Abstracts - VGB PowerTech Journal 5/2011

Operating experiences with nuclear power plants 2010

The VGB Technical Committee “Nuclear Plant Operation” has been exchanging operating experience about nuclear power plants for more than 30 years. Plant operators from several European countries are participating in the exchange. A report is given on the operating results achieved in 2010, events important to plant safety, special and relevant repair and retrofit measures from Belgium, Germany, Finland, the Netherlands, Switzerland and Spain.

New power plants in Europe - A challenge for project & quality management

Matthias Hartung

The challenges faced by power plant engineering in Europe have become more versatile and - above all - more complex. RWE has created the preconditions for setting up a uniform European negotiating basis for dealing 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 pooling of project management as well as engineering skills for the implementation of complex investment projects at international level are of decisive importance.

U.S. company’s new nuclear project progresses

Jeff Archie

Operated by South Carolina Electric & Gas Company in the south-eastern United States, V.C. Summer Nuclear Station has maintained a reputation of excellence for more than 25 years. A safety philosophy derived from nuclear plant operation guides its new nuclear project, which SCE&G has undertaken to meet the need for base load generation in its service area in a manner that is clean, safe, reliable, and efficient. In the process, SCE&G is generating jobs and boosting the economy. Site preparation has been well underway since 2009. SCE&G anticipates receiving its combined construction and operating license from the Nuclear Regulatory Commission in late 2011 or early 2012, which will allow major construction to commence.

Load cycling capabilities of German nuclear power plants (NPP)

Holger Ludwig, Tatiana Salnikova, Andrew Stockman and Ulrich Waas

Amid the discussion whether the extension of lifetime of the existing NPPs supports or constrains the increasing use of renewable energy sources in electricity generation, it is partially alleged that NPPs as typical base load power plants could only be operated at a more or less constant power output. Actually, NPPs in Germany have been designed in the seventies to compensate large load changes. The operational experience yet made clearly confirms that the design of existing NPPs is well suited for compensation of load changes due to wind fluctuations in case of further significant expansion of wind power. Furthermore, evaluation of the operational experience using up-to-date knowledge demonstrates that there are no technical safety aspects standing against routine load-following operation of the existing NPPs. Insofar, continued operation of the NPPs can (if needed) support expansion of renewable energy sources in electricity generation.

Meeting the EU 2020 renewable energy targets - The challenge of offshore wind energy

Michael Lewis

Reaching the EU 20-20 climate targets requires a strong build-up of renewables generation capacities. With the large wind resources in European waters, the development of offshore wind energy will play a key role towards target completion. The European offshore wind energy industry has strongly picked up growth in the past years and was expected to end 2010 with over 3 GW of operating capacity. With a step by step approach towards developing the next level of offshore wind energy and a project pipeline of more than 4,000 MW, E.ON plays a leading role in the offshore wind industry. The first step beyond the 20:20 envelope with Germany´s first offshore wind farm Alpha Ventus marks an important milestone for the industry’s development. (EN)

Biomass in the future European energy market

Charles Nielsen

With Europe’s ambitious target in mind to increase its share of renewable energy to 20% (a 34% share of energy for electricity production), this paper discusses the importance and challenges resulting from increased use of biomass. Biomass comprises a wide range of fuels featuring a variety of properties and qualities, and both usage and import will lead to dilemmas in relation to sustainability, area usage and food production. The paper also discusses Eurelectric’s reasons why import criteria should be defined. The challenge of establishing the required capacity and the perspectives involved in added use are addressed here based on Danish experience and observations from two decades of development programmes. The development comprises generation of infrastructure, co-firing of straw and coal, gasification, new ways of exploiting the energy in household waste and second-generation bio-ethanol production.

AVARIS: An innovative procedure to repair seal seats surfaces in gate and check valves

Karl-Heinz Herzing, Ulf Breitenberger and Armin Grieser

AVARIS (AREVA Valve Repair In-Situ) saves the plant operators time and money, as complete exchanges of valves and all related elaborate consequences become dispensable. AVARIS is of high interest in the worldwide maintenance market, as it can be applied in both nuclear and conventional power plants. Moreover, AVARIS retrofits valves in the secondary and primary circuit which even saves complex nuclear transports. AVARIS fulfils the quality requirements of third party authorities in national and international markets. Valves repaired with AVARIS correspond to their original condition concerning sealing function.

Characterisation and activation of catalysts for recombination of radiolysis gas

Michael Bolz Jan Köhler, Rolf Schorle and Achim Helf

Radiolysis gas is produced by radiolysis of cooling water during the operation of boiling water reactors. Small amounts of radiolysis gas can accumulate at dead ends of pipes in the water-steam circuit. Under certain conditions, it can accumulate even to higher concentrations. To avoid these accumulations, small catalysts are built in. As part of a diploma thesis, the catalysts were analysed and characterised.

European comparison of the water chemistry in boiling water reactors in Germany and Switzerland

Udo Krumpholz, Friedrich Seibold, Harry Neder, Bernhard Stellwag and Alexander Ländner

The paper offers an overview of the design criteria, water chemistry operational modes as well as the measured data of the power plants in Germany and Switzerland and it provides a comparison of these data with other plants in Europe. Overall the results of the performed comparison corroborate the general high level of water chemistry in European boiling water reactors.

Primary coolant technology in VVER/PWR units - Experience with preconditioning, decontamination and recontamination

Katerina Vonkova and Jan Kysela

For the latest Czech and Slovak stations commissioned (Temelín and Mochovce) a modified hot functional test (HFT) chemistry was developed in the NRI Rež. Chromium-rich surface layer formed due to modified HTF chemistry ensures lower corrosion rates and radiation field formation. Long-term operation experience from both nuclear power plants are discussed in this paper. Radiation field, occupational radiation exposure and corrosion layers evolution during the first ten years of operation are compared and presented. The operation experience from all above-mentioned units showed a low level of corrosion products in the primary system as well as low dose rates. Actual in-pile loop tests carried out at the Nuclear Research Institute (NRI) Rež are focused on the study of surface preconditioning - similar to HFT chemistry - after decontamination.

A new career path in radiation protection training: Certified Power Plant Shift Supervisor - Radiation Protection

Christoph Terbeek

Apart from theoretical knowledge, effective day-to-day radiation protection operations also require a certain measure of practical experience. Therefore, the professional degree of “Certified Radiation Worker”, issued by the Chamber of Industry and Commerce (CIC) Aachen, Germany, established at an early stage. In order to provide experienced radiation protection specialists with an attractive career path, POWERTECH TRAINING CENTER e.V., in co-operation with VGB PowerTech. e.V., the Paul Scherrer Institute (Switzerland) and the Swiss Atomic Energy Agency (ENSI), has devised a new power plant shift supervisor training course specialising in radiation protection. The vocational training degree called “Certified Power Plant Shift Supervisor - Radiation Protection” is awarded after successful completion of the advanced training examination conducted by the CIC in Essen, Germany.

Dynamic behaviour of steam turbine controller in the event of load rejection following a three-phase short circuit close to the power plant

Christian Kreischer, Jens Rosendahl, Martin Bennauer and Heribert Werthes

This paper uses simulation results to illustrate the conditions in which a double fault comprising load rejection due to a three-phase short circuit close to the power plant can be controlled. The correct response to a double fault can avoid high overspeeds and prevent tripping by the overspeed protection system, thereby increasing power plant availability. The dynamic behaviour of the generator during and after a double fault is of special significance here and must therefore be examined in greater detail.