USE OF A REAL-TIME RELAP5 MODEL TO DYNAMICALLY TEST A DIGITAL FEEDWATER CONTROL-SYSTEM FOR A BOILING WATER-REACTOR

A RELAPS/MOD3.1 model of a boiling wafer reactor and an interface are developed as a real-time test platform for a physical feedwater contro l system and turbine governors. The reactor plant modeled is Browns Fe rry unit 2. The model is used to test and tune the new digital reactor feedwater control system (RFWCS) for units 2 and 3. The set of modele d components, trips, and controls is determined based on the testing r equirements for the RFWCS. The work is performed in two phases. In the first phase, the existing plant is modeled, including the previously existing analog feedwater control system and governor. The resulting R ELAPS model is benchmarked against existing plant data. Benchmarking r esults are presented along with data on initialization to steady state . Once the benchmarking effort is completed, the control systems in th e model are altered to allow testing of the digital RFWCS in real time . An interface is developed to allow communications with the digital R FWCS and operator interaction, which allows the test platform to be us ed to determine control system response to various transients, Descrip tions of the RELAPS model and hardware and software for the interface are provided.