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Search results for: nuclear reactor materials
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Influence of operation of national experimental nuclear reactor on the natural environment
PublicationThis paper presents the impact of experimental nuclear reactor operations on the national environment, based on assessment reports of the radiological protection of active nuclear technology sources. Using the analysis of measurements carried out in the last 15 years, the trends are presented in selected elements of the environment on the Świerk Nuclear Centre site and its surroundings. In addition, the impact of research results...
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Numerical solution of fractional neutron point kinetics in nuclear reactor
PublicationThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
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Hardware-Software Implementation of Basic Principles Simulator of Nuclear Reactor Processes
PublicationThe paper presents implementation process of basic principle simulators of a nuclear reactor processes. Simulators are based on point-models of processes: kinetics of neutrons, heat generation and exchange, poisoning and burning-up nuclear fuel. Reference simulator was developed in MATLAB/Simulink without taking into account real-time operation. Second simulator was built using the toolbox xPC with hard real-time requirements....
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Cross-Platform Real-Time Nuclear Reactor Basic Principle Simulator
PublicationAbstract—In the paper several approaches to building the real-time basic principle simulators of nuclear reactor processes are presented and their characteristics are analyzed. The characteristics of developed simulators for MATLAB/Simulink including their limitations, and the idea of a cross-platform simulator independent of specific hardware or software are presented. Mathematical models of selected nuclear reactor’s processes...
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Comparative analysis of thermodynamic cycles of selected nuclear ship power plants with high-temperature helium-cooled nuclear reactor
PublicationThis paper presents a comparative analysis of thermodynamic cycles of two ship power plant systems with a high-temperature helium- cooled nuclear reactor. The first of them is a gas system with recuperator , in which classical gas chamber is substituted for a HTGR reactor (High Temperature Gas-cooled Reactor) . The second of the considered cycles is a combined gas-steam system where working medium flux from gas turbine outlet...
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Numerical solution analysis of fractional point kinetics and heat exchange in nuclear reactor
PublicationThe paper presents the neutron point kinetics and heat exchange models for the nuclear reactor. The models consist of a nonlinear system of fractional ordinary differential and algebraic equations. Two numerical algorithms are used to solve them. The first algorithm is application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. The second involves building an analog scheme in the FOMCON Toolbox...
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Fuzzy Multi-Regional Fractional PID controller for Pressurized Water nuclear Reactor
PublicationThe paper presents the methodology for the synthesis of a Fuzzy Multi-Regional Fractional Order PID controller (FMR-FOPID) used to control the average thermal power of a PWR nuclear reactor in the load following mode. The controller utilizes a set of FOPID controllers and the fuzzy logic Takagi-Sugeno reasoning system. The proposed methodology is based on two optimization parts. The first part is devoted to finding the optimal...
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Fractional neutron point kinetics equations for nuclear reactor dynamics – Numerical solution investigations
PublicationThis paper presents results concerning numerical solutions to a fractional neutron point kinetics model for a nuclear reactor. The paper discusses and expands on results presented in (Espinosa-Paredes et al., 2011). The fractional neutron point kinetics model with six groups of delayed neutron precursors was developed and a numerical solution using the Edwards’ method was proposed (Edwards et al., 2002). The mathematical model...
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Numerical Investigation of Nuclear Reactor Kinetic and Heat Transfer Fractional Model with Temperature Feedback
PublicationAbstract—In the paper, the numerical results concerning the kinetics and proposed heat exchange models in nuclear reactor based on fractional calculus are presented for typical inputs. Two fractional models are proposed and compared with the model based on ordinary derivative. The first fractional model is based on one of the generalized Cattaneo equations. The second one is based on replacing the ordinary to fractional order of...
