Abstract: In view of the field uncovering operation of steam turbine of a nuclear power unit, the center of low and low pair wheels and the clearance of flow through half cylinder are measured, and the data of the test process are analyzed, the test results provide reference for the following work of uncovering cylinder and equipment installation of the same type of steam turbine.

Key words: nuclear power turbine, low pressure cylinder, uncovering the cylinder, coupling center, flow gap