• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.94-101
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• 2015

This paper presents findings on the second-order sliding-mode controller for a nuclear research reactor. Sliding-mode controllers for nuclear reactors have been used for some time, but higher-order sliding-mode controllers have the added advantage of reduced chattering. The nonlinear model of Pakistan Research Reactor-1 has been used for higherorder sliding-mode controller design and performance evaluation. The reactor core is simulated based on point kinetics equations and one delayed neutron groups. The model assumes feedback from lumped fuel and coolant temperatures. The effect of xenon concentration is also considered. The employed method is easy to implement in practical applications, and the second-order sliding-mode control exhibits the desired dynamic properties during the entire output-tracking process. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness, and stability.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.91-99
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• 2008

The identification of thermal hazards associated with a process such as heats of reaction and understanding of thermodynamics before any large scale operations are undertaken. The evaluation of thermal behavior with operating conditions such as a reaction temperature, stirrer speed and reactants concentration in neutralization process of pigment plant are described. The experiments were performed by a sort of calorimetry with multimax reactor system The aim of the study was to evaluate the results of heat of reaction in terms of safety reliability to be practical applications. It suggested that we be proposed safe operating conditions and securities for accident prevention on reactor explosion through this study.

• Nuclear Engineering and Technology
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• v.38 no.7
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• pp.591-618
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• 2006

An integrated R&D program is being conducted to study, qualify, and in some cases, develop materials with required properties for the reactor systems being developed as part the U.S. Department of Energy's Generation IV Reactor Program. The goal of the program is to ensure that the materials research and development (R&D) needed to support Gen IV applications will comprise a comprehensive and integrated effort to identify and provide the materials data and its interpretation needed for the design and construction of the selected advanced reactor concepts. The major materials issues for the five primary systems that have been considered within the U.S. Gen IV Reactor Program-very high temperature gas-cooled, supercritical water-cooled, gas-cooled fast spectrum, lead-cooled fast spectrum, and sodium-cooled fast spectrum reactors-are described along with the R&D that has been identified to address them.

• Nuclear Engineering and Technology
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• v.39 no.4
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• pp.249-256
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• 2007

Light water reactors operated under supercritical pressure conditions have been selected as one of the promising future reactor concepts to be studied by the Generation IV International Forum. Whereas the steam cycle of such reactors can be derived from modem fossil fired power plants, the reactor itself, and in particular the reactor core, still need to be developed. Different core design concepts shall be described here to outline the strategy. A first option for near future applications is a pressurized water reactor with $380^{\circ}C$ core exit temperature, having a closed primary loop and achieving 2% pts. higher net efficiency and 24% higher specific turbine power than latest pressurized water reactors. More efficiency and turbine power can be gained from core exit temperatures around $500^{\circ}C$, which require a multi step heat up process in the core with intermediate coolant mixing, achieving up to 44% net efficiency. The paper summarizes different core and assembly design approaches which have been studied recently for such High Performance Light Water Reactors.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.905-913
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• 2017

Advanced reactor designs often feature longer operating cycles between refueling and new concepts of operation beyond traditional baseload electricity production. Owing to this increased complexity, traditional proportional-integral control may not be sufficient across all potential operating regimes. The prototypical advanced reactor (PAR) design features two independent reactor modules, each connected to a single dedicated steam generator that feeds a common balance of plant for electricity generation and process heat applications. In the current research, the PAR is expected to operate in a load-following manner to produce electricity to meet grid demand over a 24-hour period. Over the operational lifetime of the PAR system, primary and intermediate sodium pumps are expected to degrade in performance. The independent operation of the two reactor modules in the PAR may allow the system to continue operating under degraded pump performance by shifting the power production between reactor modules in order to meet overall load demands. This paper proposes a Takagi-Sugeno (T-S) fuzzy logic-based power distribution system. Two T-S fuzzy power distribution controllers have been designed and tested. Simulation shows that the devised T-S fuzzy controllers provide improved performance over traditional controls during daily load-following operation under different levels of pump degradation.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4743-4750
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• 2022

