Background: The Molten Salt Reactor (MSR) is one of the six advanced reactor types for future nuclear energy systems in the Generation IV International Forum (GIF)

possessing the advantages of good neutron economics

inherent safety

processing online

nuclear nonproliferation

etc. Due to the fluid fuel

a part of delayed neutron precursors drifts out of the reactor and decays in the loop

which is different from the solid-fuel reactor. Purpose: The distribution of delayed neutrons with different fuel velocity for Molten Salt Reactor Experiment (MSRE) is analyzed to provide reference for safety design of MSR. Methods: Based on the neutron kinetics and approximate method of homogeneous reactor

a distribution model of delayed neutron was presented. This model is applied to the distribution study of delayed neutrons with different fuel velocity. Results: The number of delayed neutrons in a core radius of 20 cm was more than that in a core radius of 30 cm. When the flow velocity of fuel decreased by a half

the discrepancy of delayed neutrons between the fifth-group and sixth-group precursors is within 6%. Conclusion: The number of delayed neutrons is increasing toward the center of reactor core. The group of delayed neutron precursors with shorter half-time has little effect on the flow velocity of molten salt.Cited