Abstract：To check the vane profile of the diffuser of a 1 000 MW reactor coolant pump (RCP), which is machined by using numerical control machining technique, a set of approaches for measuring and assessing vane profile of a throughflowcomponent are proposed. Through adopting a reverse engineering analysis software PolyWorks together with a three coordinates measuring machine, the three coordinates of vane pressure and suction sides of the diffuser are measured and the root mean square of deviation of the measured profile from the designed one is figured out. Based on a statistic and theoretical analysis on the measured profile data of the vane pressure and suction sides near the vane leading and trailing edges, a formula for estimating deviation angel of pressure or suction side profile Δβ is put forward. Moreover, a correlation for deviation angle between two vanes Δφ, and a correction formula for deviation of individual vane profile K are established. This set of methods can accurately and effectively inspect the vane profiles of a hydraulic machine and assure each profile to have the same wrap angle. Based on the measurement and evaluation of vane profiles of the diffuser of the RCP for Fuqing and Fangjiashan Nuclear Plant, all the deviation errors are allowable. As a result, the tested performance of the RCP shows that the flow rate and head deviate from the design specifications by ±2.5% and ±1.5%, respectively.