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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ORF Approximation in Numerical Analysis of Fractional Point Kinetics and Heat Exchange Model of Nuclear Reactor
PublicationThis paper presents results concerning numerical solutions of the fractional point kinetics (FPK) and heat exchange (HE) model for a nuclear reactor. The model consists of a nonlinear system of fractional and ordinary differential equations. Two methods to solve the model are compared. The first one applies Oustaloup Recursive Filter (ORF) and the second one applies Refined Oustaloup Recursive Filter (RORF). Simulation tests have...
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Comparison analysis of selected nuclear power plants supplied with helium from high-temperature gas-cooled reactor
PublicationThe article presents results of efficiency calculations for two 560 MW nuclear cycles with high-temperature gas-cooled reactor (HTGR). An assumption was made that systems of this type can be used in so-called marine nuclear power plants. The first analysed system is the nuclear steam power plant. For the steam cycle, the efficiency calculations were performed with the code DIAGAR, which is dedicated for analysing this type of systems....
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Real-Time Basic Principles Nuclear Reactor Simulator Based on Client-Server Network Architecture with WebBrowser as User Interface
PublicationThe real-time simulator of nuclear reactor basic processes (neutron kinetics, heat generation and its exchange, poisoning and burn- ing up fuel) build in a network environment is presented in this paper. The client-server architecture was introduced, where the server is a pow- erful computing unit and the web browser application is a client for user interface purposes. The challenge was to develop an application running under the...
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Analysis of effects of formation of non-condensable gases and water vapor during a severe accident in a boiling water nuclear reactor Analiza skutków powstawania niekondensujących gazów i pary wodnej podczas ciężkiej awarii wrzącego reaktora jądrowego
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Nano-structured Pt embedded in acidic salts of heteropolymolybdate matrices: MS EXAFS study
PublicationA structural study of Pt nano-catalysts is presented in the paper. The innovation in the case of the considered catalytic materials resides in the use a meso-microporous inorganic matrix of heteropolyacid salt of composition X2.5H0.5YMo12O40 where X = Rb, Cs and Y = P, Si as a catalyst support. Metallic nanoparticles were created by platinum ions reduction in a hot H2/Argon stream and were mainly located into matrix pores. As the...
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Elastic cross-section calculations for electron collisions with XY4 (X=Si,Ge; Y=H, F, Cl, Br, I) molecules
PublicationObliczano elastyczne przekroje czynne dla tetraedrycznych związków krzemu i germanu. Otrzymane wyniki porównano z innymi dostępnymi wynikami obliczeń oraz z danymi doświadczalnymi; dla energii powyżej 100 eV uzyskano zadowalającą zgodność.
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Theoretical Auger and photoionization studies for open shell atoms andions.
PublicationWykorzystano program komputerowy RATIP do badań własności atomów i jonów o dowolnej konfiguracji. Położono nacisk na obliczenia szeregu własności elektronów Augera i fotojonizacji, aby dokonać porównań z ostatnio wykonywanymi doświadczeniami.
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Individual contributions of M X-ray line from Cu- and Co-like tungsten ions and L X-ray line from Ne-like molybdenum ions – Benchmarks for new approach to determine the high-temperature tokamak plasma parameters
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Energy shift of the Lβ2 line as an ionization diagnostic for the dense plasma in the PFRP
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Modeling of soft N, M and L X-ray lines from tungsten relevant to plasma parameters in the WEST tokamak
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Dissolution of Nb-doped hydroxyapatite prepared via low-temperature mechanochemical method: Spectroscopy studies
PublicationCalcium phosphate glass ceramics with nominal hydroxyapatite stoichiometry doped with niobium were synthesized using simple as well as low-temperature mechanochemical method and then in the form of compressed pellet were submitted to the static dissolution process in distilled water for one month. The results of structural analysis, performed mainly on the base of spectroscopic methods such as: infrared absorption spectroscopy,...
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Annihilation rates of low-energy positron scattering from simple diatomic molecules
PublicationWe discuss the calculations of Zeff coefficients for a series of diatomic molecules over the range of energies below the positronium formation. During the development of a general code for polyatomic, nonlinear molecules colliding with positrons, it was discovered that the earlier one, employed only for diatomic molecules, had an error. The error is corrected and the corrected results are presented here. We also discuss a way of...
