Continuous monitoring of the pH value and the chloride concentration in the water coolant of nuclear reactors

1975 ◽  
Vol 38 (3) ◽  
pp. 182-185 ◽  
Author(s):  
L. N. Moskvin ◽  
V. M. Krasnoperov ◽  
R. G. Fokina ◽  
N. Ya. Vilkov
Keyword(s):  
Continuous Monitoring ◽  
Ph Value ◽  
Nuclear Reactors ◽  
Chloride Concentration ◽  
Water Coolant

Corrosion Resistance of High-Alloyed Material UNS N08028 in Sodium Chloride Solution

2014 ◽  
Vol 893 ◽  
pp. 440-443
Author(s):  
Li Na Zhang ◽  
Jerzy A. Szpunar ◽  
Jian Xin Dong ◽  
Mai Cang Zhang
Keyword(s):  
Corrosion Resistance ◽  
Sodium Chloride ◽  
Corrosion Rate ◽  
Current Density ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Corrosion Potential ◽  
Ph Value ◽  
Chloride Concentration ◽  
Decreasing Ph

The influence of ions chloride concentration and pH value on the corrosion resistance of high-alloyed material UNS N08028 in the sodium chloride solution is investigated. Results show that the corrosion potential is active cathodically with the increase of chloride concentration. The current density and corrosion rate both increase with increasing chloride concentration and decreasing pH value.

scholarly journals COMBINED EFFECT OF CARBONATION AND CHLORIDE AGGRESSION: DEG-RADATION OF REINFORCED CONCRETE STRUCTURES

2018 ◽  
Author(s):  
L.V. KIM ◽  
E.E. SHALYI ◽  
S.N. LEONOVICH ◽  
N.A. BUDREVICH
Keyword(s):  
Reinforced Concrete ◽  
Ph Value ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Protective Layer ◽  
Sharp Decrease ◽  
Threshold Concentration ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Cross Sectional

Corrosion reinforcement marine hydraulic structures due to chloride aggression and carbonization of concrete leads to a sharp decrease in the safety of the structure. The steel reinforcement will be subjected to a so-called depassivation process, once the chloride concentration on surface exceeds a certain threshold concentration, or the pH value in the protective layer of concrete decreases to a threshold value due to carbonation. Electrochemical reactions begin to occur with the formation of corrosion products with the penetration of oxygen on the steel reinforcement surface. This leads to cracking of the protective layer of concrete. It should also be taken into account that, due to corrosion mechanisms, the cross-sectional area of the reinforcement also decreases. The article suggests a method for predicting the complex degradation of reinforced concrete structures, taking into account various mechanisms of corrosion wear, which will allow developing effective ways to improve the durability and maintainability of structures operated in the marine environment.

scholarly journals Electrochemical Degradation of Crystal Violet Using Ti/Pt/SnO2 Electrode

2021 ◽  
Vol 11 (18) ◽  
pp. 8401
Author(s):  
Rachid El Brychy ◽  
Mohamed Moutie Rguiti ◽  
Nadia Rhazzane ◽  
Moulay Driss Mellaoui ◽  
Khalid Abbiche ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Crystal Violet ◽  
Current Density ◽  
Ph Value ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Initial Ph

Today, organic wastes (paints, pigments, etc.) are considered to be a major concern for the pollution of aqueous environments. Therefore, it is essential to find new methods to solve this problem. This research was conducted to study the use of electrochemical processes to remove organic pollutants (e.g., crystal violet (CV)) from aqueous solutions. The galvanostatic electrolysis of CV by the use of Ti/Pt/SnO2 anode, were conducted in an electrochemical cell with 100 mL of solution using Na2SO4 and NaCl as supporting electrolyte, the effect of the important electrochemical parameters: current density (20–60 mA cm−2), CV concentration (10–50 mg L−1), sodium chloride concentration (0.01–0.1 g L−1) and initial pH (2 to 10) on the efficiency of the electrochemical process was evaluated and optimized. The electrochemical treatment process of CV was monitored by the UV-visible spectrometry and the chemical oxygen demand (COD). After only 120 min, in a 0.01mol L−1 NaCl solution with a current density of 50 mA cm−2 and a pH value of 7 containing 10 mg L−1 CV, the CV removal efficiency can reach 100%, the COD removal efficiency is up to 80%. The process can therefore be considered as a suitable process for removing CV from coloured wastewater in the textile industries.

