• 환경생물
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• 제26권1호
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• pp.15-21
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• 2008

Ionizing radiation causes many alterations in photosynthetic machineries. However, there is no information about effects of ionizing radiation on the development of photosynthetic machineries in plants. We investigated the greening of etiolated mung bean seedlings after gamma-irradiation of 50 to 300 Gy. The irradiation inhibited seedling growth with great dependence on the radiation dose. In particular, growth of stems was more affected than that of hypocotyls. Irradiated leaves showed inhibition in growth, aberration in morphology, and yellowing in color depending on the radiation dose. Contents of photosynthetic pigments such as chlorophylls and carotenoids were significantly decreased in the irradiated leaves. The apparent electron transport rate for photosynthesis, ETR, was similarly changed depending on the radiation dose. However, the maximal photochemical efficiency of Photosystem II (PSII), Fv/Fm, was little affected by the irradiation. Moreover, the 50-Gy seedlings maintained the control level of light saturating for photosynthesis and showed slightly higher Fv/Fm values in spite of significant decreases in the photosynthetic pigment content and ETR. These results suggest that the inhibition of the overall photosynthetic capacity couldn’t be causally relatqaed with the repression in the initial development of irradiated seedlings and that the overall photosynthetic machineries can develop and work to some extent as a concerted system for photosynthesis even after exposure to acute doses of ionizing radiation.

• 분석과학
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• 제35권2호
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• pp.69-81
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• 2022

The method of measuring and classifying the energy category of neutrons directly using raw data acquired through a CZT detector is not satisfactory, in terms of accuracy and efficiency, because of its poor energy resolution and low measurement efficiency. Moreover, this method of measuring and analyzing the characteristics of low-energy or low-activity gamma-ray sources might be not accurate and efficient in the case of neutrons because of various factors, such as the noise of the CZT detector itself and the influence of environmental radiation. We have therefore developed an efficient method of analyzing radiation characteristics using a neutron and gamma-ray analysis algorithm for the rapid and clear identification of the type, energy, and radioactivity of gamma-ray sources as well as the detection and classification of the energy category (fast or thermal neutrons) of neutron sources, employing raw data acquired through a CZT detector. The neutron analysis algorithm is based on the fact that in the energy-spectrum channel of 558.6 keV emitted in the nuclear reaction ¹¹³Cd + ¹n → ¹¹⁴Cd + in the CZT detector, there is a notable difference in detection information between a CZT detector without a PE modulator and a CZT detector with a PE modulator, but there is no significant difference between the two detectors in other energy-spectrum channels. In addition, the gamma-ray analysis algorithm uses the difference in the detection information of the CZT detector between the unique characteristic energy-spectrum channel of a gamma-ray source and other channels. This efficient method of analyzing radiation characteristics is expected to be useful for the rapid radiation detection and accurate information collection on radiation sources, which are required to minimize radiation damage and manage accidents in national disaster situations, such as large-scale radioactivity leak accidents at nuclear power plants or nuclear material handling facilities.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.449-455
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• 2022

The rapid rise in the application of novel treatment techniques, such as intensity-modulated radiotherapy (IMRT), motivated us to survey the status of Korea's radiation safety management and the shielding designs of facilities employing medical linear accelerators (LINACs). To this end, a questionnaire was used to collect information on LINAC facilities and treatments, workload, shielding design, shielding management, and path of obtaining shielding information. Out of 100 domestic institutions, 52 responded to the survey. Approximately 70% of the institutions utilized IMRT for more than 60% of their cases, and an IMRT factor of 5 was adopted by 75% of these institutions. Over 80% of the institutions accounted for the applied time-averaged dose rate per week and instantaneous dose equivalent rates in their shielding designs. Approximately 45% of the institutions obtained important shielding information via a radiation shielding design company and the NCRP-151 report. Overall, most facilities were shown to follow the standards recommended by the relevant international agencies. However, the requirement to establish standardized shielding design information and clarify ambiguous paths for information acquisition was also highlighted. Therefore, the study's results can be used as a foundation for establishing a safety control system and for creating adequate shielding designs.

• 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.

