Research and Design of the Sodium Steam Filter System in Large Liquid Metal Cooled Fast Reactors

2017 ◽  
Author(s):  
Wang Leijian ◽  
Lu Yuan ◽  
Xiao Changzhi
Keyword(s):  
Free Surface ◽  
Chemical Properties ◽  
Liquid Sodium ◽  
Thermal Calculation ◽  
Piping System ◽  
Filtration Process ◽  
Active Chemical ◽  
High Boiling Point ◽  
Research And Design ◽  
Thermal Physical Properties

This reactor uses liquid sodium as coolant owing to its good thermal physical properties, high boiling point and compatibility of cladding material. However, the sodium has a very active chemical properties, for which the free surface of sodium must be protected by inert gas. In the high temperature environment, the sodium atoms diffusion to cover gas slowly, forming a mixed atmosphere that contained large amount of sodium steam. Sodium steam is covered with the free surface of sodium. Then metal sodium will solidify in the inner wall of the pipe or correlative valves with the reduced temperature. This reactor needs to collect and filter sodium steam in order to reduce the hazards to the equipment, piping system, valves and the other devices. Based on the previous research about the purification process of sodium, this paper compared different steam trapping filtration process and carried out the thermal calculation providing basis for research and design of large sodium cooled fast reactor sodium steam trapping filtration process and establishing a reliable sodium steam filtering system.

Structural integrity of fast reactor components

1990 ◽  
Vol 331 (1619) ◽  
pp. 419-434 ◽  
Keyword(s):  
Fast Reactor ◽  
Structural Integrity ◽  
Ambient Pressure ◽  
Failure Process ◽  
Liquid Sodium ◽  
Secondary Circuit ◽  
Deformation And Failure ◽  
Integrity Assessment ◽  
High Boiling Point ◽  
Materials Used

The paper focuses on the generic aspects of the main structural integrity issues in the liquid-sodium-cooled fast reactor. The choice of sodium as a coolant has important consequences for the deformation and failure process in the materials used for the main plant components. For example, its high boiling point means that the prim ary and secondary circuit containment operates at ambient pressure and the system loading is dominated by thermal stress. The resultant low primary stresses make leak-before-break a viable integrity criterion for all sodium boundary components. Sodium coolant operates at comparatively high temperatures and this, together with the good heat-transfer properties, means that thermal fatigue and creep are of concern, particularly in the hotter parts of the plant. A third factor concerns the steam generators, where the integrity of the sodium—water boundary is particularly important. The paper will consider the failure processes that must be addressed in relation to these conditions and the development of the integrity assessment arguments.

Slow granular filtration for water reuse

2003 ◽  
Vol 3 (4) ◽  
pp. 123-130 ◽  
Author(s):  
A. Adin
Keyword(s):  
Water Column ◽  
Water Reuse ◽  
Chemical Properties ◽  
Design Parameters ◽  
Advanced Treatment ◽  
Filtration Process ◽  
Filter Performance ◽  
Secondary Effluents ◽  
Granular Filtration ◽  
And Chemical Properties

The slow sand filtration (SSF) design parameters as known for purifying surface water cannot be copied for the treatment of secondary effluents. The objectives of the present research were to examine the possibility of slow granular filtration (SGF) as advanced treatment of secondary effluents for reuse purposes and examine filter performance under various design regimes. Slow granular filtration runs where made with four different filters at rate of 0.15 m/h. 0.6 mm, 0.25 mm sand or tuff grains or their combination were used. Grain size of 0.25 mm gave low impurities concentration in the effluent but short filtration runs. Double layer bed caused longer filtration run as well as lower impurities concentration in the effluent, Combining the tuff as the top bed layer caused longer filtration run, probably due to the morphologic and chemical properties of the tuff. The water column above the bed plays an important role in the filtration process. Intense microbiologic activity in the column changes the TSS and COD concentration as well as the availability of the biodegradable matter. The dissolved oxygen concentration in the water column above the bed, and in the bed depth can serve as a good indicator for ripening of the biological layer.

