Decoupling header steam pressure control strategy in Multi-Reactor and Multi-Load Nuclear Power Plant

Abstract

The aim of this paper is to design valve opening compensators for the header steam pressure control system of a Multi-Reactor and Multi-Load Nuclear Power Plant (MMNPP) using the feedforward compensation decoupling method. The mathematical model of the MMNPP consisting of two small modular reactor units, a steam header and three steam consuming units, (two-to-three MMNPP) was developed, including a nonlinear point reactor core model with six-group delayed neutron, an once-through steam generator (OTSG) model based on the moving boundary concept and a lumped parameter header model. Then linearization method was applied to the header model to obtain the corresponding transfer function model based on which feedforward compensators for header outlet valves were designed and integrated into the header steam pressure control system. It has been demonstrated by numerical simulation results that the developed header steam pressure control system with valve opening compensators can alleviate the coupling effect among header outlet flowrates, leading to much safer and more stable operations of the MMNPP than the existing header steam pressure control system without valve opening compensators. The control strategy given in this paper can be extended to more complex MMNPPs.