• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.290-291
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• 2011

전력산업이 발전함에 따라 전력품질 요구도 증가하고 있으나 고조파왜형률에 대한 국제기준이 제조사와 운영자의 입장에 따라 계산방법이 상충되는 부분이 현실적으로 존재하고 있는 것으로 검토되었다. 본 논문에서는 원자력발전소에 사용되는 축전지 및 충전기의 시험 및 관리규격인 ANSI/IEEE 519와 NEMA PE-5에 대한 THD 계산방식에 대한 차이점을 설명하고 현장 규제경험 사례를 통해 바람직한 관리 방향을 제시하고자 한다.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1871-1880
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• 2020

Round robin analyses for vessel failure probabilities due to PTS events are proposed for plant-specific analyses of all types of reactors developed in Korea. Four organizations, that are responsible for regulation, operation, research and design of the nuclear power plant in Korea, participated in the round robin analysis. The vessel failure probabilities from the probabilistic fracture mechanics analyses are calculated to assure the structural integrity of the reactor pressure vessel during transients that are expected to initiate PTS events. The failure probabilities due to various parameters are compared with each other. All results are obtained based on several assumptions about material properties, flaw distribution data, and transient data such as pressure, temperature, and heat transfer coefficient. The realistic input data can be used to obtain more realistic failure probabilities. The various results presented in this study will be helpful not only for benchmark calculations, result comparisons, and verification of PFM codes developed but also as a contribution to knowledge management for the future generation.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.6203-6207
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• 2012

방사선이용 기관의 증가에 따라 방사선안전규제의 수요도 지속적으로 증가하고 있으므로 방사선안전규제의 합리화를 위한 객관적인 근거자료를 도출하기 위해서 방사선안전관리자를 통한 실질적인 일반화된 측정도구를 개발하고자 하였다. US NRC NUREG 1556(방사성물질에 대한 통합지침) Vol 1~21의 내용, 원자력안전법 등의 내용을 근거로 예비문항을 작성하여 국내 방사선이용 허가기관의 약 10%에 해당되는 방사선안전관리자를 대상으로 설문조사를 실시하였다. 그 결과, 요인분석 20개 문항에 대해 3개의 요인이 추출되었다. 요인1은 '방사선안전관리 규제요건', 요인2는 '실질적인 안전규제의 부합성', 요인3은 '방사선원 분류'관련으로 각각 명명하였다. 각 요인의 분산 설명력은 요인1이 40.140%, 요인2가 13.721%, 요인3이 6.556%로서 전체 60.417%의 설명력을 나타내었다. 본 연구에서 도출된 방사선안전규제 측정도구를 사용하여 방사선안전규제 기준을 도출한다면 국제기준에 적합할 뿐만 아니라 현장의 방사선안전관리자에게 실용성 있는 기준을 제시할 수 있을 것이라고 사료된다.

• 한국안전학회지
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• 제26권2호
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• pp.6-12
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• 2011

The failure probabilities of pipes in nuclear power plants due to stress corrosion are obtained using the P-PIE program, which is developed for evaluating failure probability of pipes based on the existing PRAISE program. Leak, big leak and LOCA(loss of coolant accident) probabilities are calculated as a function of operating time for several pipes in a domestic nuclear plant. The sensitivity analysis is also performed to find out the important parameters for the failure of pipes due to stress corrosion. The results show that the steady state oxygen concentration and steady state temperature are important parameters and failure probability is very low when the oxygen concentration is maintained according to the regulation.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1698-1711
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• 2024

Heat pipe cooled reactors have gained attention as a potential solution for nuclear power generation in space and deep sea applications because of their simple design, scalability, safety and reliability. However, under complex operating conditions, a control strategy for variable load operation is necessary. This paper presents a two-dimensional transient characteristics analysis program for a heat pipe cooled reactor and proposes a variable load control strategy using the recuperator bypass (CSURB). The program was verified against previous studies, and steady-state and step-load operating conditions were calculated. For normal operating condition, the predicted temperature distribution with constant heat pipe temperature boundary conditions agrees well with the literature, with a maximum temperature difference of 0.4 K. With the implementation of the control strategy using the recuperator bypass (CSURB) proposed in this paper, it becomes feasible to achieve variable load operation and return the system to a steady state solely through the self-regulation of the reactor, without the need to operate the control drum. The average temperature difference of the fuel does not exceed 1 % at the four power levels of 70 %,80 %, 90 % and 100 % Full power. The output power of the turbine can match the load change process, and the temperature difference between the inlet and outlet of the turbine increases as the power decreases.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2047-2052
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• 2023

