METHOD FOR MANAGING WATER-CHEMISTRY

The purpose of the present invention is to improve the operation reliability and to reduce exploitation costs in nuclear power equipment by managing the water-chemistry in order to reduce the rate of deposit formation on the heating surfaces, to reduce the intensity of the corrosion process, including local corrosion types, to improve radioactivity conditions during the maintenance, to increase the efficiency of bypass filtration and to reduce the value of the sludge component in the heat-carrier. This method comprises introducing a correction additive that consists of reactive aluminium in an ionic or hydroxide form into the heat-carrier circulating in the circuit. The quantity of Al moles added is at least twice larger than the quantity of Fe in-going moles. The aluminium is dosed so that its molar concentration PAl in the heat-carrier is at least twice larger than that of the bivalent iron PFe in said heat-carrier. The aluminium is introduced in the heat-carrier in a composition of feedwater or a condensate which are fed through an aluminium-containing system. The aluminium dosage is carried out in a bypass filtration line of the circuit by feeding the heat-carrier through an aluminium-containing system such as an aluminium alloy. The aluminium dosage is carried out by electro-chemical dissolution of metallic aluminium, by loading special aluminium-containing pellets into a dosing unit or by adding alkaline-metal aluminates or aluminium hydroxides into the heat-carrier. The aluminium can also be introduced by the application of coatings or by the formation of oxide films that contain aluminium on the inner surfaces of the circuit. Cette invention a pour but d'améliorer la fiabilité de fonctionnement et de réduire les coûts d'exploitation d'installations électriques nucléaires, ceci en gérant la composition chimique de l'eau de manière à diminuer la vitesse de formation des dépôts sur les surfaces chauffantes, à réduire l'intensité du processus de corrosion, y compris les types de corrosions locales, à améliorer les conditions de radioactivité lors de l'entretien, à accroître l'efficacité du nettoyage par dérivation et à réduire la valeur de la composante des boues dans le caloporteur. Ce procédé consiste à introduire, dans le caloporteur circulant dans le circuit, un additif de correction qui consiste en de l'aluminium réactif se présentant sous une forme ionique ou hydroxyde. La quantité de moles d'Al ajoutées est au moins deux fois supérie