7,844 research outputs found

    The Low Duty Centrifugal Compressor Control System and its Impact on the Surge Pressure

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    This paper presents an analysis of the low duty compressor for marine steam generators and its running conditions. The analysed low duty compressor was observed under three different running zones caused by a throttled flow towards main steam generators. All examples were explained according to real exploitation conditions. As the low duty compressor has the highest influence on the flame stability for the main steam generators while running, it is very important to observe the constant flow towards the main steam generators. Possible flow fluctuation implies instabilities which are explained in the article and the same have to be avoided in order to assure a reliable life span of the low duty compressor and smooth operation of the main steam generators. Furthermore, for preventing efficiency losses of a steam power plant, some methods for avoiding surge effects are emphasized and recommended

    Corrosion control of nuclear steam generators under normal operation and plant-outage conditions: A review

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    Nuclear steam generators (NSGs) are key components of nuclear power plants (NPPs) since their reliability affects the overall plant performance. Corrosion control of steam generators under operation and during plant outages is attained by proper design, adequate material selection and control of water chemistry in the entire secondary cooling circuit. This article reviews the types of steam generators, the materials used for their construction (with a special focus on tubing alloys), the corrosion processes that may occur under operation and the strategies to preserve steam generators and other components of the secondary cooling system from corrosion during plant outages.Fil: Rodríguez, Martín Alejandro. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Unidad de Actividad de Materiales (CAC); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    17. Issues for Nuclear Power Plants Steam Generators

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    Steam Generators of PWR

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    Tato bakalářská práce se zabývá popisem jednotlivých konstrukčních řešení parogenerátorů. V první části bakalářské práce je popsán počátek jaderného průmyslu v Rusku. Samostatná práce se věnuje jednotlivým konstrukčním řešením. Poslední kapitola detailně popisuje jednotlivé části parogenerátoru VVER 1000. Součástí práce je tvorba 3D modelu parogenerátoru VVER 1000, který bude sloužit jako učební pomůcka v projektu Cenelín.This bachelors thesis describes various designs of steam generators. The first part of the thesis describes the beginning of the nuclear industry in Russia. The main part deals with individual design solutions. The last chapter describes in detail the various parts of the steam generator VVER 1000. The work includes creation of a 3D model of the steam generator VVER 1000, which will serve as a teaching aid in the project Cenelín.

    The Study of Multiaxial Loading and Damage to the Structure and Materials in the PWR Steam Generator of Nuclear Reactor

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    In Pressurized Water Reactor (PWR) Nuclear Power Plants (NPPs), the steam generator is crucial for transferring heat from the primary to secondary cooling systems, vital for steam production to drive turbines, and central to nuclear power safety. This study explores recent research on multi-axial loading, structural integrity, and material durability in PWR steam generators, shedding light on key factors affecting these systems. Common corrosion-related degradation in steam generators often arises from design, material, and water chemistry factors. However, the shift to All Volatile Treatment (AVT), the development of advanced material alloys, and enhanced water quality control in primary and secondary systems have significantly reduced instances of steam generator degradation. These findings promise to enhance the reliability and safety of steam generators in future nuclear applications.

    A CFD-based virtual test-rig for rotating heat exchangers

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    Rotating heat exchangers are used in steel industry, air conditioning and thermal power plants to pre-heat air used in steam generators or for waste heat recovery. Here we focus on a rotating heat exchanger on a so-called Ljungström arrangement operated in thermal power plants to pre-heat the air fed to the steam generators. In these devices the heat exchange between two fluids is achieved through a rotating matrix that gets in contact alternatively with the two fluid streams and acts as a thermal accumulator. To increase the heat capacity and the overall exchange surface, the rotating matrix is filled by a series of folded metal sheets. In the paper we de-scribe a methodology to account for the effects of the Ljungström in a virtual test-rig implemented in a Computational Fluid Dynamics environment. To this aim, a numerical model based on the work of Molinari and Cantiano was derived and implemented in the OpenFOAM library. RANS numerical results were compared with those of a mono-dimensional tool used by ENEL to design Ljungström heat exchangers and validated against available measurements in a real configuration of a thermal power plant

