Authors & Affiliations
Golosov O.A., Nikolkin V.N., Barybin A.V., Khvostov S.S.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Nikolkin V.N. – Chief Specialist, Institute of Nuclear Materials.
Barybin A.V. – Lead Specialist, Institute of Nuclear Materials.
Khvostov S.S. – Engineer, Institute of Nuclear Materials.
The paper gives the experimental results of outlow of EP-823 steel elements into lead investigated using neutron activation method. EP-823 steel samples, irradiated in IVV-2M reactor to neutron fluence of 1.1·1019 n/cm2, unoxidized and thermally oxidized in the air to reach oxide film thickness of 0.3 and 1.2 µm have been exposed to static corrosion tests in lead with unit oxygen activity at the temperature of 720°C during 55 h. It has been shown that corrosion itself and corrosion product out-flow into lead are selective in terms of steel elements. It has been established that the maximum rate of the release into molten lead was registered for iron atoms, which by ~20 times exceeds that of chromium under dissolution of an unoxidized sample with metal surface. Iron diffusion flow for sam-ples with oxide films when dissolved in lead approximately by 60-65 times exceeds chromium diffusion flow. However, oxide thickness increased by four times almost has no effect on this ratio. Along with increasing oxide film thickness, chromium atom flow rate decreases by ~2 and ~5.6 times with the oxide 0.3 and 1.2 µm thick, respectively. Diffusion flow of iron atoms into lead increases by ~30% with the oxide 0.3 µm thick, and when the oxide is 1.2 µm thick it decreases by ~2 times as compared with unoxidized steel. Iron outflow into lead is at the level of 5-15% from its concentration in the oxide film formed during testing. Chromium outflow does not exceed 1% and decreases with the increasing thickness of the initial oxide film. Iron concentration in lead volume is at the level of solubility limit; that of chromium is by 20-200 times lower.
HLMC, lead, structural steels, corrosion, corrosion products, outflow, mass transfer, temperature, nuclear reactor, solubility, concentration
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