Defect Simulation and Qualification of Visual Technique for Inspection of Vessels Internals
T. Zetterwall, M. Ryf, B. Thoren, SQC, Sweden
ABSTRACT
This paper describes briefly how the qualification process will work in Sweden and will also give an example of qualification of visual technique for inspection of vessel internals. During year 2000 the Swedish utilities and SQC together wrote a chart over the process from the need of inspection to experience after inspection. The target with this process is that all involved parts have to know what to do and when to do it in the qualification process. SQC has out from this process performed a generic time schedule for all activities and for the activities where the qualification body will be involved. The first one extends over 1,5 to 2 year and only the qualification activities over about 1 year. In accordance to this process The Swedish utilities, SQC and Westinghouse Atom TRC have performed a qualification of a generic procedure and personnel for visual technique. Since this was a new method to qualify, it took quite some time to agree on the scope of the inspection and qualification. The technique described here is CCD-camera under water on vessel inside and internals. Three major obstacles were identified. One was how to simulate surface conditions, another was how to simulate and measure relevant defects and the third was the restrictions that had to be applied to the technique. Practical trials did resolve many of the problems. Rather unusual test specimen have been designed and used in the process. In the end the procedure and personnel got qualified and successful inspections have been performed in real situations.
Publication Source: 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain. Publisher: Tecnatom s.a. - [Homepage]