Box-Behnken Design Approach Toward Predicting the Corrosion Response of 13Cr Stainless Steel

CORROSION ◽  
10.5006/3429 ◽  
2020 ◽  
Vol 76 (4) ◽  
pp. 356-365
Author(s):  
Mostafa Kazemipour ◽  
Salar Salahi ◽  
Ali Nasiri
Keyword(s):  
Stainless Steel ◽  
Environmental Factors ◽  
Corrosion Behavior ◽  
Ph Value ◽  
Chloride Concentration ◽  
Localized Corrosion ◽  
Quadratic Model ◽  
Medium Temperature ◽  
Pitting Potential ◽  
Box Behnken Design

13Cr stainless steel, the most commonly used oil country tubular good material with good mechanical and corrosion behavior, has the drawback of sensitivity to localized corrosion, particularly in offshore downhole environments, limiting the life span of the parts. A careful assessment of the corrosion behavior of the material can be done by the perception of the most influential environmental factors combined with the material’s intrinsic microstructure. This study aims to focus on the former, the effect of environmental factors, including pH, temperature, and chloride concentration, varying in the ranges of 4 to 7, 22°C to 80°C, and 1,000 mg/L to 22,000 mg/L, respectively, on the pitting corrosion behavior of 13Cr stainless steel. Adopting a response surface methodology, using a Box-Behnken design, a carefully designed set of corrosion tests at various combinations of the environmental factors were performed. Considering the pitting potential measured from the cyclic potentiodynamic polarization testing, as the response of each experiment, a quadratic model was developed correlating the studied environmental factors and the pitting potential values. Further analysis of the developed model was conducted through analysis of variance, followed by optimizing the model according to the highest, medium, and lowest pitting potentials. The optimized results confirmed that the best corrosion behavior occurs at approximately the lowest chloride concentration and temperature, and the highest pH value. However, contrary to the expectations, the worst corrosion response was detected at the medium temperature of 52°C, instead of the highest temperature of 80°C. It was concluded that at higher temperatures, the corrosion tends to be more uniform, resulting in the formation of a layer of corrosion products that covers the sample’s surface. The corrosion product layer acts as a barrier against the diffusion of the aggressive ions, causing deceleration of the corrosion reactions.

Studies on Treatment of Simulated Printing and Dyeing Wastewater on Titanium Electrode Coated MnO2 Doped with Ce

2011 ◽  
Vol 347-353 ◽  
pp. 822-825
Author(s):  
Xiao Lv Zhou ◽  
Xiao Wen Tan ◽  
Huan Li ◽  
Fei Shang
Keyword(s):  
Current Density ◽  
Ph Value ◽  
Chloride Concentration ◽  
Electrolysis Time ◽  
Dyeing Wastewater ◽  
Solution Ph ◽  
Printing And Dyeing Wastewater ◽  
Titanium Electrode ◽  
Effect Of Treatment ◽  
Optimized Conditions

Experiments on treatment of simulated printing and dyeing wastewater by prepared titanium-based electrode coated manganese dioxide doped with cerium were carried out in this paper. Factors such as current density, electrolyte concentration, solution pH value, electrolysis time, initial concentration of simulation printing and dyeing wastewater on the effect of treatment were also investigated. It is showed that: utilizing the self- prepared electrode to treat printing and dyeing wastewater in optimized conditions, which current density is 30mA/cm2, electrolyte (sodium chloride) concentration is 0.1 mol/L, electrolysis time is 80min, and pH is 9, 92% and 97% of CODcr and color removal were achieved, respectively.

scholarly journals An Automatic System for Continuous Monitoring and Sampling of Groundwater Geochemistry in Earthquake-Prone Regions of SW Taiwan

