Know-how about strong connections is an important element of the ongoing improvements at Sweden’s largest nuclear power plant – Ringhals. Through training, high performance requirements and a holistic approach the Elpress company contributes to a higher level of safety and higher future output at the nuclear power plant.
Nuclear power has gained broad public support in the wake of the global threat to climate and environment. In Sweden, more than half of the population feels that nuclear power is an important element of the energy supply in the future, according to a survey published by the University of Gothenburg in March. At Sweden’s largest nuclear power plant, Ringhals, SEK 12 billion is being invested to upgrade the safety system and bolster the protection, but also to raise the output at the same time. Upon completion of the upgrade, output will have been raised by 4 TWh to an annual production of 32 TWh of electricity. This is equivalent to the consumption of six cities of the size of Gothenburg.
The Ringhals nuclear power plant was built in the beginning of the 1970s. Now underway are a large number of projects to improve protection, increase the level of safety and raise the output. This effort includes the replacement of many components and the introduction of digital technology. The number of electrical connections will rise and they must stand up to higher loads. This is where Lagercrantz Group’s subsidiary Elpress enters the picture.
An electric connection is the junction between a cable and an electric component, or another cable. Generators, transformers, switchboards, breakers and measuring instruments are examples of common components. For a comparatively small portion of the total investment, a mechanically and electrically strong connection with a long life can be obtained with the Elpress system. The quality – in the case of Ringhals perhaps in the first instance the safety – is based on four fundamental factors:
- The cable
- The terminal / the connector
- The crimping tool
- The installer’s competence and skill
The design engineer is responsible for selecting cable qualities at a power plant such as Ringhals, and it was in connection with that effort that Elpress was contacted. In early spring 2007 Claes Uneman spent time at Ringhals together with the leading engineers.
Cables at a nuclear power plant vary in size, material and design. For each type of cable Claes presented appropriate cable terminals and customised tools and made detailed presentations on how to use them. It is important not only to understand what has to be done, but also why. That is the type of know-how that ultimately guarantees the safety. As a result hereof it was decided that Claes would conduct training of some ten supervisors, technicians and contractors who lead the improvement work. The training presents the collective resources of Elpress and includes instalments about materials, handling, combinations, systems, safety and an overarching perspective.
The basis of System Elpress is to manufacture both the crimping tool and the connection, and also to train the installers. All materials in the crimping tool as well as the connection are tested under load in accordance with the international electrical standard IEC 61238-1:2003. By delivering an entire system, Elpress is able to control all elements and can therefore assume product liability. Sales are through licensed dealers, the know-how of who constitute an integral part of the system.
Management at Ringhals obviously has an interest in doing everything possible to ensure safety and performance. As part of this work, Claes Uneman has trained a number of technicians at Elajo in Varberg. The training was conducted on one occasion and was also open to the technicians of other companies. A total of 25 persons participated, people who have subsequently worked on Ringhals projects. If there is still so much as a hint of uncertainty, technical support and qualified advice will always be available. The emergency telephone manned by Sune Dahlberg is always on call at Elpress in Kramfors.
Large investments at Ringhals
The authorities today are placing considerably higher requirements than at the time of construction start of Ringhals 1. The reactor protection was now increased to follow that development. Separation of control equipment and power supply was one of the two key features. A new cooling system is also being built, with two new water streams from the sea to the so-called condensation basin. Analysis work is being carried out at the same time to demonstrate the opportunities for raising the output while maintaining safety.
At Ringhals 2 a modernisation of the control and steering equipment has been going on for several years. An entirely new control room with digital technology will be installed during an extended shut-down in 2009. Preparations have been made for the installation work and the technology is in place with, among other things, a new simulator.
At Ringhals 3 work is under way to raise output. In January 2007 permission was granted to raise the so-called thermal effect of the reactor and as a consequence thereof raise the unit’s efficiency.
At Ringhals 4 an upgrading was begun in 2007, which included replacement of the low-pressure turbines and preparations are also being made to replace the electric generators, the high-pressure turbines and the transformers. An increase in performance is underway that involves the replacement of the three steam generators and the pressure accumulator to increase the thermal efficiency.
Quality is derived from knowledge. The safety aspect as well as the increase in power requires enormous precision and a genuine, age-resistant capacity. That applies to the material itself as well as the people who are entrusted to install the new technology. Knowledge about materials, procedures and combinations of different kinds are crucial to creating a mechanically and electrically strong connection with a long life.
Elpress training
Elpress offers training adapted to the individual company where both theoretical and practical elements are included, and when appropriate, training is arranged in the field. Elpress provides course-leaders and training material. After longer courses for installers, participants are certified after passing a final test.