Vibration Characteristics of a Perforated Plate Immersed in Fluid

2012 ◽  
Author(s):  
Tomohiro Ito ◽  
Atsuhiko Shintani ◽  
Chihiro Nakagawa
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Damping Ratio ◽  
Thermal Power ◽  
Perforated Plate ◽  
Vibration Characteristics ◽  
Chemical Plants ◽  
Perforated Plates ◽  
Stiffness Reduction ◽  
Test Models

Perforated plates are used in many mechanical structures in thermal power plants, nuclear power plants, or chemical plants etc. Cylindrical structures made by the perforated plates are also found in many places. However, vibration characteristics of the structures made by perforated plates are not fully clarified, especially for the structures immersed in liquid. The stiffness of the structures becomes smaller than that of ones made by simple plates with no holes, while the mass of the structures also becomes smaller. According to the balance between the stiffness reduction and mass reduction, natural frequencies will be decided. Moreover, added mass and added damping effects are very large in liquid, and are thought to largely change due to holes. In this study, as a fundamental step, a perforated plate is treated. The vibration characteristics such as natural frequency and damping ratio are studied for various hole numbers or various opening ratios by both numerical simulations and simple test models. Vibration tests are conducted in liquid as well as in air.

Effects of Connecting Damper on Rocking Motion of Multiple Cabinets Subjected to Seismic Excitation

2015 ◽  
Author(s):  
Tomohiro Ito ◽  
Takatsugu Kihara ◽  
Atsuhiko Shintani ◽  
Chihiro Nakagawa
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Analytical Models ◽  
Chemical Plants ◽  
Electronic Circuits ◽  
Seismic Excitations ◽  
Free Standing ◽  
Worst Case ◽  
Rocking Motion

In various industrial plants such as thermal power plants, nuclear power plants and chemical plants, numerous cabinets are used for storing the electronic circuits and devices used for controlling the plants. These cabinets are very important for maintaining stable plant operation. Some of these cabinets are simply placed on the floor as free-standing structures, and in many cases, they cannot be connected to the floor using bolts or other means for various reasons. Thus, if these cabinets are subjected to very strong seismic excitations, they will experience very large rocking motions. In the worst case, they will overturn, and the installed electronic circuits or devices will collapse which will cause a loss of plant control and could result in significant accidents. Thus, rocking motion suppression methods have been proposed for these free-standing structures. The authors have also been investigating a method that utilizes a gyro system. Connecting adjacent buildings by damping devices is a well-known architectural mitigation method that is very effective at mitigating their seismic response. The effectiveness of this method was confirmed during the Great East Japan Earthquake in 2011. In this paper, we apply the above-mentioned connecting method to free-standing cabinets in order to suppress rocking motion. There are various types of connecting devices, such as a viscous damper. In this paper, considering the characteristics of these dampers, an elasto-plastic damper is adopted as a connecting device. Analytical models of the rocking motions of control cabinets are established, and the connecting devices are expressed as dampers with a bilinear-type force-displacement characteristic. The rocking motions of the cabinets are analyzed for sinusoidal and seismic excitations by changing the aspect ratio of the cabinets, along with the yield force in the bilinear hysteretic curve. The effects of connecting devices and various parameters are evaluated and discussed in comparison with the rocking motion of a single cabinet. It is found that the proposed connecting method is very effective in suppressing the rocking motion of the free-standing cabinets subjected to base excitations when the hysteretic characteristics are properly adjusted.

scholarly journals Assessment of interannual and intra-annual atmospheric dispersion variability parameters in the Belorussian NPP siting area

2019 ◽  
Vol 135 ◽  
pp. 01038
Author(s):  
Fedor Bryukhan
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Atmospheric Dispersion ◽  
Chemical Plants ◽  
Dispersion Parameters ◽  
Acoustic Sounding ◽  
Industrial Facilities ◽  
Status Monitoring

