Tube defects monitoring method during post weld heat treatment for nuclear steam generator

摘要

PURPOSE: A method for measuring a deformity of a tube in a heat treatment process after welding a nuclear powered steam generator on a real time basis is provided to remarkably enhance the quality of a nuclear powered steam generator because a deformity of a tube generated by interference caused by a thermal strain of a tube and a tube support plate can be prevented. CONSTITUTION: A method for measuring a deformity of a tube in a heat treatment process after welding a nuclear powered steam generator is as follows. A correlation of a partial strain of a tube(4) and a voltage of an eddy current test signal is obtained. A correlation of the partial strain of the tube and a strain angle of a tube support plate(5) is obtained. A relation of a critical strain angle of the tube support plate and a critical partial strain of the tube corresponding to an allowable voltage is obtained. A deformity of the tube from a result of the strain angle of the tube support plate is monitored on a real time basis. A shape of the partial strain of the tube is figured out through a finite element analysis in a step of obtaining the correlations and tube specimens where a partial strain of a shape similar to the figured shape is generated are manufactured.