Electrochemistry Studies of Semiconductor Properties of Structure Materials in the Nuclear Power Plants by Zinc Injection Technique

The electrochemistry and semiconductor characters of oxide films formed on 304L, 316L stainless steel and alloy 600 in high temperature water with zinc addition has been studied. `Zinc injection´ as a technique which means zinc addition into the primary circuit of nuclear reactor is widely used in pressure water reactor (PWR). Dynamic polarization investigated the different corrosion potentials by zinc injection to the materials. Mott-Schottky plots analyzed the different donor and acceptor densities by zinc injection. Characterizations of the corrosion oxide layer via X-ray photoelectron spectroscopy (XPS) suggested that complex Zn-Cr-Ni-Fe oxide were formed by zinc addition into the high temperature water. Scanning electron microscope (SEM) shows smaller crystals on the surface after zinc injection. It is concluded that zinc injection is a useful method to enhance the anti-corrosion ability of materials and change the semiconductor character of oxide films formed in Fe/Ni base alloys.