scholarly journals 14C Measurements at PWR-Type Nuclear Power Plants in Three Middle European Countries

Radiocarbon ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 439-446 ◽  
Author(s):  
György Uchrin ◽  
Ede Hertelendi ◽  
Gábor Volent ◽  
Ondrej Slavik ◽  
Jozef Morávek ◽  
...  
Keyword(s):  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Discharge Rate ◽  
Continuous Increase ◽  
Mean Values ◽  
A Value ◽  
Discharge Rates ◽  
C 50 ◽  
Ring Analysis

Regular 14C sampling of discharged air began in 1988 at Paks Nuclear Power Plant (NPP), Hungary, and in 1991 at NPPs in Krsko, Slovenia and Bohunice, Slovakia. Monitoring of 14C discharges is carried out at all NPPs with similar differential samplers continuously collecting 14C in the form of 14CO2 and 14CnHm. The main results of airborne discharge monitoring are as follows: 14C activity concentration varied roughly within a factor of two around their mean values, 125 Bq m-3 and 90 Bq m-3 for Paks and for Krsko NPP, respectively. The pattern of discharge for Bohunice NPP is slightly different from that at the other two stations. At Bohunice, there has been a continuous increase in the discharge rate at power unit V1, starting with 70 Bq m-3 in 1991 and reaching a value of 190 Bq m-3 in 1995. The values for power unit V2 are 50 Bq m-3 and 82 Bq m-3. The average normalized yearly discharge rates are 0.887 (TBqGWe-1yr-1) for Paks, 0.815 (V1) and 0.500 (V2) for Bohunice, and 0.219 for Krsko. Most of the discharged 14C is in hydrocarbon form, 95% for Paks and Bohunice V2, but the CO2 fraction may reach 25% or 43% at Bohunice V1 and Krsko, respectively. At Bohunice V1, not only the discharge rate increased but the 14CO2 ratio to the total changed from 30% to 13%. The local radiological impact is estimated to be 1.5 μSv a-1 for Paks, 1.7 μSv a-1 for Bohunice, and 0.12 μSv a-1 for Krsko. The 14C excess in the environment has been measured at Paks NPP since 1989. Based on the monitoring data, the long-term average 14C excess from the Paks NPP was D14C=50% for hydrocarbons. Tree-ring analysis has shown a slight excess around Krsko NPP: D14C is equal to 199.9% for a tree at 1 km from the NPP compared with a “reference” one for which D14C was equal to 111.6% (in 1994).

Wear Characteristics of INCONEL 690 and INCONEL 600 in Elevated Temperature

2005 ◽  
Vol 297-300 ◽  
pp. 1424-1429 ◽  
Author(s):  
Sung Hoon Jeong ◽  
Young Ze Lee
Keyword(s):  
Wear Mechanisms ◽  
Nuclear Power ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Fretting Wear ◽  
Wear Characteristics ◽  
Inconel 600 ◽  
Wear Life ◽  
Inconel 690 ◽  
C 50

In this paper, the fretting wear characteristics of INCONEL 690 (I-690) and INCONEL 600 (I-600) was evaluated to verify the wear mechanism and the wear life. Because of the excellent corrosion-resistance of nickel-based alloy, those materials are used for steam generator tube in nuclear power plants. Sometimes the tubes are damaged due to small amplitude vibration, so called fretting wear. To verify the fretting wear mechanisms the wear experiment was carried with the crossed-cylinder wear tester, which used a cam to oscillate the specimen. The test was carried out at loads of 40N and 90N in elevated temperatures of water. The temperatures of water were 20°C, 50°C and 80°C. The increase of water temperature causes the oxidation of the contact area to be delayed, and the amount of wear on oxide layer to be reduced. The main wear mechanisms of fretting were abrasive wear and oxidation wear.

scholarly journals Development of an intelligent system of experimental control in the energy sector

2020 ◽  
Vol 164 ◽  
pp. 13003
Author(s):  
Larisa Grigoreva ◽  
Vladimir Grigoryev
Keyword(s):  
Control System ◽  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Intelligent System ◽  
Tight Binding ◽  
Energy Sector ◽  
Technological Parameters ◽  
Experimental Control ◽  
Physical Experiments

The article presents a completed project of an experimental control system in the energy sector. An intelligent experimental control system can be used at various types of power plants, including nuclear power units. The developed complex includes design schemes for operational monitoring and registration of rapidly changing neutron-physical and technological parameters of a nuclear power unit at the stages of commissioning of a power unit. Automated process control systems allow the collection and registration of analog parameters with a frequency of not more than 1 second, which is insufficient for correct calculations during neutron-physical experiments and power unit tests. The presented intelligent experimental control system allows the reception and registration of analog signals with a frequency of not more than 100 millisecond. A patented software implementation has been developed that provides unlimited possibilities for realizing customer requirements for operator functionality and interface, as well as the ability to avoid tight binding to specific hardware components.

