• 전기전자학회논문지
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• 제20권1호
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• pp.61-67
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• 2016

본 논문에서는 중성자 방사선 측정을 위한 고속 고정밀 중성자 측정을 위한 하드웨어 설계방법을 제안한다. 제안된 고속 고정밀 중성자 측정 장치의 하드웨어 설계는 고성능 A/D 변환기를 사용하여 고정밀 고속의 아날로그 신호를 디지털 데이터로 변환할 수 있도록 구성된다. 중성자 센서를 사용하여 입사된 중성자 방사선 입자를 검출하고, 극저전류 정밀 측정 모듈을 통해 검출된 중성자 방사선을 보다 정밀하고 빠르게 측정하는 모듈을 설계한다. 고속 고정밀 중성자 측정을 위한 하드웨어 시스템은 중성자 센서부, 가변 고전압 발생부, 극저전류 정밀 측정부, 임베디드 시스템부, 디스플레이부 등으로 구성 된다. 중성자 센서부는 고밀도 폴리에틸렌을 통해 중성자 방사선을 검출하는 기능을 수행한다. 가변 고전압 발생부는 중성자 센서가 정상적으로 운영되기 위하여 발열 및 잡음 특성에 강인한 0 ~ 2KV 가변 고전압 발생장치의 기능을 수행한다. 극저전류 정밀 측정부는 중성자 센서에서 출력되는 고정밀 고속의 극저전류 신호를 고성능 A/D 변환기를 사용하여 정밀하고 빠르게 측정하고 아날로그 신호를 디지털 신호로 변환하는 기능을 수행한다. 임베디드 시스템부는 고속 고정밀 중성자 측정을 위한 중성자 방사선 측정 기능, 가변 고전압 발생장치 제어 기능, 유무선 통신 제어 기능, 저장 기능 등을 수행한다. 제안된 고속 고정밀 중성자 측정을 위한 하드웨어를 실험한 결과, 불확도, 중성자 측정 속도, 정확도, 중성자 측정 범위 등에서 기존의 장치보다 우수한 성능이 나타남을 확인할 수가 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2221-2225
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• 2003

As a result of using a heat generator to experiment the physiological influence of the human body due to the warming effect of far-infrared radiation (FIR), the blood pressure of the subjects lowered and stabilized due the expansion of capillary vessels and salt discharge during perspiration as the temperature of the generator elevated($30{\sim}65^{\circ}C$). In case of heart rate, it decreased and stabilized when the temperature of the ‘far-infrared radiation heat generator’ was at a low temperature below $40^{\circ}C$. At a high temperature above $44^{\circ}C$, there was a slow elevation in the heart rate. However, the elevation of the heart rate is not a sudden elevation, therefore, does not give much stress to the heart.

• 대한전기학회논문지:전력기술부문A
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• 제51권1호
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• pp.23-28
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• 2002

In order to survey the radiation characteristics of pure line noise of unwanted noise from overhead high voltage AC transmission lines, a disk type gap noise generator was manufactured. Disk size which decides capacitance between the noise generator and earth was selected through preliminary indoor experiments and analysis by using surface charge method. The capacitance is one of principal parameters related to the injection of a proper noise current into lines. On the basis of the capacitance obtained from calculation, 5mm of space was given to the gap of the noise generator to be installed o test line and an aluminum disk of 60cm radius was made. The field experiments were performed with the noise generator hung on the Kochang 765 kV full scale test line. As the results, the useful data which can be used to analysis the radiation characteristics of noise from transmission lines were obtained. Those are the directivity of antenna toward the line, lateral profiles, frequency spectra, height pattern and so on.

• 소음진동
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• 제8권1호
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• pp.112-121
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• 1998

In this report, Experimental analysis for main factors and analyzing methods of electro-magnetic noise and no loading noise was conducted because of noise of AC generator, which is peripheral equipment by reduction of engine noise that would be the main cause of vehicle radiation noise. In addition, This is intended to suggest the noise reduction development basis of AC generator for actual fan and electro-magnetic noise by making-analyzing-testing it's sample.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.152-161
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• 2022

We analyzed mitigation strategies for steam generator tube rupture (SGTR) accidents using MARS code under both full-power and low-power and shutdown (LPSD) conditions. In general, there are two approaches to mitigating SGTR accidents: supplementing the reactor coolant inventory using safety injection systems and depressurizing the reactor coolant system (RCS) by cooling it down using the intact steam generator. These mitigation strategies were compared from the viewpoint of break flow from the ruptured steam generator tube, the core integrity, and the possibility of the main steam safety valves opening, which is associated with the potential release of radiation. The "cooldown strategy" is recommended for break flow control, whereas the "RCS make-up strategy" is better for RCS inventory control. Under full power, neither mitigation strategy made a significant difference except for on the break flow while, in LPSD modes, the RCS cooldown strategy resulted in lower break and discharge flows, and thus less radiation release. As a result, using the cooldown strategy for an SGTR under LPSD conditions is recommended. These results can be used as a fundamental guide for mitigation strategies for SGTR accidents according to the operational mode.

