Accumulation of radioactive corrosion products on steel surfaces of VVER type nuclear reactors. I. 110mAg

Combined effect of gamma-radiation and pH on corrosion of Ni–Cr–Fe alloy inconel 600

“…3 with the AES depth profiles presented in Fig. 2 confirms that the two different slopes in the depth profile of oxygen at.% observed at pH 10.6 are due to an oxide layer structure consisting of an inner layer of Cr III and Fe II oxides (Cr 2 O 3 /FeCr 2 O 4 ) and an outer layer of mostly Ni II 2 ). The Ni II oxide layer is absent on a surface corroded at pH 6.0 in the absence of radiation, except for a few monolayers of Ni(OH) 2 .…”

“…The overall oxide thickness is thinnest at pH 6.0 and at this pH the oxide is mainly of chromium oxides (Cr 2 O 3 and FeCr 2 O 4 ) with a very thin outer layer of Ni(OH) 2 due to significant dissolution of Ni II . The overall oxide thickness is thickest at pH 10.6 and at this pH the surface layer consists an inner layer of a mixed spinel oxide of FeCr 2 O 4 /Fe 3 O 4 /NiFe 2 O 4 and a thicker outer layer of Ni(OH) 2 .…”

“…This suggests that there has been more dissolution of Ni than Cr or Fe from the surface during the 3-d corrosion. The XPS results discussed below indicate that the outermost surface is a thin layer of hydroxides, Ni(OH) 2 and Cr(OH) 3 . The oxide layer structure is schematically shown in Fig.…”

“…Uniform corrosion introduces dissolved metal impurities in the reactor coolant and their accumulation can lead to the formation of insoluble metal oxide particulates and deposits in the coolant system. In the reactor core stable isotopes can absorb a neutron and become radioactive (e.g., forming 54 Mn, 58 Co, 59 Fe, 60 Co, or 58 Ni) [1][2][3]. Deposition of radioactive materials on coolant system components outside of the biological shielding of the reactor core creates a potential source of radiation exposure for plant workers.…”

Adsorption of fission products on stainless steel and zirconium

“…There are only a few papers dealing with uranyl adsorption on reactor materials and even less is known about the adsorption of the fission products. Room temperature adsorption of fission products from aqueous solutions on zirconium and stainless steel surfaces were investigated (Hirschberg et al 1999;Varga et al 2001;Fujii et al 2002;Vajda et al 2004). Similar experiments were done also at higher temperatures up to about 300 • C (Lister 1975(Lister , 1976(Lister , 1993Lister et al 1983;Pattison and Walton 1961).…”