Development Of Hydraulic Design Code For Fast Reactor Hydraulically Suspended Passive Shutdown Subassembly

For sodium cooled fast reactors(SFR),hydraulic suspended passive shutdown subassembly(HSPSS)can be used to work as an additional passive shutdown method.In order to improve the Inherent safety of SFR,HSPSS be used to shutdown the reactor on time during the unprotected loss of fluid(ULOF)accident which based on the anticipated transient without scram(ATWS).The rod drop curve of HSPSS that the most important parts of shutdown system is the key of this process.The main work and conclusions for HSPSS of this paper as following:(1)On the basis of HSPSS’s structural characteristics,analyze the HSPSS from two aspects(hydrodynamic and kinematics),based on the Relationship between flow distribution and the differential pressure distribution for the flow channels in HSPSS,built the model of HSPSS Hydraulic calculation,with correction of the kinematics for the moving body.This model is an method base on the Quasi steady state analysis,is applied to the case when the moving body moves slowly.(2)Base on the model of HSPSS Hydraulic calculation,design and develop the passive shutdown subassembly design program which be used to calculate the drop performance of the moving body.(3)Base on the feature of each module of the PSSD program,did some test for the submodules of PSSD program.The results show that each submodule of the program meets the design requirements.Calculated 4 different case,Verified the result of PSSD is rational and valid.(4)2 kind of experiment(Critical flow experiment and Rod dropping experiment with Coast down curve of flow)conducted to test the accuracy and reliability of PSSD program,analyze the result and then get conclusion:(1)The program can accurately predict the falling rod characteristic curve of the moving body;(2)The program can accurately calculate the falling rod characteristic parameters of the moving body.