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Journal articles on the topic 'Draft loss of steam generator'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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1

Luo, Run, Chunyu Liu, and Rafael Macián-Juan. "Investigation of Control Characteristics for a Molten Salt Reactor Plant under Normal and Accident Conditions." Energies 14, no. 17 (August 25, 2021): 5279. http://dx.doi.org/10.3390/en14175279.

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A molten salt reactor (MSR) has unique safety and economic advantages due to the liquid fluoride salt adopted as the reactor fuel and heat carrier fluid. The operation scheme and control strategy of the MSR plant are significantly different from those of traditional solid-fuel reactors because of the delayed neutron precursors drift with the liquid-fuel flow. In this paper, a simulation platform of the MSR plant is developed to study the control characteristics under normal and accident conditions. A nonlinear dynamic model of the whole system is built in the platform consisting of a liquid-fuel reactor with a graphite moderator, an intermediate heat exchanger and a steam generator. A new control strategy is presented based on a feed-forward and feedback combined scheme, a power control system and a steam temperature control system are designed to regulate load changes of the plant. Three different types of operation conditions are simulated with the control systems, including transients of normal load-follow operation, a reactivity insertion accident and a loss of flow accident. The simulation results show that the developed control system not only has a fast load-follow capability during normal operation, but also has a good control performance under accident conditions.
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2

Xu, Qi Sheng, Xiao Wei Peng, Jie Wu, Xiao Qian Ma, Yue Xi Yu, and Zhi Bin Xu. "Economic and Environmental Analysis for Steam-Driven Induced Draft Fans of 1036MW Ultra Supercritical Units." Advanced Materials Research 787 (September 2013): 553–57. http://dx.doi.org/10.4028/www.scientific.net/amr.787.553.

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Concerning the steam induced draft fan renovation tendency in large coal-fired power plants, the economic and environmental benefit are analysed for certain 1036MW ultra supercritical units. Under the same generator output, despite the power generation coal consumption for the scheme with steam induced draft fan coal increased, the auxiliary power reduced significantly which results in roughly RMB 10,657 thousands yuan economic saving every year with about 1.9 years payback period of investment. Due to the power supply coal consumption saving, the annual amount of pollutants reduction of CO2, SO2, NO2 and dust are 4440.867, 16.462, 45.514 and 220.829t, respectively.
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3

Huang, Yuchen, Lin Chen, Xianwei Huang, Xiaoze Du, and Lijun Yang. "Performance of natural draft hybrid cooling system of large scale steam turbine generator unit." Applied Thermal Engineering 122 (July 2017): 227–44. http://dx.doi.org/10.1016/j.applthermaleng.2017.04.120.

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4

Wei, Yaobing, Xin Wang, Yuanyuan Kong, and Changfeng Yan. "A probability uncertainty method of fault classification for steam turbine generator set based on Bayes and Holospectrum." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 20 (August 9, 2016): 3767–76. http://dx.doi.org/10.1177/0954406215616146.

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With the rapid development of the machinery and the increasing complexity of the steam turbine generator set, it is a great challenge for the safe and reliable operation of the steam turbine generator set. The uncertainties of fault classification and complicated working conditions become important research fields of steam turbine generator. A probability method on the uncertainty reasoning of fault classification for steam turbine generator is proposed in this paper based on the 2D-holospectrum and Bayesian decision theory. Firstly, Bayesian decision theory is adopted for the preliminary fault estimation on actual risk loss by calculating the loss expectation of each decision. Then, the area ratio of overlap region in 2D-holospectrum and the evidence theory can give the probability of the fault. Framework and model of the uncertainty reasoning are also described in this paper. Finally, the model is verified by the experiment of the rotor vibration on test rig. The results show that the method proposed is feasible for reasoning under imperfect information condition.
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5

Zhang, Li Na, Hui Zhao, and Min Shan Liu. "Research on Fluid-Structure Interaction Dynamic Characteristics of Steam Generator Heat Exchanger Tubes." Advanced Materials Research 482-484 (February 2012): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.183.

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For heat exchanger tube of steam generator, the relation between heat exchanger tube and fluid is typical fluid-structure interaction problem. Flow induced vibration has been found so far to be responsible for fatigue damage and failure of steam generator tubes, which will result in large economic loss and radioactive pollution. So the steam generator tubes are the weakest link in the primary coolant loop. Based on the synthesis of all sorts of factors influencing the dynamic characteristics of steam generator heat transfer tubes, establishing the heat transfer tube model, research on the weakening effect of fluid hole on fluid, the natural frequencies of the heat transfer tubes are analyzed under different fluid holes and fluid hole distance by numerical simulation.
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6

Kocijel, Lino, Igor Poljak, Vedran Mrzljak, and Zlatan Car. "Energy Loss Analysis at the Gland Seals of a Marine Turbo-Generator Steam Turbine." Tehnički glasnik 14, no. 1 (March 20, 2020): 19–26. http://dx.doi.org/10.31803/tg-20191031094436.

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The paper presents an analysis of marine Turbo-Generator Steam Turbine (TGST) energy losses at turbine gland seals. The analyzed TGST is one of two identical Turbo-Generator Steam Turbines mounted in the steam propulsion plant of a commercial LNG carrier. Research is based on the TGST measurement data obtained during exploitation at three different loads. The turbine front gland seal is the most important element which defines TGST operating parameters, energy losses and energy efficiencies. The front gland seal should have as many chambers as possible in order to minimize the leaked steam mass flow rate, which will result in a turbine energy losses’ decrease and in an increase in energy efficiency. The steam mass flow rate leakage through the TGST rear gland seal has a low or negligible influence on turbine operating parameters, energy losses and energy efficiencies. The highest turbine energy efficiencies are noted at a high load – on which TGST operation is preferable.
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7

Krasniqi-Alidema, Drenusha, Risto Filkoski, and Marigona Krasniqi. "Exergy efficiency analysis of lignite-fired steam generator." Thermal Science 22, no. 5 (2018): 2087–101. http://dx.doi.org/10.2298/tsci180131265k.

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The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.
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8

Song, Changyuan, Xuying Chen, Rui Hao, Dongna Cai, Xiangwei Zhu, Hao Liu, Jinzhou Chen, and Wentao Liu. "A cocoon-based 3D solar steam generator for high-performance saline water desalination." Sustainable Energy & Fuels 5, no. 16 (2021): 4126–32. http://dx.doi.org/10.1039/d1se00708d.