Study on the Corrosion Resistance of ZrN Films on the Aluminium Alloys Surface

2012 ◽  
Vol 252 ◽  
pp. 245-249
Author(s):  
Hui Qiang Wang ◽  
Wei Lian Sun ◽  
Yan Qiu Xing ◽  
Sun Bo
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Flow Rate ◽  
Chemical Properties ◽  
Nitrogen Flow ◽  
Corrosion Performance ◽  
Performance Study ◽  
Nitrogen Flow Rate ◽  
Active Chemical ◽  
Flow Rate Increase

Aluminum alloy have the active chemical properties,low standard electrode potential, and the surface will be easily forming about 1-3nm oxide film in dry air, therefore aluminum alloy have the poor corrosion resistance.ZrN film deposited by mid frequency reactive magnetron sputtering process on aluminium alloy surface in order to improve the corrosion performance. Study the influences of nitrogen flow rate, sputtering time and temperature to the corrosion performance. The results show that: The corrosion performance of ZrN films will be improved with the nitrogen flow rate increase,but when the nitrogen flow rate was more than 18sccm, ZrN film corrosion resistance will be reduce;The corrosion performance improved with the sputtering time increase,when the time reach 15min, ZrN film corrosion resistance was no longer increase;The corrosion performance improved with the temperature, when the temperature reach 130°C, the corrosion resistance was no longer increase.The best process parameters was: nitrogen flow rate 18sccm, sputtering time 15min, temperature 130°C.

Bénard–Marangoni convection at low Prandtl number

1999 ◽  
Vol 399 ◽  
pp. 251-275 ◽  
Author(s):  
THOMAS BOECK ◽  
ANDRÉ THESS
Keyword(s):  
Free Surface ◽  
Prandtl Number ◽  
Marangoni Number ◽  
Marangoni Convection ◽  
Three Dimensional ◽  
Bottom Wall ◽  
Liquid Sodium ◽  
Small Scale ◽  
Quiescent State ◽  
Two Dimensional

Surface-tension-driven Bénard convection in low-Prandtl-number fluids is studied by means of direct numerical simulation. The flow is computed in a three-dimensional rectangular domain with periodic boundary conditions in both horizontal directions and either a free-slip or no-slip bottom wall using a pseudospectral Fourier–Chebyshev discretization. Deformations of the free surface are neglected. The smallest possible domain compatible with the hexagonal flow structure at the linear stability threshold is selected. As the Marangoni number is increased from the critical value for instability of the quiescent state to approximately twice this value, the initially stationary hexagonal convection pattern becomes quickly time-dependent and eventually reaches a state of spatio-temporal chaos. No qualitative difference is observed between the zero-Prandtl-number limit and a finite Prandtl number corresponding to liquid sodium. This indicates that the zero-Prandtl-number limit provides a reasonable approximation for the prediction of low-Prandtl-number convection. For a free-slip bottom wall, the flow always remains three-dimensional. For the no-slip wall, two-dimensional solutions are observed in some interval of Marangoni numbers. Beyond the Marangoni number for onset of inertial convection in two-dimensional simulations, the convective flow becomes strongly intermittent because of the interplay of the flywheel effect and three-dimensional instabilities of the two-dimensional rolls. The velocity field in this intermittent regime is characterized by the occurrence of very small vortices at the free surface which form as a result of vortex stretching processes. Similar structures were found with the free-slip bottom at slightly smaller Marangoni number. These observations demonstrate that a high numerical resolution is necessary even at moderate Marangoni numbers in order to properly capture the small-scale dynamics of Marangoni convection at low Prandtl numbers.

