Contamination Of Coolant Research Articles

Pashukevich Motor oil performance analysis due to water and coolant contamination

Introduction. During the operation of heavy-duty diesel equipment in areas with a low-temperature climate, engine oils are contaminated by coolant and water. The ingress of these substances into the lubricant leads to a deterioration in its quality indicators, which subsequently leads to problems in the nodes of the internal combustion engine.Relevance. The deterioration of the values of engine oil quality indicators is directly related to the presence of water and coolant in it. It is not always possible to objectively track the ways of leakage of these pollutants, and this, in turn, leads to serious consequences in the form of wear of the contacting surfaces of engine parts, corrosion. It is also important to evaluate the resource of lubricant additive packages due to its dilution with water and antifreeze.Materials and methods. This paper presents the results of a literature review aimed at studying the ways of coolant and water ingress during the operation of diesel engines, their influence on the physical and chemical properties of motor oils. The brief information about the composition of the coolant is indicated.Conclusions. The ingress of water and coolant into the engine oil leads to an increase in the kinematic viscosity of the lubricant, as well as to the formation of deposits on the surfaces of the engine friction pairs. In addition, spherical compounds appear in the crankcase of the engine, which are a combination of destroyed additive packages and glycol. Oil change intervals must be monitored at an increased rate of water and coolant entering the engine oil.Scope of the study / possibility. This type of study will help to determine the causes of penetration of water and coolant into the crankcase space, to understand the consequences of using engine oil contaminated with water and coolant.Originality / value. The conducted research can be the basis for the development of recommendations for improving the maintenance of internal combustion engines for enterprises that have at their disposal cars with diesel engines in order to increase the resource of power units and reduce operating costs.

Multiphysics analysis of thermal mechanical behavior and tritium migration in FeCrAl and Cr-coated Zircaloy cladding under PWR normal operating and transient conditions

Both Cr-coated Zircaloy and the FeCrAl alloy have garnered attention as potential substitutes for PWR cladding materials, due to their impressive qualities, such as robust high-temperature oxidation and corrosion resistance. However, FeCrAl alloy is found to accelerate the tritium permeation throughout the cladding, this heightened tritium permeation prompts easier release from the cladding into the coolant. Consequently, the assessment of material tritium permeation becomes a crucial aspect in fuel performance analysis. In this work, the multiphysics models of Cr-coated Zircaloy and FeCrAl cladding are reviewed firstly. Then the multiphysics models are implemented in CAMPUS code and the validation of tritium migration model is presented. Subsequently, the fuel performance under normal and accident (LOCA and RIA) conditions and the tritium migration in three types of claddings are simulated and discussed. The simulation results show that the utilization of FeCrAl cladding, instead of Zircaloy, results in an overall reduction in fuel temperature under both normal and LOCA conditions. Furthermore, both the Cr-coated Zircaloy and FeCrAl cladding are found to effectively delay the cladding failure time under LOCA condition. However, the total strain of FeCrAl cladding is found to be significantly higher than that of the Cr-coated Zircaloy cladding under RIA condition. And the Cr-coated Zircaloy is found to have better tritium resistance effect than FeCrAl cladding, which greatly reduces the coolant contamination treatment. Therefore, based on the combined consideration of fuel performance and tritium resistance, Cr-coated Zircaloy emerges as the preferred candidate cladding over the FeCrAl cladding.

Analysis of Calculation Model for Primary Coolant Fission Products

The sources of radioactive contamination of the primary coolant by fission products when the unit is operating at the rated power are as follows: defect fuel elements with gas leakiness and substantial damages, surface contamination of the outer surfaces of fuel claddings, superficial contamination of structural materials of fuel assemblies. Initially in the reactor operation (if there are no manufacturing defects in fuel elements), the contamination of the coolant by fission products is determined by the release into the reactor coolant circuit of fission fragments of Uranium-235 (due to their kinetic energy) that is present on the outer surfaces of fuel elements as contamination in their manufacturing. During normal operation of the reactor, the integrity of cladding may fail due to various processes of corrosion fatigue type. These processes result in, first of all, micro-fissures and then in large defects in the claddings, which is accompanied by an increase in the release of fission products from fuel elements into the primary coolant.

