PROCESS OF STEAM-GENERATOR OUTAGE CONSERVATION AND EROSION REDUCTION IN NUCLEAR-POWER-PLANT HIGH-PRESSURE FEEDWATER PREHEATERS

For the purpose of protection against stagnant corrosion the secondary coolant circuit of the Paks NPP unit 2/Hungary was conserved on the basis of a new technique using octadecyl amine. The feedwater tanks, a high-pressure preheater street, the steam generators, and the cooling condenser were included into the conservation circuit. Conservation was carried out during the cooling process of the plant by dosage of the octadecyl amine emulsion at 150-degrees-C. The area to be conserved was about 25,000 m2. Based on the experience with conventional equipment an amount of octadecyl amine of 6 g/m2 was present. Efficiency of conservation has been proved with the results, in particular the iron values obtained with a conserved and a non-conserved high-pressure preheater street after restart.