Study On Corrosion Model And Experimental Verification Of CuCrZr Alloy For Fusion Reactor

In the design of Fusion Reactor,Copper chrome zirconium alloy(CuCrZr),as a candidate heat deposition material,is applied to the first wall,the divertor and the electrical connection head of International Thermonuclear Experimental Reactor(ITER).Due to the contact with cooling water,the corrosion of CuCrZr occurs.Corrosion products migrate with the cooling water and may be deposited and activated,thus becoming a part of the activated corrosion products and also a source of radiation dose for the workers in the operation and maintenance of the reactor.The independently developed CATE program of north China electric power university can perform source phase analysis well,and the influence factor of Cu can be better applied to the fusion reactor.So,it is important to study the corrosion of CuCrZr in the Fusion Reactor.However,there are not many researches on the corrosion behavior of CuCrZr under the condition of convergent reactor at home and abroad,and there is also a lack of corrosion model of CuCrZr.Therefore,the CuCrZr corrosion model under the design condition of the Fusion Reactor is shown in this paper.In this paper,the corrosion experiment of CuCrZr was carried out,and the corrosion model of CuCrZr was constructed.The experiment was divided into dynamic water corrosion experiment and continuous water corrosion experiment.The setting of dynamic water experimental parameters referred to the design parameters of ITER water cooling circuit.The experimental temperature was 150℃,the dissolved oxygen was less than 0.01mg/kg,the pH was 7(20℃),the conductivity was 0.055μS/cm,and the flow rate was 6m/s.In addition to the amount of dissolved oxygen and flow rate,the parameters of continuous water experiment are consistent with those of dynamic water experiment.The amount of dissolved oxygen is 10ppb,250ppb,1000ppb and 1500ppb.After the experiment,the corrosion weight loss curve,corrosion rate curve,surface and section morphology of the material were obtained through corrosion weight loss analysis and microscopic and microscopic analysis,and the corrosion mechanism was analyzed.According to the corrosion mechanism,CuCrZr corrosion model was constructed.The resultant conclusions are presented as the following:(1)In the dynamic water corrosion experiment,the corrosion weight loss gradually increases with time,and the corrosion rate maintains in a certain range.In the continuous water corrosion experiment,the corrosion weight loss increases gradually with time,the corrosion rate decreases with time,and finally tends to balance.(2)The corrosion mechanism is analyzed according to the microscopic and microscopic results.The erosion of the fluid affects the surface oxide layer,resulting in holes and even cracks in the oxide layer.With the passage of time,the corrosion layer is thickened,forming a certain protective effect on the internal matrix.In the continuous water corrosion experiment,Cu2O is formed on the sample surface at the initial stage of corrosion.Over time,a mixture of Cu2O and CuO forms on the sample surface.Under different dissolved oxygen conditions,the corrosion rate first increases and then decreases with the increase of dissolved oxygen.(3)According to the corrosion mechanism,the model constructed is divided into two parts.One part is the flow corrosion caused by the fluid erosion.By analyzing the influence of the fluid on the metal and the relationship between the flow velocity and the corrosion rate,the model is calculated.The other part is pure chemical corrosion,which is calculated according to the theoretical model of Cabrera and Mott and combined with the theory of internal oxidation.Finally,the CuCrZr corrosion model is obtained by combining the two parts.(4)According to the experimental data,the calculated value is verified.The CuCrZr corrosion model constructed follows the objective law of corrosion,and the relative error between the calculated value and the experimental value is about 10%,indicating that the corrosion model can be used as an empirical formula for the database and calculation of CATE program.