Preliminary Experimental Study Of Corrosion Model In Source Term Analysis Program Of Fusion Reactor

The RAFM steel is considered as a competitive candidate structural material in fusion reactors.To investigate the corrosion behavior of RAFM steel in primary water coolant of ITER and how flow velocity affect the corrosion behavior of RAFM steel,to investigate the applicability of existing corrosion model for the RAFM steel and modify the corrosion model in still water,relative experiments were carried out.The experiment consists of two parts: flowing water corrosion experiment and still water corrosion experiment.The experimental materials for flowing water corrosion experiment were CLAM,CNS-I,SCRAM-9,which all are newly developed RAFM steels in CHINA,also,T91 was chosen as contrast material.Experimental parameters were set with reference to the design condition of the primary water coolant of ITER,temperature was set to 150?,the dissolved oxygen content was <0.01mg/kg,PH is 7(20?),the conductivity was 0.055?S/cm and the flowing velocity of the water was 6m/s.The experiment contained eight time intervals,and 1500 h was the longest interval in this experiment.For still water corrosion experiment,3500 h was the longest interval in this experiment,and remaining parameters were the same as those of flowing water corrosion experiment except for the flowing velocity of the water.After experiments,part of the samples were analyzed and examined by weight change method,SEM(Scanning electron microscopy),EDS(Energy-dispersive X-ray spectroscopy)and XRD(X-ray diffraction),and weight gain curves,weight loss curves,corrosion rate curves,oxide morphology and structure in specific environment were gotten.For all materials the results indicate that as time went on,the weight gain can`t show the corrosion kinetics characteristics,the weight loss increased,while the corrosion rate decreased.Weight loss and corrosion rate follow rule of power function.In flowing water corrosion experiment,the average corrosion rate of CNS-I,SCRAM-9,CLAM and T91 were 0.0098g/(m~2·h),0.0096g/(m~2·h),0.009g/(m~2·h)and 0.0076g/(m~2·h),which showed that T91 corrosion resistance is better than other three RAFMs.In still water corrosion experiment,the average corrosion rate of CLAM and T91 were 0.001g/(m~2·h)and 0.0014g/(m~2·h),which showed that CLAM corrosion resistance is better than T91.The corrosion model at home and abroad were partly investigated and summarized,formula of corrosion rate calculation in model were derived.For flowing water corrosion experiment,models combining with the corrosion environment parameters,experimental sample and some experimental results were adopted to calculate the theoretical values of corrosion rate.For still water corrosion experiment,the exsiting model were modified to calculate the theoretical values of corrosion rate.The theoretical values were compared with the experimental values,and results showed that we can adopt the corrosion model to assess the corrosion rate of material in specific environment by selecting reasonable value of porosity.