scholarly journals IMPROVING GRINDING OF GEAR WHEELS APPLIED IN GEARBOXES OF POWER ENGINEERING

2021 ◽  
pp. 45-56
Author(s):  
Oleksiy Yakimov ◽  
Natalia Klimenko ◽  
Kateryna Kirkopulo ◽  
Andrey Pavlyshko ◽  
Sergyi Uminsky ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Operating Conditions ◽  
Power Engineering ◽  
Important Place ◽  
Continuous Increase ◽  
Method Of Calculation ◽  
Gear Grinding ◽  
Thermomechanical Processes

Development of modem power engineering follows the line of continuous increase in speed, coefficient of corrosive action and capacity of units. Gears and reducers are responsible parts of modem machinery and occupy an important place in the domestic power engineering construction. Durability and wear resistance of gears, apart from the design factors, also depends on the technological methods of treatment. The final stage of production of such wheels is the operation of gear grinding. In the process of gear grinding in a thin surface ball there are complex thermomechanical processes. As a result of short-time heating to high temperatures, structural transformations, burns, and in some cases even micro- and macro-thicknesses occur in such a surface bail. In addition, there are cases of making tooth wheels with adjacent defects grinding (for example, the appearance of the surface of the ball teeth of large tensioning forces), which reduces the life of the work, and in some cases causes a breakdown of the teeth in operating conditions. Development of effective measures to ensure the quality of the surface of the ball on the operation of grinding baggage in part depends on the possibility of predicting (or calculation) of temperatures and residual loads on the depth of the cemented teeth ball. The method of calculation of internal surplus Toads occurring during grinding of wheels with cemented steels is suggested. On the basis of the performed calculations and experiments the ways to improve the quality of production of working surfaces of gears, which are used in the wits of thermal and nuclear power plants are suggested and grounded.

ENSURING THE QUALITY OF MANUFACTURING GEAR TRANSMISSIONS IN POWER MECHANICAL ENGINEERING

2019 ◽  
pp. 155-166
Author(s):  
O. Yakimov ◽  
S. Uminsky ◽  
N. Klimenko ◽  
L. Bovnegra ◽  
Yu. Shikhireva
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Power Plants ◽  
Operating Conditions ◽  
Engineering Industry ◽  
Power Engineering ◽  
Important Place ◽  
Continuous Increase ◽  
Gear Grinding

The development of modern power engineering goes along the line of continuous increase of speeds, efficiency and power units. Gears and gearboxes are crucial parts of modern mechanisms and occupy an important place in the domestic power engineering industry. The strength and durability of gears, in addition to design factors, to a large extent depends on the processing techniques. The final stage of manufacturing such wheels is the gear grinding operation. In the process of tooth-grinding, complex and unique thermomechanical processes take place in the thin surface layer. As a result of short-term heating to high temperatures, structural transformations, called prizhogami, occur in such a surface layer, and in some cases even micro and macro-cracks. In addition, there are cases of manufacturing gears with hidden grinding defects (for example, the appearance in the surface layer of teeth of large tensile stresses), which reduces the service life, and in some cases causes the teeth to break under operating conditions. The development of effective measures to ensure the quality of the surface layer during a gear grinding operation largely depends on the ability to predict (or calculate) temperatures and residual stresses along the depth of the cemented tooth layer. A method for calculating the internal residual stresses arising during gear grinding of wheels from cemented steels is proposed. On the basis of the performed calculations and experiments, the ways of improving the quality of manufacturing the working surfaces of gears used in units of thermal and nuclear power plants are proposed and substantiated.

scholarly journals Belarus Power Engineering System Modeling Taking into Account the Nuclear Power Plant Commissioning

2021 ◽  
Vol 64 (1) ◽  
pp. 5-14
Author(s):  
A. A. Mikhalevic ◽  
U. A. Rak
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Energy Systems ◽  
Operating Conditions ◽  
Power Engineering ◽  
Power Balance ◽  
Engineering System ◽  
Large Share ◽  
Load Duration

