To predict the thermal-hydraulic(T/H)parameters of the reactor core for liquid-metal-cooled fast reactors(LMFRs),especially under flow blockage accidents,we developed a subchannel code called KMC-FB.This code uses a t...To predict the thermal-hydraulic(T/H)parameters of the reactor core for liquid-metal-cooled fast reactors(LMFRs),especially under flow blockage accidents,we developed a subchannel code called KMC-FB.This code uses a time-dependent,four-equation,singlephase flow model together with a 3D heat conduction model for the fuel rods,which is solved by numerical methods based on the finite difference method with a staggered mesh.Owing to the local effect of the blockage on the flow field,low axial flow,increased forced crossflow,and backflow occur.To more accurately simulate this problem,we implemented a robust and novel solution method.We verified the code with a low-flow(~0.01 m/s)and large-scale blockage case.For the preliminary validation,we compared our results with the experimental data of the NACIE-UP BFPS blockage test and the KIT19ROD blockage test.The results revealed that KMC-FB has sufficient solution accuracy and can be used in future flow blockage analyses for LMFRs.展开更多
A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from...A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250℃, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000℃/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.展开更多
文摘To predict the thermal-hydraulic(T/H)parameters of the reactor core for liquid-metal-cooled fast reactors(LMFRs),especially under flow blockage accidents,we developed a subchannel code called KMC-FB.This code uses a time-dependent,four-equation,singlephase flow model together with a 3D heat conduction model for the fuel rods,which is solved by numerical methods based on the finite difference method with a staggered mesh.Owing to the local effect of the blockage on the flow field,low axial flow,increased forced crossflow,and backflow occur.To more accurately simulate this problem,we implemented a robust and novel solution method.We verified the code with a low-flow(~0.01 m/s)and large-scale blockage case.For the preliminary validation,we compared our results with the experimental data of the NACIE-UP BFPS blockage test and the KIT19ROD blockage test.The results revealed that KMC-FB has sufficient solution accuracy and can be used in future flow blockage analyses for LMFRs.
文摘A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250℃, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000℃/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.
