkali activated GGBFS based composites can be synthesized using a sole alkaline activator with potential to reduce CO2 emission. The metal leaching tests revealed that there are no potential environmental pollution threats posed by the synthesized alkali activated GGBFS composites for long-term use.

An electron spin resonance study of the reactions of hydrogen atoms with halocarbons

1986 ◽  
Vol 64 (11) ◽  
pp. 2192-2195 ◽  
Author(s):  
William E. Jones ◽  
Joseph L. Ma
Keyword(s):  
Rate Constants ◽  
Gas Flow ◽  
Esr Spectroscopy ◽  
Flow System ◽  
Electron Spin Resonance Study ◽  
Absolute Rate ◽  
Hydrogen Atoms ◽  
Vinyl Halides ◽  
Spin Resonance ◽  
Spin Resonance Study

The absolute rate constants for the reaction of H atoms with methyl- and vinyl-halides have been determined using esr spectroscopy and a conventional gas flow system. The rate constants determined at 298 ± 2 K at a pressure of 0.55 Torr are methane, (1.7 ± 0.3) × 10−17; ethane, (2.3 ± 0.5) × 10−17; methylfluoride, (4 ± 3) × 10−15; methylchloride, (8 ± 2) × 10−16; methylbromide, (2.1 ± 0.6) × 10−14; vinylfluoride, (1.47 ± 0.02) × 10−13; vinylchloride, (1.66 ± 0.08) × 10−13; and vinylbromide (4.07 ± 0.73) × 10−13 in units of cm3 molecule−1 s−1.

scholarly journals DNA Methylation Changes duringIn VitroPropagation of Human Mesenchymal Stem Cells: Implications for Their Genomic Stability?

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Angela Bentivegna ◽  
Mariarosaria Miloso ◽  
Gabriele Riva ◽  
Dana Foudah ◽  
Valentina Butta ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Ex Vivo ◽  
Genomic Stability ◽  
Great Promise ◽  
Human Mscs ◽  
Low Oxygen ◽  
Long Term Culture ◽  
Functional Changes

Mesenchymal stem cells (MSCs) hold great promise for the treatment of numerous diseases. A major problem for MSC therapeutic use is represented by the very low amount of MSCs which can be isolated from different tissues; thusex vivoexpansion is indispensable. Long-term culture, however, is associated with extensive morphological and functional changes of MSCs. In addition, the concern that they may accumulate stochastic mutations which lead the risk of malignant transformation still remains. Overall, the genome of human MSCs (hMSCs) appears to be apparently stable throughout culture, though transient clonal aneuploidies have been detected. Particular attention should be given to the use of low-oxygen environment in order to increase the proliferative capacity of hMSCs, since data on the effect of hypoxic culture conditions on genomic stability are few and contradictory. Furthermore, specific and reproducible epigenetic changes were acquired by hMSCs duringex vivoexpansion, which may be connected and trigger all the biological changes observed. In this review we address current issues on long-term culture of hMSCs with a 360-degree view, starting from the genomic profiles and back, looking for an epigenetic interpretation of their genetic stability.

From one ritual to another: the long-term sequence of the Bury gallery grave (northern France, fourth–second millennia BC)

Antiquity ◽  
2017 ◽  
Vol 91 (355) ◽  
pp. 57-73
Author(s):  
Laure Salanova ◽  
Philippe Chambon ◽  
Jean-Gabriel Pariat ◽  
Anne-Sophie Marçais ◽  
Frédérique Valentin
Keyword(s):  
Northern France ◽  
Image Position

Abstract

scholarly journals Long-Term Waterlogging as Factor Contributing to Hypoxia Stress Tolerance Enhancement in Cucumber: Comparative Transcriptome Analysis of Waterlogging Sensitive and Tolerant Accessions

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 189
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Izabela Makałowska ◽  
Małgorzata Czernicka
Keyword(s):  
Stress Tolerance ◽  
De Novo ◽  
Average Length ◽  
Marker Genes ◽  
Long Term Memory ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Pre Treatment ◽  
Waterlogging Treatment

Waterlogging (WL), excess water in the soil, is a phenomenon often occurring during plant cultivation causing low oxygen levels (hypoxia) in the soil. The aim of this study was to identify candidate genes involved in long-term waterlogging tolerance in cucumber using RNA sequencing. Here, we also determined how waterlogging pre-treatment (priming) influenced long-term memory in WL tolerant (WL-T) and WL sensitive (WL-S) i.e., DH2 and DH4 accessions, respectively. This work uncovered various differentially expressed genes (DEGs) activated in the long-term recovery in both accessions. De novo assembly generated 36,712 transcripts with an average length of 2236 bp. The results revealed that long-term waterlogging had divergent impacts on gene expression in WL-T DH2 and WL-S DH4 cucumber accessions: after 7 days of waterlogging, more DEGs in comparison to control conditions were identified in WL-S DH4 (8927) than in WL-T DH2 (5957). Additionally, 11,619 and 5007 DEGs were identified after a second waterlogging treatment in the WL-S and WL-T accessions, respectively. We identified genes associated with WL in cucumber that were especially related to enhanced glycolysis, adventitious roots development, and amino acid metabolism. qRT-PCR assay for hypoxia marker genes i.e., alcohol dehydrogenase (adh), 1-aminocyclopropane-1-carboxylate oxidase (aco) and long chain acyl-CoA synthetase 6 (lacs6) confirmed differences in response to waterlogging stress between sensitive and tolerant cucumbers and effectiveness of priming to enhance stress tolerance.

scholarly journals Populations dynamics in Northern Eurasian forests: a long-term perspective from Northeast Asia

2020 ◽  
Vol 2 ◽  
Author(s):  
Junzo Uchiyama ◽  
J. Christopher Gillam ◽  
Alexander Savelyev ◽  
Chao Ning
Keyword(s):  
Northeast Asia ◽  
Image Position ◽  
Populations Dynamics

Abstract

Sign in / Sign up

Export Citation Format

Share Document