Impact of the beam pressure on the free surface of the liquid lithium target of fusion neutron sources

•We have developed a new model describing the thickness of the “beam-on” liquid target of IFMIF-type fusion neutron sources like A-FNS and IFMIF-DONES.•We have applied the developed model to calculation of the target deformation due to the intense beam injection.•We have found that the deformation of the target thickness is negligibly small under the reference design conditions of A-FNS.•The analytical results presented here may be used for a benchmark of more complicated CFD simulation for the “beam-on” target design of IFMIF-type fusion neutron sources. Accelerator-driven fusion neutron sources, e.g. Advanced Fusion Neutron Source (A-FNS) and DEMO Oriented Neutron Source (IFMIF-DONES), are being designed, based on the achievements and lessons learnt from the IFMIF/EVEDA project. The purpose of the study is to analytically evaluate the deformation of the lithium free surface, potentially created by the intense beam injection. We have developed a two-dimensional (2-D) fluid model of the “beam-on” target of an IFMIF-type fusion neutron source by extending the phenomenological 2-D model of the Li target flow of the EVEDA Lithium Test Loop (ELTL). We have derived, from the newly developed model, a practical and analytical formula of the thickness of the “beam-on” target in the flow direction with accounting for the beam injection effect. We have also evaluated the thickness of the beam-on target of A-FNS as an example of application of the derived formula. The evaluation indicates that under the reference design conditions of the accelerator and beam-on Li target of A-FNS, the deformation of the free surface of the target by the beam injection is negligibly small. The analytical results presented here may be used for a benchmark of more complicated CFD simulation for the “beam-on” target design of IFMIF-type fusion neutron sources like A-FNS and IFMIF-DONES.