• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1000-1003
• /
• 1996

Nonlinear unified predictive control(UPC) algorithm was applied to the temperature control of a batch polymerization reactor for polymethylmethacrylate(PMMA). Before the polymerization reaction is initiated, the parameters of the process model are determined by the recursive least squares(RLS) method. During the reaction, nonlinearities due to generation of heat of reaction and variation of heat transfer coefficients are predicted through the nonlinear model developed. These nonlinearities are added to the process output from the linear process model. And then, the predicted process output is used to calculate the control output sequence. The performance of nonlinear control algorithm was verified by simulation and compared with that of the linear unified predictive control algorithm. In the experiment of a batch PMMA polymerization, nonlinear unified predictive control was implemented to regulate the temperature of the reactor, and the validity of the nonlinear model was verified through the experimental results. The performance of the nonlinear controller turned out to be superior to that of the linear controller for tracking abrupt changes in setpoint.

• Journal of Korean Society on Water Environment
• /
• v.21 no.4
• /
• pp.410-415
• /
• 2005

The main purpose of this study is to evaluate the characteristics of three sets of traditional control methods (proportional, integral, and proportional - integral controls) through lab-scale biological reactor experiments. An increase in proportional gain ($K_c$) resulted in reduced dissolved oxygen (DO) offset under proportional control. An increase in integral time ($T_i$) resulted in a slower response in DO concentration with less oscillation, but took longer to get to the set point. P-I control showed more stable and efficient control of DO and airflow rates compared to either proportional control or integral control. Developed P-I control system was successfully applied to lab-scale Sequencing Batch Reactor (SBR) for treating industrial wastewater with high organic strength.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.3
• /
• pp.130-138
• /
• 1999

The feasibility of municipal sewage sludge digestion was investigated by using thermophilic anaerobic sequencing batch reactor(ASBR). One-day settle time was enough for the high performance of solid-liquid separation. The conversion of semi-continuous mode to sequencing batch mode is easily achieved without any adverse effects, although the large amount of sludge equal to the volume ratio of 0.3~06 to reactor volume was added in the feed step of the start-up. The ASBRs had higher conversion capability of organics to biogas than the control reactor. Gas yields of the ASBRs were increased by the average of 50% over the control reactor across a range of hydraulic retention time(HRT)s from 10days to 5days. The thermophilic reactors showed higher gas production than mesophilic reactor. Removal efficiencies of organic matter exceeded 80% on the basis of supernatants, except that at the reactor. Solid-liquid separation was essential in the performance of the ASBR, especially, at the lower HFT. The ASBRs were highly efficient in the retention of activated biomass within the reactor. thus compensating for increased equivalent organic loading rate through increased solids retention times followed by the increased solids, while maintaining shorter HRTs.

• Nuclear Engineering and Technology
• /
• v.52 no.3
• /
• pp.544-551
• /
• 2020

Reactor control is a standout amongst the most vital issues in the nuclear power plant. In this paper, the optimal design of variable structure controller (VSC) based on the lightning search algorithm (LSA) is proposed for a nuclear reactor power system. The LSA is a new optimization algorithm. It is used to find the optimal parameters of the VSC instead of the trial and error method or experts of the designer. The proposed algorithm is used for the tuning of the feedback gains and the sliding equation gains of the VSC to prove a good performance. Furthermore, the parameters of the VSC are tuned by the genetic algorithm (GA). Simulation tests are carried out to verify the performance and robustness of the proposed LSA-based VSC compared with GA-based VSC. The results prove the high performance and the superiority of VSC based on LSA compared with VSC based on GA.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.11
• /
• pp.1848-1853
• /
• 2016

Control Rod Position Indicator in nuclear reactor vessel has developed for small reactor in Korea. Because of severe environment in reactor vessel, target of this study is to develop the suitable position indicator. In this study, solenoid type position indicator made of Mineral Insulated Cable(MI Cable) was introduced to adapt in severe environment. And inductance of the solenoid was used to indicate the rod position for high precision. But problem of this concept is that a linear slope of inductance is changed by temperature effect. To resolve this problem, two sensing coils were introduced for temperature compensation. A role of the sensing coil is to make reference linear equation about certain temperature. To confirm this concept, also, inductance of solenoid and sensing coils were measured at room and high temperature (${\sim}300^{\circ}C$). The results of measurement show that the position error of sensing coil between room and high temperature was about 2%. But it was identified that this error was resulted from insufficient test environment (temperature error between solenoid and sensing coils was about 2% at high temperature condition). Therefore, solenoid type position indicator shows that it is very suitable in reactor vessel as a high precision rod position indicator.

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.2
• /
• pp.109-113
• /
• 2002

Van de Vusse reactor is known as a highly nonlinear chemical process and has been considered by a number of researchers as a benchmark problem for nonlinear chemical process. Various identification methods for nonlinear system are also verified by applying these methods to Van de Vusse reactor. From the point of view of identification, only the Volterra kernel of second order has been obtained until now. In this paper, the authors show that Volterra kernels of nonlinear Van de Vusse reactor of up to 3rd order are obtained by use of M-sequence correlation method. A pseudo-random M-sequence is applied to Van de Vusse reactor as an input and its output is measured. Taking the crosscorrelation function between the input and the output, we obtain up to 3rd order Volterra kernels, which is the highest order Volterra kernel obtained until now for Van de Vusse reactor. Computer simulations show that when Van de Vusse chemical process is identified by use of up to 3rd order Volterra kernels, a good agreement is observed between the calculated output and the actual output.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.18 no.2
• /
• pp.39-48
• /
• 2022

The application of digital technology to instrumentation and control systems in nuclear power plants has overcome many shortcomings of analog technology, but the threat of cybersecurity has increased. Along with other systems, the reactor protection system also uses digital-based equipment, so responding to cybersecurity threats is essential. We generally determine cybersecurity threats according to the role and function of the system. However, since the instrumentation and control system has various systems linked to each other, it is essential to analyze cybersecurity threats together between the connected systems. In this paper, we analyze the cybersecurity threat of the reactor protection system with the associated facilities. To this end, we quantitatively identified the risk of the reactor protection system by considering safety functions, a communication type, the use of analog or digital-based equipment of the associated systems, and the software vulnerability of the configuration module of the reactor protection system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.11a
• /
• pp.477-478
• /
• 2008

• The KSFM Journal of Fluid Machinery
• /
• v.14 no.2
• /
• pp.25-28
• /
• 2011

The control rod assemblies do freely fall into the reactor core by the gravity from the control rod drive mechanism. In order to achieve a rapid shutdown and control the reactor power, it is required to insert control rod assemblies as soon as possible. In this paper, we evaluated the drop time and flow characteristics caused around guide tube for SMART(System-integrated modular advanced reactor) control rod assembly. Numerical analyses are carried out with FLUENT program of computational fluid dynamics. This study results show that the drop time of the control rod assembly in the operating condition of SMART is more 20 percent rapidly than the drop time of the room temperature and ambient atmosphere condition.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.10
• /
• pp.1709-1714
• /
• 2007

It is demonstrated in this study that the nanoliter reactor arrays with an inkjet printing, can be used for high throughput screen of antibiotic function. As a model antibiotic, gramicidin was used in this study. The gramicidin embedded lipid vesicles were immobilized on the surface in the nanoliter reactor structure with control of the volume in the nanoliter reactor. By dispensing acidic drops into the reactor, the gramicidin function was monitored. The technique developed in this research also has a great potential to be used for discovery of drugs.