Recycling in demolition processes
Demolishing nuclear plants requires an entire arsenal of specialised technical methods and machines. Especially the dissembling and disposal of the reactor pressure vessel and the appliances mounted in it is a considerable challenge, since these components have been exposed to neutron irradiation for years or even decades and, as a result of neutron activation, are now radioactive themselves. Therefore, the steel that has been used in constructing the plants can only be cut up via remote control.
Here, water abrasive suspension (WAS) cutting, which has beneficial properties, is used. Garnet sand has been added to the ultra-high-pressure water jet as a fine granular, sharp-edged abrasive. During cutting, steel particles are also created, which results in large amounts of a radioactively contaminated abrasive-steel-granulate mix. Its disposal as secondary waste causes considerable costs. In order to reduce them, a method has already been developed at KIT that separates the steel particles from the abrasive with a magnet. However, the magnet can only catch steel particles from a certain minimum size on.
Scientists at the KIT Institute of Technology and Management in Construction (TMB) and the KIT Institute for Nuclear Waste Disposal (INE) have elaborated the already established magnetic separation method in order to raise the separation degree. The abrasive-steel suspension is poured into a mixing vessel. In a preliminary treatment step, fine particles are filtered out with wet sifting. This already removes around 95 per cent of the radioactive steel particles, and they can be disposed of. The remaining suspension is fed into the magnetic separator, and the steel particles sticking to the magnet are separated and collected. The residual abrasive gathers in the mixing vessel and is used again for separation. All in all, secondary waste is reduced by up to 75 per cent.
Your contact person for this offer
Dr. Aude Pélisson-Schecker,
Karlsruhe Institute of Technology (KIT)
Innovation Manager Energy, Innovation and Relations Management (IRM)
Phone: +49 721 608-25335