Influence of zinc injection on deposition of corrosion products on inner wall of heat transfer tube

Abstract

The zinc injection process has been widely used in the primary coolant of PWR nuclear power plants. This study explored its effect in the water coolant of fusion reactors. The research uses the International Thermonuclear Experimental Reactor (ITER) water-cooled experimental simulation circuit, with Fe3O4 particles as corrosion products. The deposition thickness of Fe3O4 on the wall of the stainless steel tube at temperatures from 80 °C to 150 °C was measured by a non-destructive online magnetic thickness measurement. The experimental results show that zinc injection has a significant inhibitory effect on the deposition of corrosion products on the tube wall, especially at the elbow. After adjusting the pH to the optimal value of 9, adding zinc can continue to reduce the thickness of the deposition layer. The results of the microscopic analysis indicated that the Zn injection formed a new dense surface oxide film and inhibited the deposition of Fe3O4 particles on the tube wall. The research results indicate that the chemical process of zinc injection water can be applied to the operation of the water-cooled fusion reactor in future.