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Correlation–polarization effects in electron/positron scattering from acetylene: A comparison of computational models
PublicationDifferent computational methods are employed to evaluate elastic (rotationally summed) integral and differential cross sections for low energy (below about 10 eV) positron scattering off gas-phase C2H2 molecules. The computations are carried out at the static and static-plus-polarization levels for describing the interaction forces and the correlation–polarization contributions are found to be an essential component for the correct...
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Polarisation effects in low-energy positron–molecule scattering
PublicationThe UK molecular R-matrix method has been adapted to treat positron collisions from polyatomic targets. A simple empirical enhancement factor which corrects for the underestimation of electron–positron polarisation and correlation effects in the calculations performed with the static-plus-polarization model at low scattering energies is presented. Application of this model to positron scattering from carbon dioxide at energies...
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Storing Matter’technique in SIMS depth profile analysis
PublicationSecondary ion mass spectrometry (SIMS) is a very useful technique for the analysis of layered systems. It is based on the primary ion beam sputtering of solids and mass analysis of the emitted secondary ions. A main limitation of this technique results from the direct quantitative analysis, since the ionization efficiency of a given atom is highly influenced by the neighbouring atoms at the surface. This phenomenon is known as...
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The analysis of turbine propulsion systems in nuclear submarines
PublicationThe article systematises submarines, which are presently in service, according to their propulsion types (both conventional and nuclear), power output, and submersion depth. Contemporary types of propulsion systems installed and used in submarines are discussed. Calculations were performed for the PWR (Pressurized Water Reactor) type nuclear propulsion system and the supercritical turbine propulsion system (supercritical reactor...
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Fault detection and diagnostics of complex dynamic systems using Gaussian Process Models - nuclear power plant case study
PublicationThe article examines the use of Gaussian Process Models to simulate the dynamic processes of a Pressurized Water nuclear Reactor for fault detection and diagnostics. The paper illustrates the potential of Gaussian Process Models as a tool for monitoring and predicting various fault conditions in Pressurized Water nuclear Reactor power plants, including reactor coolant flow and temperature variations, deviations from nominal working...
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Multi-nodal PWR reactor model — Methodology proposition for power distribution coefficients calculation
PublicationIn the paper the multi-nodal Pressurized Water Reactor (PWR) model called Mann’s model is presented. This models is used for modelling purposes of the heat transfer from fuel to coolant in reactor core. The authors expand widely used in literature approach by defining additional coefficients for the heat transfer model. These parameters approximate the power generation distribution in the PWR reactor core according to the to the...
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THERMODYNAMIC ANALYSIS OF A GENERATION IV SCWR NUCLEAR POWER PLANT CYCLE
PublicationThis article presents a flow and thermodynamic analysis of a Generation IV nuclear cycle. An SCWR (Supercritical water reactor) is a high temperature and high pressure reactor that uses water at a temperature above its thermodynamic critical point as the working fluid. The cycle used for the calculations consists of one interstage superheater and 7 regenerative heat exchangers. Division pressure was optimized in view of the cycle efficiency,...
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Analiza sterowania ułamkowego PIλDμ mocą reaktora jądrowego
PublicationW artykule przedstawiono syntezę regulatora PIλDμ niecałkowitego rzędu dla potrzeb sterowania mocą reaktora jądrowego lekko wodnego określanego, jako typu PWR (Pressurized Water Reactor). W tym celu wykorzystano nieliniowy model matematyczny reaktora PWR o parametrach skupionych obejmujący procesy generacji i wymiany ciepła oraz termicznych efektów reaktywnościowych. Nastawy regulatora PIλDμ niecałkowitego rzędu dobrano w sposób...