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.

scholarly journals Participation of Ukrainian NPPs in Regulating Frequency and Power in the United Energy System: Problem Analysis and Solutions

2020 ◽  
pp. 50-56
Author(s):  
V. Goldrin ◽  
I. Chervonenko ◽  
V. Zbinskiy ◽  
R. Brodich ◽  
O. Slonevskiy
Keyword(s):  
Control System ◽  
Power System ◽  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Energy System ◽  
Reactor Power ◽  
Frequency Regulation ◽  
Parallel Operation ◽  
Primary Frequency

The issue related to the participation of Ukrainian nuclear power plants in regulating frequency and power in the united energy system of Ukraine is considered in the paper. The dependence of frequency changes in the grid on the imbalance between generation and consumption of active power is presented. This can violate conditions of parallel operation of generators. Three levels of the frequency control system in the power system using backup capacities are examined. The issues of participation of nuclear power units in regulating frequency and power are studied. It is shown that the main factors limiting such participation are the characteristics of fuel assemblies. These characteristics govern the change in reactor power in a narrow range. An obstacle is also the mismatch of the characteristics of the equipment of power units for participation in regulating power system frequency. The complexity of regulating the electric power of a WWER nuclear power unit is under consideration, which is implemented by coordinated regulation of the reactor power and generator power. The regulatory requirements for the characteristics of the primary frequency regulation by nuclear power units is carried out. The possibility of their participation in the normalized primary frequency regulation are analyzed. The paper considers the concept of the National Nuclear Energy Generating Company “Energoatom” for the modernization of systems and equipment of WWER-1000 power units, which provides bringing the characteristics of power units in line with standards. The methodology for preliminary testing of the readiness of Zaporizhzhya NPP Unit 1 (“pilot” power unit) to participate in such regulation is described. The methodology involves testing at two power levels at the beginning and in the end of the fuel campaign. A signal is used to simulate a frequency deviation that is input via a separate train of the control system. The tasks, conditions and criteria for the success of the tests are described. Based on the test results, conclusions will be drawn about the possibility of the safe participation of WWER-1000 power units in the normalized frequency regulation in the united energy system of Ukraine and the necessary measures to modernize the equipment.

scholarly journals Comparison of Two Control Programs of the VVER-1000Nuclear Power Unit Using Regression Data Mining Models

2017 ◽  
pp. 11-17
Author(s):  
T. Foshch ◽  
J. Machado ◽  
F. Portela ◽  
M. Maksimov ◽  
О. Maksimova
Keyword(s):  
Data Mining ◽  
Power Unit ◽  
Regression Models ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Control Program ◽  
Control Programs ◽  
Load Following ◽  
Matlab Program

A load-following mode of nuclear power plants (NPP) is a complicated procedure, since there are significant changes in many interrelated processes. In order to show which control program (CP) of NPP is better to use, data mining (DM) techniques can be introduced. This study proposes a DM approach in order to show a possibility of using DM regression models for NPP. The datasets for DM were obtained by simulating two static CP of VVER-1000 NPP in Simulink software of Matlab program package.

scholarly journals АПАРАТНО-ПРОГРАМНЕ МОДЕЛЮВАННЯ ПІСЛЯАВАРІЙНОГО МОНІТОРИНГУ АЕС

2019 ◽  
pp. 170-188
Author(s):  
Л. М. Лутай ◽  
К. А. Добросол
Keyword(s):  
Power Unit ◽  
Mobile Communications ◽  
Data Transmission ◽  
Nuclear Power ◽  
Power Plants ◽  
Industrial Revolution ◽  
Large Data ◽  
Practical Implementation ◽  
Hardware Complex ◽  
Proposed Model

