Research On Simplified Method For Calculating Thermal Deformation Of The Pump Support In The Sodium-cooled Fast Reactor

In the sodium-cooled fast reactor,the supporting structures of the main pump,intermediate heat exchanger(IHX),independent heat exchanger(DHX)and other equipment in the upper space of the sodium pool of the primary container penetrate the upper head of the primary container.The upper region above the sodium level is covered with argon.On the normal operating conditions of the reactor,high-temperature liquid sodium transfers heat to these upper structures through natural convection,thermal radiation,etc.In order to evaluate the completeness of these structures,their temperature distribution and thermal deformation need to be calculated.At present,numerical simulation methods are generally used to obtain the temperature field and thermal deformation of these structures,while traditional numerical simulation needs to establish three-dimensional models,and it takes a lot of time to structure meshing,boundary condition investigation and other research steps,and the calculation results are often difficult to obtain experimental verification.Therefore,it is urgent to establish a set of simplified calculation methods for temperature field distribution and thermal deformation of the upper structure of the hot sodium pool with quick and experimental verification in the engineering design,so as to conduct preliminary trial calculations for the research on the thermal deformation of the pump support in the sodium-cooled fast reactor.In this study,a simplified calculation method for temperature distribution and thermal deformation of the pump support in the sodium-cooled fast reactor is proposed,and local 2D modeling calculation is used instead of detailed 3D modeling calculation.The local 2D modeling calculation will model the symmetrical surface of the pump support radially along the sodium-cooled fast reactor,separating the complete argon space into two independent enclosed spaces to ignore the influence of argon flow in the annular loop.The circular flow of argon in the annular gap helps to reduce the temperature difference between the main pump support neck near the core side and away from the core side,and will also help reduce the difference in its thermal deformation,ignoring the influence of the ring flow will make the calculation of the thermal deformation of the pump support in the sodium-cooled fast reactor conservative.The overall calculation scheme will be carried out in two steps.First of all,the experimental value of the temperature at the measuring point of the pump support in the scaled test bench is compared with the simulated value of the corresponding position of the two-dimensional model of the pump support in the scaled test bench,which illustrates the rationality of the simplified calculation method.Then,on the basis of comparing the experiment and simulation calculation of the scaled test bench,the method is further applied to the calculation of the thermal deformation of the pump support in the sodium-cooled fast reactor.Comparing the simulation calculation results of the two-dimensional model and the three-dimensional model of the thermal deformation of the pump support in the sodium-cooled fast reactor,the applicability and conservatism of the simplified calculation method in the calculation of the thermal deformation of the pump support in the sodium-cooled fast reactor are further verified.The calculation results show that the temperature simulation value of the two-dimensional model of the pump support in the scale test bench is slightly higher than the experimental value at the measurement point of the thermocouple on the pump support,but the error is less than 4%.Therefore,the simplified calculation method of local two-dimensional modeling is reasonable,and this method can be applied to the calculation of the thermal deformation of the model of the pump support in the sodium-cooled fast reactor.The thermal deformation difference between the two sides of the main pump support neck in the two-dimensional model of the main pump in the sodium-cooled fast reactor is 4.0802 mm,and the thermal deformation difference between the two sides of the main pump support neck in the three-dimensional model of the pump support in the sodium-cooled fast reactor is 3.6092 mm,The error of thermal deformation difference is 0.471mm.Therefore,the simplified calculation method of local two-dimensional modeling is reasonable,and its calculation results are conservative.