抄録
Many chemical plants in Japan were constructed in high economic growth period and still works even though designed life of equipment is over. In recent years, the number of accident due to aged degradation has been increasing Risk Based Maintenance and Inspection, one of the maintenance conceptions, has been introduced to petrochemical and power plant. Risk is defined as a function of "Consequence of Failure" and "Probability of Failure". Risk of all equipment is analyzed and then maintenance and inspection are planed m order to reduce total risk in spite of limited maintenance budget. Chemical plants in Japan prepare new standard for maintenance based on risk. FRP (Fiber Reinforced Plastic) is used as pipe, tank and duct m chemical plant because it has corrosion resistance and strength. However, FRP might degrade slowly over a few decades Since FRP and the other organic material have been used rather recently, there is not enough information of degradation compared with metal. Furthermore, effective non-destructive test (NDT) on FRP is not yet established. Hence, it is important to apply a NDT method on FRP equipment used m chemical plant and to ensure its inspection effectiveness based on Risk. In this report, the degraded FRP tank m chemical plant was inspected by UT (Ultrasonic Test) and inspection effectiveness was evaluated. Consequently, inspection for the empty tank is more effective than the full tank.
