• 방사선산업학회지
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• 제18권1호
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• pp.43-52
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• 2024

Currently, there are no interim storage facilities and permanent disposal facilities in Korea, so all spent nuclear fuels are temporarily stored. However, the temporary storage facility is approaching saturation, and as a measure to this, the 2nd Basic Plan for the Management of High-Level Radioactive Waste presented an operation plan for dry interim storage facilities and dry temporary storage facilities on the NPP on-site. The dry storage can be operated in various ways, and to select the optimal dry storage method, the reduction of exposure for workers must be considered. Accordingly, it is necessary to develop a worker exposure scenario according to the dry storage method and evaluate and compare the radiological impact for each method. The purpose of this study is to develop an exposure scenario for workers transporting spent nuclear fuel by dry storage method. To this end, first, the operation procedure of the foreign commercial spent nuclear fuel dry storage system was analyzed based on the Final Safety Analysis Report (FSAR). 1) the concrete overpack-based system, 2) the metal overpack-based system, and 3) the vertical storage module-based system were selected for analysis. Factors were assumed that could affect the type of work (working distance, working hours, number of workers, etc.) during transportation work. Finally, the work type of the processes involved in transporting spent nuclear fuel by dry storage method was set, and an exposure scenario was developed accordingly. The concrete overpack method, the metal overpack method, and the vertical storage module method were classified into a total of 31, 9, and 23 processes, respectively. The work distance, work time, and number of workers for each process were set. The product of working hours and number of workers (Man-hour) was set high in the order of concrete overpack method, vertical storage module method, and metal overpack method, and short-range work (10 cm) was most often applied to the concrete overpack method. The results of this study are expected to be used as basic data for performing radiological comparisons of transport workers by dry storage method of spent nuclear fuel.

• 한국전산구조공학회논문집
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• 제18권3호
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• pp.303-309
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• 2005

본 연구에서는 국내 원전에서 기기 정착을 위하여 가장 널리 적용되는 직매형 앵커기초를 대상으로 앵커기초의 인장 설계기준에 대한 적정성을 검토하기 위하여 수치해석이 수행되었다. 본 연구에서 수치해석모형에 적용된 파괴기준으로서 콘크리트와 같은 유사 취성재료에는 Microplane모형이, 앵커볼트와 같은 연성재료에는 탄성-완전 소성모형이 적용되었다. 그리고, 균열 발생현상을 모사하기 위하여 분산균열모형을 채택하였다. 개발된 수치해석모형은 다양한 경우의 실증시험결과를 근거로 신뢰성이 검증되었으며, 검증된 수치해석모형과 앵커볼트의 유효매입깊이를 변수로 한 다양한 경우에 대한 수치해석을 통하여 직매형 앵커기초의 인장설계기준으로서 적용이 가능한 ACI 349 Code와 CEB-FIP Code가 평가되었고, 그 보수성이 확인되었다.

• 방사선산업학회지
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• 제18권2호
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• pp.133-140
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• 2024

The Korean 2^nd basic plan for management of high-level radioactive waste presented a plan to manage spent nuclear fuel through dry storage facilities in NPP on-site. For the construction and operation of the facility, it is necessary to develop the monitoring system of the integrity of spent nuclear fuel before operation. NUREG-1536 recommends that the theoretical cask array, typically in the 2×10 array, should account for shadowing effect among the dry storage casks. The objective of this study was to evaluate neutron flux accounting for shadowing effect among dry storage casks. The neutron release rate was evaluated using ORIGEN based on the design basis fuel condition. And the simulation of dry storage casks and evaluation of the shadowing effect were performed using MCNP. Shadowing effect of other dry storage casks was the highest at the center of the dry storage facility of the 2×10 array compared with the outside of the cask. The shadowing effect of neutron flux on the surface among the metal casks was approximately 18% at point 1, 23% at point 2, and 43% at point 3. For the concrete casks, the shadowing effect of neutron flux on the surface was approximately 46% at point 1, 51% at point 2, and 52% at point 3. This means that correction is necessary to monitor the integrity of spent nuclear fuel in each dry storage cask through evaluation of shadowing effect. The results of this study will be used for comparative analysis of neutron measurement data from spent nuclear fuels in dry storage cask. Additionally, the neutron flux evaluation procedure used in this study could be used as the basic data of safety assessment of dry storage cask and development of safety guide.