Two methodologies for optical analysis of contaminated engine lubricants

The performance, efficiency and lifetime of modern combustion engines significantly depend on the quality of the engine lubricants. However, contaminants, such as gasoline, moisture, coolant and wear particles, reduce the life of engine mechanical components and lubricant quality. Therefore, direct and indirect measurements of engine lubricant properties, such as physical-mechanical, electro-magnetic, chemical and optical properties, are intensively utilized in engine condition monitoring systems and sensors developed within the last decade. Such sensors for the measurement of engine lubricant properties can be used to detect a functional limit of the in-use lubricant, increase drain interval and reduce the environmental impact. This paper proposes two new methodologies for the quantitative and qualitative analysis of the presence of contaminants in the engine lubricants. The methodologies are based on optical analysis of the distortion effect when an object image is obtained through a thin random optical medium (e.g. engine lubricant). The novelty of the proposed methodologies is in the introduction of an object with a known periodic shape behind a thin film of the contaminated lubricant. In this case, an acquired image represents a combined lubricant–object optical appearance, where an a priori known periodic structure of the object is distorted by a contaminated lubricant. In the object shape-based optical analysis, several parameters of an acquired optical image, such as the gray scale intensity of lubricant and object, shape width at object and lubricant levels, object relative intensity and width non-uniformity coefficient are newly proposed. Variations in the contaminant concentration and use of different contaminants lead to the changes of these parameters measured on-line. In the statistical optical analysis methodology, statistical auto- and cross-characteristics (e.g. auto- and cross-correlation functions, auto- and cross-spectrums, transfer function, coherence function, etc) are used for the analysis of combined object–lubricant images. Both proposed methodologies utilize the comparison of measured parameters and calculated object shape-based and statistical characteristics for fresh and contaminated lubricants. Developed methodologies are verified experimentally showing an ability to distinguish lubricant with 0%, 3%, 7% and 10% water and coolant contamination. This proves the potential applicability of the developed methodologies for on-line measurement, monitoring and control of the engine lubricant condition.

The EPMA, LA-ICP-MS and ICP-OES study of corrosion of structural materials for a nuclear reactor cooling circuit by molten fluoride salt treatment

Electron probe microanalysis (EPMA), inductively coupled plasma atomic emission spectrometry (ICP-OES), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were applied to study the interaction of molten LiF-NaF salt mixtures with candidate structural materials (alloys) for a nuclear reactor-transmutor cooling circuit. The corrosion of test ampoules and inserted test specimens made of structural materials was brought about by the action of molten LiF-NaF coolant at 680 °C and its extent and character were examined in dependence on the time of exposure. The material corrosion changes were studied by mapping the sections of ampoule walls and inserted specimen surfaces with EPMA, whereas LA-ICP-MS was employed for linear scanning the salt/ampoule wall boundary. Corrosion-released structural material, dissolved in solidified molten salt, was analyzed by ICP-OES after the salt dissolution. The melt activity was proved to induce a surficial modification of a structural material up to the depth of 15–50 µm, which was associated with the coolant contamination. The X-ray maps by EPMA with its 1-µm lateral resolution revealed compositional changes in alloys, such as regular depletion of Cr to the depth of 10–25 µm. While the lateral resolution of LA-ICP-MS with the applied laser spot diameter of 25 µm was not exactly adequate to dimensions of the corroded regions and, consequently, yielded less information in comparison with EPMA, this technique was quite sufficient for the monitoring of the presence of alloy constituents in an adhered salt layer. It was concluded that: i) the EPMA study, involving semi-quantitative elemental mapping/content profiling and detailed spot quantitative analyses makes it possible to obtain quantitative assessment of the corrosion process; ii)LA-ICP-MS profiles can be converted from signal domain to elemental contents on a semi-quantitative level when applying signal normalization to the total sum of signals.

