Abstracts - VGB PowerTech Journal 5/2006

Opening Address at the 2006 Winter Meeting of the Deutsches Atomforum e.V. Energy, Key Factor for Germany as a Location of Industry
Walter Hohlefelder
Current events have placed energy at the very top on the political agenda. Electricity and heat supplies cannot be taken for granted. A conclusive long-term energy concept urgently needs to be developed to provide a stable and, above all, reliable framework. The coming Energy Summit is hoped to pave the way for that concept. Germany can gain advantages as a location of industry only by becoming more and more independent of politically unstable regions, i.e. above all by using a broad energy mix. In this respect, which is decisive in ensuring Germany's future, nuclear power must not be left out of consideration.

Operating Experience with Nuclear Power Plants 2005
VGB-Fachausschuss Kernkraftwerksbetrieb:
For more than 30 years the VGB Technical Committee “Nuclear Power Plant Operation“ has been exchanging operating experience made in nuclear power plants. 36 nuclear power plants from Germany, Finland, France the Netherlands, Sweden, Switzerland and Spain participate in this exchange. A report is given on the operating results obtained in 2005 as well as on safety-relevant events, important repair measures, special retrofit measures and annual dose rates.

Nuclear Fusion, ITER and the Kyoto Process
Alexander Bradshaw
The aim of fusion research is to utilise the energy of the sun and the stars on earth by deriving energy from fusion of atomic nuclei. Fusion power plants could tap an almost unlimited supply of fuel and be located anywhere in the world which could make them a mainstay of a future sustainable energy supply system. The next step in international fusion research is ITER, the international large-scale experiment to be built and operated jointly by a partnership at the European site of Cadarache in France. The test reactor will produce a plasma providing energy under power plant-like conditions and thus demonstrate the physical and technical feasibility of nuclear fusion as an energy source.

Impacts on the Economy through Alternative Operating Periods of Nuclear Power Plants in Germany
Dietmar Lindenberger, Ralf Wissen, Michael Bartels, Hans-Georg Buttermann and Bernhard Hildebrand
The paper will discuss the effects of extended operating periods of existing nuclear power plants in comparison to the regulations of the Nuclear Exit Law, namely the effects of extended operating periods of nuclear power plants on the development of German power plant capacity, electricity generation, fuel consumption and fuel imports, resulting CO2 emissions, cost of electricity generation and electricity prices as well as the related production and employment effects for the energy industry and the entire economy.

System Decontamination at Stade Nuclear Power Station in the Run-up to Dismantling Procedural Implementation
Bernd Volkmann, Andreas Engemann and Lutz-Hagen Kemp
The Stade nuclear power plant, which is located right next to the river Elbe was decommissioned on 14 November 2003. Planning for the post-closure phase and later dismantling of the overall facility began already during regular operation. Chemical cleaning of radioactively contaminated surfaces, i.e. system decontamination, was prepared and carried out as a preliminary measure. The procedural implementation of the system decontamination described here incorporates stipulations for the expedient scope of the facility that is to be included in the system decontamination. As a result of the successfully completed system decontamination, it was possible to reduce substantially the dose-rate in the rooms of the facility.

System Decontamination in the Stade Nuclear Power Plant prior to Dismantling
Christoph Stiepani and Karl Seidelmann
The Stade nuclear power plant (KKS) was permanently shut down in November 2003. The primary system and the most important auxiliary systems (emergency cooling system, residual heat removal system, coolant purification system and volume control system) were chemically decontaminated. The paper describes the applied decontamination process HP/CORD® UV and the results obtained during full system decontamination. This paper explains in detail the advantages of a full system decontamination as a central measure prior to dismantling as well as the excellent decontamination results. The potential for dose rate reduction in operational power plants is also pointed out.

New Wave of Coal-to-liquids – An Opportunity to Decrease Dependency on Oil and Gas Imports and an Appropriate Approach to a Partial Revival of Domestic Coal Industries
Karsten R. Radtke, Max Heinritz-Adrian and Claudio Marsico
Throughout the world domestic coal is now once again gaining in importance. Starting with the fossil fuel, coal – especially coal of a low quality, i.e. with a high ash or sulphur content – can be subjected to a number of process steps to obtain a variety of end products, such as fuels, chemicals and even electricity. In this respect, IGCCs, which are purely coal-fired power generation plants and do not generate any other end product, are a special case. Current cost estimates for projects show that this technology is competitive. Influences of the market as well as the coal-to-liquids (CTL) and coal-to-gasoline techniques will be discussed.

