Numerical Simulation Of Shaft Jamming Of One Primary Pump In Fast Reactor

The geometric size of the pool sodium cooling fast reactor is large,and the internal components of the reactor are more complex and the structure is more complex,which makes the flow and heat transfer of the hot sodium pool and the cold sodium pool in the system complicated.Under the accident condition of a one-loop pump stuck shaft,the complex structure in the reactor leads to a high degree of uncertainty and asymmetry in the flow field and thermal field of the system,and the backflow of coolant through the pressure pipe may occur.Most of the existing one-or two-dimensional programs are based on the theoretical operating state of the reactor.Unable to accurately solve the 3D thermal hydraulic properties of fast reactors.In this paper,the calculation model range is determined for CEFR(China Experimental Fast Reactor),the full-power operation condition and the stuck shaft working condition of the first-loop system.With the help of porous media model and contact thermal resistance method,the conceptual model is obtained after simplifying the calculation model.The overall grid adopts the Poly method in Fluent Meshing,sets the flow resistance,heat source power and cooling power in key areas,simulates the full power operation condition of the first loop of the fast reactor based on the Coupled algorithm,compares the simulation results with the calculation results of the one-dimensional program,and verifies the grid independence,and finally obtains a suitable mesh model.Based on the full-power operation condition of the sodium-cooled fast reactor first-circuit system,a three-dimensional numerical simulation of the accident condition of a first-circuit pump jam shaft was carried out,and the three-dimensional thermal hydraulic parameters of the whole reactor were obtained.The calculation shows that the flow field and thermal field distribution in the reactor have obvious asymmetry under the jamming accident condition.The thermal stratification phenomenon of the hot sodium pool is obvious,and the reverse flow phenomenon occurs at the fault loop exit,fault loop pressure pipe,intermediate heat exchanger and other positions of the main container cooling system.Among them,the flow ratio of normal loop sodium pump pressure pipe,core outlet and fault loop sodium pump pressure pipe is 3:2:1.The fault loop intermediate heat exchanger has a total of 70 seconds from the beginning of the backflow to the strong backflow phenomenon.By establishing the calculation model of the first circuit system of sodium-cooled fast reactor,the numerical simulation of the stuck shaft working condition is carried out,and the three-dimensional thermal hydraulic characteristics under the accident condition in the reactor are obtained.It provides an important reference for the design and simulation analysis of the structure in the reactor.