ICONE11-36560 MODELING CORROSION IN OXYGENCONTROLLED LBE SYSTEMS

It is widely recognized that the corrosiveness of Lead-Bismuth Eutectic (LBE) represents a critical obstacle toward its use in nuclear systems. Active oxygen control in LBE can promote the formation of "self-healing" oxide films on the structural material surface, drastically reducing steel corrosion and coolant contamination. Many testing experiments have been performed and the results support the premise. However, the results remain scattered and difficult to interpret and use. This paper reports the comprehensive results from modeling corrosion in LBE systems. The model couples the chemical reactions to mass transport in hydrodynamic flows, and provides a useful tool to interpret the test results in a quantitative framework and apply the data rationally for general applications. Systematic studies illustrate the effects of the flow rate, the oxygen concentration in LBE and the system temperature profile on corrosion rates and distribution.

Active control of oxygen in molten lead–bismuth eutectic systems to prevent steel corrosion and coolant contamination

The thermodynamic basis for controlling oxygen level in lead–bismuth to prevent steel corrosion and coolant contamination is examined. The operational conditions, including the thermodynamic activity of oxygen, cover gas oxygen partial pressure, mixtures of H 2 and H 2O (steam) to obtain such low oxygen partial pressure (<10 −24 atm or around 10 −6 wt% in lead–bismuth), and the voltage signals of one type of oxygen sensors (with a solid electrolyte and molten bismuth reference electrode) are calculated. These results provide the guidance to implement the oxygen control technique.

Coolant contamination of sintered bronze parts

The problems encountered with sintered metal parts in printer magnet units and the analytical methods used to determine the failure mechanism and type of contamination present are discussed. These methods involved the use of Fourier transform IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and wet chemical techniques. The mechanical device employed for laboratory simulation of the failure mechanism is also discussed. This investigation indicates that a cutting fluid used to machine parts was the primary source of contamination. Residual cutting fluid in the presence of a sliding mating surface resulted in the formation of a viscous waxy build-up on the mating surfaces, which adversely influenced the motion of the print hammer.

Air Contamination of KUR

The air contamination of caused dy the operation of Kyoto University Reserch Reactor has been investigated. At the power of the reactor of 5000KW, the radioactive gas production observed are about 160μCi/sec activated by the opened beam tubes and also about 200μCi/sec by the primary coolant contamination, respectively. And the producions of radioactive dust is about 0.0003μCi/sec. It is clear that these amounts of concentrations may be changed by the conditions of reactor room ventilation, conditions of primary coolant and reactor power.

A review of pebble bed reactors and the characteristics of packed beds

This paper gives a general picture of the pebble bed reactor concept up to the present time. The main advantages and disadvantages are listed, these being chiefly concerned with the rather unique spherical fuel element. The principal performance and design data etc. are given for an experimental pebble bed reactor and power plant as conceived by the Oak Ridge design team. Also included are data and a description of the BBC-Krupp reactor (AVR) of the pebble bed type under construction at Julich in West Germany; mention is also made of a possible West German pebble bed power reactor (THTR). An account is given of the Australian work on pebble bed reactors which differs from all others in the choice of support material for the fuel. A more detailed account follows of three important aspects of this reactor type—fuel elements, coolant contamination and fuel handling. This is followed by sections on the heat transfer and fluid dynamic characteristics of packed beds, of which the pebble bed reactor is an example. In conclusion some of the principal research and development problems associated with this reactor concept are discussed. An Appendix summarizes the various pebble bed reactors conceived since the original conceptual design by Farrington Daniels in 1944.

Structural analysis of fuel growth in fuel plates

Depletion of fissionable fuels is accompanied by a volumetric increase. In order to prevent coolant contamination, this volume increase must be withstood by the fuel plate cladding. If the cladding is too thin large strains and resulting failure may take place. By defining an effective stress-strain curve of the fuel region, data from small irradiation specimens can be analyzed. Results, which can be extended to other plate geometries, can be used for two purposes: to insure cladding integrity and to determine distortion or instability of fuel plates caused by fuel growth. An example of an effective stress-strain curve derived from SM-2 irradiation test specimens is included.