Development of the air jet curtain covering surface with gas phase under the water

Welding of structures such as pressure vessels is carried out for maintenance of nuclear power plants. For shortening the work process and reducing exposure radiation, development of a technique to weld is carried out without discharging the water from the pressure vessel. However, the welding must be done in an inert gas condition, and therefore it is necessary to remote the water around the welding point. We developed the air jet curtain technology which made possible the removal of water by feeding gas to keep the welding point in the gas phase. (author)