• International Journal of Safety
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• 제8권1호
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• pp.24-31
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• 2009

An effective assessment for decommissioning safety of nuclear facilities requires basic knowledge about possible risks, characteristics of potential hazards, and comprehensive understanding of the associated cause-effect relationships within a decommissioning for nuclear facility. This paper proposes an approach to develop the hierarchical structure and hazards of dealing with improving the complexity and uncertainty for decommissioning safety assessment of nuclear facilities and the resolutions are proposed to improve the complexity and uncertainty for decommissioning safety assessment of nuclear facilities. These resolutions can provide a comprehensive view of the risks in the decommissioning activities of a nuclear facility.

• 한국방사선학회논문지
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• 제9권3호
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• pp.125-130
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• 2015

방사선은 의료 분야 뿐 아니라 공업 분야, 농업 및 식품생명 분야 등에 이용되고, 소규모 방사선이용시설의 운영이 증가하고 있는 상황이다. 이에 소규모 방사선이용시설의 해체에 대한 관심을 가질 필요성이 있고, 시설 해체 시 발생될 문제점에 대해 예측해 볼 필요성이 있다. 원자력발전소 등의 대형방사선이용시설의 해체에 대한 대비는 진행되고 있으나, 상대적으로 위험성이 적은 소규모 방사선이용시설의 해체에 대해서는 대비가 부족한 상황이다. 사이클로트론의 방사화나 브라질 고이아니아의 방사성물질 누출사고를 생각해보면 소규모 방사선이용시설의 사고 시 그 영향은 대형 방사선이용시설에 비해 작지 않다. 이에 따라 본 연구에서는 국내에 비해 상대적으로 소규모 방사선이용시설 해체 사례가 많은 국외의 사례 중 국내에서 많이 가동되고 있는 사이클로트론, 방사선치료시설 등 시설별 특징에 대해 분석하였다. 또한, 소규모 방사선이용시설 해체 시 각 시설별 또는 공통적인 문제점으로는 시설과 선원의 재사용, 공간 부족, 이해 당사자의 개입, 대중의 방사선 노출이 나타났다. 이를 바탕으로 향후 소규모 방사선이용시설 해체 시 문제점을 해결할 수 있는 방안을 마련할 때 도움이 될 것으로 사료된다.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3505-3516
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• 2021

During nuclear facility decommissioning, workers are continuously exposed to high-level radiation. Hence, adequate path planning is critical to protect workers from unnecessary radiation exposure. This work discusses recent development in radioactive path planning and the algorithms recommended for the task. Specifically, we review the conventional methods for nuclear decommissioning path planning, analyze the techniques utilized in developing algorithms, and enumerate the decision factors that should be considered to optimize path planning algorithms. As a major contribution, we present the quantitative performance comparison of different algorithms utilized in solving path planning problems in nuclear decommissioning and highlight their merits and drawbacks. Also, we discuss techniques and critical consideration necessary for efficient application of robots and robotic path planning algorithms in nuclear facility decommissioning. Moreover, we analyze the influence of obstacles and the environmental/radioactive source dynamics on algorithms' efficiency. Finally, we recommend future research focus and highlight critical improvements required for the existing approaches towards a safer and cost-effective nuclear-decommissioning project.

• 소프트웨어공학소사이어티 논문지
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• 제25권1호
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• pp.11-18
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• 2012

원자력 시설 해체 사업은 해체 시 방사성 물질이 발생하기 때문에 시설 해체에 있어서 일반적인 해체 공법을 사용하기 어렵다. 그렇기 때문에 원자력 시설의 해체 계획을 수립하는데 해체 대상시설의 성격을 조사하고 파악하는 것이 매우 중요하며 해체 대상 원자력 시설의 특성 자료 조사는 해체 폐기물의 양을 예측하고 해체 사업의 비용 산정에 크게 활용이 된다. 한국원자력연구원에서는 이를 목적으로 해체사업 대상 시설의 특성자료를 관리하는 시스템 DEFACS(Decommissioning Facility Characterization DB System)을 개발하였다. 그러나 원자력 시설 해체에는 시간이 오래 걸리기 때문에 부득이하게 해체 사업 중에 시스템을 개발하였고 이는 지속적인 요구사항의 변경이 발생하는 원인이 되었다. 이러한 이유로 개발에 있어서 일반적인 개발 프로세스를 적용키 어려웠던 바, 본 논문에서는 개발 중 요구사항 변경에 대한 효율적인 대응을 하기 위하여 기존의 CBD(Compoenent Based Development) 프로세스를 CD(Component Development)와 CBSD(Component Based Software Development)로 구분하여 변경사항에 대한 핸들링을 하나의 컴포넌트로 다루고 컴포넌트 별로 CBD를 재적용하여 재귀적으로 프로세스를 핸들링한다. 이로써 컴포넌트 변경에 대한 전체 시스템의 변경점을 최소화하고 컴포넌트와 프로세스의 독립성을 강화함으로써 요구사항 변경으로 인한 프로세스의 중지를 최소화 하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2016년도 추계학술논문요약집
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• pp.351-352
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• 2016

