A Generation Risk Assessment for CCWS at UCN 3

Generation Risk Assessment (GRA) is defined as, ' ... the process of predicting the risk of a generation loss during a future operation by estimating the probability and duration of a plant trip or derate due to equipment degradation or failure.' GRA is to a lost generation (MWh/yr) as Probabilistic Safety Assessment (PSA) is to a core damage frequency. 'Generation Risk' is used as a means of determining where capital improvements or decreased (increased) maintenance is appropriate. Also, GRA will help spare parts inventory control, trip monitor development, etc., and eventually become a basis for Nuclear Asset Management. There are two methods to build a GRA model: 1) To build a GRA model from scratch by considering a plant trip, 2) To convert an existing PSA model to a GRA one. A GRA model for a Component Cooling Water System (CCWS) of UCN 3 was developed by converting the existing PSA results. It is not necessary to model an entire plant before applying a GRA. The GRA for the CCWS of UCN 3 is described in this paper