• 대한기계학회논문집A
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• 제37권12호
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• pp.1567-1572
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• 2013

방사성동위원소 열전발전기는 장반감기 알파 혹은 베타 핵종에서 방출하는 하전입자를 차폐하여 방사선에너지를 열에너지로 전환하고 이때 발생하는 열전재료의 온도차를 이용하여 전력을 생산하는 시스템이다. 이 기술은 에너지 밀도가 높고 수명이 길며 신뢰성이 높아 우주개발, 국방 등 극한 환경에서 사용되는 장치, 센서 및 로봇 등의 에너지원으로 그 효용성이 매우 높다. 본 연구에서는 방사선 차폐해석 및 열전달 해석을 통하여 차폐체, 그리고 최대 온도구배를 가지는 열전재료의 형상과 배치를 결정하여 열전발전기 기초설계를 도출하였다.

• 전기학회논문지
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• 제58권3호
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• pp.486-495
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• 2009

This paper proposes a new methodology on reliability evaluation of a power system including solar cell generators (SCG). The SCGs using renewable energy resource such as solar radiation(SR) should be modeled as multi-state operational model because the uncertainty of the resource supply may occur an effect as same as the forced outage of generator in viewpoint of adequacy reliability of system. While a two-state model is well suited for modeling conventional generators, a multi-state model is needed to model the SCGs due to the random variation of solar radiation. This makes the method of calculating reliability evaluation indices of the SCG different from the conventional generator. After identifying the typical pattern of the SR probability distribution function(pdf) from SR actual data, this paper describes modelling, methodology and details process for reliability evaluation of the solar cell generators integrated with power system. Two test results indicate the viability of the proposed method.

• 한국방사선학회논문지
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• 제12권7호
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• pp.895-908
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• 2018

의료방사선의 관리에서 가장 중요한 사항은 진료의 적정성을 확보하면서 방사선위해를 최소화하는 것이다. 국제원자력기구는 진단방사선 분야의 선량 감소 방법에 대한 지침서를 만들어 환자피폭선량을 측정하여 각 국가에 사용하도록 권고하고 있다. 또한 국내에서도 우리나라의 실정에 맞게 각 촬영마다 환자 피폭 선량값을 연구하여 진단참고준위를 제시하였다.환자가 질병 때문에 방사선 진료를 받는 것은 방사선 때문에 일어날 수 있는 위해보다 그것으로 얻어지는 이익이 크기 때문이다. 병실 이동검사와 같이 자신의 질병과 무관하게 방사선에 노출되는 환자 및 보호자들의 피폭을 줄이기 위해서는 환자, 방사선사, 의사 및 의료기관의 노력이 가장 중요하다.이에 본 연구에서는 개선방안의 일환으로 MG로 병실의 이동 검사에 대한 문제점을 제시하고 이 문제점을 근거로 하여 산란선으로 예상되는 공간선량률을 분석하였다. MG에 자체 개발한 방어벽을 설치하여 방어벽 설치 전후의 공간선량률을 측정하여 그 감소율을 분석하였다. 최종적으로 이 자료들을 종합하여 MG에 방어벽을 부착하여 방사선사의 병실이동에 대한 부담감의 최소화, 병실 이동검사로 인한 방사선사, 환자 및 보호자를 방사선 노출로부터 보호하고, 검사로 인한 주위 환자 및 보호자의 불편을 최소화하는데 의의가 있다. 이와 같은 개선안에 대해 보다 효율적인 시행을 위하여 MG에 대한 새로운 법 제도가 마련되면, 향후 예상되는 비용, 인력, 고객만족도 및 더욱 더 안정적인 피폭감소방안이 정착될 것이라 사료된다.

• 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.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3854-3859
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• 2023

Background: This study aims to develop an evaluator that can quickly and accurately evaluate the shielding of low-energy industrial radiation generators. Methods: We used PyQt to develop a graphical user interface (GUI)-based program and employed the calculation methodology reported in the National Council on Radiation Protection and Measurements (NCRP)-49 for shielding calculations. We gathered the necessary factors for shielding evaluation using two libraries designed for Python, pandas and NumPy, and processed them into a database. We verified the effectiveness of the proposed program by comparing the results with those from safety reports of six domestic facilities. Results: After verifying the effectiveness of the program using the NCRP-49 example, we obtained an average error rate of 1.73%. When comparing the facility safety report and results obtained using the program, we found that the error rate was between 1.09% and 6.51%. However, facilities that did not use a defined shielding methodology were underestimated by 31.82% compared with the program (the final barrier thickness satisfied the shielding standard). Conclusion: The developed program provides a fast and accurate shielding evaluation that can assist personnel that work in radiation generator facilities and government officials in reviewing safety.