Design of Machine for Dismantling Biological Shield Concrete

The design requirements of machines to be used for dismantling biological shield concrete in a commercial nuclear power plant and two concepts of dismantling machines are discussed. The concrete structure surrounding the reactor is irradiated during operation and the radiation inside the structure is quite high. Therefore, dismantling work should be carried out by remote operation. The durability, reliability, maintainability, operability, ease of installation, minimal disposal of part of the machine, and cost are important requirements for machines to be used in dismantling reactors. Machines that can be decontaminated easily will realize these demands. One conceptual machine that employs a diamond saw as a dismantling device is suitable to cut into the circumference of the radioactive biological shield. The other is an on-wall-travelling platform mounting a cutting device. The platform will move on the wall and is fixed to the wall firmly by a stud welding or concrete anchor.