AREVA Fatigue Concept (AFC). Live demonstration of a modern fatigue monitoring system FAMOS i

The prevention of fatigue damage is to be considered as a crucial issue in the view of changing boundary conditions: code modifications, long term operation, new plants with operating periods of 60 years. The AREVA Fatigue Concept (AFC) provides for a multiple step and multidisciplinary process (process engineering, fatigue monitoring, fatigue analyses etc.) against fatigue before and during the entire operation of nuclear power plants (NPPs). The ensuing fatigue analyses are based on the real operational loads measured continuously on site in the plant by means of an installed fatigue monitoring system. This way, realistic load data are available and qualified fatigue usage factors can be determined. Locations of potential fatigue failure are reliably identified and expensive cost for inspection can be essentially reduced. The direct processing of the measured temperatures can immediately be used for a Fast Fatigue Evaluation (FFE). FFE calculates the real stress history in form of a six stress tensor approach. The shape functions of fatigue relevant NPP parts are included. Based on the stress history the fatigue evaluation is the last step. Effects based on environmental fatigue influence can also be analyzed inside AFC. The fatigue calculation workflow will be processed on the FAMOS i (i stands for ''integrated'') demonstration wall (cf. Figure 1). Starting with the measurement of transient temperatures, the thermal loads will be shown with the FAMOS i-viewer software. Within the next step the inner wall temperature is calculated, which is based on the FAMOS i measurements. In a third step the computation of the stress history is done, followed by the combination of the relevant stress ranges for the purpose of a particular fatigue usage calculation. In addition, a short overview will be given about the requirements and solutions of an effective modern measurement system, followed by showing the benefit of local monitoring for NPP owners. (orig.)