Simulation,Optimization And Control Of Modular High Temperature Gas-cooled Reactor Nuclear Power Plant

As a new type of advanced nuclear power plant with the features of Generation IV nuclear energy system, HTR-PM is based on High Temperature Gas-cooled Reactor-Pebble Bed Module reactor type, and its mode is "Dual-Modules with One-Turbine (DMOT)". It has the features of nonlinear, strong coupling, large time delay and parameter time-varying, which is the typical characteristics of large-scale complex systems. It’s a difficult question, that how the multivariable system of HTR-PM should be controlled in order to achieve fast and smooth operation under wide range load change. Operational and control characteristics analysis of HTR-PM is based on computer simulation, so it is of great significance to achieve fast simulation. Based on the lumped parameter dynamic model of HTR-PM, this thesis focused on the simulation, optimization and control of HTR-PM, and satisfactory results were achieved.The main research work of the thesis is listed as follows:1. Water/steam properties calculation mechanism equations, which would be frequently used in the lumped parameter dynamic model of HTR-PM, were established according to IAPWS-IF97. Discrete model of HTR-PM was developed, using finite element orthogonal collocation method. Both nested sequential method and simultaneous method were applied to the simulation of HTR-PM. Then the results from both methods were compared with each other and analyzed on accuracy and efficiency.2. Process mechanism of HTR-PM was studied, and then a open-loop dynamic optimization proposition was proposed targeted at rapid and smooth load changing. The proposition was verified on simulations under wide range load change conditions, and application prospects of the dynamic optimization of HTR-PM were discussed. The reason non-smooth functions were leaded into HTR-PM dynamic model and the impact on dynamic optimization’s solution due to non-smooth functions were analyzed, then effective smoothing approaches were proposed. 3. Operational and control characteristics and difficulties were researched and analyzed. A mechanism-based nonlinear model predictive controller was established under the framework of hierarchical coordinated control system. A NMPC simulation platform of HTR-PM was developed based on simultaneous approach and lots of simulation work was done to verify the control performance of INMPC in terms of wide range load change, under step disturbance and model mismatch.Finally, a Summary of this thesis was given and future research prospect was discussed.