Application of abrasive water suspension jets for nuclear dismantling

The abrasive water jet cutting technology has been successfully introduced into many applications, such as cutting off- and onshore and in industrial manufacturing, cleaning, decoating and others. Although the characteristic advantages of the technology are well known and clearly defined (, there have only been a few applications in the field of nuclear decommissioning. Between 1981 and 1986 the Abrasive Water Injection Jet (AWIJ) has been used to cut the biological shield of a nuclear power plant in Japan(2), but no inset of the Abrasive Water Suspension Jet could be found in literature. Due to the increasing research activities and the recent technical developments, the AWSJ became an alternative cutting technique for decommissioning purposes. The pressure has been increased up to 200 MPa to reach a drastic reduction of the required water and abrasive flow rate. For the same hydraulic power input and the same abrasive flow rate the AWSJ cuts at least twice as deep as an AWIJ. And because the AWSJ carries no air into the cutting process, the risk of aerosols is very small. In December 1997 the on site test of the high pressure AWSJ in an activated environment took place at the VAK power plant in Kahl, Germany. Not the cutting process itself was the critical topic, but the adaptation of the technique to the frame conditions. The lower core shroud was dismantled under water in a depth of 6 m and the cutting process had to be carried out remote controlled by manipulators and video cameras. The paper describes the results of the final investigations, a tool for the simulation of the cutting process and will give some information about the application at the VAK.