• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.879-884
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• 1995

The results of performance assessment analyses have shown that the long-lived radionuclides such as I-129 control the potential individual dose impact to the public. I-129 is difficult-to-measure(DTM) in low-level waste because it is non-gamma emitting radionuclides and exists at extremely low concentrations in radioactive waste generated by nuclear reactors. In this study, computer modeling technique to predict release rate of I-129 is developed to provide another tools far performance assessment of land disposal facilities and characteristics of radwaste. Model suggested in this study will give conservative values of I-129 release rate far determination of radwaste characteristics. More detailed approach is implemented to account for release conditions of fuel source-nuclides. 1-131 concentration measured from reactor coolant and released fraction from tramp fuel have dominant roles in calculating release rate of I-129 with fuel defect conditions.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.274-276
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• 2016

2014년 12월, 한국수력원자력의 사이버테러, 이란의 원자력 농축시설을 대상으로 한 사이버공격 등 국내외에서 원자력시설을 대상으로 한 사이버공격이 발생하고 있다. 이에 따라, 사이버보안 중요성이 증가하면서 방사선 재해방지와 공공의 안전을 위한 효과적인 규제체계의 필요성이 증가하였다. 한국원자력통제기술원은 개정된 방사능방재법에 따라 2014년부터 사이버보안 정기검사를 수행하고 있으며, 정기검사에 활용할 취약점 점검툴을 통해 정기검사의 효과성 및 수행능력을 향상시키고자 한다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.1-7
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• 2019

In this paper, the regulations and technical standards related to qualification of safety grade equipment in nuclear power plants are critically reviewed with the qualification procedure in terms of structures, systems, and equipment in nuclear power plants. These facilities should be designed and constructed to protect from natural conditions or disasters and to perform their safety functions even in case of postulated accidents. Equipment Qualification is to demonstrate that the safety related equipment is designed and constructed to perform their safety functions under normal and accident conditions. It is classified into environmental qualification and seismic qualification.

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.25-38
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• 2023

Instrumentation and control systems measure and control various variables of nuclear facilities to operate nuclear power plants safely. A diverse protection system, a representative instrumentation and control system, generates a reactor trip and turbine trip signal by high pressure in a pressurizer and containment to satisfy the design requirements 10CFR50.62. Also, it generates an auxiliary feedwater actuation signal by low water levels in steam generators. Cybersecurity has become more critical as digital technology is gradually applied to solve problems such as performance degradation due to aging of analog equipment, increased maintenance costs, and product discontinuation. This paper analyzed possible cybersecurity threat scenarios in the diverse protection system using attack trees. Based on the analyzed cybersecurity threat scenario, we calculated the probability of attack occurrence and confirmed the cybersecurity risk in connection with the asset value.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.188-190
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• 2020

최근 4차 산업혁명과 더불어 센서 네트워크와 같은 최신 무선통신 기술들의 기반시설 적용을 위한 연구들이 활발하게 이루어지고 있다. 원자력시설 또한, 보안 및 비상대응 시스템에 무선통신을 적용하기 위한 연구들이 진행되고 있으며, 미국과 UAE의 경우 이미 원자력시설에 무선통신을 적용하여 사용하고 있다. 그러나 무선통신의 경우, 물리적인 네트워크 접근 경로가 존재하지 않기 때문에 통신 경로에 대한 접근통제가 불가능하며 광범위한 지역에 네트워크를 설치하는 경우 중계 단말 수량의 증가로 인한 접근통제 취약점이 발생할 가능성이 있다. 이와 같은 무선통신의 특성 때문에 원자력시설의 필수디지털자산에 무선 네트워크를 적용 시 현재의 통신 경로 접근통제 등의 유선 통신을 기준으로 작성된 접근통제 규제기준으로는 무선통신에 대한 접근통제를 이행하기에는 부족함이 있다. 이에 본 논문에서는 무선 네트워크 접근통제를 위한 규제 기준 개선안을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.302-305
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• 2020

정보처리기술이 발달함에 따라 원자력시설에 대한 사이버침해 가능성이 갈수록 높아지고 있다. 방사능방재법 및 관련 법령에 의거하여 국내 원자력시설은 각 시설 별 사이버사건 비상대응 절차를 수립하고 절차의 유효성 및 비상대응조직의 대응역량을 제고하기 위한 목적의 주기적인 사이버사건 대응훈련을 실시하고 있으며, 규제기관의 독립적인 훈련평가 결과를 통해 많은 개선사항이 도출되고 있다. 본 논문에서는 현행 원자력시설의 사이버사건 대응훈련 체계를 분석하여 사이버사건대응 훈련 정책의 개념에 대해, 국내·외 기준에 따른 사이버사건 대응훈련 정책의 요소를 식별하여 이를 개선하기 위한 구체적인 규제방안을 제시한다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.1
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• pp.81-89
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• 2024