• 한국전산구조공학회논문집
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• 제27권5호
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• pp.437-450
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• 2014

원전의 항공기 충돌 리스크 평가에 사용되는 대표매개변수를 선정하기 위한 방법론을 개발하였다. 대상 원전은 국내의 대표적인 경수로형 원전 중 하나로 선정하여 3차원 유한요소 해석 모델을 구축하였다. 콘크리트 재료모델에는 소성손상모델이 적용되었으며, 강재는 다중선형곡선거동을 가지는 것으로 모델링하였다. 운동에너지, 전체 충격량, 최대 충격량, 최대 하중등 4종의 대표매개변수 후보군을 선정하였다. 각각의 매개변수 후보군은 모두 충돌 속도와 질량의 함수로 표현되므로, 충돌속도 50~200m/s, 항공유량 30~90%의 범위에 대하여 매개변수값을 도출하고 충돌 해석을 수행하여, 충돌 시의 구조 응답과의 상관관계를 분석하였다. 모든 해석에서 항공기의 기종은 보잉767 기종으로 선정하였다. 충돌해석에는 Riera의 하중-시간 이력 함수를 이용한 해석기법을 적용하였다. 매개변수와 충돌 시 응답의 상관관계 적합성은 결정계수값을 이용하여 분석하였다. 4 종의 대표매개변수 후보군 중 최대 하중값이 가장 직관적일 뿐만 아니라 본 연구에서의 해석 케이스에서는 응답과의 상관성도 가장 뛰어난 것으로 나타남에 따라, 항공기충돌 리스크 평가를 위하여 가장 적합한 매개변수라 할 수 있을 것으로 판단되었다.

• 한국전산구조공학회논문집
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• 제28권6호
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• pp.715-722
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• 2015

프리스트레스(PS) 긴장재의 긴장력 관리는 거더 성능관리에 있어 매우 중요한 항목이나 현재는 시공시 설계 긴장력의 도입 여부만을 검증한 후 공용시에는 그 관리가 이루어지지 않는 실정이다. 이에 본 연구에서는 PSC 거더의 제작단계에서부터 공용시까지 생애주기 동안의 긴장력 관리가 가능한 PSC 거더를 제안하기 위한 기초 연구로서, 현재의 기술수준으로 사용 가능한 센서들을 이용하여 PS 긴장력을 측정하는 실험 연구를 수행하였다. 소규모 거더를 제작하여 4종류의 센서를 설치하였고, 긴장력을 도입하면서 각 센서들의 적용성과 정확성을 평가하였다. 실험결과에 따르면, 중공로드셀은 편심하중이 작용하는 경우 기준값보다 하중을 높게 평가하는 경향이 있었다. EM 센서는 실용이 가능한 정확도를 보여주었으며, 콘크리트 내부의 긴장재를 따라 어느 위치에서도 설치할 수 있다.

• 시스템엔지니어링학술지
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• 제17권1호
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• pp.65-75
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• 2021

When the decommissioning of South Korea nuclear power plants is promoted in earnest with the permanent shutdown of Kori Unit 1 in 2017, a large amount of various types of radioactive waste will be generated. For minimal generation and safe management of decommissioning waste, the waste should be made by appropriate classification of the dismantling waste characteristics in accordance with physical, chemical and radiological characteristics to meet the acceptance criteria of disposal facilities. Replacing the preliminary inspection at the site for the compliance of the waste acceptance criteria (WAC) of medium and low-level radioactive waste with the generator's own radioactive waste certification program (WCP), from the perspective of disposal, the optimization of waste management at the national level contributes to the efficient availability of disposal, such as the processing of non-conforming radioactive wastes at the site. To this end, it is important to evaluate radioactivity in each system and area such as nuclear reactors before decommissioning is carried out in earnest, and the prior removal of harmful wastes is important. From waste collection to waste disposal, decommissioning waste should be managed at each stage in consideration of the acceptance criteria of disposal facilities to minimize the generation of non-conforming waste.