Comprehensive Research Facility for Fusion Technology (CRAFT) is a technology development and validation platform for fusion technology in China. Neutral beam injection is one of the most important auxiliary heating and current drive methods in magnetically confined controlled fusion. Consequently, a negative ion based neutral beam injector (NNBI) testing facility with a beam energy of 400 keV is being developed in CRAFT. The core snubber, which provides an equivalent parallel resistance and inductance, will be used as the main surge suppression method for the CRAFT NNBI power supply system. In this paper, a core snubber for CRAFT NNBI based on Fe-based amorphous alloy is designed. The transmission line resistance, inductance, and capacitance of the high-voltage circuit have been considered during the design process. The snubber is made thin and long for even weight distribution while ensuring choke capacity. One of the snubber units was tested on the test bench. The test results indicate that the choke capacity of the snubber meets the requirement and can achieve significant suppression of peak ignition current and oscillation.
© 2025 Author(s). Published under an exclusive license by AIP Publishing.