• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1195-1205
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• 2022

Recent developments on spectral diffusion algorithms, i.e., algorithms which exploit the projection of the solution on the eigenfunctions of the Laplacian operator, demonstrated their effective applicability in fast transient conditions. Nevertheless, the numerical error introduced by these algorithms, together with the uncertainties associated with model parameters, may impact the reliability of the predictions on short-lived volatile fission product release from nuclear fuel. In this work, we provide an upper bound on the numerical error introduced by the presented spectral diffusion algorithm, in both constant and time-varying conditions, depending on the number of modes and on the time discretization. The definition of this upper bound allows introducing a methodology to a priori bound the numerical error on short-lived volatile fission product retention.

• Fire Science and Engineering
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• v.30 no.3
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• pp.79-85
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• 2016

Serious electrical problems, such as shorts, ground faults, or circuits, often cause fire events in the fire proof zone of nuclear power plants. These would be directed to the loss of safe shutdown capabilities performed by safety-related systems and equipment. The fire event can be treated with the basic design principle that safety systems should maintain their functions with redundancy and independency. In the case of a cable fire in the main control room, operators cannot perform their mission properly and can misjudge the situation because of spurious operation, incorrect indication or instrument. These would deteriorate the plant capabilities of safety shutdown and result in disastrous conditions. Therefore, during a main control room fire, 5 minutes of operator action time is very important to operate the safety shutdown components. This paper describes the cable functional failure temperature criteria and conducted a cable functional failure time evaluation using Fire Dynamic Simulator to obtain the operator action time for a main control room fire.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.437-443
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• 1997

DYLAM and its related applications are reviewed in detail and found to have many favorable characteristics. Concerning human factor analysis, the study demonstrates that DYLAM methodology represents an appropriate tool to study man-machine behavior provided that DYLAM is used to model machine behavior and an appropriate operator interface human factor model is included. A hybrid model which is a synthesis of the DYLAM model, a system thermodynamic simulation model and a neural network predicative model, is implemented and used to analyze dynamically the CANDU pressurizer system.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.103-108
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• 1995

By applying the P$_1$ and P$_2$ equations to the operator form of a synthetic acceleration, we derive the p,-acceleration (diffusion synthetic acceleration: DSA) and P$_2$-acceleration (p$_2$SA) schemes in one dimensional slab geometry. We Fourier-analyze the derived acceleration schemes with the discrete-ordinates transport equation and showed that the DSA outperforms the P$_2$SA. These results confirm that one cannot simply assume that replacement of the DSA with a higher order approximation will lead to a better acceleration performance.

• Language and Information
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• v.5 no.2
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• pp.75-86
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• 2001

Generic sentences assert generic properties of single individuals or those of plural individuals. It means the generic quantifier Gen can quantify over single and plural entities. Among the generic meaning information represented in terms of the tripartite structure, the information not in the nuclear scope part, but rather in the restrictor part is related to which individuals generic sentences assert of. The plurality in the nuclear scope part cannot be described by making the generic operator Gen quantify over plural entities: Generic sentences with collective predicates like gather, and those with dependent plurals predicate of generic properties of single individuals. On the contrary, the plural information in restrictor part leads Gen to quantify eve. plural entities.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.329-334
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• 1998

원자력발전소와 같이 복잡하고 안전성이 강조되는 경보처리 및 표시계통은 개발개념의 적합성 (설계요건의 타당성), 적용된 알고리즘의 완결성(지식기반과 소프트웨어의 확인)과 인간공학적 유용성의 평가가 상당히 중요하다. 동적 경보계통(Alarm and Diagnosis-Integrated Operator Support System : ADIOS)은 다음과 같은 실험을 통해 경보처리 알고리즘의 완결성과 인간공학적 유용성을 확인하였다.·예비기능시험(Preliminary functional test)·Petri net 을 이용한 알고리즘의 완결성 확인(Verification)·전규모 시뮬레이션 환경에서의 인간공학적 성능평가(Validation and Evaluation)

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.5 no.2
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• pp.40-44
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• 2009

In this study, Event Corrective Action Supporting System (ECAS) is developed for the accident evaluation in nuclear power plant. The ECAS system can be used in supporting regulator and/or operator under event situation in nuclear power plants. The ECAS system consists of 5 modules including failure location module, failure analysis module, failure integrity evaluation module, system vulnerability evaluation module, and reporting and operating experience feedback module. The ECAS system will be used as sub module of Knowledge-Based Event Evaluation Network (K-EvENT) which is developing for the against the accident in nuclear power plants.

• Journal of the Korean Institute of Intelligent Systems
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• v.5 no.3
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• pp.52-63
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• 1995

A neuro-fuzzy algorithm is presented for nuclear reactor power control in a pressurized water reactor. Automatic reacotr power control is complicated by the use of control rods because of highly nonlinear dynamics in the axial power shape. Thus, manual shaped controls are usually employed even for the limited capability during the power maneuvers. In an attempt to achieve automatic shape control, a neuro-fuzzy approach is considered because fuzzy algorithms are good at various aspects of operator's knowledge representation while neural networks are efficinet structures capable of learning from experience and adaptation to a changing nuclear core state. In the proposed neuro-fuzzy control scheme, the rule base is formulated based ona multi-input multi-output system and the dynamic back-propagation is used for learning. The neuro-fuzzy powere control algorithm has been tested using simulation fesponses of a Korean standard pressurized water reactor. The results illustrate that the proposed control algorithm would be a parctical strategy for automatic nuclear reactor power control.

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.619-626
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• 2018

Most publications confirm that an ecological interface is a very efficient tool to supporting operators in recognition of complex and unusual situations and in decision-making. The present article describes the experience of implementation of an ecological interface concept for visualization of material balance in a drum separator of RBMK-type NPPs. Functional analysis of the domain area was carried out and revealed main factors and contributors to the balance. The proposed ecological display was designed to facilitate execution of the most complicated cognitive operations, such as comparison, summarizing, prediction, etc. The experimental series carried out at NPPs demonstrated considerable reduction of operators' mental load, time of reaction, and error rate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.318-319
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• 2018

Protective coatings at nuclear power plants should be designed to withstand exposure to ambient conditions during normal operation or design-basis accidents. However, there was a change in the perception of the protective coating to the revision of the Regulatory Guidelines by the NRC in July 2000. In other words, maintenance guidelines have been strengthened in order to minimize the clogging of the cooling water system due to the substances in the containment building. Therefore, KHNP, the contractor and operator of the nuclear power plant, plans to develop the coating system for nuclear power plants in accordance with the regulation, and plans to develop its own coating expert.