Abstract: The invention relates to a method and device for unclogging the top surface of the tube plate of a steam generator comprising, in a cylindrical vessel, a bundle of bent tubes of inverted U-shape and connected to a tube plate. The unclogging is achieved by two water jets under high pressure coming from projection heads and which can be directed towards the tube plate. These two water jets are moved simultaneously and symetrically with respect to the diametric boundary line of two zones in the form of a semi-circle on the tube plate. At the same time the detached sludge is removed by aspiration of this sludge throughout the length of the peripheral zone of the tube plate.