Identification of atmospheric boundary layer (ABL) radionuclide dispersion conditions, which are characterized by ABL dispersion parameters, plays an important role in evaluating the radiation safety of nuclear power plants (NPPs) and establishing engineering protection thereof. Therefore, the ABL status monitoring observations are launched at the stage of in-situ NPP construction. When analyzing and predicting radiation situation in the NPP vicinity areas, it is of great importance to determine the parameters of atmospheric dispersion variability with time. The ABL status monitoring at the Belorussian NPP site has been carried out since September 2014 by means of acoustic and radio-acoustic sounding of the ABL. The present study is aimed at assessing interannual and intra-annual variability of atmospheric dispersion parameters in the Belorussian NPP siting area on the basis of the monitoring data. The relative interannual stability of the main average annual atmospheric dispersion characteristics (vertical temperature gradient, wind speed and direction) over the observation period has been revealed. At the same time, the average seasonal values of the dispersion parameters are characterized by significant fluctuations thereof during the annual course. The prospects of the ABL status monitoring for other potentially hazardous industrial facilities, such as thermal power plants and chemical plants, are also noted.

Power Cycles of Generation III and III+ Nuclear Power Plants

2014 ◽  
Author(s):  
Alexey Dragunov ◽  
Eugene Saltanov ◽  
Igor Pioro ◽  
Pavel Kirillov ◽  
Romney Duffey
Keyword(s):  
Renewable Energy ◽  
Natural Gas ◽  
Thermal Efficiency ◽  
Nuclear Power ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Electrical Energy ◽  
Energy Sources ◽  
Thermal Power Plants

It is well known that the electrical-power generation is the key factor for advances in any other industries, agriculture and level of living. In general, electrical energy can be generated by: 1) non-renewable-energy sources such as coal, natural gas, oil, and nuclear; and 2) renewable-energy sources such as hydro, wind, solar, biomass, geothermal and marine. However, the main sources for electrical-energy generation are: 1) thermal - primary coal and secondary natural gas; 2) “large” hydro and 3) nuclear. The rest of the energy sources might have visible impact just in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that they are still the largest emitters of carbon dioxide into atmosphere. Due to that, reliable non-fossil-fuel energy generation, such as nuclear power, becomes more and more attractive. However, current Nuclear Power Plants (NPPs) are way behind by thermal efficiency (30–42%) compared to that of advanced thermal power plants. Therefore, it is important to consider various ways to enhance thermal efficiency of NPPs. The paper presents comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.

scholarly journals PRELIMINARY DESIGN OF RDE FEEDWATER PUMP IMPELLER

2018 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Sri Sudadiyo
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Thermal Power ◽  
Performance Characteristics ◽  
Preliminary Design ◽  
Triangle Diagram ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Feedwater Pump

Nowadays, pumps are being widely used in the thermal power generation including nuclear power plants. Reaktor Daya Eksperimental (RDE) is a proposed nuclear reactor concept for the type of nuclear power plant in Indonesia. This RDE has thermal power 10 MWth, and uses a feedwater pump within its steam cycle. The performance of feedwater pump depends on size and geometry of impeller model, such as the number of blades and the blade angle. The purpose of this study is to perform a preliminary design on an impeller of feedwater pump for RDE and to simulate its performance characteristics. The Fortran code is used as an aid in data calculation in order to rapidly compute the blade shape of feedwater pump impeller, particularly for a RDE case. The calculations analyses is solved by utilizing empirical correlations, which are related to size and geometry of a pump impeller model, while performance characteristics analysis is done based on velocity triangle diagram. The effect of leakage, pass through the impeller due to the required clearances between the feedwater pump impeller and the volute channel, is also considered. Comparison between the feedwater pump of HTR-10 and of RDE shows similarity in the trend line of curve shape. These characteristics curves will be very useful for the values prediction of performance of a RDE feedwater pump. Preliminary design of feedwater pump provides the size and geometry of impeller blade model with 5-blades, inlet angle 14.5 degrees, exit angle 25 degrees, inside diameter 81.3 mm, exit diameter 275.2 mm, thickness 4.7 mm, and height 14.1 mm. In addition, the optimal values of performance characteristics were obtained when flow capacity was 4.8 kg/s, fluid head was 29.1 m, shaft mechanical power was 2.64 kW, and efficiency was 52 % at rotational speed 1750 rpm.Keywords: Blade, impeller, pump, RDEDESAIN AWAL IMPELER POMPA AIR UMPAN RDE. Saat ini, pompa digunakan secara luas dalam pembangkit tenaga termal termasuk pembangkit listrik tenaga nuklir. Reaktor Daya Eksperimental (RDE) merupakan konsep reaktor nuklir yang diusulkan untuk tipe PLTN di Indonesia. RDE ini memiliki daya termal 10 MWth, dan menggunakan pompa air umpan dalam siklus uapnya. Kinerja pompa air umpan bergantung pada ukuran dan geometri model impeller, seperti jumlah sudu dan sudut sudu. Tujuan dari penelitian ini adalah untuk membuat rancangan awal impeller pompa air umpan untuk RDE dan untuk mensimulasikan karakteristik kinerjanya. Kode Fortran digunakan sebagai bantuan dalam penghitungan data untuk untuk mengkalkulasi secara cepat bentuk sudu impeller pompa air umpan, terutama pada kasus RDE. Analisis perhitungan dipecahkan menggunakan korelasi empiris yang terkait dengan ukuran dan geometri model impeller pompa, sedangkan analisis karakteristik kinerja dilakukan berdasarkan diagram segitiga kecepatan. Pengaruh bocoran, melalui impeler akibat celah yang diperlukan antara impeller pompa air umpan dan saluran volute, juga dipertimbangkan. Perbandingan antara pompa air umpan HTR-10 dan RDE menunjukkan kemiripan dalam garis tren bentuk kurva. Kurva karakteristik ini akan sangat berguna untuk perkiraan nilai kinerja pompa air umpan RDE. Desain awal pompa air umpan memberikan ukuran dan geometri model sudu impeller dengan 5-sudu, sudut masuk 14,5 derajat, sudut keluar 25 derajat, diameter dalam 81,3 mm, diameter luar 275,2 mm, ketebalan 4,7 mm, dan tinggi 14,1 mm. Selain itu, nilai optimal karakteristik kinerja diperoleh ketika kapasitas aliran 4,8 kg/s, head fluida 29,1 m, tenaga mekanik poros 2,64 kW, dan efisiensi 52 % pada kecepatan putaran 1750 rpm.Kata kunci: Sudu, impeler, pompa, RDE

