Abstract: This invention provides a method and an apparatus for removing scales from hot-rolled steel strips to produce steel strips with excellent surface conditions. In a pickling facility to pickle the hot-rolled steel strip, the pickling method of this invention passes an electric current through the continuously fed, hot-rolled steel strip in one or more of a plurality of pickling tanks. A means to supply an electric current is also provided.

Abstract: The present invention is concerned with a method of reducing radioactivity in a nuclear plant by preliminarily forming oxide films on the surfaces of metallic structural members to be in contact with high-temperature and high-pressure reactor water containing radioactive substances before said metallic members are exposed to said reactor water. The method is characterized by the steps of subjecting said structural members to a first-step oxidation treatment of heating said structural members in an environment of a high temperature, and further subjecting the thus treated structural members to a second step oxidation treatment of heating said treated structural members in an environment having a higher oxidizing capacity than that of said environment in said first-step oxidation treatment to form a denser oxide film than an oxide film obtained in said first step oxidation treatment. According to the present invention, radioactivity in the nuclear plant can be reduced remarkably.

Abstract: A method of inhibiting corrosion of carbon steel piping of condensate and feed water systems in a power generating plant, characterized by continuing the water in said piping to flow after also said plant has been shut down until it is restarted up and by keeping the specific electric conductivity of flowing water at 0.5 .mu.S/cm or less.