The article presents the analysis of the specific features of modeling the operation of energy systems with a large share of nuclear power plants (NPP). The study of operating conditions and characteristics of different power units showed that a power engineering system with a large share of NPP and CHPP requires more detailed modeling of operating modes of generating equipment. Besides, with an increase in the share of installations using renewable energy sources, these requirements are becoming tougher. A review of the literature revealed that most often the curve of the load duration and its distribution between blocks are used for modeling energy systems. However, since this method does not reflect a chronological sequence, it can only be used if there are no difficulties with ensuring power balance. Along with this, when the share of CHP and nuclear power plants is high, to maintain a balance of power one must know the parameters and a set of powered equipment not only currently but, also, in the previous period. But this is impossible if a curve of load duration is used. For modeling, it is necessary to use an hourly load curve and to calculate the state of the energy system for each subsequent hour in chronological order. In the course of a comparative analysis of available computer programs, it was not possible to identify a suitable model among the existing ones. The article presents a mathematical model developed by the authors, which makes us possible to simulate the operation of a power engineering system with a large share of NPP and CHPP while maintaining the power balance for each hour of the forecast period. Verification of the proposed model showed good accuracy of the methods used.

Architecting “Maintenance Program” for Piping and Pipe Support

2013 ◽  
Author(s):  
Koichi Tsumori ◽  
Yoshizumi Fukuhara ◽  
Hiroyuki Terunuma ◽  
Koji Yamamoto ◽  
Satoshi Momiyama
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Industry ◽  
Maintenance Management ◽  
3D Cad ◽  
Cad System ◽  
Nuclear Disaster ◽  
Safety Regulations ◽  
Maintenance Program

A new inspection standard that enhanced quality of operating /maintenance management of the nuclear power plant was introduced in 2009. After the Fukushima Daiichi nuclear disaster (Mar. 11th 2011), the situation surrounding the nuclear industry has dramatically changed, and the requirement for maintenance management of nuclear power plants is pushed for more stringent nuclear safety regulations. The new inspection standard requires enhancing equipment maintenance. It is necessary to enhance maintenance of not only equipment but also piping and pipe support. In this paper, we built the methodology for enhancing maintenance plan by rationalizing and visualizing of piping and pipe support based on the “Maintenance Program” in cooperating with 3D-CAD system.

ANALYSIS OF THE RADIOLOGICAL SAFETY CONTROL LEVEL VERSUS THE EXPOSURE OF RADIATION WORKERS IN SOUTH KOREA FROM 2008–17

2018 ◽  
Vol 184 (1) ◽  
pp. 98-108
Author(s):  
Sang-Tae Kim ◽  
Jaeryong Yoo
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Radiation Safety ◽  
Safety Management ◽  
Control Level ◽  
Radioactive Isotopes ◽  
Safety Control ◽  
Level Versus ◽  
Radiation Workers

Abstract In this study, the radiation exposure of workers at workplaces registered and licensed between 2008 and 2017 for the production/sale/use of radioactive isotopes (RI) and radioactive generators (RG) was analysed to evaluate the quality of radiation safety management controls in use. The number of facilities using RIs increased by ~26% from 2008 to 2017 whereas the number of facilities using RGs increased by ~166% over the same period. There were 33 029 radiation workers in all fields in 2008, and the number increased by ~32% to 43 467 by 2017. However, the collective effective dose of radiation received by workers decreased in all industries except for those working in nuclear power plants. In other words, the quality of radiation safety management improved over that same time period due to the systematic, continuous introduction of safety mechanisms by the regulatory authority.