    Managing steam generator excess units at PT. YKL

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    Purpose - This paper is to apply lean principles to eliminate excess steam generators in the company.A multifunctional team which has a strong knowledge on process, simulation tools, and broad projects knowledge were involved. Methodology/Approach – PT. YKL has five steam stations for running its business, extracting oil from its reservoir.The steam stations are home for 218 steam generators units. As its oil reservoirs mature, naturally the reservoirs require less steam.As the demand drops, PT.YKL needs to balance the supply. As a result, they have excess number of steam generators.They are initially identified it by collecting the unit’s allocation for maintenance and other shutdown issue per steam stations.This available-unit less maintenance-allocation shows the true steam generators supply capability.On the demand side, PT. YKL also looked at its demand forecast profile in the years to come.Defining the excess unit per steam station limits the number of excess unit they can eliminate.To maximize it, PT. YKL totally changed the way they defined the excess.By collecting all the excess in once steam station, they can maximize the number of excess.However, they need to ensure that the remaining steam generators can satisfy the customer’s requirements (in term of flow and pressure).Here simulation tools played its key role.Findings - It was found the implementation of this lean initiative was successfully decommissioned 46 excess steam generators from 218 steam generators.Research limitations / implications: The simulation tool could not exactly represent the actual key process parameters.Site tweaking was stil needed to adjust the key process parameters to achieve the expected performance measures.Value – Limiting the boundaries to define the number of steam generator excess reduce the number of excess unit PT.YKL can claim.By creatively enlarging the boundaries definition to beyond steam station level maximize the number of excess PT. YKL can claim.The project was successfully booked Total Accrued Financial Benefit is $ 5 MM

    Conceptual Design of the Steam Generators for the EU DEMO WCLL Reactor

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    In the framework of the EUROfusion Horizon Europe Programme, ENEA and its linked third parties are in charge of the conceptual design of the steam generators belonging to EU DEMO WCLL Breeding Blanket Primary Heat Transfer Systems (BB PHTSs). In particular, in 2021, design activities and supporting numerical simulations were carried out in order to achieve a feasible and robust preliminary concept design of the Once Through Steam Generators (OTSGs), selected as reference technology for the DEMO Balance of Plant at the end of the Horizon 2020 Programme. The design of these components is very challenging. In fact, the steam generators have to deliver the thermal power removed from the two principal blanket subsystems, i.e., the First Wall (FW) and the Breeding Zone (BZ), to the Power Conversion System (PCS) for its conversion into electricity, operating under plasma pulsed regime and staying in dwell period at a very low power level (decay power). Consequently, the OTSG stability and control represent a key point for these systems' operability and the success of a DEMO BoP configuration with direct coupling between the BB PHTS and the PCS. In this paper, the authors reported and critically discussed the FW and BZ steam generators' thermal-hydraulic and mechanical design, the developed 3D CAD models, as well as the main results of the stability analyses and the control strategy to be adopted

    The design of a sodium steam generator solid model for the simulation of thermohydraulic processes

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    The peculiarities of the sodium-heated steam generators are presented. The importance of the thermohydraulic simulation for the optimization of the steam generators operating modes is shown. Described is the design of a steam superheater unit solid model of the NPP with a BN-800 reactor for the thermohydraulic simulation with SolidWorks software.Представлены особенности парогенераторов, обогреваемых натриевым теплоносителем. Показана важность теплогидравлического моделирования для оптимизации режимов эксплуатации парогенераторов. Описано построение твердотельной модели пароперегревательного модуля парогенератора АЭС с реактором БН-800 для теплогидравлического моделирования в программном пакете SolidWorks

    Nuclear Safety Evaluation in Steam Generators

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    Import 05/08/2014Tato bakalářská práce se zabývá hodnocením všech typů parogenerátoru a porovnání jejich základních parametrů s ohledem na jadernou bezpečnost. V prvních kapitolách jsou popsány parametry určitých parogenerátorů. Dále je přiblížen samotný zjednodušený tepelný výpočet parogenerátoru a výpočet potřebné teplosměnné plochy. Na základě výpočtu byla zvolena jedna vhodná varianta parogenerátoru. V závěru jsou parogenerátory srovnány podle jejich poruchovosti.This bachelor thesis deals with the evaluation of all types of steam generator and comparing their basic parameters with regard to nuclear safety. In the first chapters describe the specific parameters of steam generators. It is zoomed in very simplified calculation of thermal steam generator and calculate the required heat transfer area. On the basis of calculation was chosen one suitable variant of the steam generator. At the end are steam generators compared according to their failure.361 - Katedra energetikyvelmi dobř