Corrosion behaviour of stainless steel surfaces formed upon chemical decontamination

Comprehensive investigation of the corrosion state of the heat exchanger tubes of steam generators. Part I. General corrosion state and morphology

“…Sample Nos. 1, 2, 9, 22, 6, 12, 18, 21 (38.10%) belong in the first cluster; 3, 4, 13 (14.29%) in the second; while 5,8,10,19,15,7,14,11,17,16 samples in the third one with highest share of 47.62%. The first cluster, into which the reference sample #22 was classified to, has a cluster centroid of minus 69.0 mV corrosion potential, 45.8 nA cm À2 corrosion current density, 1.01 lA cm À2 passivity current density and that of 0.51 lm year À1 corrosion rate.…”

“…The main characteristics of the samples are given in Table 1. The surface decontamination procedure (where done) was carried out at Paks NPP in real plant environment, according to the AP-CITROX technology [7,8].…”

“…Although numerous studies dealing with the corrosion features, structure and composition of oxide layers formed on the surfaces of the heat exchanger tubing of various SGs have been published (see e.g. [3,4,[7][8][9][10][11][12][13][14] and references therein), only very limited information on the detrimental corrosion effects of the AP-CITROX chemical decontamination technology is available in the relevant literature [4,[7][8][9][12][13][14]. The applied version of the AP-CITROX procedure is an eight-step process, including an oxidizing pre-treatment of the surface with alkaline potassium permanganate followed by washing with a concentrated mixture of citric and oxalic acids to remove the contaminated surface layer [7,8].…”

Comparison of Decontamination Standards

“…It is important to mention that simulation exercises, for both major and minor contamination events, may be essential for coordination and execution of a response [6][7][8][9][10][11][12]. Table 2) after drying.…”

Removal of metals and organics in a chemical decontamination process solution: Laboratory and semi-pilot scale experiments

“…The process involves dissolution of the radioactive contaminants themselves or the matrix (oxide films or deposits), which are trapped by chelating agents. Proper chemical decontaminating agents consisting of ethylenediaminetetraacetic acid (EDTA) and oxalic acid are often used to remove metal oxides such as magnetite (Fe 3 O 4 ), nickel ferrite (NiFeO 4 ), hematite (Fe 2 O 3 ) and chromium oxides in the chemical decontamination methods [14,15].…”