Corrosion behaviour of stainless steel surfaces formed upon chemical decontamination

In the VVER-type pressurised water nuclear reactors, the so-called AP-CITRO X method (AP: alkaline permanganate; CITROX: citric and oxalic acids) is wi dely used for the chemical decontamination of the austenitic stainless stee l piping in steam generators. In the present work we report some new findin gs obtained by voltammetric, gravimetric, gamma -spectrometric, surface spe ctroscopic (SEM-EDX) and in situ radiotracer studies of the passive layers formed on austenitic stainless steel type 08XI8H10T (GOST5632-61) during th e surface decontamination by the AP-CITROX procedure. The experimental resu lts reveal that the AP-CITROX decontamination procedure, performed even in three consecutive cycles, does not exert detrimental corrosion effects, but rather substantially improves the passivity of the surface oxide layer. (C ) 2001 Elsevier Science Ltd. All rights reserved.