FAC Management Strategy from the Stage of Construction

Topic :

Wall thinning management

ABSTRACT :

 The operating nuclear plants in Korea are 20 units and 6 units, such as SKN-1,2,3,4 and SWN-1,2, are under construction. In addition, 4 units are scheduled for construction by 2030. In the terms of FAC management for the carbon steel piping of the plants, CHECWORKS program have been adapted since 1998 and currently used CHECWORKS Version 3.0. Even if the catastrophic failures related to wall thinning, such as Surry-2 and Mihama-3, have not been experienced in Korea, the operating plants have also been experienced wall thinning problems caused by FAC. The FAC management strategy of Korean plants is composed of five stages, which are the design, construction, pre-operation, commercial operation and operational feedback stages. The pipe wall thickness, material and layout against FAC are reflected in the stage of design. The construction of CHECWORKS DB and the determination of UT inspection points are performed in the stages of construction and pre-operation. One of the most important factors is to take the initial thickness data for FAC susceptible components, which should be taken prior to commercial operation. The initial thickness data will be used as a important baseline to determine the pipe inspection cycles and the replacement timing.