Macroanalysis

microanalysis for the crack and composition analysis for chemical deposits on inner tubes are conducted. It demonstrates that main reasons of water wall leakage of boiler No.1 at Shimon plant are as follows: the mechanical property of material reduced due to feed water depositing and heat transfer deterioration

the thermal fatigue of water wall because of alternative thermal stress during unit operation

startup and shutdown. As a result

Specific preventative measures of water wall tubes failure are put forward