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9

Mrzljak, Vedran, Paolo Blecich, Nikola Anđelić, and Ivan Lorencin. "Energy and Exergy Analyses of Forced Draft Fan for Marine Steam Propulsion System during Load Change." Journal of Marine Science and Engineering 7, no. 11 (October 28, 2019): 381. http://dx.doi.org/10.3390/jmse7110381.

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A forced draft fan, used for the supply of combustion air into the steam generator of the conventional liquefied natural gas (LNG) carrier was analyzed from the aspect of energy and exergy. The power delivered from the induction motor to the fan was calculated using the manufacturer’s data. The most significant impact on the fan energy power losses is from the air temperature difference between the fan outlet and inlet. The fan energy power losses are inversely proportional to the fan energy efficiency, and the values are between 19.9% and 63.4%, for the entire range of observed steam system loads. The fan exergy destruction depends primarily on the driving power and on the air mass flow rate. At higher loads, an important influence on the fan exergy destruction is from the air pressure at the fan outlet. The exergy efficiency change of the analyzed fan, for the range of observed steam system loads, is directly proportional to the rate of change in the air mass flow, whereas the obtained values of exergy efficiency are between 5.10% and 53.93%. The impact of ambient temperature on the fan exergy destruction and exergy efficiency exhibits is different than in most other steam system components. A change in ambient temperature of 10 °C causes a change in the exergy efficiency of the forced draft fan less than 0.5% in the entire range of observed steam loads.
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10

Jin, H., M. Ishida, M. Kobayashi, and M. Nunokawa. "Exergy Evaluation of Two Current Advanced Power Plants: Supercritical Steam Turbine and Combined Cycle." Journal of Energy Resources Technology 119, no. 4 (December 1, 1997): 250–56. http://dx.doi.org/10.1115/1.2794998.

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Two operating advanced power plants, a supercritical steam plant and a gas-steam turbine combined cycle, have been analyzed using a methodology of graphical exergy analysis (EUDs). The comparison of two plants, which may provide the detailed information on internal phenomena, points out several inefficient segments in the combined cycle plant: higher exergy loss caused by mixing in the combustor, higher exergy waste from the heat recovery steam generator, and higher exergy loss by inefficiency in the power section, especially in the steam turbine. On the basis of these fundamental features of each plant, we recommend several schemes for improving the thermal efficiency of current advanced power plants.
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11

Mokros, Sarah G., Peter Ross Underhill, Jordan E. Morelli, and Thomas W. Krause. "Pulsed Eddy Current Inspection of Wall Loss in Steam Generator Trefoil Broach Supports." IEEE Sensors Journal 17, no. 2 (January 15, 2017): 444–49. http://dx.doi.org/10.1109/jsen.2016.2631541.

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12

Vučković, Goran, Mića Vukić, Mirko Stojiljković, and Miloš Simonović. "SPLITTING THE TOTAL EXERGY DESTRUCTION INTO THE ENDOGENOUS AND EXOGENOUS PARTS OF THE THERMAL PROCESSES IN A REAL INDUSTRIAL PLANT." Facta Universitatis, Series: Mechanical Engineering 14, no. 2 (August 2, 2016): 199. http://dx.doi.org/10.22190/fume1602199v.

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The total exergy destruction occurring in a component is not only due to the component itself (endogenous exergy destruction) but is also caused by the inefficiencies of the remaining system components (exogenous exergy destruction). Hence care must be taken in using the total exergy destruction of a component for making decisions to optimize the overall energy system. In this paper, a complex industrial plant is analyzed by splitting the component’s exergy destruction into its endogenous part (the part resulting totally from the component’s irreversibilities) and its exogenous part (resulting from the irreversibilities of the other components within the system). It is observed that the steam generator has the dominant effect. From the total exergy destruction in the steam generator, 1,097.63 kW or 96.95% come from internal irreversibilities in the component, while the influence of other components on the loss of useful work in the steam generator is only 3.05%.
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13

Huang, Ning, Zhenlin Li, and Baoshan Zhu. "Cavitating Flow Suppression in the Draft Tube of a Cryogenic Turbine Expander through Runner Optimization." Processes 8, no. 3 (February 27, 2020): 270. http://dx.doi.org/10.3390/pr8030270.

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The application of a cryogenic liquefied natural gas expander can reduce the production of flash steam and improve the efficiency of natural gas liquefaction. Like traditional hydraulic machinery, cavitation will occur during the operation of a liquefied natural gas expander, in particular, there is a strong vortex flow in the draft tube, and the cavitation phenomenon is serious. In this paper, the energy loss coefficient of the draft tube is used to describe the cavitation flow in the draft tube, and the goal of reducing the cavitation in the draft tube is achieved through the optimization design of the runner. Different runner models within the range of design parameters were obtained using the Latin hypercube test, and the relationship between design parameters and objective functions is constructed by a second-order response surface model. Finally, the optimized runners were obtained using a genetic algorithm. The effects of blade loading distribution and blade lean angles on the cavitation in the draft tube were studied. According to the optimization results, the blade loading distribution and blade lean angles are recommended in the end.
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14

Virtanen, E., T. Haapalehto, and J. Kouhia. "Analysis of steam generator loss-of-feedwater experiments with APROS and RELAP5/MOD3.1 computer codes." Nuclear Engineering and Design 177, no. 1-3 (December 1997): 147–53. http://dx.doi.org/10.1016/s0029-5493(97)00191-x.

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15

Liao, Y., S. Guentay, and D. Suckow. "The Once-Through Mode of Steam Generator Reflux Condensation in Loss-of-Coolant Accident Scenarios." Nuclear Technology 175, no. 3 (September 2011): 510–19. http://dx.doi.org/10.13182/nt11-a12502.

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16

Gazizova, Olga V., Alexandr P. Sokolov, Nikolay T. Patshin, and Yulia N. Kondrashova. "Analysis of Permissibility of the Excitation Loss Mode of the Synchronous Generator in the Conditions of the Industrial Electrical Supply System." Electrotechnical Systems and Complexes, no. 2(43) (June 28, 2019): 12–18. http://dx.doi.org/10.18503/2311-8318-2019-2(43)-12-18.

