Model predictive control for sodium fast reactors based on Laguerre functions and FPGA-in-the-loop environment

Abstract

This paper proposes a multiple-input multiple-output (MIMO) model predictive control (MPC) design with constraints and Laguerre functions using the simplified model of the primary system (reactor core and intermediate heat exchanger (IHX)) of a prototypical sodium fast reactor (SFR). The control aims at tracking the reactor power, sodium tank temperature and the primary inlet plenum temperature when the reactor operates at 100% capacity by controlling the reactivity and the secondary sodium flow rate. For comparison criteria, this paper simulates the insertion of disturbances related to the reactivity and the sodium inlet temperature. The analysis includes the simulation of the insertion of disturbances in the reactivity and the sodium inlet temperature. The controller design was developed in MATLAB and Simulink, and was tested under a variety of reactivity disturbances (−1 and −5 cents) and a sodium inlet temperature disturbance of +10 °F. In each case studied, the MPC tracked the outputs effectively. The proposed MPC-SFR obtained a faster and more robust disturbance rejection regarding insertion of reactivity and sodium inlet temperature when compared with SFR controlled by digital PI controllers (PI-SFR). Finally, the controller was embedded in a Field Programmable Gate Array (FPGA) device in order to demonstrate the FPGA-in-the-loop (FIL) feature and to compare it with the results using MATLAB-Simulink.