Abstract: In neutral beam injector (NBI) system, it is important to choose proper ferromagnetic material to inhibit fault current and consume fault energy. To find appropriate type of material, the features of some typical ferromagnetic materials were fully analyzed. The test platform was established to conduct short circuit experiment with 1:10 scale for choosing the optimal material. Simulations were implemented to compare the effects of distributed core snubber with concentrated core snubber. The results show that the developed distributed core snubber could ensure 80 kV neutral beam injector system running safety and the fault energy could be limited to five joules.