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Technical and economic conditions of supplying residential consumers with heat from nuclear power plant
PublicationThe reduction of CO2 emission requires technological shift towards carbon-free options. Cogeneration of electricity and heat based on coal and natural gas will experience generation cost increase, if the costs of emissions are imposed on the plant operators. Therefore, nuclear and renewable options should be considered. In this paper, we present the concept of electricity and heat supply system with nuclear condensing turbine adapted...
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Analysis of possible application of high-temperature nuclear reactors to contemporary large-output steam power plants on ships
PublicationThis paper is aimed at analysis of possible application of helium to cooling high-temperature nuclear reactor to be used for generating steam in contemporary ship steam-turbine power plants of a large output with taking into account in particular variable operational parameters. In the first part of the paper types of contemporary ship power plants are presented. Features of today applied PWR reactors and proposed HTR reactors...
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Wieloobszarowa rozmyta regulacja PID mocy reaktora jądrowego
PublicationW artykule przedstawiono wieloobszarowy regulator rozmyty z lokalnymi regulatorami PID dla sterowania mocą reaktora jądrowego typu PWR. Wykorzystano model matematyczny o parametrach skupionych reaktora PWR obejmujący procesy generacji i wymiany ciepła oraz efektów reaktywnościowych. Nastawy lokalnych regulatorów PID zostały dobrane w sposób optymalny, minimalizując całkowy wskaźnik jakości ISE. Na przykładzie pokazano że zastosowane...
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Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant
PublicationIn the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR) working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller...
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Implementation of the FOPID Algorithm in the PLC Controller - PWR Thermal Power Control Case Study
PublicationIn the paper authors describe proposition of design and verification procedures of the discrete Fractional Order PID (FOPID) algorithm for control of the Pressurized Water Reactor (PWR) thermal power near its nominal operating point. The FOPID algorithm synthesis consists of: off-line optimal tunning of its parameters in continuous time-domain with LQ (Linear Quadratic) performance index and simplified models of nuclear reactor...
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Comparison of state feedback and PID control of pressurizer water level in nuclear power plant
PublicationThe pressurizer water level control system in nuclear power plant with pressurized water reactor (PWR) is responsible for coolant mass balance. The main control goal is to stabilize the water level at a reference value and to suppress the effect of time-varying disturbances (e.g. coolant leakage in primary circuit pipeline system). In the process of PWR power plant operation incorrect water level may disturb pressure control or...
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Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublicationThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
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Recurrent Neural Network Based Adaptive Variable-Order Fractional PID Controller for Small Modular Reactor Thermal Power Control
PublicationThis paper presents the synthesis of an adaptive PID type controller in which the variable-order fractional operators are used. Due to the implementation difficulties of fractional order operators, both with a fixed and variable order, on digital control platforms caused by the requirement of infinite memory resources, the fractional operators that are part of the discussed controller were approximated by recurrent neural networks...
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Nuclear Power Plant Steam Turbine - Modeling for Model Based Control Purposes
PublicationThe nature of the processes taking place in a nuclear power plant (NPP) steam turbine is the reason why their modeling is very difficult, especially when the model is intended to be used for on-line optimal model based process control over a wide range of operating conditions, caused by changing electrical power demand e.g. when combined heat and power mode of work is utilized. The paper presents three nonlinear models of NPP steam...
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Approximation of Fractional Order Dynamic Systems Using Elman, GRU and LSTM Neural Networks
PublicationIn the paper, authors explore the possibility of using the recurrent neural networks (RNN) - Elman, GRU and LSTM - for an approximation of the solution of the fractional-orders differential equations. The RNN network parameters are estimated via optimisation with the second order L-BFGS algorithm. It is done based on data from four systems: simple first and second fractional order LTI systems, a system of fractional-order point...
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Neural modelling of dynamic systems with time delays based on an adjusted NEAT algorithm
PublicationA problem related to the development of an algorithm designed to find an architecture of artificial neural network used for black-box modelling of dynamic systems with time delays has been addressed in this paper. The proposed algorithm is based on a well-known NeuroEvolution of Augmenting Topologies (NEAT) algorithm. The NEAT algorithm has been adjusted by allowing additional connections within an artificial neural network and...
