Power-Level Control for MHTGRs with Time-Delay in Helium Temperature Measurement

The modular high temperature gas-cooled reactor (MHTGR), which has the inherent safety feature, high thermal efficiency and satisfactory economic feasibility, can be applied for electricity and process heat production. Power-level control is an important technique for providing both the stable operation and load-following performance. Since the coolant temperature sensors of an MHTGR are usually installed near the primary side of the corresponding steam generator, there must be time-delay effect in the feedback loop of the coolant temperatures. Moreover, the measurement signal transducing may also induce time-delay effect. Therefore, it is meaningful to give the power-level control design method by considering this time-delay effect. In this paper, a simple output-feedback power-level control is proposed for the MHTGRs by using the delayed measurement signal of average reactor coolant temperature. In the aspect of theoretical analysis, a sufficient condition, under which it is well guaranteed that this newly-built power-level control is a globally asymptotic stabilizer, is firstly given. In the aspect of verification, numerical simulation results not only verify the feasibility of the theoretical results but also show the relationship between the performance and values of parameters of this novel power-level controller. The meaning of this work lies in two aspects. The first one is deeply revealing the relationship between the closed-loop stability and values of the controller parameters. The second one is giving the approach of designing a simple and effective power-level control strategy to suppress the negative influence induced by the time-delay in the feedback loop of the coolant temperatures.