Study on the relationship between Fe3O4 fouling and NiFe2O4 oxide layer in the secondary circuit of nuclear steam generator

2022 ◽  
Vol 717 ◽  
pp. 122001
Author(s):  
Wenyang JIA ◽  
Lu REN ◽  
Jian XU ◽  
Shicheng WANG ◽  
Tetsuo SHOJI ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Steam Generator ◽  
Secondary Circuit ◽  
The Relationship

Analysis of Droplet Impacting on Inclined Wall

2020 ◽  
Author(s):  
Bowen Chen ◽  
Bo Wang ◽  
Bingzheng Ke ◽  
Ru Li ◽  
Ruifeng Tian
Keyword(s):  
Steam Generator ◽  
High Speed ◽  
Nuclear Power ◽  
Separation Efficiency ◽  
Inertial Force ◽  
High Speed Photography ◽  
Separation Mechanism ◽  
The Relationship ◽  
Plate Separator

Abstract The steam generator is an important part of the nuclear power plant, and the corrugated plate separator plays the important role of drying steam in the steam generator to improve power generation efficiency and protect the safety of the system. The separation mechanism of the corrugated plate separator is relatively complicated. The droplets are moved by the drag force of the steam and gravity in the corrugated plate separator, and captured by the wall of the corrugated plate separator. When the velocity is increased, the inertial force of droplet is increased, so that the droplet is more easily captured by the wall of the corrugated plate separator, and the separation efficiency of the corrugated plate separator is increased. In this paper, the phenomenon of droplet impact on the inclined wall is studied by high-speed photography technology, and the cause and mechanism of the phenomenon are analyzed. By analyzing the spreading and splashing on the droplets impacting on the inclined wall, the relationship between the inclination angle of the droplet impacting on the inclined wall and the spreading is obtained, and the influence of droplets with different Weber numbers, and dry and wetted walls were analyzed, which provide a basis for the optimization of the corrugated plate separator.

The Relationship between Tensile Ductility Loss and Microstructures for the Hot Exposed γ-Tial Alloys

2012 ◽  
Vol 452-453 ◽  
pp. 1361-1364 ◽  
Author(s):  
Yong Juan Jing ◽  
Xiao Hong Li ◽  
Xi Shan Yue
Keyword(s):  
Critical Temperature ◽  
Oxide Layer ◽  
Tensile Ductility ◽  
Tial Alloys ◽  
Ductility Loss ◽  
The Matrix ◽  
The Relationship ◽  
Exposure Process

In this paper, the relationship between the tensile ductility loss and the conditions including the exposure process and microstructures for the hot exposed TiAl alloys was researched. The critical temperature corresponding to the ambient tensile ductility loss to 0.8% was sensitive to the microstructure. It was 800°C/100h exposure for the near fully lamella microstructure. Due to the oriented lamella, the near fully lamella microstructure was benefit for forming the oxide layer rich in Al to present further oxidation of the matrix.

The Water Ingress Mass Analysis on Steam Generator Heat-Exchange Tube Rupture Accident of High Temperature Gas-Cooled Reactor

2009 ◽  
Author(s):  
Yan Wang ◽  
Yanhua Zheng ◽  
Fu Li ◽  
Lei Shi ◽  
Zhiwei Zhou
Keyword(s):  
High Temperature ◽  
Heat Exchange ◽  
Steam Generator ◽  
Mechanical Load ◽  
Radioactive Isotopes ◽  
Primary Circuit ◽  
Secondary Circuit ◽  
Water Ingress ◽  
Heat Exchange Tube ◽  
High Temperature Gas

The module high temperature gas-cooled reactor (HTGR) is an advanced reactor with high safety level. The steam generator heat-exchange tube rupture (SGTR) accident (or water ingress accident) is an important and particular accident which will result in water ingress to the primary circuit of reactor. Water ingress may, in turn, result in chemical reaction of graphite fuel and structure with water, causing release of radioactive isotopes and generation of explosive gaseous in large quantity. The analysis of SGTR is significant for verifying the inherent safety characteristics of HTGR. One of the key factors is to estimate the amount of water ingress mass which is used to evaluate the severity of the accident consequence. The 200MWe high temperature gas-cooled reactor, which is designed by the Institute of Nuclear and New Energy Technology of Tsinghua University, is selected as an example to analyze. The accident scenarios of double-ended rupture of both single and two heat-exchange tubes at the inlet and outlet of steam generator are simulated respectively by RETRAN-02. The results show that the amount of water ingress mass is related to the break location, the number of ruptured tubes (or the break size). The greater the number of ruptured tubes or the break size, the larger the amount of water ingress mass. It is important to design the draining pipe line with reasonable diameter, which should be optimized based on economy and safety considerations for preventing large water ingress to the reactor primary circuit, restricting the change rate of mechanical load on SG, and reducing the radioactive isotopes release to the secondary circuit.

