Novel principle for removing deposits accumulated at the tube plate of steam generators of pressurised water nuclear power stations

摘要

Novel device for removing deposits accumulated at the tube plate of steam generators of pressurised water nuclear power stations. A system for removing the sludge which can accumulate between the heat exchanger tubes fixed to the tube plate of a steam generator. In brief, the system for removing the sludge comprises a lancing assembly which can move along a guide which is fixed by an adapted flange to the handhole or eyehole and to the central pillar or to the handhole or eyehole diametrically opposite the first by a hydraulically controlled attachment or a flange which is also adapted. The said system is characterised in that the medium pressure lateral driving water injection and low pressure suction assemblies essentially comprise tube assemblies with regulable and adjustable lengths according to the quantity of deposit to be removed and according to the position of the mobile lancing device along its guide and controlled from the same side of the steam generator. The advantage of the said system lies in the fact that the control itself of the lancing is performed remotely, the presence of a single operator is required near the steam generator. In order to clarify the advantage of the said system, the regulation of the tubes for suction and injection of the water for driving the mixture of deposit and water consists in optimising the whole operation for cleaning the tube plate of the said steam generators.