• 한국정보전자통신기술학회논문지
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• 제11권6호
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• pp.793-799
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• 2018

CCD카메라는 방사선에 쉽게 열화되어 고방사선구역에서는 촬상관을 이용한 일체화된 카메라가 사용되고 있다. 이를 방사선에 강한 전자부품을 사용한 카메라헤드부와 방사선에 약한 TR, IC등을 사용한 원격제어부로 분리제작한 내 방사선 카메라시스템을 구현하였다. 실험결과 전자부품 중 가장 먼저 손상된 것은 수평 및 수직 동기 발생 IC이었으며 $2{\times}10^5{\sim}10^6rad$의 방사선이 누적되면 정상적인 기능이 상실됨을 확인하였다. 또한 원격화를 위한 신호전송 케이블은 입출력 버퍼회로를 부가하고 쉴드와 케이블의 폐루프면적을 감소시켜 신호 손실보정 및 노이즈를 제거하였다. 따라서 전체의 시스템을 교체하는 것이 아니라 카메라 헤드부분만을 교체하여 사용할 수 있으므로 실용적이며 관리 유지비용이 많이 절감 될 것으로 기대된다.

• 한국정보통신학회논문지
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• 제18권6호
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• pp.1488-1493
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• 2014

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류 안전 보안 핵심기술 개발이 이루어지고 있다. 이러한 국제적 정서에 발맞추어, 국내에서도 감마선 핵종을 검출할 수 있는 휴대용 방사선 검출 장치에 대한 관심이 높아지고 있다. 본 논문에서는 Cortex-A9을 이용한 휴대용 방사선 검출장치 플랫폼 검출 성능의 향상을 위한 연구하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.202-205
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• 2016

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류안전 보안 핵심기술 개발이 이루어지고 있다. 이러한 국제적 정서에 발맞추어, 국내에서도 감마선 핵종을 검출할 수 있는 휴대용 방사선 검출 장치에 대한 관심이 높아지고 있다. 본 논문에서는 방사선 검출에 대한 검사 장비의 성능을 높이려고 온도 보정 Algorithm을 적용한 Digital 휴대용 방사선 검출기 구현에 대한 연구를 제안하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.373-376
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• 2014

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 해운물류 안전 보안 핵심기술 개발이 이루어지고 있다. 이러한 국제적 정서에 발맞추어, 국내에서도 감마선 핵종을 검출할 수 있는 휴대용 방사선 검출 장치에 대한 관심이 높아지고 있다. 본 논문에서는 Cortex-A9을 이용한 휴대용 방사선 검출장치 플랫폼 검출 성능의 향상을 위한 연구를 제안한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.1023-1026
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• 2013

위 펄스형 방사선에 노출된 전자장비는 전자소자 내부에서 발생되는 전자-정공쌍(EHP)과 이들이 형성한 순간 광전류로 Upset, Latchup, Burn out 과 같은 다양한 피해를 입게 된다. 이와같은 손상은 군무기체계나 우주항공 장비의 경우 군전력 손실이나 장비의 기능정지로 나타나 국가적으로 큰 손실을 초래할 수 있다. 본 연구에서는 펄스형 감마방사선으로 부터 전자장비/소자를 보호하기 위한 방호기술개발의 일환으로 '방사선 감지 및 제어장치'를 구현하고 대표적으로 군장비에 사용되는 전자소자에 대한 기능검증을 시도하였다. 펄스 방사선에 Latchup 및 Burn out 손상특성을 나타내는 LM118 소자에 개발한 '방사선 감지 및 제어장치'를 적용하여 펄스방사선 조사시험을 수행한 결과 LM118이 안전하게 보호됨을 확인하였다.

• Journal of the Korean Data and Information Science Society
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• 제17권2호
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• pp.581-598
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• 2006

In many epidemiological and medical studies, a number of cancer mortalities in categorical classification may be considered as having Poisson distribution with person-years at risk depending upon time. The cancer mortalities have been evaluated by additive or multiplicative models with regard to background and excess risks based on several covariances such as sex, age at the time of bombings, time at exposure, or ionizing radiation, cigarette smoking habits, duration of smoking habits, etc. An interest herein is to examine an additive, synergistic, or antagonistic relationship between radiation exposures and cigarette smoking habits for cancer mortalities. The results revealed a highly significant antagonistic in uence for cancer mortalities from all non-hematologic findings, lung and respiratory system with negative interaction between radiation exposures and cigarette smoking amounts.