Heat pipe cooled nuclear reactor has been a very attractive technical solution to provide the power for deep space applications. In this paper, a 200 kWe space nuclear reactor power design has been proposed based on the combination of an integrated UN ceramic fuel, a heat pipe cooling system and the Stirling power generators. Neutronics and thermal analysis have been performed on the space nuclear reactor. It was found that the entire reactor core has at least 3.9 $ subcritical even under the worst-case submersion accident superimposed a single safety drum failure, and results from fuel temperature coefficient, neutron spectrum and power distribution analysis also showed that this reactor design satisfies the neutronics requirements. Thermal analysis showed that the power in the core can be successfully removed both in normal operation or under one or more heat pipes failure scenarios.

• Nuclear Engineering and Technology
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• v.45 no.3
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• pp.401-414
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• 2013

HTR50S is a small modular reactor system based on HTGR. It is designed for a triad of applications to be implemented in successive stages. In the first stage, a base plant for heat and power is constructed of the fuel proven in JAEA's $950^{\circ}C$, 30MWt test reactor HTTR and a conventional steam turbine to minimize development risk. While the outlet temperature is lowered to $750^{\circ}C$ for the steam turbine, thermal power is raised to 50MWt by enabling 40% greater power density in 20% taller core than the HTTR. However the fuel temperature limit and reactor pressure vessel diameter are kept. In second stage, a new fuel that is currently under development at JAEA will allow the core outlet temperature to be raised to $900^{\circ}C$ for the purpose of demonstrating more efficient gas turbine power generation and high temperature heat supply. The third stage adds a demonstration of nuclear-heated hydrogen production by a thermochemical process. A licensing approach to coupling high temperature industrial process to nuclear reactor will be developed. The low initial risk and the high longer-term potential for performance expansion attract development of the HTR50S as a multipurpose industrial or distributed energy source.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.5
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• pp.483-490
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• 1999

In this paper, the cost-effective design of output reactor which is USCD to suppress the over-voltage at the m motor terminal in the Adjustable Speed Drives(ASD) application is proposed. In the elevator drive svstem. the R IXlwer cable length is relatively shorter than other ASD applications and then the over voltage at the motor terminal depends on the frequency characteristics of the output reactor at the over voltage operating frequency. The over-voltage suppression mechanism of output reactor in ASD application is analyzed and the dominant parameters of output reactor for the over-voltage supression are extracted. Using these as the design values and considering the high frequency characteristics of iron core in the reactor. a new c cost-effective structure of output reactor is proposed. Experimental results of the conventional reactor and the p proposed reactor with a l5kW induction motor are given to verify the propoSLD scheme.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.931-936
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• 1992

In operational pont of view, the batch reactor is quite different from the continuous reactor in that it is completely in unsteady states. This makes process variables swing over wide ranges and the process disclose its nonlinerarities. For the most part these nonlinearities are due to reaction heat. Accordingly it is very important to know the informations of reaction heat. This paper presents the method of reaction heat measurement in industrial batch reator which furnishes the limited measurable points. The informations of reaction heat are utilized in modeling of the batch reactor as well as deciding the stability and control variables.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.225-230
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• 2008

Reactor starting method has the advantage of simplicity and closed transition in spite of lower starting torque per kVA. This method allows a smooth start with almost no observable disturbance on transition and is suitable for applications such as centrifugal pumps or fans. Reactive power doesn't contribute to work but needs to sustain the electromagnetic field required for the induction motor to operate. Starting power factor of induction motor is specially lower than running power factor. Power factor application is needed to compensate for the lower power factor of induction motor. This power factor compensation systems is occasionally being hit by the effects of the starting reactor connection position at the starting, stopping of high-voltage induction motor. This paper describes voltage and current stress affected by the installation position of power factor compensation application at the reactor starting method.