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Modern operating conditions of large industrial enterprises require the provision of high reliability of power supply to consumers while reducing the cost of the electricity consumed. These requirements are ensured by the widespread introduction of own sources of electrical energy. These include combined heat and power plants, gas turbines, gas pistons and steam and gas power plants. At the same time, there is a significant complication of the industrial network configuration and possible emergency modes. One of the emergency modes in such networks is the loss of excitation of the synchronous generator. The admissibility of such a regime is specified by regulatory documents. In this situation, the generator goes into asynchronous mode and consumes reactive power from the network. The purpose of this work is to identify the admissibility of the synchronous generator operation for a certain time in the asynchronous mode as a result of the loss of excitation. An algorithm has been developed to calculate the transient electromechanical process of a synchronous generator taking into account the loss of machine excitation. Investigations have been carried out for various operating modes of an industrial power plant taking into account the initial generator load using the KATRAN software. The calculation results allow determining the generator load by active power at which the synchronous generator can operate in the asynchronous mode without excitation.
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17

McKay, Helen, Nathan Griffiths, Phillip Taylor, Theo Damoulas, and Zhou Xu. "Bi-directional online transfer learning: a framework." Annals of Telecommunications 75, no. 9-10 (October 2020): 523–47. http://dx.doi.org/10.1007/s12243-020-00776-1.

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Abstract Transfer learning uses knowledge learnt in source domains to aid predictions in a target domain. When source and target domains are online, they are susceptible to concept drift, which may alter the mapping of knowledge between them. Drifts in online environments can make additional information available in each domain, necessitating continuing knowledge transfer both from source to target and vice versa. To address this, we introduce the Bi-directional Online Transfer Learning (BOTL) framework, which uses knowledge learnt in each online domain to aid predictions in others. We introduce two variants of BOTL that incorporate model culling to minimise negative transfer in frameworks with high volumes of model transfer. We consider the theoretical loss of BOTL, which indicates that BOTL achieves a loss no worse than the underlying concept drift detection algorithm. We evaluate BOTL using two existing concept drift detection algorithms: RePro and ADWIN. Additionally, we present a concept drift detection algorithm, Adaptive Windowing with Proactive drift detection (AWPro), which reduces the computation and communication demands of BOTL. Empirical results are presented using two data stream generators: the drifting hyperplane emulator and the smart home heating simulator, and real-world data predicting Time To Collision (TTC) from vehicle telemetry. The evaluation shows BOTL and its variants outperform the concept drift detection strategies and the existing state-of-the-art online transfer learning technique.
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18

Pillet, Joël, Enrico Deri, Franck David, and André Adobes. "Measurement of pressure loss throughout a clogged steam generator tube support plate in two-phase flow." Nuclear Engineering and Design 370 (December 2020): 110921. http://dx.doi.org/10.1016/j.nucengdes.2020.110921.

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19

ASAKA, Hideaki, and Yutaka KUKITA. "Intentional Depressurization of Steam Generator Secondary Side during a PWR Small-Break Loss-of-Coolant Accident." Journal of Nuclear Science and Technology 32, no. 2 (February 1995): 101–10. http://dx.doi.org/10.1080/18811248.1995.9731679.

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20

Marn, Jure, Marjan Delić, and Leopold Škerget. "Experimental models of medium break loss of coolant accidents with and without steam generator tube rupture." International Journal of Pressure Vessels and Piping 80, no. 10 (October 2003): 737–44. http://dx.doi.org/10.1016/j.ijpvp.2003.08.001.

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21

Ren, Meng Meng, Shu Zhong Wang, Li Li Qian, and Yan Hui Li. "High-Pressure Direct-Fired Steam-Gas Generator (HDSG) for Heavy Oil Recovery." Applied Mechanics and Materials 577 (July 2014): 523–26. http://dx.doi.org/10.4028/www.scientific.net/amm.577.523.

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High-pressure direct-fired steam-gas generator (HDSG) is to produce multiplex thermal fluid (contains water, CO2, N2 etc.) through efficient direct-contact heat transfer, which would utilize the flue gas heat and reduce the gas emission caused by ordinary boiler. Furthermore, the multiplex thermal fluid can promote the heavy oil recovery by both steam flooding and miscible flooding. This paper introduced three kinds of HDSG: pressurized submerged combustion vaporization (PSCV), multiplex thermal fluid generator and supercritical hydrothermal combustor, which are different in work pressure and method of mixing water and flue gas. Then, we discussed the economic efficiency of HDSG used for heavy oil recovery and concluded that although the pressurization of fuel and oxygen would cost as much as the energy saved by utilizing the flue gas heat, using HDSG for heavy oil recovery has other incalculable benefits such as miscible flooding, waste water treatment and reduction of heat loss through injection well. Finally, we indicated that supercritical hydrothermal combustor will be the trendy of HDSG and pointed out the future research should be carried out on the heat and mass transfer characteristic of the combustion field when water presents and the combustion stability and completeness when pressure increases.
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22

Hochreiter, L. E., S. V. Fanto, L. E. Conway, and L. K. Lau. "Integral Testing of the AP600 Passive Emergency Core Cooling Systems." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 207, no. 4 (November 1993): 259–68. http://dx.doi.org/10.1243/pime_proc_1993_207_048_02.

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In support of the development of AP600, Westinghouse is conducting two integral systems tests to examine the performance of the passive safety systems. A full-height, full-pressure test is being performed to simulate a small loss-of-coolant, steam generator tube rupture and large steam line break events. A one-quarter scale, low-pressure test is being performed to simulate transients with emphasis on the transition to the natural circulation post-accident, long-term cooling mode and to demonstrate the long-term cooling capability. Each of the tests will provide detailed experimental results for verification of the accident analysis computer codes.
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23

Li, Zhi, Zhong Min Li, and Zhan Liang Yan. "Energy and Exergy Analysis for Three Type 500MW Steam Power Plants." Applied Mechanics and Materials 148-149 (December 2011): 1131–36. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.1131.

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The paper shows the comparison of energy and exergy analysis of thermal power plants based on advanced steam parameters in China climatic conditions. The research contains coal-based thermal power plants using sub-critical, super-critical, and ultra-supercritical steam conditions. The design configurations of 500 MW unit size were considered. The research contains the effect of condenser pressure on plant and exergy efficiency. The effect of high grade coal on performance parameters as compared to typical China low grade coal was also studied. The major exergy loss took place in coal combustion followed by the steam generator. Due to condenser pressure limitation, the maximum possible overall energy efficiency was found to be about 44.4% with the ultra-supercritical power plant. Installing coal-based thermal power plants based on advanced steam parameters in China will be a prospective option aiding energy self-sufficiency.
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24

Perdana, Iqbal Nusya. "Replacement of several single function generator protection relay at Badak LNG." MATEC Web of Conferences 277 (2019): 03008. http://dx.doi.org/10.1051/matecconf/201927703008.