2021 ◽  
Vol 9 ◽  
Author(s):  
Ching-Chou Fu ◽  
Chun-Wei Lai ◽  
Tsanyao Frank Yang ◽  
David R. Hilton ◽  
Cheng-Hong Chen ◽  
...  
Keyword(s):  
Automatic System ◽  
Continuous Monitoring ◽  
Inorganic Carbon ◽  
Hot Springs ◽  
Dissolved Inorganic Carbon ◽  
Chloride Concentration ◽  
Temporal Analysis ◽  
Automated System ◽  
Dissolved Gas ◽  
Tectonic Structures

Previous studies have revealed that gas compositions of fluid samples collected from southwestern Taiwan, where many hot springs and mud volcanoes are distributed along with tectonic structures, show significant variation before and after some disaster seismic events. Such variations, including radon activity, CH4/CO2, and 3He/4He ratios of gas compositions, are considered precursors of earthquakes in this area. An automatic system for continuous on-line gas monitoring and groundwater sampling was established at Yun-Shui (YS), where an artesian well located at an active fault zone in SW Taiwan, to validate the relationship between fluid compositions and seismicity. It is equipped with a quadrupole mass spectrometer (QMS) and a radon detector for in-situ measurement of the dissolved gas composition. Variations of dissolved gas compositions are transmitted to the laboratory through the internet. Furthermore, a syringe pump apparatus for the retrieval and temporal analysis of helium (SPARTAH) is also installed for off-line laboratory analysis for obtaining the detailed time-series records of helium, hydrogen, oxygen, and dissolved inorganic carbon (DIC) isotopic compositions as well as dissolved inorganic carbon and chloride concentration of water samples at this station. After continuous monitoring for several months, two substantial anomalies of multiparameter were observed prior to the significant earthquakes. This automated system has been demonstrated to be feasible for long-term continuous seismo-geochemical research in this area.

scholarly journals Reinforced Concrete under the Action of Carbonization and Chloride Aggression: a Probabilistic Model for Service Life Prediction

2019 ◽  
Vol 18 (4) ◽  
pp. 284-291 ◽  
Author(s):  
S. N. Leonovich ◽  
E. E. Shalyi ◽  
L. V. Kim
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Life Prediction ◽  
Ph Value ◽  
Chloride Concentration ◽  
Protective Layer ◽  
Service Life Prediction ◽  
Simultaneous Action ◽  
Shelf Zone ◽  
Reinforcement Corrosion

Reinforcement corrosion of marine and coastal hydraulic structures due to chloride aggression and concrete carbonization leads to a sharp decrease in structure safety. The reinforcement is subjected to a depassivation process as soon as a chloride concentration on its surface exceeds a certain threshold concentration, or the pH value in a concrete protective layer is decreased to a threshold value due to carbonation. Electrochemical reactions are realized with formation of corrosion products due to penetration of oxygen up to reinforcement surface. This leads to cracking of the concrete protective layer and decrease in reinforcement cross-section. The paper proposes a method for predicting a complex degradation of reinforced concrete structures with due account of various mechanisms of corrosion wear that allows to develop efficient methods for improvement of structure durability and maintainability which are operated in the marine environment. A methodology for forecasting of reinforced concrete service life prediction has been developed under a combined effect of carbonization and chloride aggression while using finite-difference and probability models. The paper takes into account initiation periods of reinforcement corrosion and propagation periods for conditions of Sakhalin shelf zone. Field surveys of Kholmsk and Korsakov port facilities are presented in the paper. Carbonization front and chloride content have been estimated according to depth of the concrete protective layer. The paper proposes a model that allows to determine an average period prior to repair while taking into account rate of concrete protective layer degradation caused by simultaneous action of two corrosion processes: carbonization and chloride aggression.

