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Von Lavante D.,RWE Technology GmbH | Kuhn D.,Karlsruhe Institute of Technology | Von Lavante E.,University of Duisburg - Essen
International Conference on Nuclear Engineering, Proceedings, ICONE | Year: 2012

The present paper describes a back-fit solution proposed by RWE Technology GmbH for adding passive cooling functions to existing nuclear power plants. The Fukushima accidents have high-lighted the need for managing station black-out events and coping with the complete loss of the ultimate heat sink for long time durations, combined with the unavailability of adequate off-site supplies and adequate emergency personnel for days. In an ideal world, a nuclear power plant should be able to sustain its essential cooling functions, i.e. preventing degradation of core and spent fuel pool inventories, following a reactor trip in complete autarchy for a nearly indefinite amount of time. RWE Technology is currently investigating a back-fit solution involving "self- propelling" cooling systems1 that deliver exactly this long term autarchy. The cooling system utilizes the temperature difference between the hotter reactor core or spent fuel pond with the surrounding ultimate heat sink (ambient air) to drive its coolant like a classical heat machine. The cooling loop itself is the heat machine, but its sole purpose is to merely achieve sufficient thermal efficiency to drive itself and to establish convective cooling (∼2% thermal efficiency). This is realized by the use of a Joule/Brayton Cycle employing supercritical CO2. The special properties of supercritical CO2are essential for this system to be practicable. Above a temperature of 30.97°C and a pressure of 73.7bar CO2 becomes a super dense gas with densities similar to that of a typical liquid (∼400kg/m3), viscosities similar tothat of a gas (∼3×105Pas) and gas like compressibility. This allows for an extremely compact cooling system that can drive itself on very small temperature differences. The presented parametric studies show that a back-fitable system for long-term spent fuel pool cooling is viable to deliver excess electrical power for emergency systems of approximately 100kW. In temperate climates with peak air temperatures of up to 35°C, the system can power itself and its air coolers at spent fuel pool temperatures of 85°C, although with little excess electrical power left. Different back-fit strategies for PWR and BWR reactor core decay heat removal are discussed and the size of piping, heat exchangers and turbo-machinery are briefly evaluated. It was found that depending on the strategy, a cooling system capable of removing all decay heat from a reactor core would employ piping diameters between 100150mm and the investigated compact and sealed turbine-alternator-compressor unit would be sufficiently small to be integrated into the piping. Copyright © 2012 by ASME.

Fubi M.,RWE Technology GmbH | Krull F.F.,RWE Technology GmbH | Ladwig M.,Alstom
VGB PowerTech | Year: 2012

Due to higher demands for load compensation caused by more power generation from renewable energy sources in the market, together with possible grid constraints and uncertainty as to its amelioration, flexibility requirements on the conventional power plant portfolio will increase. As has been demonstrated by the selected examples of two of the most modern power plants in the world: Lingen CCPP and Westphalia HCPP in Germany, our engineers have implemented custom-made technical solutions to increase power plant flexibility together with power plant efficiency. In.

Rodriguez S.,Alstom | Pfohl R.,Alstom | Safari H.,Alstom | Dubois R.,RWE Technology GmbH | Wittner S.,RWE Technology GmbH
VGB PowerTech | Year: 2012

Driven by the globalisation of the markets, power plant components are manufactured in different countries and sent later to the final destination. Size and weight of many components and also the complexity and length of the transport routes require to use highly sophisticated logistics based on various means of transportation by sea and by land. Critical points during transport include the continuous maintenance, monitoring and documentation of the preservation measures set in the factory to withstand the exposure of the components to different and partially adverse ambient conditions. This publication gives an overview of innovative systems for maintainance and monitoring for exampleofa 1,300 MVA generator stator. These will enable the factory set parameters of preservation readjust automatically. Parallel parameters for assessing the preservation status are recognized, recorded and regularly transmitted via GSM to the experts from manufacturers and operators. Hance, the state of preservation of this valuable cargo can be checked daily and - as needed - short-term measures can be taken to prevent undue influence and avoid costly damages.

Maier G.,Fraunhofer Institute for Mechanics of Materials | Hubsch O.,Fraunhofer Institute for Mechanics of Materials | Riedel H.,Fraunhofer Institute for Mechanics of Materials | Somsen C.,Ruhr University Bochum | And 2 more authors.
MATEC Web of Conferences | Year: 2014

The present work deals with the thermomechanical fatigue and low-cycle fatigue behavior of C-263 in two different material conditions. Microstructural characteristics and fracture modes are investigated with light and electron microscopy. The experimental results indicate that viscoplastic deformations depend on the heat treatment or rather on the current state of the microstructure. The measured data are used to adjust the parameters of a Chaboche type model and a fracture-mechanics based model for fatigue lifetime prediction. The Chaboche model is able to describe the essential phenomena of time and temperature dependent cyclic plasticity including the complex cyclic hardening during thermo-cyclic loading of both material conditions with a unique set of material parameters. This could be achieved by including an additional internal variable into the Chaboche model which accounts for changes in the precipitation microstructure during high temperature loading. Furthermore, the proposed lifetime model is well suited for a common fatigue life prediction of both investigated heats. The deformation and lifetime models are implemented into a user defined material routine. In this work, the material routine is applied for the lifetime prediction of a critical power plant component using the finite element method. © 2014 Owned by the authors, published by EDP Sciences.

