Performance tests of helium circulator under abnormal cooling conditions - 18523

Helium circulator is one of the key equipment of High-temperature Gas-cooled Reactor Pebble-bed Module (HTR-PM) and the unique rotating equipment of primary loop. It transports heat generated by fission reactions from reactor core to steam generator by forcing helium circulating in primary loop. As the study on the characteristics of helium circulator in HTGR was limited and the advanced designs integrated with many new technologies, a prototype of helium circulator was manufactured. It was supported by Active Magnetic Bearings (AMBs), and was assembled in a pressure vessel. The prototype was tested in Engineering Test Facility - Helium Circulator (ETF-HC), which is a full scale, rated flow rate and power, engineering test loop. Although performance tests under normal operation condition were successfully fulfilled, the complete features and performance still need further verification, especially for abnormal cooling conditions. Thus performance tests under abnormal cooling operation conditions were carried out. Tests such as temporary coolant loss of motor and AMBs cooler and abnormal high-temperature cooling water condition were fulfilled. All performance tests results showed that helium circulator met the entire requirement of HTR-PM plant under abnormal cooling conditions and validated its safety and reliability. (authors)