Application of Supercritical Fluids in Thermal- and Nuclear-Power Engineering

2021 ◽  
pp. 601-658
Author(s):  
Igor L. Pioro
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Supercritical Fluids ◽  
Nuclear Power ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Thermal Power Plants ◽  
Power Cycles

Supercritical Fluids (SCFs) have unique thermophyscial properties and heat-transfer characteristics, which make them very attractive for use in power industry. In this chapter, specifics of thermophysical properties and heat transfer of SCFs such as water, carbon dioxide, and helium are considered and discussed. Also, particularities of heat transfer at Supercritical Pressures (SCPs) are presented, and the most accurate heat-transfer correlations are listed. Supercritical Water (SCW) is widely used as the working fluid in the SCP Rankine “steam”-turbine cycle in fossil-fuel thermal power plants. This increase in thermal efficiency is possible by application of high-temperature reactors and power cycles. Currently, six concepts of Generation-IV reactors are being developed, with coolant outlet temperatures of 500°C~1000°C. SCFs will be used as coolants (helium in GFRs and VHTRs, and SCW in SCWRs) and/or working fluids in power cycles (helium, mixture of nitrogen (80%) and helium (20%), nitrogen and carbon dioxide in Brayton gas-turbine cycles, and SCW/“steam” in Rankine cycle).

Development of Robotic Inspection System for Small Pipelines

2000 ◽  
Author(s):  
Jinwu Qian ◽  
Yanan Zhang ◽  
Weiming Cheng ◽  
Linyong Shen ◽  
Jianliang Su ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Industry ◽  
Inspection System ◽  
Chemical Plants ◽  
Micro Robot ◽  
Potential Applications ◽  
Inspection Systems ◽  
Development Goals ◽  
Further Development

Automated probing and inspection inside small pipelines have become a hot topic among the micro-robot researchers in both universities and companies worldwide. The reason for that is the potential applications in nuclear power plants (PWR), civil engineering (gas and water) and in chemical plants and so on. This paper outlines the R & D activities on robotic inspection systems for 20mm-diameter pipelines conducted at Shanghai University in collaboration with NDT Center for Nuclear Industry. The locomotion mechanism comparison and synthesis are covered first. Several robotic inspection systems and different locomotion mechanisms are presented. Further development goals underway are briefly discussed.

