Corrosion Behavior Of CuCrZr Alloy For Fusion Reactor In High-temperature And High-pressure Water

In the design of fusion reactor,the divertor and the first wall heat sink material CuCrZr alloy is served in high temperature and high pressure coolant water,resulting in CuCrZr alloy corrosion.On one hand,the corrosion of CuCrZr alloy in coolant water affects the integrity,performance and lifetime of the components,on the other hand,the corrosion products are parts of the activated corrosion products(ACPs)after deposition and activation.Thus,it is important to study the corrosion behavior of CuCrZr alloy in coolant water,both for the safe operation and ACPs analysis of fusion reactor.However,in the existing literature,corrosion experiments of CuCrZr alloy,especially corrosion experiments in pipeline test benches similar to those of reactor coolant circuits,are rarely reported.In this thesis,corrosion experiments on CuCrZr alloy in the simulated fusion reactor operating environment(cooling water temperature 150?,dissolved oxygen<10ppb)were performed.The experiments consists two major parts.First part was flowing water experiment performed on high-temperature flowing-water loop with a flow rate of 6m/s and the second part was continuous water experiment performed on continuous high-temperature and high-pressure experimental device with a flow rate of 0.214×10-6m/s.The microstructure and chemical composition of the corrosion products were observed by SEM + EDS,XRD,AES and other instruments.Then,Experimental results of flowing water and continuous water were compared.Based on Corrosion process of CuCrZr alloy in cooling water,the influences of water flow velocity on the corrosion of CuCrZr alloy were discussed.Results show that(1)In flowing water,mass loss curve is approximately linear with time and the fitting formula is m=-0.13514+0.01053t.Corrosion rate is about 3×10-9kg/(m2·s).In continuous water,the mass loss accorded with power function with time and the fitting formula is m=0.06216t0.32786.The corrosion rate is 1.27×10-10kg/(m2·s)after 1500h exposure.(2)Results of Surface microscopic analysis shows that the corrosion products of CuCrZr alloy are mixture of CuO and Cu2O,both in flowing water and in continuous water.In flowing water,the corrosion product particles are larger(0.5 ?m),and the surface of the sample is completely covered by the oxide particles from the early stage of 100h.However,in continuous water smaller corrosion particles(less than the detection line)are formed.The original wear marks is clearly visible after 1500h exposure.(3)The measurement on thickness of the corrosion product shows that only the thickness of oxide layers corroded for 800h can be measured in the samples of flowing water corrosion and the thickness of oxide layers after 100h and 1500h are under the limit.In the continuous water-corroded samples,the thickness of oxide layer after 800h and 1500 was 0.55 and 0.75 respectively,and the thickness of oxide layer after 100h is under the limit.(4)By analyzing the corrosion process of CuCrZr alloy in cooling water,it can be known that the influence of cooling water velocity on the corrosion of CuCrZr alloy was considered as the direct change of the oxide film thickness and the mass transfer coefficient of flow boundary layer on the material surface.