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Badak LNG is a company that operates the largest LNG Plant in Indonesia with maximum production capacity of 22.5 MTPA. The company operates twelve (12) steam turbine generators and one gas turbine generator and one diesel engine generator to supply electricity for process, utility, storage, loading and plant support facility areas, which constitutes the criticality of power generator equipment to keep the reliability of production process. Generator protection relay is one of the equipment that monitors and protects the generator from fault resulting from either internal or external disturbance, preventing the generator from serious damages. Before 2015, Badak LNG used single function relays to protect the generators. The generators are protected by stator differential protection (87), current unbalance (46), loss of excitation (40), reverse power (32), time overcurrent with voltage restraint (51V), and time overcurrent ground (51G). These single function relays wield more disadvantages compared to the newer technology held by the digital relays. Since 2015, Badak LNG have started to replace the single function generator protection relays with the digital type ones.
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25

Vyshemirsky, M., O. Zhabin, and S. Ostapchuk. "Analysis of SG Feeding by Mobile Pump under Total Blackout of NPP with VVER-1000/320." Nuclear and Radiation Safety, no. 4(72) (November 14, 2016): 25–31. http://dx.doi.org/10.32918/nrs.2016.4(72).04.

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The paper presents the analysis of steam generator feeding by mobile pump under power unit total blackout with loss of heat removal to the ultimate heat sink. Thermohydraulic model of NPP with VVER-1000/320 for RELAP5/MOD3.2 was used in calculations. The assessment of hydraulic loss of mobile pump head was performed based on initial data of Zaporizhzhya NPP Unit 1. Results of thermohydraulic calculations confirmed the effectiveness of SG feeding via mobile pump at an early and late stages of the accident and revealed typical aspects of the transient progression.
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26

He, Qing, and Jian Ding Zhang. "Application of Improved Genetic Algorithm in Maintenance Decision for Turbine-Generator Unit." Applied Mechanics and Materials 44-47 (December 2010): 2940–44. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.2940.

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The complicated function relations are more prone to appear in the maintenance scheduling of steam-turbine generator unit. Many constrained conditions are often attendant with these function relations. In these situations, the traditional method often can not obtain the exact value. The genetic algorithm (GA), a kind of the heuristic algorithms, does not need the function own good analytic properties. In addition, as the operating unit of GA is the group, so it applies to the parallel computing process. In GA executive process, the offspring continually inherit the genes from the parents, so it is more prone to be involved in the local convergence. An improved genetic algorithm is proposed and used in the model of maintenance decision of turbine-generator unit under. The goal of the model is to seek to the rational maintenance scheduling of the generator unit, so as to minimize the sum of the maintenance expense, the loss of the profit on the generated energy, and the loss of the penalty. It is proved by the example that IGA is highly efficient.
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27

Museba, Tinofirei, Fulufhelo Nelwamondo, and Khmaies Ouahada. "An Adaptive Heterogeneous Online Learning Ensemble Classifier for Nonstationary Environments." Computational Intelligence and Neuroscience 2021 (March 15, 2021): 1–11. http://dx.doi.org/10.1155/2021/6669706.

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In recent years, the prevalence of technological advances has led to an enormous and ever-increasing amount of data that are now commonly available in a streaming fashion. In such nonstationary environments, the underlying process generating the data stream is characterized by an intrinsic nonstationary or evolving or drifting phenomenon known as concept drift. Given the increasingly common applications whose data generation mechanisms are susceptible to change, the need for effective and efficient algorithms for learning from and adapting to evolving or drifting environments can hardly be overstated. In dynamic environments associated with concept drift, learning models are frequently updated to adapt to changes in the underlying probability distribution of the data. A lot of work in the area of learning in nonstationary environments focuses on updating the learning predictive model to optimize recovery from concept drift and convergence to new concepts by adjusting parameters and discarding poorly performing models while little effort has been dedicated to investigate what type of learning model is suitable at any given time for different types of concept drift. In this paper, we investigate the impact of heterogeneous online ensemble learning based on online model selection for predictive modeling in dynamic environments. We propose a novel heterogeneous ensemble approach based on online dynamic ensemble selection that accurately interchanges between different types of base models in an ensemble to enhance its predictive performance in nonstationary environments. The approach is known as Heterogeneous Dynamic Ensemble Selection based on Accuracy and Diversity (HDES-AD) and makes use of models generated by different base learners to increase diversity to circumvent problems associated with existing dynamic ensemble classifiers that may experience loss of diversity due to the exclusion of base learners generated by different base algorithms. The algorithm is evaluated on artificial and real-world datasets with well-known online homogeneous online ensemble approaches such as DDD, AFWE, and OAUE. The results show that HDES-AD performed significantly better than the other three homogeneous online ensemble approaches in nonstationary environments.
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ANAND, SANJEEV, ANKUSH GUPTA, and SUDHIR KUMAR TYAGI. "EXERGY ANALYSIS OF A LiBr–H2O VAPOR ABSORPTION REFRIGERATION PLANT: A CASE STUDY." International Journal of Air-Conditioning and Refrigeration 22, no. 02 (April 29, 2014): 1450010. http://dx.doi.org/10.1142/s2010132514500102.

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This communication presents the energy and exergy analysis of an actual double effect steam powered LiBr – H 2 O vapor absorption refrigeration plant. Exergy loss, COP, exergy efficiency and heat rate for each component of the system are calculated. The effect of generator as well as evaporator temperature on the COP and exergy efficiency is evaluated and it is found that the irreversibility rate is highest in the generator while it is found to be the lowest in the case of absorber and condenser. It is also found that the COP of the system increases with the increase in the evaporator temperature while it is found to be reverse in case of exergy efficiency. Results revealed that average exergy loss is highest in the generator as compared to other components. The results obtained are helpful for designers to bring changes in the actual system for performance optimization and less wastage of energy. The study clearly explain the operational and maintenance problems in the machine and point out the areas of energy wastage which the operational engineer should look into for the optimum operation of the plant.
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29

De, S., and P. K. Nag. "Effect of supplementary firing on the performance of an integrated gasification combined cycle power plant." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 214, no. 1 (February 1, 2000): 53–60. http://dx.doi.org/10.1243/0957650001537859.

