Evaluation of corrosion on generating tube in water tube boiler

Kawasaki, Ichio ; Ishiyama, Toru ; Usui, Masahiro*; Murakami, Toshinori*

There are 4-boiler systems in Nuclear Fuel Cycle Engineering Laboratories. These has been operated in over 16 years. In one of them, the leakage that occurred at generating tube was found at Dec. 2011. The investigation of the leakage was carried out. The leaked generating tube was removed, and the part of leakage was cut off, and the deposit around the leakage was removed to analyze the cause of leakage. The analysis was carried out by SEM,EDX,WDX and XRD. etc. Elements of the deposit accumulated to surface of water drum are mainly O, Fe and S, and then many of component was sulfide. Therefore it seems that generating tube was corroded by sulfide. In future plan, operating method will be review to reduce the deposit, and check item will be selected to find the deposit earlier. This report was described about variously activity for the investigation and a future action.