Scholven Power Plant Unit C: Replacement and Upgrade of the Control System
Ralf Hartwiger and Eckhard Schröder
At the end of October 2005 E.ON finished the upgrade of the control system in unit C of its coal-fired Scholven plant. The scope of the project covered the control system of the unit, including DENOX, flue-gas cleaning and steam turbine. The unit was back in operation after only ten weeks standstill. E.ON did not only replace the phased-out hardwired control system but also improved the turbine’s hydraulic and electronic protection and automation system. To achieve this goal some innovative technologies were applied for the project to demand changes and participation in short-term energy market opportunities.

Preventing Standstill Corrosion on the LP Turbine in the Bexbach Power Plant through Optimised Shutdown Procedures
Frank Udo Leidich and Andreas Klein
In the past, a series of damage cases was found on LP turbine rotors, specifically on the LP blading. The damage was attributable to localised pitting corrosion attacks and, in some cases, required costly rehabilitation measures. This phenomenon mainly occurred in power plants operated with frequent start-ups and shutdowns, since localised pitting corrosion can take place during standstill phases. The Bexbach power plant is operated as medium load station. In order to prevent corrosive attacks on turbine parts during outages on weekends, the turbine shutdown procedure was modified in such a way that corrosion would be prevented during normal weekend downtimes thanks to a reduced relative humidity inside the LP turbine casing. Thus, a specific measuring and diagnostic method was developed for correcting and evaluating the relevant influential factors.

Fire Protection Measures upon Maintenance Activities in Power Plants
Ulrich Fischer
Fires causing damage worth several millions demonstrate that fire protection prior to maintenance activities is an important measure to increase plant safety and to avoid such costly damage. Statistics show that around 6 % of all fires are due to improper hot works. The confirmed reasons can mainly be found in human error. Thus, it is required to take provisions in the run-up to maintenance activities to counteract such damage. Besides technical fire fighting, a tailor-made fire protection concept that fits into the maintenance activities is among the most important measures. The main contents of fire protection concepts are contained in the relevant regulations of the Employer’s Liability Insurance Association as well as in the VGB Guideline R 108.

Condensate Water Treatment by Adsorption onto an Activated Carbon Grade with High Activity and Low Silicate Leaching
Joachim Herzer
Granular activated carbon (GAC) is frequently used to remove dissolved organic impurities from condensate water. An optimal adsorption capacity and GAC life time are achieved by matching the size of the target organics versus the pore size distribution of the activated carbon. From a product range of over 150 activated carbon grades, eight different NORIT GAC types are available for condensate water polishing. Differences between these grades apply to adsorption properties, hydraulic properties and purity. Guidelines for design and operation of the GAC stage are provided.

Production of Liquid De-icer by Evaporation of FGD Waste Water at the Nordjyllandsvaerket Power Plant Unit 3
Niels Ole Knudsen
The Elsam-owned, Danish 380 MWe pulverised coal-fired power plant ”Nordjyllandsværket, unit 3”, commissioned in 1998, is equipped with a limestone-based Mitsubishi Heavy Industries (MHI) flue gas desulphurisation plant. After six years of operation the rotary regenerative gas-gas heater had to be replaced due to corrosion and increased pressure drop. At the same time, intensified environmental regulation on the FGD wastewater outlet forced Nordjyllandsværket to evaporate all liquid effluents. The upgrading has almost been completed in September 2005 with the commissioning of an evaporator for the FGD waste water. The final product, i.e. a concentrated calcium chloride solution – brine – will be sold as a liquid de-icer.

NH4OH-inject Optimising of a Selective Catalytic Reduction (SCR) Flue Gas Cleaning System via Fuzzy Control at the Municipal Waste Plant Flötzersteig
Erich Pawelka, Marcus Kuhn and Christian Gierend
After implementation of fuzzy combustion control system (furnace 1 in the year 2001, furnace 2 and 3 in the year 2002) for all three furnaces in the municipal waste treatment plant “Flötzersteig“ the flue gas volume increased as a result of a higher efficiency of the furnaces. The new fuzzy control system guarantees the safe observance of the clean gas emission control standards and lower emission, too. Fuzzy combustion control system and fuzzy ammonia water control system react both automatically to manage changing operating conditions.