HFIPS has recently successfully debugged the CRAFT Negative Neutral Beam Injection (NNBI) 1kW@4.5K helium cryogenic system. This cutting-edge system met all the required performance indicators, marking a significant milestone in the development of fusion reactor critical systems.
The NNBI helium cryogenic system plays a vital role in the construction of CRAFT. It provides crucial low-temperature cooling conditions necessary for testing and operating the NNBI test equipment, beam source test platform, and super high pumping speed cryopump.
Comprised of several components, including the helium compressor system, 1kW@4.5K refrigerator cold box, liquid helium Dewar, distribution valve box, helium recovery and purification system, helium storage system, liquid nitrogen system, cryogenic transmission line, and cryogenic control system, the NNBI helium cryogenic system offers comprehensive functionality.
At its core, the system features a 1kW@4.5K helium refrigerator that is pre-cooled by liquid nitrogen. The refrigeration cycle employs three aerodynamic gas bearing turbine expanders to achieve a cooling capacity of 4.5K in the temperature zone. Additionally, the refrigerator incorporates two 80K cryogenic absorbers designed to switch and regenerate each other, ensuring continuous long-term operation.
This work provides essential support for the development of NNBI system and establishes an engineering foundation for the design, construction, and operation of cryogenic systems for neutral beam implantation.
