‘Hot Reheat Line’, which is the reheat steam pipeline among power plant pipe system supplies the reheated steam to the turbine and maintains the constant levels in temperature, pressure and flow rate through equalizing pipeline connected by branching from the main lines. As such a type of piping is the basic configuration of the power plant pipe, most of the coal-fired power plants have the same configuration, which thereby makes damages take place in the similar section and pattern.
Similar pipe damages used to occur so repeatedly over time that the only way available would be to adjust the support devices and restore the damages tentatively through repair welding, as a sort of follow-up measure. In this study, it is assumed that the most integral state of the piping should be those initially installed based on the design, so that the pipelines in the Cold condition could be positioned close to the initial construction state, under which the changes of the stress distribution responding to changes of pipe positions would be confirmed by using AutoPIPE, a commercial pipe analysis program. thereafter, the strain gauges for high-temperature purpose are put up on the highly stressed sections to acquire the data concerned, with which the verification and evaluation processes could be carried out against the results of program analysis.