Production of Four Interfacial Active Rhamnolipids from n-Alkanes or Glycerol by Resting Cells of Pseudomonas species DSM 2874

1985 ◽  
Vol 40 (1-2) ◽  
pp. 61-67 ◽  
Author(s):  
C. Syldatk ◽  
S. Lang ◽  
U. Matulovic ◽  
F. Wagner
Keyword(s):  
Sodium Chloride ◽  
Phosphate Buffer ◽  
Chloride Solution ◽  
Time Course ◽  
Ph Value ◽  
Cell Concentration ◽  
Chloride Concentration ◽  
Resting Cells ◽  
Pseudomonas Species ◽  
Optimal Ph

In a simple phosphate buffer or a sodium chloride solution resting cells of Pseudomonas spec. DSM 2874 produced up to 15 g/l of different rhamnolipids. The rhamnolipid composition of the organic crude extract depended on the temperature during the cultivation and on the C-source. The optimal sodium chloride concentration for rhamnolipid formation was about 100 mᴍ/l and the optimal phosphate buffer concentration about 65 mᴍ/l. The optimal pH-value for the production of rhamnolipids from n-alkanes or glycerol was in the range pH 6.0-7.2. While rhamnolipid formation with glycerol as the sole C-source showed a wide optimum ranging from 27° up to 37 °C, production of rhamnolipids from n-alkanes had a sharp optimum at 37 °C. The addition of multivalent cations, different N-sources and EDTA caused an inhibition of rhamnolipid formation, while the n-alkane concentration had no influence. Specific rhamnolipid formation decreased with increasing cell concentration. Various C-sources were suitable for the formation of rhamnolipids by resting cells of Pseudomonas spec. DSM 2874. Yields, which were comparable to those obtained on n-alkanes or glycerol, were found for stearic acid, fatty alcohols and vegetable oils. A study of the time course of glycolipid production of resting cells was carried out in a 20 1- biorcactor with an intcnsor system and with n-tetradecane as the sole C-source.

scholarly journals Problems of abnormal dynamics of thermal hydraulic processes in prospective reactors with supercritical parameters of light water coolant

2021 ◽  
Vol 21 (2) ◽  
pp. 3-16
Author(s):  
I. G. Sharayevsky ◽  
◽  
N. M. Fialko ◽  
A. V. Nosovskyi ◽  
L. B. Zimin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fuel Element ◽  
Nuclear Reactors ◽  
Physical Nature ◽  
Physical Sign ◽  
Water Coolant ◽  
Technical Problems ◽  
Light Water ◽  
Supercritical Parameters ◽  
Emergency Mode

A complex of scientific and technical problems directly related to the priority of ensuring the operational safety and reliability of the cores of promising power nuclear reactors with supercritical thermodynamic parameters of a light-water coolant is systematized. The problems of implementation of effective heat removal from the surface of fuel elements and ensuring reliable calculation of thermal and hydrodynamic processes in turbulent flows of a supercritical coolant are considered. The main attention in the consideration of thermohydraulic processes in the near-critical region is paid to the conditionality of the physical nature of these processes by the regularities of transformation of the thermophysical properties of the coolant with changes in its temperature. It is noted that these phenomena have not been sufficiently studied and that modern designers of nuclear reactors with supercritical parameters practically do not have physically substantiated adequate ideas about the physical nature of an emergency mode of deteriorated heat transfer, which can arise unpredictably on the surface of a fuel element even if it is continuously cooled by a coolant with supercritical parameters. It is only known that the main physical sign of the occurrence of this emergency mode is a significant deterioration in heat transfer, which becomes abnormally low, but the physical reasons for such a dangerous anomaly are currently unknown. Based on the analysis of the molecular kinetics data of the near-wall coolant layer, it was proposed to consider such facts of an emergency decrease in the heat transfer intensity due to the appearance of an unknown pseudo-film boiling regime on the fuel element surface. In this context, it is shown that under the conditions under study, macromolecular assemblies in the form of pseudo-vapor formations can appear on the heat exchange surface, as a result of which the heat transfer on the fuel element surface is disturbed. Using experimental data, it is shown that there is a rather deep physical analogy between heat transfer in a supercritical thermodynamic system and the subcooled boiling process at subcritical parameters of the coolant. The dynamics of changes in the characteristics of the experimental spectra of acoustic emission of pseudo-boiling with a sequential increase in the thermal load is analyzed and it is shown that these phenomena can, in principle, be used in promising systems for diagnostic monitoring of reactors with supercritical parameters for early detection of the initial phases of pseudo-boiling and prompt prevention of the occurrence of emergency modes of deteriorated heat transfer

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