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 & mu;m. Despite the intrinsic localised morphology of the corrosion attack on AISI 304 sample surface, scanning electron microscopy showed good reproducibility of the process.