Operating experience with nuclear power plants 2012
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 2012, events important to plant safety, special and relevant repair, and retrofit measures from Belgium, Germany, Finland, the Netherlands, Switzerland, and Spain.
Benefit of ageing management in German nuclear power plants - Aspects of KTA 1403 referring to residual commercial power operation and post-shutdown operation
Pablo Barreiro, Thomas Bever, Gerhard Brast, Björn Elsche, Patrick Grossmann, Frank Hüttner, Thomas Linnemann, Sven H. Reese, Swen-Olaf Smit, Martin Widera and Ralf-Mchael Zander
Ageing management (AM) in nuclear power plants became a topic of debate in Germany in the late 1990s. AM was comprehensively practiced on a high level in German nuclear power plants from their start of commercial operation in form of operation’s surveillance, staggered and non-destructive testing, and preventive maintenance programs. The nuclear standard KTA 1403, “Ageing Management in Nuclear Power Plants” is a formal basis for the management process which united the existing and approved activities in order to cope with relevant ageing mechanisms. Experience accumulated in plant-specific execution of the AM process on the basis of KTA 1403 is considered and summarised.
Understanding by seeing - Thermal hydraulics using a glass model of a pressurised water reactor
The simulation centre runs a glass model of a two-loop pressurised water reactor (KWU design) of the scale 1:10. Phenomena occurring in a nuclear power plant can be shown similar to two-phase flows. The glass model is also suited for making exercises related to plant operations, events, and malfunctions as well as thermo hydraulic effects of a nuclear power plant with light water reactor. Training of personnel using the glass model reveals complex phenomena of thermo hydraulics.
Fatigue evaluation including environmental effects for primary circuit components in nuclear power plants
Johannes Seichter, Sven H. Reese and Dietmar Klucke
The influence of LWR coolant environment to the lifetime of materials in nuclear power plants is being discussed internationally. Environmental phenomena had been investigated in laboratory tests and published in recent years. The discussion is mainly focused both on the transition from laboratory to real plant components and on numerical calculation procedures. Since publishing of the NUREG/CR-6909 report in 2007, formulae for calculating the Fen factors have been modified several times. Various calculation procedures are discussed and recommendations are made how to avoid extremely conservative results.
CARINA - A programme for experimental investigation of the irradiation behaviour of German reactor pressure vessel material
Hieronymus Hein, Elisabeth Keim, Eduard Pechler, Pal Efsing, Jens Ganswind, René Knobel, Günter König Pablo Barreiro, Martin Widera and André de Jong
The proof of a sufficient safety margin against brittle fracture of the reactor pressure vessel (RPV) is an important part of the operational safety of nuclear power plants. The RPV safety assessment procedure applicable in Germany is described in KTA 3201.2 of the Nuclear Safety Standard Commission (KTA). In the recently completed research project CARINA (Characteristics of Irradiated German RPV Materials), the data base for pre-irradiated original RPV steels of German PWR construction lines was extended by comprehensive fracture toughness testing. The data obtained are a major contribution to the development of Master Curve applications to be integrated in German standards.
Full system decontamination at the German Unterweser nuclear power plant
Christian Topf, Luis Sempere-Belda, Michael Fischer, Kai Tscheschlok and Christian Volkmann
In order to decrease the high collective personnel dose effectively at the German nuclear power plant Unterweser (KKU), Areva GmbH and KKU jointly started planning the chemical decontamination of the primary coolant circuit and the auxiliary systems (FSD) in the beginning of 2009. Fhe FSD was performed in autumn 2012 using mainly plant internal systems and components in combination with the HP/CORD® UV process and AMDA® (Automated Modular Decontamination Appliance) - Areva’s established and proven decontamination technology. With the onsite performance at KKU, the first FSD of a shut down plant in Germany in the aftermath of the Fukushima accident has been completed with great success.
Impact of load follow operation on the chemistry of the primary and secondary circuit of a pressurised water reactor
Michael Bolz, Andreas Speck, Fred Böttcher and Steffen Riehm
This paper summarises first experience with load follow operation in two pressurised water reactors (KKP2 and GKNI) with regard to chemistry and radiology. The most important mechanisms of dose rate built-up on the primary side are described. The primary side chemistry is aiming at the avoidance or at least the delay of dose rate built-up as far as possible. The secondary circuit is operated according to the H-AVT chemistry (high pH, treatment with volatile chemicals) to minimise the release of metals from carbon- and low alloy steels. The impact of load follow operation on the corrosion protection of the carbon- and low alloy steels on the secondary side due to changes of physico-chemical conditions is discussed.
Deep geological disposal of nuclear waste in the Swedish crystalline bedrock
Claes Thegerström and Saida Laarouchi Engström
Nuclear power companies in Sweden jointly established the Swedish Nuclear Fuel and Waste Management Company (SKB, Svensk Kärnbränslehantering AB) in the 1970s. SKB’s assignment is to manage and dispose of all radioactive waste from Swedish nuclear power plants in such a way as to secure maximum safety for human beings and the environment. Since 1992 a stepwise process has been under way, aiming at finding a site for a final repository for spent nuclear fuel.
Adiabatic compressed air energy storage - Status and perspectives
Sebastian Freund, Roland Marquardt and Peter Moser
This paper gives an overview about compressed air energy storage (CAES) technology and a summary of the ADELE programme, a multi-year R&D programme undertaken by a consortium led by RWE Power to develop adiabatic (A) CAES technology and commercialise the first plant. The ACAES technology is to utilise waste heat developing upon compression in order to increase the entire efficiency. The ADELE-ING project is to provide the basis for making the decision on the construction of a 85 MW prototype.
Process optimisation of lime milk leaching and control of cold lime softening at the power plant STEAG Fenne
Christian Martin, Helmut Arenz and Ralf Wysk
An increase in turbidity in the cleaned water of the cold lime softener higher than the raw water input of the river Saar was observed at the Fenne site at some days in 2009. Also the post-installed sand filter could not restrain the fine particles. Under these circumstances the demineralisation water production had serious problems because of heavily fouled membranes in the reverse osmosis system. Only the immense personal actions of the operating staff could enable the reliability of the water preparation system on site. Together with Nalco the power plant service department implemented a plant audit on site. The purpose of the plant audit was to find the reason for the bottleneck in water preparation and to optimise and automate the water treatment system under the aspects of economical reliability and control efficiency.
Future of sewage sludge in disposal
The thermal treatment of sewage sludge is changing continuously. In the future, the disposal of sewage sludge is framed and will be adjust by the idea of resource saving. Simultaneously due the amendment of the 17th BImSchV emission control will be encouraged.
Noise emissions upon the construction of power plants - Appropriate assessment, or is the German AVV Baulärm contemporary?
Within the scope of licensing procedures also the noise caused during plant construction is more and more discussed between project proponents and neighbours affected by the project. An essential point of criticism in this context is the fact that the regulation for the assessment of construction noise - the General Administrative Regulation on the Protection against Construction Noise (AVV Baulärm) became effective already in 1970, and, naturally, the regulations are being debated today. A profound examination of the regulations of AVV Baulärm shows that the requirements can be met when taking into account further standards. Thus, suitable methods exist to predict construction noise in an appropriate way.