Risk-informed approach has been widely applied in the safety design, regulation, and operation of nuclear reactors. It has been commonly accepted that risk-informed design optimization should be used in the innovative reactor designs to make nuclear system highly safe and reliable. In spite of the risk-informed approach has been used in some advanced nuclear reactors designs, such as Westinghouse IRIS, Gen-IV sodium fast reactors and lead-based fast reactors, the process of risk-informed design of nuclear reactors is hardly to carry out when passive system reliability should be integrated in the framework. A practical method for new passive safety reactors based on probabilistic safety assessment (PSA) and passive system reliability analyze linking is proposed in this paper. New three-dimension frequency-consequence curve based on risk concept with three variables is used in this method. The proposed method has been applied to the determination optimization of design options selection in a 10 MWth lead-based research reactor(LR) to obtain one optimized system design in conceptual design stage, using the integrated reliability and probabilistic safety assessment program RiskA, and the computation resources and time consumption in this process was demonstrated reasonable and acceptable.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.288-288
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• 2000

Reactor vessel is one of the most important equipment with regard to the safety of nuclear power plant. Thus nuclear regulation requires its periodical examination by certified inspection experts. Conventional reactor inspection machines are obsolete, hard to handle, and very expensive. To solve these problems we developed robotic reactor vessel inspection system which are small, easy to use for inspection, cost effective, and convenient in operation. This paper describes the main features of Main Control System which is one part of robotic inspection equipment we developed.

• 대한인간공학회지
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• 제35권4호
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• pp.263-275
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• 2016

Objective: This paper introduces the regulatory oversight approaches and issues to consider in the course of safety culture oversight model development in the nuclear field. Common understanding on regulatory oversight and present practices of international communities are briefly reviewed. The nuclear safety culture oversight model of Korea is explained focusing on the development of safety culture definition and components, and their basic meanings. Oversight components are identified to represent the multiple human and organizational elements which can affect and reinforce elements of defense in depth system for nuclear safety. Result of validation study on safety culture components is briefly introduced too. Finally, the results of the application of the model are presented to show its effectiveness and feasibility. Background: The oversight of nuclear licensee's safety culture has been an important regulatory issue in the international community of nuclear safety regulation. Concurrent with the significant events that started to occur in the early 2000s and that had implications about safety culture of the operating organizations, it has been natural for regulators to pay attention to appropriate methods and even philosophy for intervening the licensee's safety culture. Although safety culture has been emphasized for last 30 years as a prerequisite to ensure high level of nuclear safety, it has not been of regulatory scope and has a unique dilemma between external oversight and the voluntary nature of culture. Safety culture oversight is a new regulatory challenge that needs to be approached taking into consideration of the uncontrollable aspects of cultural changes and the impacts on licensee's safety culture. Although researchers and industrial practitioners still struggle with measuring, evaluating, managing and changing safety culture, it was recognized that efforts to observe and influence licensees' safety culture should not be delayed. Method: Safety culture components which regulatory oversight will have to focus on are developed by benchmarking the concept of physical barriers and introducing the defense in depth philosophy into organizational system. Therefore, this paper begins with review of international regulatory oversight approaches and issues associated with the regulatory oversight of safety culture, followed by the development of oversight model. The validity of the model was verified by statistical analysis with the survey result obtained from survey administration to NPP employees in Korea. The developed safety culture oversight model and components were used in the "safety culture inspection" activities of the Korean regulatory body. Results: The developed safety culture model was confirmed to be valid in terms of content, construct and criterion validity. And the actual applicability in the nuclear operating organization was verified after series of pilot "safety culture inspection" activities. Conclusion: The application of the nuclear safety culture oversight model to operating organization of NPPs showed promising results for regulatory tools required for the organizations to improve their safety culture. Application: The developed oversight model and components might be used in the inspection activities and regulatory oversight of NPP operating organization's safety culture.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• 대한핵의학회지
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• 제38권2호
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• pp.140-142
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• 2004

As a molecular imaging is the most up-to-date technology in Nuclear Medicine, it has complicate ethical and regulatory problems. For animal experiment, we have to follow institutional animal care committee. for clinical experiment, we have to get approval of Institutional Review Board according to Helsinki declaration. In addition, approval from Korea Food and Drug Administration (KFDA) is essential for manufacturing and commercialization. However, too much regulation would suppress development of new technology, which would result in the loss of national competitive power. In addition, most new radioactive ligands for molecular imaging are administered to human at sub-pharmacological and sub-toxicological level. In conclusion, a balanced regulation is essential for the safety of clinical application and development of new technology.