Hydrogen generation by water radiolysis with immersion of oxidation products of Zircaloy-4

2015 ◽  
Vol 52 (10) ◽  
pp. 1303-1307 ◽  
Author(s):  
Yoshinobu Matsumoto ◽  
Thi-Mai-Dung Do ◽  
Masao Inoue ◽  
Ryuji Nagaishi ◽  
Toru Ogawa
Keyword(s):  
Hydrogen Generation ◽  
Oxidation Products ◽  
Water Radiolysis

Review on Water Radiolysis in the Fukushima Daiichi Accident: Potential Cause of Hydrogen Generation and Explosion

2014 ◽  
Author(s):  
Genn Saji
Keyword(s):  
Hydrogen Generation ◽  
Hydrogen Gas ◽  
Severe Accident ◽  
Normal Operation ◽  
Water Radiolysis ◽  
Chain Reactions ◽  
Decay Heat ◽  
Severe Accidents ◽  
Heat Curve ◽  
Fukushima Daiichi

Although the water radiolysis, decomposition of water by radiation, is a well-known phenomenon the exact mechanism is not well characterized especially for severe accidents. The author first reviewed the water radiolysis phenomena in LWRs during normal operation to severe accidents (e.g., TMI- and Chernobyl accidents) and performed a scoping estimation of the amount of radiological hydrogen generation, accumulation and release for the Fukushima Daiichi accident. The estimation incorporates the decay heat curve after a reactor trip combined with G-values. As much as 450 cubic meters-STP of accumulated hydrogen gas is estimated to be located inside the PCV just prior to the hydrogen explosion which occurred a day after the reactor trip in Unit 1. When a set of radiological chain reactions are incorporated the resultant reverse reactions substantially reduce the hydrogen generation, even when removal of molecular products (i.e., oxygen and hydrogen) is assumed stripped rapidly from boiling water through bubbles. Even in the most favorable configuration a typical amount of hydrogen gas reduces to only several tens of cubic meters. Finally, the author tested a new mechanism, “radiation-induced electrolysis,” which had been applied to his corrosion studies for last several years. His theory has been verified with the published in-pile test data, although he has never tried to apply this to his severe accident study. The predicted results indicated that the total inventory of hydrogen gas inside RPV may reach as much as 1000 cubic meters in just 3 hours during the SBO due to a high decay heat soon after the reactor trip through this process.

scholarly journals The influence of various sized zircaloy-4 oxidation products on hydrogen generation of the water solution by Co-60 gamma radiolysis

2020 ◽  
Vol 7 (3) ◽  
pp. 19-00562-19-00562
Author(s):  
Yoshinobu MATSUMOTO ◽  
Tatsuya SUZUKI ◽  
Toru OGAWA ◽  
Masao INOUE ◽  
Ryuji NAGAISHI
Keyword(s):  
Hydrogen Generation ◽  
Water Solution ◽  
Oxidation Products ◽  
Gamma Radiolysis

The Anticoagulant Activity of 3.3’-(p-Alkylthio-Benzylidene)-Bis-4-Hydroxycoumarins and Their Oxidation Products

1967 ◽  
Vol 17 (01/02) ◽  
pp. 277-286 ◽  
Author(s):  
Maria Gumińska ◽  
M Eckstein ◽  
Barbara Stachurska ◽  
J Sulko
Keyword(s):  
Biological Activity ◽  
Anticoagulant Activity ◽  
Oxidation Products ◽  
Para Position ◽  
Sulphur Atom ◽  
Group I ◽  
One Step

SummaryThe anticoagulant activity of 3.3’-(benzylidene)-bis-4-hydroxycoumarin derivatives has been estimated by one step Quick’s method. The derivatives contained the following groups in the para position of benzylidene residue: NCS- (I), CH3-S- (II), CH3-SO-(III), CH3-S02- (IV), C2H5-S- (V), C2H5-SO- (VI), C2H5-S02- (VII). All these compounds were much more active than 3.3’-(benzylidene)-bis-4-hydroxycoumarin itself.Compounds possessing the ethyl chain at the sulphur atom (V, VI, VII) were more active than methyl homologues (II, III, IV). Comparison of the activity of the series of thio-, sulphoxy-, and sulphonyl-derivatives showed that among methyl- and ethyl-derivatives those with the sulphoxy grouping (III, VI) displayed the greatest anticoagulant activity. The action of sulphonyl (IV, VII) and thio-derivatives (II, V) was weaker and shortest. The derivative with the NCS-group (I) possessed a relatively the lowest activity among the investigated compounds. 3.3’-(p-Ethylsulphoxybenzyl-idene)-bis-4-hydroxycoumarin (VI), with distinct biological activity reached about ½ of dicoumarol activity.