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An automatic selection of optimal recurrent neural network architecture for processes dynamics modelling purposes
PublicationA problem related to the development of algorithms designed to find the structure of artificial neural network used for behavioural (black-box) modelling of selected dynamic processes has been addressed in this paper. The research has included four original proposals of algorithms dedicated to neural network architecture search. Algorithms have been based on well-known optimisation techniques such as evolutionary algorithms and...
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Web-based real-time simulation system
PublicationThe paper presents the development of a simulation system composed of a real-time plant simulator with real-time controller included in the software-in-the-loop structure using web-based communication. The client-server architecture build in a TCP/IP network environment was introduced, where the server is a computing unit for real-time high temporal resolution plant simulation (and optionally also as controllers' platform) and...
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Nodal models of Pressurized Water Reactor core for control purposes – A comparison study
PublicationThe paper focuses on the presentation and comparison of basic nodal and expanded multi-nodal models of the Pressurized Water Reactor (PWR) core, which includes neutron kinetics, heat transfer between fuel and coolant, and internal and external reactivity feedback processes. In the expanded multi-nodal model, the authors introduce a novel approach to the implementation of thermal power distribution phenomena into the multi-node...
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Current situation in Polish nuclear medicine and Polish example of model Nuclear Medicine Centre meeting European Union requirements
PublicationNuclear medicine is currently a well-established part of medicine. It is applied in many fields of clinical medicine and science like endocrinology, oncology, cardiology, molecular medicine and engineering, radiopharmacy, physics and information science. Due to its increasing importance and application, several regulation and supervision bodies have been founded to ensure safe usage of radiation and to improve diagnostic and therapeutic...
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Human factors in nuclear power engineering in Polish conditions
PublicationThe paper “Human factors in nuclear power engineering in polish conditions” focuses on analysis of dynamics of preparing polish society to build first nuclear power plant in XXI century in Poland. Authors compare experience from constructing nuclear power plant Sizewell B (Great Britain) and Sizewell C, which is in preparation phase with polish nuclear power program. Paper includes aspects e.g. of creating nuclear safety culture...
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Human Factors in Nuclear Power Engineering in Polish Conditions
PublicationThe paper “Human factors in nuclear power engineering in polish conditions” focuses on analysis of dynamics of preparing polish society to build fi rst nuclear power plant in XXI century in Poland. Authors compare experience from constructing nuclear power plant Sizewell B (Great Britain) and Sizewell C, which is in preparation phase with polish nuclear power program. Paper includes aspects e.g. of creating nuclear safety culture and...
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Neutral earthing reactor protection
PublicationThe IEEE and CIGRE recommend protection systems for high voltage shunt reactors. Unfortunately the recommendations do not include guidelines for the protection of neutral earthing reactors, which are often connected to shunt reactors to increase the effectiveness of single pole auto-reclosing. The paper discusses earthing reactor protection issues with particular emphasis on the detection of internal faults. An analysis carried...
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Insights Into Hydrodynamics of Spinning Fluids Reactor
PublicationSpinning fluids reactor (SFR) is one of the most efficient gas-liquid contacting system with high potential of application in many fields. The unique solution of SFR is the contacting of two spinning fluids which generated centrifugal force. The aim of this study was to investigate the pressure field distribution on the inner surface of reactors dispersing element. Obtained results confirm the high heterogeneity of the field pressure...
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Profitability criteria of partial cogeneration in nuclear power plant.
PublicationIn this paper, profitability criteria and calculation methodology of profitability conditions for partial cogeneration in nuclear power plant (NPP) was presented. Considered NPP supplies electricity to consumers through public power system, whereas heat is expected to be supplied to consumption regions via long-distance heat transport line. First proposed profitability criterion was total annual costs of electricity and heat delivered...