Endurance test of full-scale mock-up helium circulator for HTR-PM

The High-temperature Gas-cooled Reactor Pebble-bed Module (HTR-PM) will be built as the world's first pebble-bed modular HTGR commercial demonstration plant through the Chinese National Science and Technology program. HTR-PM is expected to generate electricity during 2018 in Shidao Bay, China. Helium circulator is a critical component required for HTR-PM to circulate reactor coolant through the reactor core and steam generators. Since there is no engineering experience with this circulator, a full-scale mock-up was manufactured for tests. The whole parameters of the mock-up were as same as the actual plant circulator for HTR-PM. The mock-up design is a vertical layout with its rotor supported by active magnetic bearings. The whole mock-up including motor and cooler are sealed in a pressure vessel. Since the mock-up is a large mechanical-electrical system and the design includes many new systems, extensive tests are needed to ensure its safety and reliability. An Engineering Test Facility for Helium Circulator (ETF-HC) was then built in Institute of Nuclear and New Energy Technology (INET). Firstly, factory nitrogen tests were conducted by the manufacturer and the customer. After the successful factory tests, the mock-up was delivered to INET to be tested on ETF-HC. One and a half years were spent for the helium endurance tests, including time spent on resolving several helium sealing problems. The mock-up run continuously for 50 h at the rated conditions. Fifty service cycle tests were also conducted. More than 500 operating hours were accumulated during the endurance tests. The final performance shows that the mock-up of helium circulator meets the design requirements and is reliable.