Identification of an equivalent electrical model to a natural circulation BWR core model

Highlights: → Electrical model of the natural circulation BWR (NCBWR) is developed. → The core processes are modeled with the reduced model. → Reactivity due to Doppler effect, void fraction and control rod is considered. → Predictions in steady state are compared with behavior of the power as a function of an ESBWR core flow. → The results show excellent agreement. - Abstract: In this work the developing of an electrical model of the natural circulation BWR (NCBWR) from analogies between coolant pressures drops, mass flow rates, and electrical voltages and currents, is presented. The electrical model allows estimating the coolant flows in the core, which is complex in NCBWR. The core processes (nuclear-thermo-hydraulics) are modeled with the reduced model where the reactor power is calculated from a point kinetics model with one group of delay neutrons. The reactivity due to Doppler effect, void fraction and control rod was considered. The predictions in steady state were compared with behavior of the power as a function of an ESBWR core flow, showing excellent agreement. The transient behavior considers positive reactivity due to extraction of the control rods.