Sludge Removal of a Nuclear Steam Generator by an Ultrasonic Means

Blockage of crevices such as the quarter-foil of the support plate of nuclear steam generator (S/G) is often observed in Korean nuclear power plants. Blockage of the quarter-foil often causes oscillation of S/G water level. By chemical cleaning, the scale or sludge could be effectively removed. However, it is very expensive and time consuming especially to remove scale deposited in crevices. Therefore, a new method of using ultrasonic means to remove scale accumulated in the crevices is being developed. In this paper, we suggested a new method of applying ultrasonic energy directly to the tube sheet of nuclear S/G to remove scale in the quarter-foil