| Breeding blanket is the core component of a fusion reactor,its main functions are to produce tritium for self-sustaining,to bring the fusion energy out for electricity generation and to shield the neutron radiation.In this paper,based on the characteristics of Water Cooled Ceramic Breeder(WCCB)blanket layering arranged along the radial direction,a method of "3D+1D+3D"is proposed.In the initial stage of iterative optimization,the 1D cylindrical neutronic model and 2D thermal hydraulic model are used to perform the analyses.The efficiency of blanket design is improved from the perspective of simplifying the analysis model.Based on this goal,an integrated optimization design platform for multiple physical fields is developed,covering three fields of neutronics,thermo-hydraulics and structure analyses.After the definition of initial blanket radial arrangement and the constraints by clicking on the Graphical User Interface(GUI),the complete operations in the blanket design can be automatically achieved,such as writing MCNP input file,creating a CFD and ANSYS geometry and numerical model,defining the material type,applying the boundary conditions,data transmission between the different programs and data processing,etc.,it can help the user to avoid the unnecessary repetitive work,greatly improve the working efficiency.The radial distribution of nuclear power density is studied.When the blanket materials are simplified as the single material of tritium breeder,the relative deviation between exponential function and the actual distribution is only 8%,and it becomes 16.7%in breeder unit after the cooling plate is inserted.Based on the exponential distribution of nuclear power density,the mathematical model of nuclear thermal coupling for breeder unit is established,and the linear relationship between the peak temperature and the radial size of tritium breeder is obtained.This relationship is implanted into the platform,and the optimal radial building can be quickly determined.This platform is used to optimize the radial layout of all the blankets in the CFETR.Based on the optimal radial layout,3D neutronic model is established,and the overall TBR is 1.21,which achieves the tritium self-sufficiency.The full 3D outboard blanket model located on the equatorial plane is established,and the fluid-solid coupling analyses is carried out.Compared with the "3D slice" model,the boundary conditions are fewer,and the results are more reliable.The results satisfy with the thermal hydraulic requirements,including the temperature field of each component,the flow rate of each channel and the total pressure drop.The validity and accuracy of the"3D+1D+3D" method and the integrated optimization design platform for multiple physical fields are verified by comparing the the neutronics and thermal hydraulic results between low and high dimensions.As an important part of blanket,the first wall is directly exposed to the high radiation heat.The characteristics of enhanced heat transfer and flow resistance of FW in WCCB blanket is analyzed.Under the newly results of heat flux distribution in European DEMO,the heat removal ability and thermal safety of FW in water-cooled liquid lithium lead cladding(WCLL)is evaluated.Furthermore,the channel structure and cooling system are optimized.It is found that the limiter or special baffle plate should be placed at the upper X point in DEMO to reduce the heat flux below 1.34MW/m2.In addition,the present thermal design safe enough to avoid the Departure from Nuclear Boiling(DNB).For the requirements of CFETR operating in two phases with different power(200MW and 1GW),the WCCB blanket which can endure the two fusion power simultaneously is developed.This can avoid the operation of replacing the blanket during the conversion of the high and low power mode of the fusion reactor,materials such as tritium breeder,neutron multiplier and steel structure can be saved to improve the operation economy of CFETR. |
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