Corrosion of some V- and Nb-base alloys under irradiation in water

Abstract

In the work, results of the irradiation influence in first circuit water of the SM reactor on the weight alteration, phase composition of corrosion products, and rupture type of some V- and Nb-base alloys are presented. The irradiation was carried out at 50–65°C in water and at 70–95°C in helium for comparison to neutron fluence of ≃5 × 10 21 n/cm 2 ( E > 0.1 MeV). Water rate was about 13.5 m/s and dissolved oxygen content was 550–720 ppb. As it is shown, V-alloys have undergone the strong corrosion in water under irradiation already at such low temperature as 50–65°C. The maximum corrosion rate occurs with V–3.0Ti alloy (about 900 μm/yr), and the minimal with the V–6.1Cr–5.3Ti–ZrC alloy (about 50 μm/yr). The corrosion products are oxides: V 2O 5 for pure vanadium, TiO 2 for V–3.0Ti alloy and TiO for V–4.4Cr–3.9Ti. The overwhelming majority of corrosion products are taken away by the water flow. These results compare with the data of the autoclave testings carried out in the Argonne National Laboratory.