Maier G.,Fraunhofer Institute for Mechanics of Materials | Riedel H.,Fraunhofer Institute for Mechanics of Materials | Nieweg B.,Fraunhofer Institute for Mechanics of Materials | Somsen C.,Ruhr University Bochum | And 3 more authors.
Materials at High Temperatures | Year: 2013

Different heats of the nickel-base Alloy 617B are tested under in-phase and out-of-phase thermo-mechanical fatigue (TMF) conditions at temperatures between 50 and 900 °C. During one of the TMF tests the growth of microcracks is observed using the replica technique. After the tests, some of the specimens are inspected by scanning electron microscopy in order to analyse the prevailing damage mechanisms compared with those observed in isothermal low-cycle fatigue (LCF) tests. In addition, a Chaboche-type model and a fracture-mechanics-based lifetime model are employed to describe the cyclic viscoplastic deformation and fatigue lifetime. The Chaboche model adjusted to isothermal data is found to reasonably predict the cyclic viscoplastic behaviour of thermo-mechanically loaded specimens. Lifetime data of TMF tests fall into a common scatter band with LCF tests at temperatures above 400 °C if the test results are analysed based on the introduced lifetime model.

The delivery of power plants, systems and their components within the framework of projects or individual orders comprises also the supply of the documentation (technical data and documents) necessary for operation and maintenance activities. The existing VGB Guideline for the supply of Technical Documentation published in 2003 did not meet any more the current regulatory and operational requirements. Therefore, in 2010 VGB published a completely revised new edition of this guideline. With this guideline a practical standard was developed which clarifies as precisely as possible all major issues related to the delivery and take-over of the technical documentation. Within this paper, the most significant innovations of the guideline will be presented. The challenges of suppliers and plant operators to meet the new requirements of the VGB-R 171 are described.

The challenges faced by power plant engineering in Europe have become more versatile and - above all - more complex. Changing market requirements, a change of thinking in society and among policy-makers driven by global warming and the use of new materials and technologies require utilities to adopt a new approach in planning and implementing major projects. By pooling its project management and engineering capacities in RWE Technology, RWE has created the preconditions for setting up a uniform European negotiating basis for our dealings with contracting parties, suppliers, building contractors and service providers. In addition, merging employees from our core markets is efficiently promoting the technology and best-practice transfer within the Group. In this context, the harmonisation of standards and the pooling of project management and engineering skills for the implementation of complex investment projects at international level are of decisive importance. Our commitment to providing high-quality services on time and at optimal cost while taking account of the most exacting health and safety standards is the basis of our success and has top priority. The following article discusses the specific steps involved in this process.

Maier G.,Fraunhofer Institute for Mechanics of Materials | Riedel H.,Fraunhofer Institute for Mechanics of Materials | Seifert T.,Fraunhofer Institute for Mechanics of Materials | Klower J.,ThyssenKrupp | Mohrmann R.,RWE Technology GmbH
Advanced Materials Research | Year: 2011

Isothermal low cycle fatigue and thermomechanical fatigue tests are performed on Alloy617B in the solution-annealed and stabilized condition at temperatures between room temperature and 900 °C. In addition, the replica technique is applied to study the growth of microcracks. The Chaboche model is found to describe the cyclic viscoplastic behavior of both heats, except the pronounced cyclic hardening in the low-temperature branches of the TMF tests. A lifetime model based on the cyclic crack-tip opening displacement and the cyclic J integral is used to describe the measured lifetimes and crack growth rates. However, the description is not fully consistent, since the data for room temperature and for temperatures above 400 deg;C fall into two separate scatter bands. © (2011) Trans Tech Publications Switzerland.

Based on the positive experience with the integration of control and signalling of the auxiliary power supply switchgear into the I und C system SPPA-T-3000 of Siemens by way of IEC 61850 protocol in the Neurath power plant FIG project, the concept was further advanced for the power plant new build projects of the Westfalen power plant at Hamm and the Eemshaven power station in the Netherlands. The development aimed to integrate all other components of auxiliary power supply, such as transformers, battery systems as well as rectifiers and inverters, directly into the main 1 und C system on the basis of the IEC 61850 protocol, apart from the medium-voltage and lowvoltage switchgear.

At RWE there are two possible processing models for the construction of new power plants. One is the turn-key award and the other is the lot award. Both models make the same claim, namely the construction of a state-ofthe-art power plant in compliance with quality standards and legal requirements. For new power plants, the aim is to achieve the maximum possible level of efficiency. To this end, higher live steam temperatures and pressures are applied. Accordingly, highly heat resistant materials are required, which make special demands in terms of material quality and processing. Changing market conditions mean that, due to competition and the available production and manufacturing capacities, a global supplier market must be accepted. Control of these suppliers is a special challenge for operators and plant constructors alike, as new technologies and the use of new materials require an appropriate and acceptable quality of execution.

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