Reactor load tracking control plays a vital role in enhancing the peak regulation capability and operational stability of power grids. As typical complex physical facilities, nuclear reactors feature strong coupling, time-varying behaviors, and high nonlinearity, and their dynamic models cover the complex coupling effects among neutron kinetics, thermohydraulics, and other multiphysical processes. Most existing predictive control methods are developed based on linearized system models, which ignore high-order nonlinear terms and further trigger model mismatch problems. Besides, iterative updates of linearized models will bring heavy computational pressure to real-time online operation. To solve the above drawbacks, this study develops an improved control strategy integrating nonlinear disturbance observer (NDO) and parameter identification with continuous-time nonlinear generalized predictive control (NGPC). Compared with discrete-time control frameworks, continuous-time–based NGPC can better capture the intrinsic nonlinear dynamics of reactors and mitigate adverse effects brought by modeling errors. Unlike traditional control methods that only adopt fixed nominal models, the proposed strategy adopts the Levenberg–Marquardt algorithm to identify time-varying degradation parameters during reactor operation. Meanwhile, the designed NDO is applied to real-time observation of unknown lumped disturbances, and the estimated disturbance values are fed into the NGPC loop to establish a dynamic disturbance compensation module. This design effectively improves the robustness and antidisturbance ability of the overall reactor control system. Finally, comparative load tracking experiments are conducted among PID, NGPC, and the proposed NDO–NGPC + identification method. The results demonstrate that the NDO–NGPC + identification strategy exhibits superior tracking accuracy and disturbance suppression performance in the presence of both step and sinusoidal disturbances, validating its effectiveness in improving reactor control performance under complex operating conditions.
This paper proposes a three-phase reliability model based on piecewise intensity functions for repairable systems in a nuclear power plant. Model parameters are estimated by least-squares fitting to the empirical mean cumulative function (MCF), with two change points determined via a global grid search. The model’s fitting accuracy is evaluated using the Akaike information criterion (AIC) and sum of squared errors (SSEs), while its predictive capability is assessed via root mean square error (RMSE) under leave-one-out cross-validation. A case study on repairable drum screens in the nuclear power plant demonstrates that the three-phase model outperforms power law, two-phase, and bathtub-shaped reliability models in both fitting accuracy and predictive capability, effectively capturing the three-stage evolution of the system reliability: random failures with constant failure intensity, a transition phase marked by gradually increasing failure intensity, and wear-out failures associated with accelerated degradation. Maintenance recommendations for the drum screens are informed by the failure characteristics unveiled by the reliability model.
High-temperature heat pipes, as a type of heat pipe that operates in environments above 450°C, have excellent heat transfer performance, good isothermal characteristics, and variable heat flux, making them highly suitable for the transmission and utilization of high-grade heat in fields, such as aerospace, nuclear energy utilization, and solar energy utilization. The latest progresses in high-temperature heat pipe technology research are introduced, including experimental and numerical simulation studies of high-temperature heat pipes, as well as application research of high-temperature heat pipe technology in aerospace, nuclear energy utilization, and solar energy utilization. By summarizing the key issues in current heat pipe research, some directions for further in-depth research on high-temperature heat pipes in engineering applications are pointed out, and specific suggestions are proposed for further research on high-temperature heat pipe technology.
Since the Fukushima nuclear disaster, there has been a lot of negative sentiment toward nuclear power plants, and the general trend has been to extend the operation of existing plants rather than build new ones. However, public anxiety remains. This study analyzes the influence of public health concerns on the extended operation of nuclear power plants. To do so, we analyzed the effects of perceived health and perceived health threat on extended operation while controlling for regional variables and the risk perception paradigm. The results showed that living in a compensation area, having experienced a nuclear accident, experiencing a delay in regional development, and having a negative image of the region were associated with lower acceptance of extended operation. On the other hand, perceived benefits and knowledge increased agreement with extended operation. As for the health factors, perceived health threat decreased support for extended operation. In particular, this perceived threat suppressed the effect of perceived benefits, while perceived health played a role in facilitating the effect of negative stigma.
One of the major challenges facing modern nuclear power engineering is the management of radioactive waste, particularly its accumulation and disposal. This article presents an experimental electroslag remelting facility developed for processing radioactively contaminated metals and alloys. In addition, the results of preliminary experiments on the remelting of radioactively contaminated 12X18H10T stainless steel pipes are presented. These pipes were previously used in the technological channels of the IVG.1 research reactor. The results show that electroslag remelting leads to a redistribution of gamma-emitting radionuclides between the metallic and slag phases, resulting in a decrease in their specific activity in the steel. However, the obtained steel does not meet clearance criteria for unrestricted use due to residual Co-60 activity. Nevertheless, electroslag remelting has been shown to be a promising method for decontamination of radioactively contaminated steel, with further improvement possible through optimization of process parameters.
