News - Published on 19 June 2024

Design of a Saw for the Dismantling of a Nuclear Reactor

For 30 years, KARL HUGO has been manufacturing welded mechanical tools for the maintenance and upkeep of nuclear power plants in Belgium, France, and Germany. KARL HUGO's teams put all their expertise to work for large groups by manufacturing tools and solutions that allow them to operate within the reactors.

The material dismantling of a nuclear power plant is a major technical challenge. It is supported by technological innovations aimed at improving the efficiency and safety of operations. A Belgian company specializing in nuclear maintenance has been awarded the contract to dismantle the Emsland power plant in Germany. They called on the expertise of the KARL HUGO Engineering Department to develop a saw used during the deconstruction of the reactor. “We have developed a saw with a rotating and tilting table,“ explains Gerd Reiter, Senior Project Manager.

The table with guiding mast and band saw were custom-designed to be installed in the plant's maintenance room, where the reactor pressure vessel, weighing 154 tons and 9 meters high, will be cut. “The structure of the table is made of steel and covered with a 500 to 1000 µm layer of special paint allowing it to work underwater. It measures 6 meters long, 5 meters wide, and has a height of 2 meters,“ specifies the Project Manager. “It weighs 36 tons and has a load capacity of 87 tons.“ The saw, made of stainless steel, weighs 600 kg. Its guiding mast is 11 meters high. In addition to designing these two elements, KARL HUGO's design office engineers also finalized the manufacturing and installation plans for the hydraulic and electrical equipment.

The dismantling of the reactor will take place in several stages. The first step will be to remove the upper structure of the 49-ton reactor and place it on the table. Then, the 61 guide tubes of the control rod will be cut one by one. This will be followed by the other parts of the reactor. “To ensure the correct position of each element to be sawn on the rotating and tilting table, we developed a ratchet system that allows the table to turn at a defined distance to cut the pieces.“ The table can also be tilted 90° to facilitate cutting by the saw. The various components, some of which are still radioactive, will be cut to the required dimensions for the waste treatment process.

All elements of the saw and the rotating table were machined at KARL HUGO. Once the assembly phase is complete, the testing phase can begin with a provisional 7-meter test mast. Additionally, a special container has been built to test the saw underwater. “Before shipping the material to the client, we will perform a dynamic test with 110% of the maximum load, or at least 96 tons.“ Then, a static test with 125% of the maximum load will be conducted for 15 minutes to check for any deformations. “The reactor dismantling phase is expected to begin at the end of December 2024, beginning of January 2025,“ concludes the Project Manager.

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