• Journal of Radiation Protection and Research
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• 제28권2호
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• pp.127-135
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• 2003

The primary contributors to the total occupational radiation exposure in operating nuclear power plants are operation and maintenance activities doting refueling outages. The Advanced Power Reactor 1400 (APR1400) includes a number of design improvements and plans to utilize advanced maintenance methods and robotics to minimize the annual collective dose. The major radiation exposure reduction features implemented in APR1400 are a permanent refueling pool seal, quick opening transfer tube blind flange, improved hydrogen peroxide injection at shutdown, improved permanent steam generator work platforms, and more effective temporary shielding. The estimated average annual occupational radiation exposure for APR1400 based on the reference plant experience and an engineering judgment is determined to be in the order of 0.4 man-Sv, which is well within the design goal of 1 man-Sv. The basis of this average annual occupational radiation exposure estimation is an eighteen (18) month fuel cycle with maintenance performed to steam generators and reactor coolant pumps during refueling outage. The outage duration is assumed to be 28 days. The outage work is to be performed on a 24 hour per day basis, seven (7) days a week with overlapping twelve (12) hour work shifts. The occupational radiation exposure for APR1400 is also determined by an alternate method which consists of estimating radiation exposures expected for the major activities during the refueling outage. The major outage activities that cause the majority of the total radiation exposure during refueling outage such as fuel handling, reactor coolant pump maintenance, steam generator inspection and maintenance, reactor vessel head area maintenance, decontamination, and ICI & instrumentation maintenance activities are evaluated at a task level. The calculated value using this method is in close agreement with the value of 0.4 man-Sv, that has been determined based on the experience aid engineering judgement. Therefore, with the As Low As Reasonably Achievable (ALARA) advanced design features incorporated in the design, APR1400 design is to meet its design goal with sufficient margin, that is, more than a factor of two (2), if operated on art eighteen (18) month fuel cycle.

• Journal of Korean Society for Atmospheric Environment
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• 제10권E호
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• pp.299-302
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• 1994

At a nuclear power plant, environmental radioactivity monitoring is routine work for the radiation safety management For the environmental monitoring of tritium($^3$H) activity in water sampled liquid scintillation counting( LSC) method is applied to measure low- energy beta activity from tritium in the samples. The $^3$H activity is measured using the BECKMAN 5801 system at the KRISS( Korea Research Institute of Standards and Science) for evaluating the lower limits of detection( LLD) of $^3$H measurement and the measuring capability of low-level $^3$H activity at four nuclear Power Plant sites. The LSC systems used for low-level $^3$H activity measurements at the nuclear Power Plants are confirmed to satisfy throughout an intercomparison study under the experimental arrangements by the KRISS.

• Journal of Radiation Protection and Research
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• 제39권2호
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• pp.118-126
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• 2014

향후 여론의 주도층이 될 일부 초, 중, 고등학생을 대상으로 방사선이용 분야 중 일반적으로 사회적 수용성이 절실히 필요한 방사선조사식품, 원자력발전, 의료방사선에 대한 인식, 지식 및 태도를 설문 조사한 결과 사회적 수용성 증진을 위한 교육적 근거가 일부 도출되었다. 첫째, 여학생 중심의 수업과 남학생 중심의 수업설계에 차별화된 전략이 필요하다. 여학생 보다 남학생이 방사선조사식품의 객관적 지식수준(p<0.039), 원자력발전의 필요성(p<0.001) 및 객관적 지식(p<0.001), 우리나라 원자력발전소 건설 찬성태도 (p<0.000), 의료방사선의 필요성(p<0.001) 및 객관적 지식(p<0.001), 의료방사선 이용 태도(p<0.007, p<0.001)가 모두 높기 때문이다. 둘째, 원자력발전의 필요성, 안전성에 대한 국민 이해를 돕기 위한 설명에서는 의료방사선의 필요성과 안전성에 대한 정보를 함께 제공하는 것이 교육효과를 높일 수 있다. 남, 여학생 모두 의료방사선이 가장 필요하며(p<0.001), 의료방사선이 가장 안전하며(p<0.001), 원자력 발전이 가장 안전하지 않다고(p<0.013) 인식하고 있다. 또한 의료방사선과 원자력 발전의 상관관계가 가장 높게 나타났기 때문이다. 셋째, 초, 중, 고등학생이 방사선이용 분야별로 인식의 패턴이 다르므로 학급별로 차별화된 강의내용이 필요하다. 초등학생은 원자력발전에 대한 교육흥미도가 높고(p<0.005), 방사선조사식품이 안전하다고 인식하고 있으며(p<0.001), 방사선조사식품을 섭취하겠다는 태도가 가장 높았다(p<0.001). 중학생은 의료방사선에 대한 교육흥미도가 높고(p<0.018), 원자력발전(p<0.001)과 의료방사선(p<0.002)에 대해 안전하다고 인식하고 있으며, 치료 방사선이용 태도가 가장 높았다(p<0.001). 고등학생은 원자력발전(p<0.001)과 의료방사선(p<0.001)에 대한 객관적 지식수준이 가장 높고, 의료방사선이 가장 필요하다고 인식하고 있으나(p<0.017), 원자력발전이 가장 안전하지 않다고 인식하고 있다(p<0.001). 방사선조사식품 섭취 태도(p<0.001), 거주지에 원자력발전 건설을 찬성하는 태도(p<0.001) 모두 낮았다. 넷째, 객관적 지식 중심의 교육제공보다 인식변화 및 태도증진을 위한 교육프로그램이 제공되어야 한다. 객관적 지식과 방사선조사식품의 필요성, 객관적 지식과 원자력발전에 대한 안전성 및 교육흥미도, 객관적 지식과 의료방사선의 교육흥미도 및 정보습득에는 상관관계가 없었다. 특히, 고등학생의 경우 객관적 지식수준은 가장 높았으나 거주지의 원자력발전 건설에 대해 찬성하는 태도와 방사선조사식품 섭취태도가 가장 낮았기 때문이다. 국내에서 원자력 및 방사선이용에 대한 사회적 수용성을 향상시키기 위해 필요성과 안전성에 대한 인식과 지식 및 태도 향상에 관한 교육프로그램을 전략적으로 제공하는 것이 바람직하다.