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1951-1956
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• 2019

As a part of the preliminary decommissioning plan of KEPCO-NF fuel fabrication facility, DCGLs of three target radionuclides, ²³⁴U, ²³⁵U, and ²³⁸U, were derived using RESRAD-BUILD code and contaminated areas of the facility were classified based on contamination levels from the derived DCGLs. From code simulations, one-room modeling results showed that the grinding room in building #2 was the most restrictive (DCGL_gross = 10493.01 Bq/㎡). The DCGL_gross results in contaminated areas from one-room modeling were slightly more conservative than three-room modeling. Prior to the code simulation, field survey and measurements conducted by each survey unit. For a conservative approach, the most restrictive DCGL_gross in each survey unit was taken as a reference to classify the contaminated areas of the facility. Accordingly, seven rooms and 37 rooms in the nuclear-fuel buildings were classified as Class 1 and Class 2, respectively. As expected, fuel material handling and processing rooms such as the grinding room, sintering room, compressing room, and powder collecting room were included in the Class 1 area.

• 방사성폐기물학회지
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• 제20권4호
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• pp.511-521
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• 2022

Decommissioning of nuclear power plants generates a large amount of radioactive waste in a short period. Moreover, Radioactive waste has various forms including a large volumes of metal, concrete, and solid waste. The disposal of decommissioning waste using 200 L drums is inefficient in terms of economics, work efficiency, and radiation safety. Therefore, The Korea Radioactive Waste Agency is developing large containers for the packaging, transportation, and disposal of decommissioning waste. Assessing disposability considering the characteristics of the radioactive waste and facility, convenience of operation, and safety of workers is necessary. In this study, the exposure dose rate of workers during the disposal of new containers was evaluated using Monte Carlo N-Particle Transport code. Six normal and four abnormal scenarios were derived for the assessment of the dose rate in a near surface disposal facility operation. The results showed that the calculated dose rates in all normal scenarios were lower than the direct exposure dose limitation of workers in the safety analysis report. In abnormal scenarios, the work hours with dose rates below 20 mSv·y^-1 were calculated. The results of this study will be useful in establishing the optimal radiation work conditions.

• Nuclear Engineering and Technology
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• 제34권6호
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• pp.610-618
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• 2002

A study of the conceptual data modeling to realize the decommissioning database on the HRR-1&2 was carried out. In this study, the current state of the abroad decommissioning database was investigated to make a reference of the database. A scope of the construction of decommissioning database has been set up based on user requirements. Then, a theory of the database construction was established and a scheme on the decommissioning information was classified . The facility information, work information, radioactive waste information, and radiological information dealing with the decommissioning database were extracted through interviews with an expert group and also decided upon the system configuration of the decommissioning database. A code which is composed of 17 bit was produced considering the construction, scheme and information. The results of the conceptual data modeling and the classification scheme will be used as basic data to create a prototype design of the decommissioning database.

• 방사성폐기물학회지
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• 제21권3호
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• pp.329-345
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• 2023

This paper described a method for analyzing the structural performance of a metal container used for disposing radioactive waste generated during the decommissioning of a nuclear power plant, and numerical analysis results of a method for reinforcing the container. The containers to be analyzed were those that can be used in near-surface and landfill disposal facilities scheduled to be operated at the Gyeongju radioactive waste disposal facility. Structural reinforcement of the container was performed by lattice reinforcement, column reinforcement, and bottom plate reinforcement. Accordingly, a total of 14 reinforcement cases were modeled. The external force causing damage to the container was set equivalent to the impact of a 9-m fall, accounting for the height of the vault at the near-surface disposal facility. The reinforcement methods with a high contribution to the structural performance of the container were concluded to be lattice and column reinforcements.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.76-84
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• 2021

Radioactive waste generated from nuclear power plant decommissioning shall be strictly managed so that radioactive materials above the allowable limit are not leaked into the environment. Radioactive wastes shall be classified and treated for management based on characteristics such as the type of waste, physicochemical properties, nuclide concentration and radioactivity. Waste characterization report shall be prepared and submitted to the disposal facility operator to ensure that the treated waste is suitable for disposal. The disposal facility operator shall review the waste Characterization report and visit the nuclear power plant decommissioning site to ensure that the wastes are processed step by step according to the plan. The waste Characterization report may be used as input data to evaluate disposal facility safety. Domestic and foreign data are collected and reviewed to confirm the entire processes from waste generation to delivery. This paper proposes the method to prepare the waste Characterization report which contains data and information on waste characteristics, treatment facilities & method and packaging method & container.