Mechanistic Insights into Fe Catalyzed α-C-H Oxidations of Tertiary Amines

2019 ◽  
Author(s):  
Christopher J. Legacy ◽  
Frederick T. Greenaway ◽  
Marion Emmert
Keyword(s):  
Free Radical ◽  
Catalytic Mechanism ◽  
Catalyst System ◽  
Oxidation Products ◽  
Tertiary Amines ◽  
Catalyst Activation ◽  
Rate Determining Step ◽  
Fe Catalyst ◽  
Ligand Coordination ◽  
Rate Kinetics

We report detailed mechanistic investigations of an iron-based catalyst system, which allows the α-C-H oxidation of a wide variety of amines, including acyclic tertiary aliphatic amines, to afford dealkylated or amide products. In contrast to other catalysts that affect α-C-H oxidations of tertiary amines, the system under investigation employs exclusively peroxy esters as oxidants. More common oxidants (e.g. tBuOOH) previously reported to affect amine oxidations via free radical pathways do not provide amine α-C-H oxidation products in combination with the herein described catalyst system. Motivated by this difference in reactivity to more common free radical systems, the investigations described herein employ initial rate kinetics, kinetic profiling, Eyring studies, kinetic isotope effect studies, Hammett studies, ligand coordination studies, and EPR studies to shed light on the Fe catalyst system. The obtained data suggest that the catalytic mechanism proceeds through C-H abstraction at a coordinated substrate molecule. This rate-determining step occurs either at an Fe(IV) oxo pathway or a 2-electron pathway at a Fe(II) intermediate with bound oxidant. We further show via kinetic profiling and EPR studies that catalyst activation follows a radical pathway, which is initiated by hydrolysis of PhCO3 tBu to tBuOOH in the reaction mixture. Overall, the obtained mechanistic data support a non-classical, Fe catalyzed pathway that requires substrate binding, thus inducing selectivity for α-C-H functionalization.<br>

Study on the Oxidation Products of Hemp Seed Oil and its Application in Cosmetics

2020 ◽  
Vol 57 (3) ◽  
pp. 230-236 ◽  
Author(s):  
Yawei Huang ◽  
Liujun Pei ◽  
Xiaomin Gu ◽  
Jiping Wang
Keyword(s):  
Seed Oil ◽  
Oxidation Products ◽  
Hemp Seed

Comparative TG/DTG/DTA+FTIR Studies Concerning the Stability of Some Mineral and Vegetable Electro-Insulating Fluids

2018 ◽  
Vol 69 (9) ◽  
pp. 2366-2371
Author(s):  
Andrei Cucos ◽  
Petru Budrugeac ◽  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Andreea Voina
Keyword(s):  
Vegetable Oils ◽  
Electrical Equipment ◽  
Inert Atmosphere ◽  
Oxidation Products ◽  
Gaseous Products ◽  
Mineral Oils ◽  
Ftir Studies ◽  
Dta Analysis ◽  
Anti Oxidant ◽  
The Stability

Thermal TG/DTG/DTA analysis coupled with FTIR spectroscopy was applied to some sorts of mineral and vegetable oils used in electrical equipment. On heating in inert atmosphere, it was observed that the mineral oils vaporize, while the vegetable oils undergo hydrolysis, yielding fatty acids as main volatiles, as indicated by FTIR. In synthetic air, the FTIR spectra of gaseous products confirm the presence of similar oxidation products, both for mineral and vegetable oils. The TG results indicated that the vegetable-based oils exhibit a substantially higher thermal stability than the mineral oils. The presence or absence of anti-oxidant inhibitors in these oils greatly influences the onset of the oxidation process in air environment factor, as results from the DTA results.

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