Abstract: For the LOCA qualification test of residual heat removal pump motor of CPR1000 unit, the key technology are to realize the thermal shock in a LOCA test vessel of a test facility and the smooth running of the motor. A great flow rate saturated steam source with pressure 1MPa was introduced to the facility, which resulted in the critical steam flow during the shock process of the test. Combining the source with reasonable system design of the facility led to the shock about 12 seconds. A hydraulic dynamometer was employed as the motor load. The motor, installed inside the vessel, was connected with the dynamometer outside the vessel by an intermediate shaft. The position of the motor shaft and the intermediate shaft compared with that of dynamometer shaft changed continuously due to different temperature between inside and outside the vessel and different material. To reduce the vibration of the drive system, the intermediate shaft was fixed on the vessel wall, and larger deflection couplings and the pre-adjustment installation were adopted.During the test, the motor ran smoothly. The test for the full-scale motor with full load was conducted successfully.