Nonlinear adaptive power-level control for the modular high temperature gas-cooled reactors

After the Fukushima nuclear accident, much more attention has been drawn on the safety issues. Improvement of the safety has become the focus of the developing trend of the nuclear energy systems. Due to the inherent safety feature and the potential economic competitiveness, the modular high temperature gas-cooled reactor (MHTGR) has been seen as the central part of the next general of nuclear plant (NGNP). Power-level control is one of the key techniques that guarantee the safe, stable and efficient operation for any nuclear reactors. Since the MHTGR dynamics has the characteristics of strong nonlinearity and uncertainty, for improving the operation performance, it is meaningful to develop the nonlinear adaptive power-level control law for the MHTGR. Based on using the natural dynamic features beneficial to system stabilization, a novel nonlinear adaptive power-level controller is given for the MHTGR in this paper. It is proved theoretically that this newly-built controller not only provides globally asymptotic closed-loop stability but also is adaptive to the system uncertainty. This control law is then applied to the power-level regulation of the pebble-bed MHTGR of the HTR-PM power plant. Numerical simulation results show the feasibility of this control law and the relationship between the performance and controller parameters.