35000 h of operational experience with the drum life assessment system in Trbovlje

This paper deals with the operating experience of the power plant life asse ssment system observing the boiler drum only. The scope of the assessment s ystem is the range of a thick wall vessel operating at temperatures below 4 00 degrees C. The system was initiated by boiler drums with the same materi al properties having suffered ruptures during pressure test after urgent re pairs on other steam generating equipment. The main concern was focused on the high life reduction during the ambient temperature 1.5 x p pressure tes t, when the actual damage cases occurred. With growing experience the evalu ation of fatigue is extended to normal operation, start up and shut of peri ods. The systems have been enhanced and have successfully reduced the opera tional fatigue sources. The resulting improvement in material life use has been enhanced 4-5 times over the results from the first year in operation. (C) 1999 Elsevier Science S.A. All rights reserved.