scholarly journals A Study of Anodising Behaviour of Al-Si Components Produced by Rheocasting

2019 ◽  
Vol 285 ◽  
pp. 39-44
Author(s):  
Bai Wei Zhu ◽  
Salem Seifeddine ◽  
Anders E.W. Jarfors ◽  
Peter Leisner ◽  
Caterina Zanella
Keyword(s):  
Oxide Layer ◽  
Layer Thickness ◽  
Casting Machine ◽  
Treatment Method ◽  
Al Alloy ◽  
Oxide Layer Thickness ◽  
Liquid Segregation ◽  
Pre Treatment ◽  
Pressure Die Casting ◽  
The Relationship

This paper aims to investigate the anodising behaviour of Al-Si components produced by rheocasting, to understand the effect of the surface liquid segregation (SLS) on the anodising response. The material investigated was EN AC 42000 Al-alloy with an addition of 150 ppm Sr. The component was rheocast and conventionally liquid cast for benchmarking. The RheoMetalTM process was used to prepare slurry and subsequently cast using a vertical pressure die casting machine. Prior to anodising, mechanical grinding was used as pre-treatment method for selected samples as comparison with components in the as-cast state. Anodising was performed on the components using a constant controlled voltage at 25 V, in 1 M H2SO4, at room temperature. The duration of anodising was varied from 30 mins to 120 mins to examine the relationship between oxide layer thickness and the anodising time. The oxide layer was investigated and characterised. The results demonstrated that the presence of the SLS layer, which was enriched with alloying elements, had a significant influence on the anodising behaviour of the cast component. The oxide layer thickness of the components produced by rheocasting and fully liquid casting was measured and compared. The relations between the oxide layer thickness and anodising time, as well as the casting methods are presented and discussed in this paper.

The Morphological Development of Ordered Nanotube Structure due to the Anodization of Ti Foil with Axial and Radial Current Flow

2020 ◽  
Vol 16 ◽  
Author(s):  
Kar Chun Lee ◽  
Khairul Arifah Saharudin ◽  
Srimala Sreekantan
Keyword(s):  
Oxide Layer ◽  
Plastic Flow ◽  
Current Flow ◽  
Axial Flow ◽  
Morphological Development ◽  
High Symmetry ◽  
Flow Mechanism ◽  
Potential Applications ◽  
And Performance ◽  
The Relationship

Background: One dimensional titania nanotube (TNT) have attracted increasing scientific and technological attention due to their physical properties and their potential applications. Dimensionality and well aligned ordered structure have a crucial role in determining the properties and performance of titania nanotubes. Therefore, an understanding on the transformation and growth mechanisms to explain the origin of this nanomaterial symmetry is of great importance. Objectives: The relationship between the direction of current flow and the morphology of the anodized foil was investigated to understand the influence of a compact oxide layer formation towards growth of nanotubes. Methods: To achieve the purpose, single (SA) and double-sided anodization (DA) were performed to control the direction of the current flow in this experiment by immersing one side and both sides, respectively in electrolyte containing 0.6 wt% of NH4F, 1.0 wt% of H2O2, and 98.4 wt% of ethylene glycol (EG) at 60V. Results: It was found that the channelling of current flow into axial and radial directions influenced the effectiveness of oxygen species in the formation of an initial oxide layer. The field-assisted dissolution of the compact oxide layer results in low-symmetry nanotube arrangement. Whereas, the growth at the interface, which is governed by plastic flow mechanism, results in high-symmetry nanotube arrangement in a hexagonal form. These findings offer an integrated perspective when determining whether plastic flow mechanism or field-assisted dissolution occurs during anodization. Octahedral titania crystals were also found on the surface of the anodized film which indicates the possibility of forming facet structures via anodization. Conclusion: This research successfully showed the influence of current flow via SA & DA on the growth of TiO2 nanotubes. An axial flow of current in Ti foil during SA resulted in disordered nanotubes while radial flow of current during DA stemmed the growth of nanotube from the Ti-TiO2 interface to form well oriented hexagonal nanotubes structures.

Analyses of Free Span Oxide Layers on SG Tubes of NPP Temelin

2008 ◽  
Author(s):  
A. Hojna ◽  
V. Hanus ◽  
V. Pisarik ◽  
M. Postler ◽  
J. Burda ◽  
...  
Keyword(s):  
Free Surface ◽  
Oxide Layer ◽  
Steam Generator ◽  
Feed Water ◽  
Oxide Layers ◽  
The Real ◽  
Secondary Side

The differences in deposit layers on steam generator (SG) tubes of WWER NPP Temelin have been observed, namely in compactness and adhesiveness. The samples of the oxide layers have been taken from different SG during outage of the two units and analyzed. Results of the analyses are compared to previous results on deposit layers created during operation of SG model. The model simulates secondary side of SG tubes operation; the original feed water from the NPP Temelin has been used for tests. Deposit built up on tubes inside the model on the free surface is related to the real SG tube deposits and differences of the oxide layer morphologies are discussed.