Design, Analysis and System-Level Modelling of a Single Axis Capacitive Accelerometer

2016 ◽  
Author(s):  
Zakriya Mohammed ◽  
Owais Talaat Waheed ◽  
Ibrahim (Abe) M. Elfadel ◽  
Aveek Chatterjee ◽  
Mahmoud Rasras
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Noise Analysis ◽  
Linear Displacement ◽  
Operating Conditions ◽  
System Level ◽  
Complete Analysis ◽  
Capacitive Accelerometer ◽  
Static Capacitance ◽  
Cross Axis

The paper demonstrates the design and complete analysis of 1-axis MEMS capacitive accelerometer. The design is optimized for high linearity, high sensitivity, and low cross-axis sensitivity. The noise analysis is done to assure satisfactory performance under operating conditions. This includes the mechanical noise of accelerometer, noise due to interface electronics and noise caused by radiation. The latter noise will arise when such accelerometer is deployed in radioactive (e.g., nuclear power plants) or space environments. The static capacitance is calculated to be 4.58 pF/side. A linear displacement sensitivity of 0.012μm/g (g = 9.8m/s2) is observed in the range of ±15g. The differential capacitive sensitivity of the device is 90fF/g. Furthermore, a low cross-axis sensitivity of 0.024fF/g is computed. The effect of radiation is mathematically modelled and possibility of using these devices in radioactive environment is explored. The simulated noise floor of the device with electronic circuit is 0.165mg/Hz1/2.

Turbo Gas Power Plants Performance Evaluation for Putting Into Commercial Operation

2009 ◽  
Author(s):  
Erik Rosado Tamariz ◽  
Norberto Pe´rez Rodri´guez ◽  
Rafael Garci´a Illescas
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Performance Test ◽  
Operating Conditions ◽  
Technical Requirements ◽  
Requirements Specifications ◽  
Commercial Operation ◽  
International Regulations ◽  
Operational Tests

In order to evaluate the performance of new turbo gas power plants for putting in commercial operation, it was necessary to supervise, test and, if so the case, to approve the works of commissioning, operational and acceptance of all equipments and systems that constitute the power plant. All this was done with the aim of guaranteeing the satisfactory operation of these elements to accomplish the function for which they were developed. These activities were conducted at the request of the customer to confirm and observe that the evidence of the tests was carried out according to the specifications and international regulations. The putting into commercial operation activities were done in collaboration with the supplier and manufacturer of equipment, the client and the institution responsible for certification and approval of the plant. All this in a logical and chronological order for the sequence of commissioning tests, operation and acceptance. Commissioning tests were carried out on-site at normal operating conditions, according to the design and operation needs of each power plant of a group of 14. Once the commissioning tests were completely executed and in a satisfactory manner, operational tests of the plants were developed. This was done by considering that they must operate reliable, stable, safe and automatically, satisfying at least, one hundred hours of continuous operation at full load. After evaluating the operational capacity of the machine, it was necessary to determinate the quality of the plant by carrying out a performance test. Finally, it was verified if every unit fulfills the technical requirements established in terms of heat capacity of the machine, noise levels and emissions. As a result of this process, it is guaranteed to the customer that the turbo gas power plants, their systems and equipments, satisfy the requirements, specifications and conditions in agreement with the supplier and manufacturers referring to the putting into commercial operation of the plant.

Thermal Design Options Using Uranium Carbide and Uranium Dicarbide in SCWR Uniformly-Heated Fuel Channel

2009 ◽  
Author(s):  
Leyland J. Allison ◽  
Lisa Grande ◽  
Sally Mikhael ◽  
Adrianexy Rodriguez Prado ◽  
Bryan Villamere ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Operating Conditions ◽  
Thermal Design ◽  
Nuclear Fuels ◽  
Viable Option ◽  
Bulk Fluid ◽  
Fuel Channel ◽  
Uranium Carbide

