Karlsruhe. Since early today (25 August 2014), Unit 2 of the Philippsburg (KKP 2) nuclear power plant has been reconnected to the grid following its annual overhaul. Over the last few weeks, inspection and maintenance work has been conducted at the plant, nuclear fuel rods are being replaced, and several technical projects have been implemented. Around 1,200 additional employees from manufacturer and specialty companies have supported the extensive work during the overhaul. The entire team has completed around 5,600 individual measures.
"For almost the last 30 years, Unit 2 in Philippsburg has made an important contribution to grid stability and supply security in Baden-Württemberg," notes Jörg Michels, Management Chairman at EnKK and Technical Managing Director of the Philippsburg power plant. "A high level of security is the top priority for us – whether during operation, post-processing, as well as in the decommissioning and dismantling of nuclear power plants. Our investments in the overhaul of KKP 2 are consequently an important building block in the implementation of this safety philosophy."
Overhaul activities characterised by outstanding teamwork
"Collaboration between internal and external employees once again functioned very well during this overhaul," reports Thomas Franke, head of the Unit 2 plant. "Along with numerous routine works, we also carried out several maintenance measures to large-scale components. These included the basic overhauling of one of the three feedwater pumps, with the motor being inspected on the other. An inspection was also conducted on one of the four main coolant pumps. An eddy current test was carried out on two of the four steam generators. A motor and pump inspection was conducted on one of six main coolant pumps, and the motor was replaced on another. One of the six main coolant pumps was also inspected. Maintenance work was conducted on the motors and generators of four of the eight emergency electricity supply units."
The machine transformer that was installed – as planned – during the overhaul exhibited deviations during the measurements that were subsequently carried out. It had previously been subjected to a fundamental retrofit at the manufacturing plant, and had been checked in-depth. "By way of precaution, we uninstalled the transformer, and replaced it with the tried and tested reserve transformer," explains Jörg Michels. The machine transformer is one of two transformers in the KKP 2 that convert the electrical voltage that is generated in the power plant into the high voltage that is required for feeding into the transmission grid. The transformer that has been removed will be returned by rail to the manufacturing plant in Nuremberg, where it will undergo further fundamental checking and testing.
The restoration work was conducted under the supervision of the Ministry of the Environment, Climate and Energy Industry of Baden-Württemberg, and was overseen by surveyors from the TÜV inspection group and KeTAG (Nuclear Technology Surveyors Working Group of Baden-Württemberg). After the work was accepted, the Ministry consented to the plant's recommissioning.
Unit 2 at the Philippsburg nuclear power plant is a pressurised water reactor with electric output of 1,468 megawatts. The plant was commissioned in 1984, and produced around nine billion kWh of electricity in 2013.
EnBW Kernkraft GmbH (EnKK) operates Unit 2. EnKK stands for safety in operation and post-processing, as well as in the decommissioning and dismantling of nuclear power plants in Baden-Württemberg. In Neckarwestheim und Philippsburg, EnKK produces electricity with one nuclear power plant respectively (GKN II and KKP 2). A further plant that no longer produces electricity is located at each of the sites (GKN I and KKP 1). EnKK is currently preparing for the decommissioning of these plants that have been shut down, and has already submitted the first applications to this end. At the Obrigheim site, the dismantling of the nuclear power plant located there, which commenced in 2008, is making good progress.