INNOVATIVE UNDERWATER CUTTING PROCEDURES FOR THE DISMANTLING OF TWO GERMAN NUCLEAR POWER PLANTS

The two power stations, KRB A and VAK, represent the first generation of Boiling Water Reactors in Germany. VAK (Versuchsatomkraftwerk Kahl), located in Kahl, near Frankfurt, was Germany’s very first nuclear power plant and served mainly scientific purposes, while KRB A (Kernkraftwerk RWE-Bayernwerk, Block A), located in Gundremmingen, near Munich, was Germany’s first commercial reactor. Both plants are shut down and decommissioning is under way. Up to now more than 70 % of the systems have already been dismantled and decontaminated. In KRB A for instance about 6,500 tons of contaminated material has been treated, allowing to recycle 93 % and leaving only 7 % of radioactive waste for final storage. The actual work in both projects is focused on dismantling the reactor pressure vessels and its internal components. Besides extensive experiences in both plants with mechanical tools, like sawing, shearing and grinding, two innovative cutting procedures are applied for this purpose, i.e. plasma arc cutting and abrasive water suspension jet (AWSJ). The application of plasma cutting in KRB A and AWSJ-technique in VAK has qualified these procedures as state-of-theart in the nuclear field.