Abstract
This study used RETRAN analysis model to analyze turbine trip and load rejection of Taiwan Power Company Lungmen Nuclear Power Plant’s startup test at 100% power and 100% core flow. This analysis model includes thermal flow control volume and junctions, control system, heat hydraulic mode, safety system, one-dimensional core neutron dynamic mode and power heat hydraulic calculation.In Lungmen RETRAN mode, a main steam piping is simulated as four real lines of reality power plant. The simulated control system includes four parts: pressure control system, water level control system, feedwater control system, speed control system in reactor internal pumps.This study has two transient events, turbine trip and load rejection. The turbine trip event, above 40% power, triggers the fast open of the bypass valves. Upon the turbine trip, the turbine stop valves are closed. To minimize steam bypassed to the main condenser, recirculation flow is automatically runback and a SCRRI (selected control rod run in) is initiated to reduce reactor power. The load rejection causes the fast opening of the bypass valves. Steam bypass will sufficiently control the pressure, because the bypass capacity is 110% rated capacity. A SCRRI and RIP runback are initiated to reduce reactor power, to mitigate the steam bypassed to the condenser.Besides, this study analyzes the effects of whole core transience by the changing of turbine bypass flow, runback rate of RIPS and SCRRI with sensitivity analysis. The results show that turbine bypass flow effected dome pressure most. RIPS runback rate and SCRRI influence fewer. This study verifies is that analysis results are conforming test criteria. This demonstrates that Lungmen RETRAN model is consistency and availability. And the results also provide some things that have to pay attention to of the reality startup test for Lungmen in the future.