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The effect of supplementary firing on the performance of an integrated gasification combined cycle (IGCC) power plant is studied. The results are presented with respect to a simple ‘unfired’ IGCC power plant with single pressure power generation for both the gas and the steam cycles as reference. The gases are assumed as real with variable specific heats. It is found that the most favourable benefit of supplementary firing can be obtained for a low temperature ratio R T only. For higher R T, only a gain in work output is possible with a reverse effect on the overall efficiency of the plant. The second law analysis reveals that the exergy loss in the heat-recovery steam generator is most significant as the amount of supplementary firing increases. It is also noteworthy that, although the total exergy loss of the plant decreases with higher supplementary firing for a low R T (= 3.0), the reverse is the case for a higher R T (= 6.0).
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30

Mu, Yu, Gui Min Sheng, Hong Xia, Pu Nan Sun, and Yan Qian. "Study on Fault Diagnosis Method for Nuclear Power Plant Based on Fuzzy Rough Sets and Decision Tree." Advanced Materials Research 981 (July 2014): 701–5. http://dx.doi.org/10.4028/www.scientific.net/amr.981.701.

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The technology of real-time fault diagnosis for nuclear power plants (NPP) has great significance to improve the safety and economy of reactor. Nuclear power plants are complex system, which collect and monitor the vast parameters. A parameter reduction method based on fuzzy rough sets was proposed. According to the characteristics the parameters were fuzzed, and they were reducted using the algorithm of forward greedy search. The decision tree was applied to learn from training samples which were the typical faults of nuclear power plant, i.e., loss of coolant accident (LOCA), feed water pipe rupture, steam generator tube rupture (SGTR), main steam pipe rupture, and diagnose by using the acquired knowledge. The result shows that this method can diagnose the faults of the NPP rapidly and accurately.
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31

Shi, Hao, Qi Cai, and Yuqing Chen. "Sensitivity Evaluation of AP1000 Nuclear Power Plant Best Estimation Model." Science and Technology of Nuclear Installations 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/9304520.

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The best estimation process of AP1000 Nuclear Power Plant (NPP) requires proper selections of parameters and models so as to obtain the most accurate results compared with the actual design parameters. Therefore, it is necessary to identify and evaluate the influences of these parameters and modeling approaches quantitatively and qualitatively. Based on the best estimate thermal-hydraulic system code RELAP5/MOD3.2, sensitivity analysis has been performed on core partition methods, parameters, and model selections in AP1000 Nuclear Power Plant, like the core channel number, pressurizer node number, feedwater temperature, and so forth. The results show that core channel number, core channel node number, and the pressurizer node number have apparent influences on the coolant temperature variation and pressure drop through the reactor. The feedwater temperature is a sensitive factor to the Steam Generator (SG) outlet temperature and the Steam Generator outlet pressure. In addition, the cross-flow model nearly has no effects on the coolant temperature variation and pressure drop in the reactor, in both the steady state and the loss of power transient. Furthermore, some fittest parameters with which the most accurate results could be obtained have been put forward for the nuclear system simulation.
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32

LIM, HEOK-SOON, TAE-YOUNG SONG, MOON-GOO CHI, and SEOUNG-RAE KIM. "STEAM GENERATOR TUBE INTEGRITY ANALYSIS OF A TOTAL LOSS OF ALL HEAT SINKS ACCIDENT FOR WOLSONG NPP UNIT 1." Nuclear Engineering and Technology 46, no. 1 (February 2014): 39–46. http://dx.doi.org/10.5516/net.02.2013.019.

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33

Choi, Ki-Yong, Yeon-Sik Kim, Chul-Hwa Song, and Won-Pil Baek. "Major Achievements and Prospect of the ATLAS Integral Effect Tests." Science and Technology of Nuclear Installations 2012 (2012): 1–18. http://dx.doi.org/10.1155/2012/375070.

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A large-scale thermal-hydraulic integral effect test facility, ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation), has been operated by KAERI. The reference plant of ATLAS is the APR1400 (Advanced Power Reactor, 1400 MWe). Since 2007, an extensive series of experimental works were successfully carried out, including large break loss of coolant accident tests, small break loss of coolant accident tests at various break locations, steam generator tube rupture tests, feed line break tests, and steam line break tests. These tests contributed toward an understanding of the unique thermal-hydraulic behavior, resolving the safety-related concerns and providing validation data for evaluation of the safety analysis codes and methodology for the advanced pressurized water reactor, APR1400. Major discoveries and lessons found in the past integral effect tests are summarized in this paper. As the demand for integral effect tests is on the rise due to the active national nuclear R&D program in Korea, the future prospects of the application of the ATLAS facility are also discussed.
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34

Al-Dohani, Nawar Saif, S. Nayak Nagaraj, A. Anarghya, and V. N. Abhishek. "Development of Powerhouse Using Fresnel lens." MATEC Web of Conferences 144 (2018): 04006. http://dx.doi.org/10.1051/matecconf/201814404006.

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Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors). Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.
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Vihavainen, J., V. Riikonen, and R. Kyrki-Rajamäki. "TRACE code modeling of the horizontal steam generator of the PACTEL facility and calculation of a loss-of-feedwater experiment." Annals of Nuclear Energy 37, no. 11 (November 2010): 1494–501. http://dx.doi.org/10.1016/j.anucene.2010.06.013.

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36

Bai, Jun Hua, Chun Bo Hu, and Jia Ming Li. "The Interior Ballistic Research for Gas-Steam Launching System with Water Injection in Block." Applied Mechanics and Materials 232 (November 2012): 765–69. http://dx.doi.org/10.4028/www.scientific.net/amm.232.765.

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Gas-steam launching system with water injection in block can overcome the problem of horizontal or large-angle launching, and gets more and more value in recent years. Based on the characteristic of launching system, the model was built with several assumptions, which could provide reference and technique for developing the new launching system. And the generator result was verified by the experimental one. The interior ballistic characteristics were researched by calculation result under different deep and injection water mass conditions. The comparison of the simulation results and theory analysis indicates the model was rational and valid, and different launching deep and cooling water mass had effect on ballistics, more water can cool down the silo, but also brings more energy loss, and deeper launch needs more energy, so good design is required to fit the parameters demand in all respects.
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37

Nag, P. K., and S. De. "Study of thermodynamic performance of an integrated gasification combined cycle power plant." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, no. 2 (March 1, 1998): 89–95. http://dx.doi.org/10.1243/0957650981536619.

