Development of the fault diagnostic techniques using reactor noise analysis

The unfavorable phenomena, such as flow induced vibration and aging process in reactor internals, cause degradation of structural integrity and may result in loosing some mechanical binding components which might impact other equipments and components or cause flow blockage. Since these malfunctions and potential failures change reactor noise signal, it is necessary to analyze reactor noise signal for early fault diagnosis in the point of view safety and plant economics. The objectives of this study are to establish fault diagnostic techniques for reactor internals, particularly CSB (core support barrel) and TS (thermal shied), using reactor noise. In this study, an analysis technique for the reactor internal vibration using the reactor noise was proposed. With the proposed reactor noise analysis techniques the dynamic characteristics of German Obrigheim NPP reactor internals were also identified from in-core neutron, reactor coolant pressure, and displacement signals that jointly measured by KAERI in Korea and IKPH in Germany. (author). 20 refs., 7 tabs., 354 figs