Damaged T23 Reheater Tube

[91RepairGuy]

Our HRSG just recently experienced a perforated plate failure. Several sections of the perf plate broke off and damaged the front of the Reheater tube panels. We discovered flat spots and irregular surfaces as well as fin damage. One tube had a thicknesses of 0.116 and 0.119 and another damaged tube had a thickness of 0.120.

The data sheet for reheater tubing specified 2" dia tubing x 0.120 minimum thicknes, SA-213-T23. The thickness range recorded during UT varied from 0.116 to 0.185.

With two tubes being below minimum thickness and one tube at minimum thickness, should we be concerned? The damaged tubes are the first row of tubes downstream of the gas turbine and behind the perf plate. Will there be high stress areas at the damaged areas? Your advice is greatly appreciated.

 

[metengr]

Since these are considered locally thinned areas (LTA) from mechanical damage, and you verified the LTA's have the wall thickness as stated above, I would perform a surface nondestructive test (NDT) of the LTA. If the NDT results show no indications, I would not be concerned.