Mammoet removes Lingen nuclear power plant steam converters
The Lingen nuclear power plant in Germany, which was permanently shut down in 1977, is now in the process of being decommissioned by Mammoet. The Dutch giant was contracted to remove the two steam converters, each weighing around 155t, from the control area of the power plant. Mammoet executed the job on time and with no incidents, in compliance with regulatory requirements in nuclear facilities.
Due to radiation protection requirements, all the tooling, equipment and 100t of manufactured steelwork had to pass radiation checks before entering the control area. This major factor, in terms of time, had to be taken into account at the start of all planning to meet the deadline.
First, a support strap had to be installed onto the first steam converter. Because it was installed in a narrow alcove, the upright positioned component was hard to access and first had to be jacked up with hydraulic climbing jacks and moved laterally. Then, a temporary lifting device took over the steam converter. It was pushed out gradually, with a skidding device, and placed onto a skidding track horizontally. The steam converter was then rotated by 90 degrees and lowered.
In this position, the large component could be removed from the control area to a gantry built several storeys high against the building exterior, though only a few centimetres of clearance were available due to interfering edges and the narrow diameter of the opening.
After removal, the converter was lifted from this portal gantry in a tandem operation, by a mobile crane, weighing 1200-tonne and another weighing 750-tonnes. It was then loaded for transport. The second steam converter followed in the same procedure. In addition, four subcoolers were also moved and handed over to the customer for loading into special containers.
Stefan Lindemann, Project Manager Dismantling Large Components at RWE Nuclear GmbH said: “We were very satisfied with the technical solution and the cooperation with Mammoet. The very well planned and safe removal of the steam converters was an important step in the overall decommissioning process.”