An Integrated Method of FVM and SPH for Treating Melting Process of Quartz Ingot

2018 ◽  
Author(s):  
Zhongyi Liu ◽  
Jing Wang ◽  
Qianli Ma ◽  
Haisheng Fang
Keyword(s):  
Free Surface ◽  
Large Deformation ◽  
Data Exchange ◽  
Thermal Field ◽  
Melting Process ◽  
Thermal Calculation ◽  
Complex Flow ◽  
Heater Temperature ◽  
Integrated Method ◽  
Hot Zone

The melting of quartz ingot undergoes solid-liquid phase transition, free-surface, large deformation and other complex flow. Thermal field is the fundamental driving factor during the process. Thus, new method of computing the complex flow and thermal field simultaneously needs to be developed. An integrated method of the finite volume method (FVM) and smoothed particle hydrodynamics (SPH) is proposed to combine the advantages of SPH in the complex flow and FVM in the thermal calculation. The method, a solver conjugate scheme, is implemented through the data exchange between the FVM sub-solver and the SPH sub-solver. The sub-solver of FVM focuses on thermal calculation, and SPH concentrates on complex flow with free-surface and large deformation. The inverse distance weighted (IDW) interpolation and spatial matching are employed to translate data from FVM to SPH and from SPH to FVM separately. The mechanism how the heater temperature affects the thermal field is investigated. The conclusion is that the increasing heater temperature affects the hot zone by raising the sidewalls temperature mainly, thus employing additional heating or cooling ways for controlling the temperature of the sidewalls is an efficient direction to optimize the hot zone design.

Hawthorn - A Health Food

2011 ◽  
Vol 140 ◽  
pp. 350-354 ◽  
Author(s):  
Jun Yan Han ◽  
De Hong Tan ◽  
Guang Chun Liu
Keyword(s):  
Chemical Properties ◽  
Pharmacological Properties ◽  
Health Food ◽  
Medicinal Value ◽  
Active Chemical ◽  
Wide Range ◽  
The World ◽  
Cardiac Disorders ◽  
Hawthorn Fruit ◽  
Digestive Disorders

The genus of Crataegus (hawthorn) is cultivated in many parts of the world. and regarded as medicinal plant in many countries. Hawthorn fruit is commonly used to cure scurvy, constipation and digestive disorders, Hawthorn flowers and leaves are often used against mild cardiac disorders. Modern studies found extracts of Hawthorn fruits, flowers and leaves possess a wide range of pharmacological properties, the pharmacological properties of Hawthorn are mostly related to the involved phenolic compounds including flavonoids. In this article, the active chemical properties and medicinal value of Hawthorn are reviewed.

The Evaluation Method of Uranium Hexafluoride Leakage Accident Release Source Term

2017 ◽  
Author(s):  
Chen Lei ◽  
Wang Ning
Keyword(s):  
Evaluation Method ◽  
Source Term ◽  
Chemical Properties ◽  
Uranium Hexafluoride ◽  
Chemical Toxicity ◽  
Uranium Enrichment ◽  
Uranium Fuel ◽  
Nuclear Fuel Element ◽  
Active Chemical ◽  
Enrichment Process

Uranium hexafluoride is the intermediate material of uranium fuel enrichment process, which is widely used in uranium conversion plant, uranium enrichment plant and nuclear fuel element plant[1]. Because of its active chemical properties and its radioactive and chemical toxicity, great importance should be attached to the uranium hexafluoride release accident. This paper describes the possible leakage scenarios for uranium hexafluoride accident. And the general step of the evaluation for uranium hexafluoride leakage accident release source term is given, as well as an application example for the feed facility of a gaseous diffusion plant.

scholarly journals Single-step dynamic dewatering of microalgae from dilute suspensions using flocculant assisted filtration

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Mutah Musa ◽  
Andrew Ward ◽  
Godwin A. Ayoko ◽  
Christine Rösch ◽  
Richard Brown ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Single Step ◽  
Chemometric Analysis ◽  
System Stability ◽  
Superior Performance ◽  
Process Conditions ◽  
Filtration Process ◽  
Time Saving ◽  
Charge Neutralization ◽  
Dynamic Filtration