• Journal of Radiation Protection and Research
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• 제29권1호
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• pp.9-15
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• 2004

방사선에 의해 유도되는 사람 말초혈액 림프구 미소핵 관찰빈도를 높이면서 생물학적 선량평가법으로서 활용 가능성을 확인하고자 본 연구를 수행하였다. 우선 5명의 건강한 사람으로부터 혈액을 제공 받아 선량영역을 0에서 800cGy로 하여 감마선$(^{137}Cs)$을 조사 한 후 김사와 아크리딘 오렌지 형광 염색하고 미소핵 출현빈도를 비교하였다. 아크리딘 오렌지 염색법을 이용하여 미소핵을 관찰하였을 때, 김사 염색법에 비교하여 적갈색의 비특이성 과립과 녹황색의 DNA가 붉은색의 세포질을 배경으로 명확히 구별되었을 뿐만 아니라 선량이 증가하면서 검출율도 높았다. 아울러, 말초혈액 T와 B-림프구에 대하여 선량영역을 0에서 50cGy로 하여 방사선을 조사한 후 미소핵 출현빈도를 아크리딘 오렌지 염색하여 김사염색과 비교한 바, B-림프구에서 선량이 증가하면서 적어도 2배 이상 높게 관찰되었다. 본 실험 결과, 사람 말초 혈액 B-림프구를 대상으로 한 아크리딘 오렌지 형광염색 미소핵 분석법은 저선량 방사선 인체영향 평가나 과피폭 선량추정시 활용이 가능 할 것으로 생각된다.

• Steel and Composite Structures
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• 제50권3호
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• pp.299-318
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• 2024

The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

• Journal of Radiation Protection and Research
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• 제38권4호
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• pp.237-241
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• 2013

국내 가압경수로형 원전 계획예방정비기간에 수행되는 주요 방사선작업에 대한 감마선 에너지 분포를 측정하였다. 고방사선구역 작업시 종사자가 착용하는 대표적인 납 차폐복에 대하여 감마선 에너지 분포에 따른 차폐효과를 평가하기 위해 전산모사 방법을 이용하였다. 전산모사는 MIRD형 인체모형에 추가적으로 납 차폐복을 모델링하고 측정된 감마선 에너지 정보를 이용하여 수행하였다. 주요 방사선작업의 평균 감마선 에너지는 일반적으로 방사선방호 과정에서 적용되는 기준 방사선에너지 보다 낮은 것으로 평가되었다. 방사선 방호 목적을 달성하기 위한 효율적인 납 차폐복 착용을 위해 방사선작업 지역의 방사선에너지 분포평가의 필요성을 확인하였다.

• 디지털산업정보학회논문지
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• 제10권3호
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• pp.41-48
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• 2014

This paper provides the design of system software for the management of radiation dose that is generated by using computerized tomography(CT). Recently, the radiation leakage incident of Japanese nuclear power plant was in the news internationally and there is a growing interest not only in nuclear power plant but in medical radiation exposure. In spite of the fact that currently safety management of radiation is under control only the workers of the radiation involved, now the exposure management of patients have been required. As surgery and inspections using the radiation have increased, this medical radiation exposure is increasing too. But it is a real situation that medical institutions don't know the level of radiation exposure applied to the patient. Therefore, a system for managing the radiation exposure of a patient from the medical institution is required. This paper proposes a design of a software program that manages the radiation exposure of CT which is a typical imaging tool to use the radiation in the medical institution. By check the amount of radiation dose and set the limit of dose, we would be of help to optimize the medical exposure of the patient.

• 방사성폐기물학회지
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• 제19권2호
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• pp.243-253
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• 2021

In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.

• Journal of Power Electronics
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• 제10권4호
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• pp.405-411
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• 2010

This paper proposes a novel tracking algorithm considering radiation to improve the power of a photovoltaic (PV) tracking system. The sensor method used in a conventional PV plant is unable to track the sun's exact position when the intensity of solar radiation is low. It also has the problem of malfunctions in the tracking system due to rapid changes in the climate. The program method generates power loss due to unnecessary operation of the tracking system because it is not adapted to various weather conditions. This tracking system does not increase the power above that of a power of tracking system fixed at a specific position due to these problems. To reduce the power loss, this paper proposes a novel control algorithm for a tracking system and proves the validity of the proposed control algorithm through a comparison with the conventional PV tracking method.

• 대한수의학회지
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• 제43권3호
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• pp.333-338
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• 2003

Cytogenetic and hematological analysis was performed in bovine peripheral blood from the regions around Wolsong nuclear power plant and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from cattle was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dare of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the bovine lymphocytes exposed in vitro to radiation over the range from 0 Gy to 4 Gy. MN rates in lymphocytes of cattle from Wolsong nuclear power plant and control area were 9.87/1,000 and 9.60/1,000, respectively. There were no significant differences in MN frequencies and hematological values in cattle between Wolsong and control area. The study indicates that the MN assay is a rapid, sensitive and accurate method that can be used to monitor a large population exposed to radiation.