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        검색결과 3

        1.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 일본잎갈나무 임분의 지위지수식을 도출하고, 지위지수별 연평균생장량의 차이 및 연평균생장량을 구할 수 있는 추정식을 도출하고자 수행되었다. 본 분석은 국가산림조사에서 일본잎갈나무림으로 판단된 표준지를 대상으로 하였으며, 이용된 표준지 개소수는 576개소였다. 지위지수는 Schumacher 모델을 적용시켜 도출하였으며, 이의 통계적 적합도는 59%였고, 편의는 –0.0002으로 아주 낮게 나타났다. 따라서 추정식은 활용에 있어 문제가 없을 것임을 확인할 수 있었다. 지위지수의 높고 낮음에 따라 연평균생장량의 평균값이 차이가 발생하는지 확인하기 위해 시도한 t-test는 5% 유의수준에서 유의성이 인정되었다. 그러므로 일본잎갈나무를 심을 때 적지적수에 조림한다면, 본 분석 결과와 같이 연평균생장량도 우수하게 될 것이다. 연평균생장량은 지위지수가 변함에 따라 발생할 수 있는 것이므로, 지위지수를 설명변수로 하는 연평균생장량 추정식이 국내 처음으로 도출되었다. 본 분석은 직선식, 곡선식, 지수식 등 5가지 수식을 적용시켰으며, 분석 결과, 식의 적합도 지수는 0.25∼0.26의 범위에 있었고, 편의는 –0.0002∼0.0016, 오차의 표준오차는 2.88∼2.92 인 것으로 나타났다. 도출된 5개 수식에 대해 지위지수를 X축으로 하는 잔차도를 그려본 결과, 잔차는 모두 “0”을 중심으로 고르게 분포하고 있어, 통계적 수치 등을 고려할 때 본 추정식은 충분히 사용 가능할 것이다.
        4,000원
        2.
        2022.05 서비스 종료(열람 제한)
        Radioactive waste generated during the decommissioning of Kori Unit 1 can be packaged in a transport container under development and transported to a disposal facility by sea transport or land transport. In this study, the cost of each transport method was evaluated by considering the methods of land transport, sea transport, and parallel transport of the radioactive waste dismantled at Kori Unit 1. In evaluating the shipping cost, the shipping cost was evaluated by assuming the construction of a new ship without considering shipping by CHEONG JEONG NURI, which is currently carrying operational waste. Since the cargo hold of CHEONG JEONG NURI was built to fit the existing operating waste transport container and is not suitable for transporting the transport container currently under development, sea transport using CHEONG JEONG NURI was excluded in this paper. In the case of on-road transportation, the final fare for each distance was calculated in accordance with the Enforcement Decree of the Freight Vehicle Transportation Business Act, and the cost of onroad transportation was evaluated by estimating the labor cost of the input manpower required for onroad transportation. The cost of on-road transportation was estimated to be approximately KRW 510 million, the product of the total number of transports 459 times the sum of the cost of transportation vehicle freight cost of about KRW 720,000 and the labor cost of input personnel of KRW 380,000. It is difficult to predict the cost of building a new ship at this point, as the cost of building new ship is determined by the cost of number of items such as ship design specifications and material prices, labor costs, and finance costs at the time of construction. Accordingly, considering the 2% annual inflation rate based on the shipbuilding cost (about KRW 26 billion) and financing cost (about KRW 12 billion) at the time of construction of the CHEONG JEONG NURI (2005 yr.), decommissioning of Kori Unit 1 (2025 yr.) construction cost finance cost was estimated and evaluated. According to the result of comparing the transport cost for each transport scenario, land transport is about 510 million won, which is advantageous in terms of economic feasibility compared to the sea transport scenario. However, when transporting by land, it is disadvantageous in terms of acceptability of residents because it is transported multiple times on general roads. The cost of building a new ship is about KRW 56.4 billion, which is disadvantageous in terms of the cost of transporting waste from the dismantling of Kori Unit 1. But, in the future, cost reduction can be expected if waste materials issued when dismantling nuclear power plants are transported.
        3.
        2022.05 서비스 종료(열람 제한)
        Glass fiber, which was used as an insulation material in pipes near the steam generator system of nuclear power plants, is brittle and the size of crushed particles is small, so glass fiber radioactive waste (GFRW) can cause exposure of workers through skin and breathing during transport and handling accidents. In this study, Q-system which developed IAEA (International Atomic Energy Agency) for setting the limit of radioactivity in the package is used to confirm the risk of exposure due to an accident when transporting and handling GFRW. Also, the evaluated exposure dose was compared with the domestic legal effective dose limit to confirm safety. Q-system is an evaluation method that can derive doses according to exposure pathway (EP) and radioactivity. Exposure doses are calculated by dividing into five EP: QA, QB, QC, QD, and QE. Since the Q-system is used to set the limit of radioactivity that the dose limits is satisfied to nearby workers even in package handling accidents, the following conservative assumptions were applied to each EP. QA, QB are external EP of assuming complete loss of package shielding by accident and radiation are received for 30 minutes at 1 m, QC is an internal EP that considers the fraction of nuclides released into the air and breathing rate during accident, and QD is an external EP that skin contamination for 5 hours. Finally, QE is an internal and external EP by inert gases (He, Ne, Ar, Kr, Xe, Rn) among the released gaseous nuclides, but the QE pathway was excluded from the evaluation because the corresponding nuclide was not present in the GFRW products used for evaluation. In this study, the safety evaluation of GFRW was performed package shielding loss and radioactive material leakage due to single package accident according to assumption of four pathways, and the nuclide information used the average radioactivity for each nuclide of GFRW. As a result of the dose evaluation, QA was evaluated as 2.73×10−5 mSv, QB as 1.06×10−6 mSv, QC as 7.53×10−3 mSv, and QD as 2.10×10−6 mSv, respectively, and the total exposure dose was only 7.56×10−3 mSv, it was confirmed that when compared to the legal limits of the general public (1 mSv) and workers (20 mSv) 0.756% and 0.038%, respectively. In this study, it was confirmed that the legal limitations of the general public and workers were satisfied evens in the event of an accident as a result of evaluating the exposure dose of nearby targets for package shielding loss and radioactive material leakage while transporting GFRW. In the future, the types of accidents will be subdivided into falling, fire, and transportation, and detailed evaluation will be conducted by applying the resulting accident assumptions to the EP.