Modelling of corrosion and iron transport in the primary heat transport system of CANDU reactors.

摘要

The corrosion and material, especially iron, transport in the primary heat transport system of CANDU-6 reactors has been modelled. Flow-accelerated corrosion (FAC) occurs in the outlet feeders because of the high coolant velocity and the coolant unsaturated with dissolved iron causing the dissolution of magnetite. The FAC was modeled from first principles, taking account of electrochemical potential, oxide film precipitation and dissolution, mass transfer and flow-induced erosion of oxide particles. The corrosion rate in the inlet feeders is low compared to that in the outlet feeders because the coolant is saturated in the inlet feeders. In the steam generator tubes and the reactor core, magnetite deposition occurs. Good agreement with measurements was obtained for the circuit. The model provides good predictions for corrosion and iron transport in the primary heat transport circuit and is capable of making predictions under different chemistry conditions.