Method for radioactive decontamination of the metal wall of a fluid circulation equipment

Abstract

The invention relates to a method for radioactive decontamination of the inner face of the metal wall of equipment used for circulating a fluid in a nuclear installation, the wall being made of a metal alloy and the inner face of this wall being covered with a surface layer of metal oxides, the method comprising at least one step a) of dissolving the surface layer of metal oxides, followed by a step b) of corroding the inner face of the wall, and being characterized in that: (1) steps a) and b) comprise circulating in the equipment a reducing aqueous solution with a temperature of at least 75 °C; (2) step a) comprises, simultaneously with the circulation of the reducing aqueous solution in the equipment, a polarization of the wall to a potential lower than the corrosion potential of the metal alloy in contact with the reducing aqueous solution;and (3) the polarization of the wall is stopped at the end of step a). Applications: nuclear field, in particular for the decommissioning of metallic equipment into conventional waste or for carrying out an "extensive remediation" of this equipment.