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Computational analysis is performed to investigate the effects of the pressure ratio of the gas cycle (Rp) and the temperature ratio across the combustion chamber (RT) on the thermodynamic performance of an integrated gasification combined cycle (IGCC) power plant with single pressure power generation for both the gas and steam cycles. The gases are assumed to be real ones that follow the Redlich-Kwong equation of state. The overall efficiency of the cycle (η) is found to be maximum at an optimum pressure ratio of the gas cycle for a given temperature ratio. The second law analysis indicates that maximum exergy is destroyed in the process of gasification and is not at all affected by the temperature ratio, while the effect of the pressure ratio on it is also not very significant. The exergy loss in the combustor is found to decrease with an increase in either of the ratios. For the heat recovery steam generator (HRSG), it increases with a higher temperature ratio and decreases with a higher pressure ratio. The total exergy loss of the cycle is found to decrease with either of these two ratios while the other is held constant.
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38

Valencia Ochoa, Guillermo, Carlos Acevedo Peñaloza, and Jorge Duarte Forero. "Thermo-Economic Assessment of a Gas Microturbine-Absorption Chiller Trigeneration System under Different Compressor Inlet Air Temperatures." Energies 12, no. 24 (December 6, 2019): 4643. http://dx.doi.org/10.3390/en12244643.

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This manuscript presents a thermo-economic analysis for a trigeneration system integrated by an absorption refrigeration chiller, a gas microturbine, and the heat recovery steam generation subsystem. The effect of the compressor inlet air temperature on the thermo-economic performance of the trigeneration system was studied and analyzed in detail based on a validated model. Then, we determined the critical operating conditions for which the trigeneration system presents the greatest exergy destruction, producing an increase in the costs associated with loss of exergy, relative costs, and operation and maintenance costs. The results also show that the combustion chamber of the gas microturbine is the component with the greatest exergy destruction (29.24%), followed by the generator of the absorption refrigeration chiller (26.25%). In addition, the compressor inlet air temperature increases from 305.15 K to 315.15 K, causing a decrease in the relative cost difference of the evaporator (21.63%). Likewise, the exergo-economic factor in the heat exchanger and generator presented an increase of 6.53% and 2.84%, respectively.
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39

Mwaura, Anselim M., and Yong-Kuo Liu. "Prediction of the Loss of Feed Water Fault Signatures Using Machine Learning Techniques." Science and Technology of Nuclear Installations 2021 (August 9, 2021): 1–13. http://dx.doi.org/10.1155/2021/5511735.

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Fault diagnosis occurrence and its precise prediction in nuclear power plants are extremely important in avoiding disastrous consequences. The inherent limitations of the current fault diagnosis methods make machine learning techniques and their hybrid methodologies possible solutions to remedy this challenge. This study sought to develop, examine, compare, and contrast three robust machine learning methodologies of adaptive neurofuzzy inference system, long short-term memory, and radial basis function network by modeling the loss of feed water event using RELAP5. The performance indices of residual plots, mean absolute percentage error, root mean squared error, and coefficient of determination were used to determine the most suitable algorithms for accurately diagnosing the loss of feed water transient signatures. The study found out that the adaptive neurofuzzy inference system model outperformed the other schemes when predicting the temperature of the steam generator tubes, the radial basis function network scheme was best suited in forecasting the mass flow rate at the core inlet, while the long short-term memory algorithm was best suited for the estimation of the severities of the loss of the feed water fault.
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40

Prayogo, Irvan, and Noeroel Widajati. "PERBEDAAN GANGGUAN PENDENGARAN AKIBAT BISING ANTARA OPERATOR CCR PLTU DENGAN PLTGUDI PT PJB UP GRESIK." Indonesian Journal of Occupational Safety and Health 4, no. 2 (March 16, 2017): 103. http://dx.doi.org/10.20473/ijosh.v4i2.2015.103-112.

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ABSTRACTThe role of central control room (CCR) operator in Steam Power Plant (PLTU) or Gas and Steam Power Plant (PLTGU) of a work environment has high noise intensity with range (62.2– 99.8 dBA). Noise resulting from the process of production of electrical energy by machinery such as power generation unit boiler/HRSG, turbine, generator, condenser and other supporting equipment can cause Noise Induced Hearing Loss (NIHL). Study with cross-sectional design aims to analyze the difference in Noise Induced Hearing Loss between shift operator CCR PLTU and PLTGU PT PJB UP Gresik. Research on samples taken with the technique of simple random sampling with the majority of respondents were ≥ 40 years old, have a working periode ≥ 4 years, have a work area with a level of intensity noise > 85 dBA, long exposure noise ≤ 1 hour and good level of compliance of the use of ear protection in both of units. There was a difference of NIHL shift operator CCR PLTU and PLTGU. The number ofoperator who have experienced hearing loss due to noise on the shift operator CCR PLTU greater than PLTGU. Shift operator CCR PLTU and PLTGU are advised to obey and comply with safe working hours in areas with particular noise intensity has been set and the use of ear protection with right, also have to perform regular an audiometry exam tests so that the function of hearing of shift operator CCR could in monitor continuously.Keywords: central control room operator, power plant, noise induced hearing loss
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41

Zaki, Su'ud, Nuri Trianti, and Rosidah M. Indah. "Preliminary Analysis of Unprotected Loss of Heat Sink in Small Long Life Gas Cooled Fast Reactor." Applied Mechanics and Materials 751 (April 2015): 268–72. http://dx.doi.org/10.4028/www.scientific.net/amm.751.268.

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The failure of the secondary side in Gas Cooled Fast Reactor system, which may contain co-generation system, will cause loss of heat sink (LOHS) accident. In this study accident analysis of unprotected loss of heat sink due to the failure of the secondary cooling system has been investigated. The thermal hydraulic model include transient hot spot channel model in the core, steam generator, and related systems. Natural circulation based heat removal system is important to ensure inherent safety capability during unprotected accidents. Therefore the system similar to RVACS (reactor vessel auxiliary cooling system) is also plays important role to limit the level of consequence during the accident. As the results some simulations for small 60 MWt gas cooled fast reactors has been performed and the results show that the reactor can anticipate the failure of the secondary system by reducing power through reactivity feedback and remove the rest of heat through natural circulations based decay heat removal (RVACS system).
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42

Skalozubov, V., V. Spinov, D. Spinov, Т. Gablaya, V. Kochnyeva, and Yu Komarov. "SUBSTANTIATION OF MODERNIZED BLACKOUT & LOSS-OF-COOLANT ACCIDENT MANAGEMENT STRATEGY AT NUCLEAR POWER PLANTS WITH WWER." Odes’kyi Politechnichnyi Universytet Pratsi 2, no. 61 (2020): 70–77. http://dx.doi.org/10.15276/opu.2.61.2020.08.