Abstract Background Dewatering constitutes a major challenge to the production of microalgae, accounting for 20–30% of the product cost. This presents a setback for the applicability of microalgae in the development of several sustainable products. This study presents an investigation into the dynamic dewatering of microalgae in a combined flocculation-filtration process. The effect of process conditions on the performance of 12 flocculants and their mixtures was assessed. Results The mechanism of flocculation via the electrostatic path was dominated by charge neutralization and subsequently followed bridging in a ‘sweep flocculation’ process. Cationic polyacrylamide (CPAM) based flocculants recorded the highest biomass retention with PAM1 and PAM2 attaining 99 and 98% retention with flocculant dosages of 10 and 15 mg/L respectively. Polyvinylamine (PVAM) was also found to improve system stability across the pH range 4–10. Alum was observed to be only effective in charge neutralization, bringing the system close to its isoelectric point (IEP). Chemometric analysis using the multi-criteria decision methods, PROMETHEE and GAIA, was applied to provide a sequential performance ranking based on the net outranking flow (ф) from 207 observations. A graphical exploration of the flocculant performance pattern, grouping the observations into clusters in relation to the decision axis ($$\pi$$ π ), which indicated the weighted resultant of most favorable performance for all criteria was explored. Conclusion CPAM based flocculants and their mixtures demonstrated superior performance due to their viscoelastic behaviour under turbulence. The use of PVAM or alum in mixtures with CPAM reduced the required doses of both flocculants, which will provide beneficial financial impact for largescale microalgae dewatering in a flocculant assisted dynamic filtration process. Chemometric analysis based on the physico-chemical properties of the system provides a time saving assessment of performance across several criteria. The study findings provide an important foundation for flocculant assisted dynamic filtration processes.

scholarly journals Antibacterial Activity and Impact of Different Antiseptics on Biofilm-Contaminated Implant Surfaces

2019 ◽  
Vol 9 (24) ◽  
pp. 5467
Author(s):  
Marco Lollobrigida ◽  
Simone Filardo ◽  
Rosa Sessa ◽  
Marisa Di Pietro ◽  
Giuseppina Bozzuto ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Sodium Hypochlorite ◽  
Spectroscopic Analysis ◽  
Chemical Properties ◽  
Bacterial Count ◽  
Sem Analysis ◽  
Liquid Sodium ◽  
Chemical Agent ◽  
Implant Surface ◽  
Sterile Saline

Several antiseptic agents have been proposed for the treatment of peri-implantitis as a complementary therapeutic strategy in addition to mechanical devices. The aim of this study was to compare six different antiseptics, as well as alternative formulations of the same chemical agent, with respect to their decontamination efficacy and impact on chemical properties of the implant surface. Titanium disks with a micro-rough surface, previously contaminated with Porphyromonas gingivalis and Streptococcus mutans biofilms, were treated for 2 min with different antiseptics (liquid sodium hypochlorite 5.25%, gel sodium hypochlorite 5.25%, liquid chlorhexidine 0.2%, gel chlorhexidine 1%, gel citric acid 40%, and gel orthophosphoric acid 37%) or sterile saline solution (control) and their antibacterial activity as well as their ability to remove biofilm were assessed by viable bacterial count and scanning electron microscopy, respectively. Spectroscopic analysis was also performed on non-contaminated disks after exposure to the antiseptics, in order to detect any change in the elemental composition of the titanium surface. All the antimicrobial formulations examined were effective against P. gingivalis and S. mutans biofilms. SEM analysis revealed however that liquid sodium hypochlorite 5.25% was more effective in dissolving biofilm residues. Spectroscopic analysis detected traces of the antiseptics, probably due to insufficient rinsing of the titanium surfaces. In conclusion, since gel formulations of these antiseptic agents possessed a similar antibacterial activity to the liquid formulations, these may be proposed as alternative treatments given their properties to avoid overflows and increase contact time without significant side effects on the bone.

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