Abstract: Water lubricated thrust bearings in reactor coolant pumps (RCP) experience thermal transient processes during the accident conditions. A thermal-solid coupling model is developed for the thermal transient processes by finite element method. Based on the developed model, conventional double-layer and triple-layer thrust pads are analyzed to obtain the surface deformation during the thermal transient processes. In particularly, the effect of the thickness of heat insulation layer in triple-layer pad on surface deformation is discussed. Subsequently, several suppression methods to reduce the concave deformation of the pad surface are analyzed. The simulations indicate that the leading mechanism of forming the concave deformation is the uneven distribution of tile surface temperature field during the thermal transient processes. With this understanding, a new type of thrust pad having the edge of the thrust pad surface wrapped is proposed, which is verified by simulation to efficiently reduce the concave deformation during the thermal transient processes. This work provides a new thought to design the thrust pad of the water lubricated thrust bearings in RCP.

Key words: thrust bearings, thrust pad, thermal transient, pad surface deformation