Design aspects and achievements of active magnetic bearing research for HTR-10GT

The project of direct helium turbine power conversion cycle of the 10 MW high-temperature gas-cooled reactor (HTR-10GT) program is to set up a direct helium cycle with a helium turbine and generator system to replace the current heat exchange system and steam cycle. This program is supported by Chinese government and will be assumed by the Institute of Nuclear and New Energy Technology (INET) at Tsinghua University of China. Instead of ordinary mechanical bearing, active magnetic bearing (AMB) has been chosen to support the helium turbine and generator rotors in this project. Until now, no experience on AMB running in reactor or in helium environment has been performed. So, the AMB research and experiment would at least go through several convictive stages to finally match the requirements of the HTR-10GT program. The magnetic bearing laboratory of INET has begun to work on this project in 2002. Till now, a control method of exceeding two bending frequency has been successfully tested on a small test rig. A high load AMB for 3500 kg generator rotor suspension has been constructed and long-term running tests have just been finished. In addition, the general design of a high-temperature AMB test rig has already been finished. All these achievements on AMB research show that we are well on the way to the ultimate goal of direct helium cycle. Today the final joint experiment of turbine and generator is already under detailed planning.