From the beginning of the XXI century mankind is experiencing the fourth Industrial Revolution Industry 4.0. This process is a massive introduction of cyber-physics systems, systems for processing and analysis of large data arrays, the use of InternetofThings in industry and automation, and widespread digitization [1]. InternetofThings closely connects various types and types of devices, enterprises, technology, mobile communications, etc. [2]. Such an association within the industry poses high requirements for safety, reliability, speed, uninterrupted work and protection of devices, as well as communication channels between them. On its own, high requirements apply when it comes to objects with critical infrastructure. The category of such include nuclear power plants (NPPs). In this article, a model for data transmission to a crisis center in the event of an accident is proposed. Also presented software and technical implementation of the proposed model. This work is devoted to the creation of a prototype of a software and hardware complex simulating the process of monitoring the NPP power unit. Software-hardware complex is a practical implementation of one of the proposed models of systems after emergency monitoring (RAMS). The development consists of two levels. At the lower level, which is the hardware level, there are sensors, microcontroller, hardware. At the upper level is the information system, which allows within the crisis center to get the values of indicators from the sensors in a convenient and visual form, to store, archive data. In addition, the crisis center has the ability to control the system stabilization of the power unit during an accident, for example, by switching on cooling devices. Data from the power unit can be quickly received by external experts (EEs) located in other countries of the world, without losing time to install software applications or specific software. Crisis center and a group of external experts take decisions on the elimination of the accident or through the usual situation. Due to the proposed model of data transmission, it is possible to obtain as much data as possible about the state of the accident for further liquidation. The article also presents the experimental part of the work.

Results from tests of modernized moisture separator-reheater of K-500-65/3000 turbine plants of the power unit No. 4 at the Leningrad Nuclear Power Plants (NPP)

2012 ◽  
Vol 59 (2) ◽  
pp. 113-118 ◽  
Author(s):  
M. A. Gotovskii ◽  
B. S. Fokin ◽  
M. Ya. Belen’kii ◽  
M. E. Lebedev ◽  
M. A. Blinov ◽  
...  
Keyword(s):  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Moisture Separator

scholarly journals Features of modeling the system of turbine unit with a variable contact zone of its stator parts

2021 ◽  
Vol 3 (10) ◽  
Author(s):  
S. V. Krasnikov
Keyword(s):  
Power Unit ◽  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Forced Oscillations ◽  
Vibration Displacement ◽  
Number Of Factors ◽  
Modeling Systems ◽  
Three Dimensional Models ◽  
The Impact

AbstractModeling of stator parts of power units of thermal and nuclear power plants is carried out according to several standard schemes. Common methods of modeling systems with non-uniform and non-stationary contact of stator elements lead to significant errors in calculating the amplitudes of forced vibration displacement at a given external load. The object of this paper is to analyze errors in calculating the displacement amplitudes of forced oscillations in different modeling schemes according to the standard approach and developing a method for constructing a quasi-dynamic model taking into account the time-varying contact of the system’s stator parts as well as other factors. To do this, the author has developed a series of models with different degrees of sampling and considering different system factors. Particular attention is paid to the impact of factors arising from the long operation of the power plant (subsidence of foundation). The modeling was carried out taking into account the calculation method. The finite element method was used to perform calculations. The results of the calculation of forced oscillation displacement amplitudes are available to show the areas of application of different types of three-dimensional models of the steam power unit. The results of research conducted on the developed models show the impossibility of using standard simulation schemes for systems with a variable contact between its stator elements, as shown by the example of a power unit with steam turbine. The efficiency of using the models taking into account the variable contact between the stator parts and other factors to calculate the displacement amplitudes of the forced oscillations with high accuracy is likewise presented. Every specialist should be aware of the factors that influence the research results. This paper is concerned with assessment of the influence of a number of factors on the results of calculating the vibrations of a complex mechanical system.

The Effects of Ion Implantation on the Surface Features of Inconel 600

1985 ◽  
Vol 43 ◽  
pp. 288-289
Author(s):  
John D. Rubio
Keyword(s):  
Grain Boundary ◽  
Ion Implantation ◽  
Nuclear Power ◽  
Power Plants ◽  
Surface Region ◽  
Selective Dissolution ◽  
Boundary Region ◽  
Near Surface ◽  
Inconel 600 ◽  
Steam Generator Tubing

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.

Work structure in nuclear power plants

1983 ◽  
Author(s):  
Marjorie B. Bauman ◽  
Richard F. Pain ◽  
Harold P. Van Cott ◽  
Margery K. Davidson
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Work Structure
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