Highly radioactive waste is solidified to restrict leaching, retain its shape, and maintain its structural stability to prevent it from affecting humans and the environment as much as possible. This operation should be performed consistently regardless of whether the waste is homogeneous or heterogeneous. However, currently, there are no specific performance requirements for heterogeneous waste in Korea. This study reviewed domestic research results and the status of overseas applications, and proposed immobilization requirements for heterogeneous waste to be applied in Korea. IAEA safety standards, domestic laws, and waste acceptance criteria were reviewed. The status of heterogeneous waste immobilization in countries such as the United States, France, and Spain was reviewed. Most countries treat heterogeneous waste by encasing it in concrete, and impose immobilization requirements on this concrete. Based on these data, safety standards for the thickness, compressive strength, and diffusion limit of this concrete material were proposed as immobilization requirements for heterogeneous waste disposal in Korea. Quantitative values for the above requirements need to be derived through quantitative assessments based on the characteristics of domestic heterogeneous waste and disposal facilities.

• Nuclear Engineering and Technology
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• v.44 no.3
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• pp.249-260
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• 2012

Main focus of the combined nuclear research activities at Aachen University (RWTH) and the Research Center J$\ddot{u}$lich (J$\ddot{U}$LICH) is the experimental and analytical investigation of containment phenomena and processes. We are deeply convinced that reliable simulations for operation, design basis and beyond-design basis accidents of nuclear power plants need the application of so-called lumped-parameter (LP) based codes as well as computational fluid dynamics (CFD) codes in an indispensable manner. The LP code being used at our institutions is the GRS code COCOSYS and the CFD tool is ANSYS CFX mostly used in German nuclear research. Both codes are applied for safety analyses especially of beyond design accidents. Focal point of the work is containment thermal-hydraulics, but source term relevant investigations for aerosol and iodine behavior are performed as well. To increase the capability of COCOSYS and CFX detailed models for specific features, e.g. recombiner behavior including chimney effect, building condenser, and wall condensation are developed and validated against facilities at different scales. The close connection between analytical and experimental activities is notable and identifying feature of the RWTH/J$\ddot{U}$LICH activities.

• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.350-360
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• 2000

In Korea, the dose limits are reduced and are set at the ICRP-60 iimits. However, derived limits tabulated as MPC in air and water are still specified in Notice No.98-12. There are some discrepancies between the primary dose limits and MPCs in air and water. Therefore, in order to accept ICRP-60 recommendations fully, derived limits such as ALI, DAC, ECL for radiological protection against ionizing radiation based on ICRP-60 recommendations were calculated using modified methods of those of 10 CFR part 20, dose limits and committed effective dose coefficients of the Basic Safety Standards of the IAEA. The derived limits in this study were also compared with those prescribed in 10 CFR part 20 as well as MPCs of Notice No. 98-12 in order to analyze the impact of implementing derived limits on nuclear facilities. ECLs in air and water for the control of radioactive discharge into the environment in this study are shown to have lower values (i.e. more conservative), for most part, than those in Notice No. 98-12. Especially, for uranium elements, ECLs in water are approximately a magnitude in the order of two lower than those in Notice No.98-12.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.369-370
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• 2006

During demonstrations of a process conditioning spent nuclear fuels, it is necessary to transport and handle Spent fuel road cuts from Post Irradiation Examination facility to Slitting device in The hot cell. the spent fuel pellets which are highly radioactive materials are separated with its clad and are fed into the next conditioning process. For this, a spent fuel rod, 3.5 m long, is cut by 25 cm long which is suitable length for the decladding process. These rod-cuts are packed into the capsule and are moved to the ACPF(Advanced spent nuclear fuel Conditioning Process Facility). In the ACPF, Once the capsule is unloaded in the ACPF, Capsule is taken out one-by-one and installed on the decladding device. In these processes, the crushed spent fuel pellet can be scattered inside the facilities and thus it contaminate the hot cell. In this paper, we developed the specially designed transportation and storage device for spent nuclear fuel capsules.