Research on Natural Convection of Two-Layer Corium Pools

2020 ◽  
Author(s):  
Simin Luo ◽  
Hongping Sun ◽  
Yapei Zhang ◽  
Junmei Wu ◽  
Suizheng Qiu ◽  
...  
Keyword(s):  
Natural Convection ◽  
Oxide Layer ◽  
Metal Layer ◽  
Immiscible Fluid ◽  
Important Research ◽  
Research Focus ◽  
Layer System ◽  
Focusing Effect ◽  
Total Pool ◽  
The Relationship

Abstract As a promising mitigation strategy, In-vessel-retention (IVR) has been an important research focus in realms of nuclear safety analysis. For IVR analysis, it’s of importance to study the natural convection behaviors of the corium pool formed in the lower plenum of the reactor vessel. Because of the different densities between corium compositions, typically the corium pool is believed to evolve to two-layer configurations, with a heavier oxide layer at bottom and a metal layer on top. To know better the convection behaviors of the layered corium pools, research was performed both experimentally and numerically. The test section for the experiment is a two-dimensional semi-ellipsoidal slice, which measures a span of 1.2m, a total pool depth of 0.75m and a thickness of 0.2m. Two immiscible fluid, i.e. fluorinert fluid FC-40 and water, were chosen to simulate the oxide layer and the metal layer respectively. Based on the experimental settings, numerical simulations were performed, and the results were compared with the experimental data. Further, discussions were made on the focusing effect, the relationship between the temperature and the velocity field, and also the coupling modes in the two-layer system. These results offer more details to the knowledge of layered corium pools and can be helpful for IVR analysis.

The Relationship Between Oxide Adherence and Porcelain-Metal Bonding

1988 ◽  
Vol 67 (2) ◽  
pp. 474-478 ◽  
Author(s):  
J.R. Mackert ◽  
R.D. Ringle ◽  
E.E. Parry ◽  
A.L. Evans ◽  
C.W. Fairhurst
Keyword(s):  
Oxide Layer ◽  
Strong Correlation ◽  
Linear Regression Analysis ◽  
Metal Interface ◽  
Metal Bonding ◽  
Literature Evidence ◽  
Oxide Adherence ◽  
The Relationship ◽  
Metal Bonds ◽  
Adherence Strength

The lack of a reliable bond test has hindered the elucidation of the mechanism for porcelain-metal bonding in dental systems, because a test capable of detecting differences among porcelain-metal bonds of various qualities is required before the reasons for these differences may be ascertained. A method was developed in the present study whereby specimens of alloys with differing physical properties may be deformed to a constant strain to yield a fracture surface suitable for measurement of the area fraction of retained porcelain by an x-ray spectrometric technique described previously. The method proved sufficiently discriminating that significant differences could be found in 48 of the possible 66 comparisons among alloys and treatments. Linear regression analysis revealed a strong correlation (r 2 = 0.947) between the area fractions of retained porcelain measured in the present study and the oxide adherence strength values measured previously. This strong correlation, when considered in light of the literature evidence for the presence of an oxide layer at the porcelain-metal interface, provides compelling support for the oxide layer theory of porcelain-metal bonding in dental alloy systems.

Study on the Modeling and Simulation of the Horizontal Steam Generator in VVER-1000

2021 ◽  
Author(s):  
Ru Zhang ◽  
Junyan Qing ◽  
Xiaolong Bi ◽  
Guanfu Jiang ◽  
Peiwei Sun ◽  
...  
Keyword(s):  
Steam Generator ◽  
Nuclear Power ◽  
Tube Bundle ◽  
Natural Circulation ◽  
Thermal Power ◽  
Secondary Circuit ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Horizontal Steam Generator ◽  
Secondary Side

Abstract Steam Generator (SG) is one of the main components of the power cycle in pressurized water reactor (PWR), and it is the hub of primary coolant circuit and secondary circuit, so the thermal hydraulic analysis of the SG is crucial in the system design and safety analysis of the PWR. The horizontal steam generator (HSG) is one of the main types SG in the PWR nuclear power plant (NPP), and its advantages are that it has more secondary side water capacity and good safety and reliability. The VVER-1000 is a PWR with a thermal power of 3000 MW, and has four HSGs for four loops. The RELAP5 has been used to model the VVER-1000’s HSG and performs the analysis described in this paper. The HSG tube bundle is modeled by three horizontal channels, and the steam control volumes above the heat transfer tube bundle are modeled with three volumes. The steam space is modeled as a steam separator and the steam reception shield is the dryer. The HSG secondary side downcomers are represented with a separate component to provide the power of the natural circulation. To verify the accuracy of the model, three different typical conditions are simulated. The simulation results show that the model built in this paper can correctly simulate the operation of the HSG in VVER-1000.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

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