SuperCritical Water-cooled nuclear Reactor (SCWR) options are one of the six reactor options identified in Generation IV International Forum (GIF). In these reactors the light-water coolant is pressurized to supercritical pressures (up to approximately 25 MPa). This allows the coolant to remain as a single-phase fluid even under supercritical temperatures (up to approximately 625°C). SCW Nuclear Power Plants (NPPs) are of such great interest, because their operating conditions allow for a significant increase in thermal efficiency when compared to that of modern conventional water-cooled NPPs. Direct-cycle SCW NPPs do not require the use of steam generators, steam dryers, etc. allowing for a simplified NPP design. This paper shows that new nuclear fuels such as Uranium Carbide (UC) and Uranium Dicarbide (UC2) are viable option for the SCWRs. It is believed they have great potential due to their higher thermal conductivity and corresponding to that lower fuel centerline temperature compared to those of conventional nuclear fuels such as uranium dioxide, thoria and MOX. Two conditions that must be met are: 1) keep the fuel centreline temperature below 1850°C (industry accepted limit), and 2) keep the sheath temperature below 850°C (design limit). These conditions ensure that SCWRs will operate efficiently and safely. It has been determined that Inconel-600 is a viable option for a sheath material. A generic SCWR fuel channel was considered with a 43-element bundle. Therefore, bulk-fluid, sheath and fuel centreline and HTC profiles were calculated along the heated length of a fuel channel.

Digital Instrumentation and Control Systems Upgrades in Current Generation Nuclear Power Plants

2010 ◽  
Author(s):  
Steven A. Arndt
Keyword(s):  
United States ◽  
Cyber Security ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Plant Protection ◽  
The United States ◽  
Regulatory Compliance ◽  
Digital Systems

Over the past 20 years, the nuclear power industry in the United States (U.S.) has been slowly replacing old, obsolete, and difficult-to-maintain analog technology for its nuclear power plant protection, control, and instrumentation systems with digital systems. The advantages of digital technology, including more accurate and stable measurements and the ability to improve diagnostics capability and system reliability, have led to an ever increasing move to complete these upgrades. Because of the difficulties with establishing digital systems safety based on analysis or tests, the safety demonstration for these systems relies heavily on establishing the quality of the design and development of the hardware and software. In the United States, the U.S. Nuclear Regulatory Commission (NRC) has established detailed guidelines for establishing and documenting an appropriate safety demonstration for digital systems in NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition,” Chapter 7, “Instrumentation and Controls,” Revision 5, issued March 2007 [1], and in a number of regulatory guides and interim staff guidance documents. However, despite the fact that the United States has a well-defined review process, a number of significant challenges associated with the design, licensing, and implementation of upgrades to digital systems for U.S. plants have emerged. Among these challenges have been problems with the quality of the systems and the supporting software verification and validation (V&V) processes, challenges with determining the optimum balance between the enhanced capabilities for the new systems and the desire to maintain system simplicity, challenges with cyber security, and challenges with developing the information needed to support the review of new systems for regulatory compliance.

Environmental Fatigue Test of CF8M With a Small Autoclave Simulating PWR Conditions

2008 ◽  
Author(s):  
Il-Seok Jeong ◽  
Gag-Hyeon Ha ◽  
Tae-Ryoung Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Low Cycle Fatigue ◽  
Test Procedure ◽  
Cyclic Strain ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Measuring Instruments ◽  
Pressurized Water Reactor ◽  
Pressurized Water

To develop a fatigue design curve of cast stainless steel CF8M used in primary piping material of nuclear power plants, low-cycle fatigue tests have been conducted by Korea Electric Power Research Institute (KEPRI). A small autoclave simulated the environment of a pressurized water reactor (PWR), 15 MPa and 315 °C. Fatigue life was measured in terms of the number of cycles with the variation of strain amplitudes at 0.04%/s strain rate. A small autoclave of 1 liter and cylindrical solid fatigue specimens were used for the strain-controlled low cycle environmental fatigue tests to make the experiments convenient. However, it was difficult to install displacement measuring instruments at the target length of the specimens inside the autoclave. To mitigate the difficulty displacement data measured at the shoulders of the specimen were calibrated based on the data relation of the target and shoulder length of the specimen during hot air test conditions. KEPRI developed a test procedure to perform low cycle environmental fatigue tests in the small autoclave. The procedure corrects the cyclic strain hardening effect by performing additional tests in high temperature air condition. KEPRI verified that the corrected test result agreed well with that of finite element method analysis. The process of correcting environmental fatigue data would be useful for producing reliable fatigue curves using a small autoclave simulating the operating conditions of a PWR.

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