Neutronic Calculation And Analysis Of CFETR Helium Cooled Ceramic Breeder Blanket

China Fusion Engineering Test Reactor(CFETR)is a superconducting Tokamak test reactor that is currently being designed to verify the tritium self-sustaining,plasma steady-state operation and so on.As the core component of the fusion reactor,the blanket is responsible for the important role of tritium breeding,energy conversion and radiation shielding,Therefore,the blanket design is an important step in the overall design of the fusion reactor.The neutronics analysis for the blanket design is to verify the rationality and engineering feasibility of the blanket design,and on the other hand,to ensure the safe operation of the reactor and the safety of the radiation after the shutdown.In this paper,CFETR helium cooled ceramic breeder blanket is taken as the research object.Firstly,three-dimensional neutronics model is carried out according to the design.Then,the CFETR helium cooled ceramic breeder blanket is carried out from the aspects of neutron transport and neutron activation.The calculation of neutron transport is carried out using the Monte Carlo transport program MCNP and the nuclear database FENDL2.1 published by the International Atomic Energy Agency,the research contents include tritium breeding ratio,neutron wall loading,neutron flux density,nuclear heat distribution,helium production rate and atomic displacement damage.The results show that the CFETR helium cooled ceramic breeder blanket scheme has good tritium breeding capacity,which satisfies the requirements of tritium self-sustaining,and has good neutron shielding performance because the neutron flux descent is in accordance with the expectation.In addition,the helium production rate and the atomic displacement damage of the blanket materials during the reactor operation are also within the acceptable range,indicating that the anti-radiation performance of the blanket materials is good.The neutron activation analysis is performed using the European Activation Analysis Program FISPACT and EAF nuclear databases,the study includes radioactivity,decay heat and shutdown dose rate.The results of activation studies show that the radioactivity generated in the blanket at the beginning of the reactor shutdown is mainly from the tritium produced by the reaction of neutron and tritium breeder Li4Si04;the decay heat is mainly caused by the radionuclide 56 Mn and 55 Fe generated by the activation of structural material Eurofer steel;the radiation dose is highest on the first wall,the shutdown dose rate can be reduced to the remote operation dose rate level lOmSv/h in several decades after the reactor shutdown,and hundreds years will be taken to achieve the manual operation dose rate level 10?Sv/h.