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The analysis of the known results of RELAP5/V.3.2 simulation for loss of coolant & blackout accidents at WWER nuclear power plants showed that the design accident management strategies with design passive safety systems do not provide the necessary safety conditions for the maximum permissible temperature of fuel claddings, the minimum permissible level of coolant in the reactor and feed water in the steam generators. A conservative thermohydrodynamic model for a design and modernized blackout & loss-of-coolant accident management strategy at a nuclear power plant with WWER has been developed. Design passive safety systems carry out the design accident management strategy: pressurizer safety valves, secondary steam relief valves, and hydraulic reservoirs of the emergency core cooling system of the reactor. Promising afterheat removal passive systems and the reactor level and steam generator water level control systems carry out the modernized blackout & loss-of-coolant accident management strategy. The main conservative assumptions of the presented model of blackout & loss-of-coolant accidents: complete long-term failure of all electric pumps of active safety systems, the temperature of nuclear fuel in the central part of the fuel matrix is assumed as the maximum allowable one, effect of “run down” flow of a turbine feed pump and the coolant level in pressurizer on accident process is not considered. Computational modelling has found that violations of the safety conditions are over the entire range of leak sizes for the design blackout & loss-of-coolant accident management strategy. For the modernized blackout & loss-of-coolant accident management strategy, safety conditions are provided for 72 hours of the accident and more. The presented results of computational modelling of blackout accident management strategies for nuclear power plants can be used to modernize and improve symptom-informed emergency instructions and guidelines for the severe accident management at nuclear power plants with WWER. Application of the results of computational modelling of blackout accident management strategies is generally not substantiated for other types of reactor facilities. In this case, it is necessary to develop calculated models for blackout accident management taking into account the specifics of the structural and technical characteristics and operating conditions for safety related systems of nuclear power plants.
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43

Tu, Shan, Qi Zhou, Jian Liu Jian, Cong Qiang Ding, and Shu Ming Wu. "Application Study on Low Vacuum Circulating Water Heat Supply of a 50 MW Turbine." Advanced Materials Research 953-954 (June 2014): 896–99. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.896.

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This topic mainly research the high back pressure heat supply technology of steam turbine generator unit and the correlation analysis of turbine under high back pressure operating condition. High back pressure heat supply is an energy saving technology developed in order to meet the requirements of energy saving and environmental protection. This technology can not only reduce the cold end losses to improve the thermal efficiency of power plant, but also decrease the energy loss and pollution emissions because it take the place of traditional heating boiler. High back pressure heat supply of steam turbine is to increase the quantity of air inlet and outlet as well as exhaust temperature through improving turbine back pressure. For condensing steam turbine unit of 50 MW studied in this article, back pressure of which rise to 0.032MPa from 0.0046MPa, and the exhaust temperature will increase to 70 °C respectively. Through the calculation of rated condition and variable condition, we can obtain the impact to the unit due to the change of back pressure, and for unit of 50 MW can reduce 30876.9 tons of standard coal consumption in a heating period. It can also decrease the emission of carbon dioxide, sulfur dioxide, smoke and ashes, which effect of energy saving and emission reducing is very obvious.
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44

Kočiško, Marek, Petr Baron, Monika Telíšková, Jozef Török, and Anna Bašistová. "Research into Correlation between the Lubrication Mode of Contact Surfaces and Dynamic Parameters of Turbo-Generator Transmissions." Advances in Materials Science and Engineering 2019 (October 9, 2019): 1–10. http://dx.doi.org/10.1155/2019/8148697.

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The paper presents the results of an experimental study aimed at assessing the correlation between the measurement of dynamic parameters (vibration, high-frequency vibration, and acoustic emission) and the analysis of friction mode and the state of lubrication of the contact surfaces of two gearboxes in the turbo-generator assembly (high-speed single-body steam turbine—gearbox—generator) with the transmission power of no more than 50 MW. The analysis confirmed the assumption of a significant correlation of the monitored high-frequency vibration signal with the unsatisfactory engagement of the gear teeth. Through vibration analysis, an increased level of the tooth vibration component and vibration multiples with increased acoustic emission were identified in gearbox operation. The gear oil of one of the gearboxes examined showed a loss of additive elements in the real operation of the contact surfaces of the teeth engagement. The trend analysis confirmed the complexity of the monitored transmission operation in terms of the friction mode and the influence of the oil quality on the state of the tooth flank microgeometry.
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45

Abramov, A. V., E. O. Kovalev, P. A. Kolesnikov, R. R. Mukhametov, M. Yu Naumenko, O. A. Nikitin, D. V. Petrov, et al. "Investigation of Processes in Lead Coolant with Loss-of-Integrity of a Heat-Exchange Tube in a Brest-OD-300 Steam Generator." Atomic Energy 119, no. 3 (December 18, 2015): 200–206. http://dx.doi.org/10.1007/s10512-015-0041-3.

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46

Zaki, Su'ud. "Unprotected Loss of Flow Accident in Small Long Life Gas Cooled Fast Reactor." Applied Mechanics and Materials 751 (April 2015): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amm.751.263.

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In post Fukushima nuclear accidents inherent safety capability is necessary against some standard accidents such as unprotected loss of flow (ULOF), unprotected rod run-out transient over power (UTOP), unprotected loss of heat sink (ULOHS). Gas cooled fast reactors is one of the important candidate of 4th generation nuclear power plant and in this paper the safety analysis related to unprotected loss of flow in small long life gas cooled fast reactors has been performed. Accident analysis of unprotected loss of flow include coupled neutronic and thermal hydraulic analysis which include adiabatic model in nodal approach of time dependent multigroup diffusion equations. The thermal hydraulic model include transient model in the core, steam generator, and related systems. Natural circulation based heat removal system is important to ensure inherent safety capability during unprotected accidents. Therefore the system similar to RVACS (reactor vessel auxiliary cooling system) is investigated. As the results some simulations for small 60 MWt gas cooled fast reactors has been performed and the results show that the reactor can anticipate complete pumping failure inherently by reducing power through reactivity feedback and remove the rest of heat through natural circulations.
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47

МАКСИМОВ, Н. М. "HEAT BALANCE OF WAX HEATING UNITS." VESTNIK RIAZANSKOGO GOSUDARSTVENNOGO AGROTEHNOLOGICHESKOGO UNIVERSITETA IM P A KOSTYCHEVA, no. 1(49) (March 30, 2021): 142–49. http://dx.doi.org/10.36508/rsatu.2021.49.1.021.

