Optimization for the HP-CORD UV chemical decontamination process for AISI 304 stainless steel

The decontamination of stainless-steel surfaces in Light Water Reactors components, that may suffer from nuclear activation and contamination, is still a topic that deserves research and development studies. In this paper, the HP-CORD-UV chemical method for the removal of thin surface layers from AISI 304 stainless steel samples is addressed, considering multiple cycles of oxidation and cleaning. A procedure for the optimization of the oxidation phase considering in particular the pH of the solution, the ([KMnO4]/[H+] ratio), and the immersion time (oxidation time), was developed and is here presented. The experimental results show that 10 oxidation cycles at pH 3, [MnO4-] = [H+], for 2 h, followed by 30 min of cleaning in oxalic acid, allowed to reach a thickness of dissolved metal of about 3–4 μm. Despite the intrinsic localised morphology of the corrosion attack on AISI 304 sample surface, scanning electron microscopy showed good reproducibility of the process.