Background: Transient curves are essential for the stress analysis of related equipments in nuclear power plant (NPP). The actually operating data or the design transient data of a NPP usually consist of a large number of data points with very short time intervals. To simplify the analysis

transient curves are generally piecewise linearized in advance. Up to now

the piecewise linearization of transient curves is accomplished manually. Purpose: The aim is to develop a method for the piecewise linearization of transient curves

and to implement it by programming. Methods: First of all

the fitting line of a number of data points was obtained by the least square method. The segment of the fitting line is set while the accumulation error of linearization exceeds the preset limit with the increasing number of points. Then

the linearization of subsequent data points was begun from the last point of the preceding curve segment to get the next segment in the same way

and continue until the final data point involved. Finally

averageing of junction points is taken for the segment connection. Results: A computer program named PLTC (Piecewise Linearization for Transient Curves) was implemented and verified by the linearization of the standard sine curve and typical transient curves of a NPP. Conclusion: The method and the PLTC program can be well used to the piecewise linearization of transient curves

with improving efficiency and precision.Cited