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Проблема и цель. Целью проводимых исследований является теоретическое обоснование и практическая реализация технологии производства воска на пасеках. Объект исследования: агрегаты для вытопки воска, включающие парогенератор для выработки перегретого пара и паровую рамочную воскотопку. Необходимость проводимых исследований вызвана дефицитом воска на внутреннем рынке Российской Федерации, а также малой производительностью и эффективностью выпускаемых промышленностью агрегатов для вытопки воска. Сложившаяся ситуация требует разработки усовершенствованной технологии получения пасечного воска с минимальными затратами. Методология. Для достижения цели исследования и ответа на поставленные вопросы был сделан анализ литературы и проведены теоретические исследования. В статье представлена конструктивно-технологическая схема установок для вытопки воска. Была составлена схема теплового баланса с наглядным распределением потерь тепла при работе исследуемых агрегатов. Теоретический анализ потерь тепла при вытопке воска производился с использованием известных законов и формул теории теплообмена, а также с учётом накопленного опыта учёными Рязанского ГАТУ им. П.А. Костычева, занимавшимися исследованиями работы агрегатов для вытопки воска. Результаты. Была получена методика расчёта теплового баланса агрегатов для вытопки воска с использованием основных законов теплообмена и даны формулы для определения количества теплоты, требуемой для вытопки воска. Приведены формулы для расчёта термического КПД установок и тепловой мощности парогенератора. Намечены пути дальнейшей модернизации агрегатов для вытопки воска. Заключение. Проведённые теоретические исследования показали, что тепловая мощность парогенератора зависит от ряда факторов: затрат тепла на разогрев воскосырья, рамок, воды; от размеров и свойств материалов парогенератора и воскотопки. Дальнейшим этапом повышения эффективности работы агрегатов может стать подбор и установка теплоизоляционных материалов, что позволит сократить потери тепла в окружающую среду и, тем самым, повысить термический КПД агрегатов для вытопки воска. Problem and goal. The purpose of the research is the theoretical justifcation and practical implementation of the technology of wax production in apiaries. Object of research: units for melting wax, including a steam generator for generating superheated steam and a steam frame wax burner. The need for research is caused by the shortage of wax in the domestic market of the Russian Federation, as well as the low productivity and efciency of industrial units for melting wax. The current situation requires the development of an improved technology for obtaining beeswax with minimal costs. Methodology. To achieve the goal of the study and answer the questions posed, an analysis of the literature was made and theoretical studies were conducted. The article presents a design and technological scheme of installations for wax melting. A diagram of the heat balance was drawn up with a visual distribution of heat losses during the operation of the studied units. The theoretical analysis of heat loss during wax melting was carried out using the well-known laws and formulas of the theory of heat transfer, as well as taking into account the accumulated experience of scientists from the Ryazan State Agrotechnological University named after I. P.A. Kostychev, who researched the operation of units for melting wax. Results. A method was obtained for calculating the thermal balance of wax heating units using the basic laws of heat transfer and formulas were given for determining the amount of heat required for wax heating. Formulas for calculating the thermal efciency of plants and the thermal power of the steam generator are given. The ways of further modernization of the units for melting wax are outlined. Conclusion. The theoretical studies have shown that the heat capacity of the steam generator depends on a number of factors: the cost of heat to warm up vascolare the water, from the size and properties of materials generator and extractors. A further step in improving the efciency of the units can be the selection and installation of thermal insulation materials, which will reduce heat loss to the environment and, thereby, increase the thermal efciency of the units for melting wax.
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48

Qi, Huan Huan, and Zhong Xiu Zeng. "Nonlinear Dynamic Analysis of RCS LOCA Based on Secondary Development of ANSYS." Applied Mechanics and Materials 105-107 (September 2011): 334–38. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.334.

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Research of loss of coolant accident (LOCA) postulated on the nuclear reactor coolant system (RCS) was investigated with ANSYS program. Secondary development of ANSYS was performed to form the customized module for implementing effective and efficient RCS LOCA nonlinear analysis. A standard analysis procedure was established. It has following functions, such as parameters and modular system modeling, automatically set break, static pilot analysis, LOCA nonlinear dynamic calculation and automatic reports generation. Main pipes, Steam generator and reactor coolant pump models were molded by parameterized modular modeling method. Those models considered the nonlinear factors, such as material nonlinearities, gap and so on, constructed component model libraries of RCS. Comparing the results calculated by ANSYS and program-specific, it is showed that the results are generally consistent.
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49

Andrea, Pucciarelli, Galleni Francesco, Moscardini Marigrazia, Martelli Daniele, and Forgione Nicola. "STH/CFD Coupled Simulation of the Protected Loss of Flow Accident in the CIRCE-HERO Facility." Applied Sciences 10, no. 20 (October 10, 2020): 7032. http://dx.doi.org/10.3390/app10207032.

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The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident (PLOFA). The facility consists of an internal loop, equipped with a fuel pin simulator and a steam generator, and an external pool. In this coupling application, the System code RELAP5 is adopted for the simulation of the internal loop while the CFD code ANSYS Fluent is used for the sake of simulating the pool. The connection between the two addressed domains is provided at the inlet and outlet section of the internal loop; a thermal coupling is also performed in order to reproduce the observed thermal stratification phenomenon. The obtained results are promising and a good agreement was obtained for both the mass flow rates and temperature measurements. Capabilities and limitations of the adopted coupling technique are discussed in the present paper also providing suggestions for improvements and developments to be achieved in the frame of future applications.
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50

Jeong, Sung Hoon, Chi Yong Park, and Young Ze Lee. "Fretting Wear Characteristics of INCONEL 690 and INCONEL 600 in Water Environment." Key Engineering Materials 297-300 (November 2005): 1412–17. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1412.

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Fretting is the oscillatory motion with very small amplitudes, which usually occurs between two solid surfaces in contact. Fretting wear is the removal of material from contacting surfaces through fretting action. Fretting wear of steam generator tubes in nuclear power plant becomes a serious problem in recent years. The materials for the tubes usually are INCONEL 690 (I-690) and INCONEL 600 (I-600). In this paper, fretting wear tests for I-690 and I-600 were performed under various applied loads in water at room temperature. Results showed that the fretting wear loss of I-690 and I-600 tubes was largely influenced by stick-slip. The fretting wear mechanisms were the abrasive wear in slip regime and the delamination wear in stick regime. Also, I-690 had somewhat better wear resistance than I-600.
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