THE FAILURE EVALUATION AND APPLICATION OF POWER PLANT BOILER MEMBRANE TYPE WATER-COOLED WALL BASED ON RISK-BASED INSPECTION

In recent years, Ultra supercritical power plant boiler in China is developing very rapidly, therefore,using the RBI risk evaluation method to carry out inspection of large power station boiler is very necessary. Operation practice shows that the membrane type water-wall is one of the main risk parts of large power plant boiler. Research has shown that typical failure area of membrane type water-wall is layer nearby the burner; Most of failure positions are in high heat flux region, the fins weld joint; Failure mechanism is comprehensive factors,such as,the welding deformation, weld defects and fins weld crack, foreign bodies blocked, blowing loss thinning, short-term over temperature overheating. On this basis, the application of RBI risk assessment method, analyzed the risk level and failure consequences of a power plant boiler membrane type water wall, the risk matrix is obtained, proposed the,corresponding test strategy, for the RBI technology application to evaluation of power plant boiler components provides a new method of failure risk.