Dynamics and stability of turbine-pumping system for gas coolant supply in a NPP

A simplified mathematical model of turbine-pumping assembly (TPA) dynamics is developed. TPA is used for gas coolant supply in a coolant circuit of NPP with HTR reactor. Stability of the stationary solution of mathematical model equations has been investigated; transients under the most characteristic accident conditions have been calculated. The mathematical model of TPA dynamics is a system of non-linear differential and algebraic equations. Some other stationary solutions may exist in such a nonlinear system besides the solution corresponding to the nominal mode of operation at the same parameter values. The presence of only one stable state of equilibrium is detected by special investigation of equations considered with parameters corresponding to the 200 MW NPP and to TPA with capacity of 2500 HP and the rotor rotational speed of 7x104 rev/min order. The conclusion that the TPA is stable and well regulated assembly introducing no anomalies in NPP dynamics, is made