Ni-Coated Optical Fibers by Electroless Plating

2000 ◽  
Vol 6 (S2) ◽  
pp. 456-457
Author(s):  
Yuli Lin ◽  
Li-Jang Hwang
Keyword(s):  
Optical Fibers ◽  
Vapor Deposition ◽  
Nuclear Power ◽  
Power Plants ◽  
Linear Expansion ◽  
Chemical Vapor ◽  
High Strength ◽  
Metal Coating ◽  
Chemical Plants ◽  
Silica Substrate

Optical fibers have been extensively employed in a variety of fields. However, the need of high strength, excellent resistance to moisture permeation and tolerance to heat becomes apparent when such optical fibers are used in nuclear power plants and chemical plants in particular. Plastic coatings as conventional made of optical fibers cables would be replaced by the optical fiber coated with a layer of metal.Several techniques have been applied to make a metal coating for the optical fibers. Dipping method, to pass optical fibers through a bath containing metal melt, was found the simplest. This dipping method, however, suffers from a disadvantage of a generation of a microbent due to the differences of the linear expansion between metal and the silica substrate [1]. Moreover, the control of the thickness was found difficult using the dipping method. Chemical vapor deposition was also used to form the metal coating on optical fibers.

Research on Combined Peak Load Regulation with Hydropower, Thermal Power and Nuclear Power Plants

2014 ◽  
Vol 986-987 ◽  
pp. 465-469 ◽  
Author(s):  
Gang Wang ◽  
Xiao Dong Ma ◽  
Chao Wang ◽  
Peng Ye
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Power Grid ◽  
Thermal Power ◽  
Operation Mode ◽  
Peak Load ◽  
Generating Capacity ◽  
Load Regulation ◽  
Set Up ◽  
Research Show

Base on Nuclear Power Plant (NPP) participating in peak load regulation of power grid, this paper studies the operation mode of hydropower, thermal power and NPP in Combined Peak Load Regulation. The optimization model for Peaking depth of NPP was set up. The case based on actual power grid were calculated and analyzed, results of the research show that in combined peak load regulation of hydropower, thermal power and NPP, a reasonable peaking depth of NPP will effectively alleviate the peaking pressure of power grid, avoid start-stop of thermal power and abandoned water of hydropower, while ensuring the hydroelectric generating capacity in the low load periods, and ensure thermal power output smooth, it further reduce the operating costs, verify the effectiveness of the model.

Determining the thermal power outputs of small high-temperature nuclear power plants

1976 ◽  
Vol 41 (6) ◽  
pp. 1076-1078
Author(s):  
A. I. El'tsov ◽  
A. K. Zabavin ◽  
Yu. A. Kotel'nikov ◽  
A. A. Labut ◽  
E. P. Larin ◽  
...  
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Thermal Power ◽  
Power Outputs

scholarly journals Comparison of the most likely low-emission electricity production systems in Estonia

2021 ◽  
Author(s):  
Zachariah Baird ◽  
Dmitri Neshumayev ◽  
Oliver Järvik ◽  
Kody M. Powell
Keyword(s):  
Energy Storage ◽  
Wind Turbines ◽  
Nuclear Power ◽  
Oil Shale ◽  
Power Plants ◽  
Thermal Power ◽  
Carbon Capture And Storage ◽  
Electricity Production ◽  
Levelized Cost Of Electricity ◽  
Low Emission

To meet targets for reducing greenhouse gas emissions, many countries, including Estonia, must transition to low-emission electricity sources. Based on current circumstances, the most likely options in Estonia are renewables with energy storage, oil shale power plants with carbon capture and storage (CCS), or the combination of renewables and either oil shale or nuclear power plants. Here we compare these different scenarios to help determine which would be the most promising based on current information. For the comparison we performed simulations to assess how various systems meet the electricity demand in Estonia and at what cost.Based on our simulation results and literature data, combining wind turbines with thermal power plants would provide grid stability at a more affordable cost. Using nuclear power to compliment wind turbines would lead to an overall levelized cost of electricity (LCOE) in the range of 68 to 150 EUR/MWh (median of 103 EUR/MWh). Using oil shale power plants with CCS would give a cost between 91 and 163 EUR/MWh (median of 118 EUR/MWh). By comparison, using only renewables and energy storage would have an LCOE of 106 to 241 EUR/MWh (median of 153 EUR/MWh).

Sign in / Sign up

Export Citation Format

Share Document