• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.250-251
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• 2011

• Journal of Food Hygiene and Safety
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• v.2 no.3
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• pp.97-102
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• 1987

The effects of gamma irradiation on microbiological and physicochemical qualities in raw ingredients (thirteen kinds of cereal grain and their by-product) of mixed feeds were investigated. The total aerobic bacteria counts in the samples were $10^2\;to\;10^6/g$. They were sterlllzed to a undetectable level by 5 to 7 kGy irradiation. Coliforms were contaminated in high levels in all sample, ranging from $10^2\;to\;10^6/g$. They were radiation-llensitive and completely eliminated by irradiation with 3 to 5 kGy. Total fungi, ranging from $10^2\;to\;10^4/g$, mainly osmophiles were identified as Aspergillus and Penicillium. They were eliminated below identification limit by 5 to 7 kGy irradiation. Seven kinds of species, including Aspergillus IkrlJUB. were identified as a potential mycotoxin producers. Physicochemical qualities, such as total amino acid content, total sugar content. TBA value and color difference showed that an optimum dose of irradiation was less detrimental than ethylene oxide fumigation.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.280-285
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• 2011

As the plants grow in a fixed place, they can be a good indicator which reflects the level of environmental pollution. It is necessary for them to develop a strategy to cope with stress under unfavorable environmental conditions. In this study, spindle trees ($Euonymus$ $japonica$) were collected from a clean area (Kijang) as well as a heavily polluted area (Onsan) to check applicability of irradiation combined with plant bioassay to environmental monitoring. The leaves were irradiated with 0, 50 and 100 Gy of gamma rays, and then evaluated for antioxidative capacity with 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and superoxide dismutase (SOD) analysis. The result shows that there was no significant changes in SOD and EDA (Electron Donationg Ability) in the samples collected from a polluted area. In the meanwhile, SOD increased in the samples from a clean area until 6 to 10 hours after irradiation, then it decreased gradually until 24 hours after irradiation. In conclusion, the plants in the polluted area have developed higher resistance to oxidative stress induced by ionizing radiation than those in the relatively clean area. Irradiation combined with plant bioassay on enzymatic activities and free radical scavenging capacity has proven to be a possible tool for biomonitoring the environmental pollution.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.3
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• pp.159-165
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• 2005

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

• Korean journal of food and cookery science
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• v.6 no.2
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• pp.97-104
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• 1990

건조 수산가공품 및 혼합조미료 각 5종의 위생적 살균 및 저장방법의 개발을 목적으로 현행살균 방법으로 살균효과의 불충분, 제품의 품질저하, 약제성분의 잔유 등 많은 문제점을 내포한 ethylene oxide에 의한훈증처리와 방사선 조사와의 미생물 살균효과, 이화학적 특성 및 관능적 품질에 미치는 영향을 검토한 결과는 다음과 같다. 시료의 미생물 오염은 전 세균이 $10^3~10^7$ CFU/g으로 그중 90%이상이 내열성 세균이었으며, 곰팡이류는 $10^2~10^3$ CFU/g, 대장균도 시료 5종에서 $10^2~10^6$ CFU/g이나 오염되었다. 살균효과 실험에서 대장균군, 곰팡이류는 5~10 kGy 방사선 조사로서 완전 사멸되었으며, 전세균도 오염도가 매우 높았던 혼합조미료 몇종을 제외하고는 제거되었다. 반면, ethylene oxide훈증처리는 전 미생물의 살균이 불충분하였다. 이 화학적 특성 즉, TBA가 TMA-N 함량, 아미노산, 무기질, 색도 등은 적정 선량의 방사선 조사로서는 무처리구 시료와 거의 차이가 없었으나, ethylene oxide 훈증처리구는 심한 품질의 변화를 나타내었다. 또한 관능검사에 의한 전반적 기호성에 있어서도 방사선조사구가 무처리구 및 ethylene oxide 처리구보다 유의적으로 우수함을 나타냈다.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.94-98
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• 2011

Purpose: The radiation exposure from radioisotope at the hands and foots of radiation workers who works in PET/CT part at the department of nuclear medicine was investigated in this study. Materials and Methods: From 4th August 2010 to 14th January 2011, 6 radio-technologists' radiation on hands and feet were measured. All radio-technologist have been examined around 8; morning, 12; afternoon, and 16 o'clock; evening, respectively. SPSS version 17 was used for statistical analysis. Results: The statistical significances were calculated in several ways. The radiation from both hands and feet in the Morning was lower than Afternoon and Evening. In some cases, the detected radiation showed extremely high values in data. In order to find the effect of the ${\gamma}$-ray on the hand, the estimated doses were presumably calculated, however, the exposure dose on feet were unmeasured. Conclusion: Even if the radiation exposure from the radioisotope at the hands and feet were under the limitations, it is definitely needs to prevent the radiation-contamination. Therefore, the radio-technologists need to have a proper radiation-dealing-procedure of their own, and must try to prevent a radiation exposure by themselves.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.24-31
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• 2004

In order to decommission safely nuclear power plant, it is necessary for the procedure of residual radioactivity investigation in site to provide detailed guidance for planning, implementing, and evaluating environmental and facility radiological surveys conducted to demonstrate compliance with a dose or risk-based regulation. This study presents the procedure of residual radioactivity investigation in decommissioning site - Historical Site Assessment, Scoping Survey, characterization Survey, Remedial Action Support Survey, Final Status Survey - on the basis of MARSSIM(Multi-Agency Radiation Survey and Site Investigation Manual) and investigation cases of decommissioned or decommissioning nuclear power plant.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.112-118
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• 1988

The effect of gamma irradiation of microbiological and physicochemical properties of raw ingredients (thirteen kinds of protein sources) for the mixed feed were investigated. The total aerobic bacteria counts in the samples was ranged from $10^2$ to $10^7$cells/g. After 5 to 7 kGy irradiation, the total count was reduced by 3 to 4 log cycles. Coliforms were detected in seven samples and the range was from $10^4$ to $10^6$cells/g. Enteric pathogens were found only in fish meal and poultry byproduct as $10^2$ to $10^6$cells/g. They were sensitive to radiation and completely sterilized by 3 to 5 kGy irradiation. Total fungi count was ranged from $10^1$ to $10^4$cells/g in all samples. They were osmophiles such as Aspergillus, Penicillium, Cladosporium, Aureobasidium and Rhizopus and were destroyed by 3 to 7 kGy irradiation. Five species of potential mycotoxin producers including Aspergillus flavus were also identified. Physicochemical properties, such as total amino acid content, TBA value, POV and color difference showed that irradiation with optimum does was less detrimental than autoclaving.

• Journal of the Korean Society of Radiology
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• v.16 no.2
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• pp.185-194
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• 2022

The decommission of nuclear legacy sites, which have been contaminated by previous activities such as uranium mining & milling as well as nuclear tests, has started to gain global attention. Within the Korean peninsula, Republic of Korea(ROK)has had experience in dismantling research reactors. For the Democratic People's Republic of Korea(DPRK), the possibility of nuclear activities being implemented and operations records being managed without consideration of the latest nuclear safety regulations are high. Hence, the chances of DPRK's sites remaining as nuclear legacy is also high. This study investigates approaches and considerations that needs to be taken in account in the event of a nuclear legacy site occurrence, reviewing its international cases for the solution of the legacy sites. The regulation, process of optimization, and stakeholder engagement for a nuclear legacy site should be considered in such an event. Developing legacy site response plans can be used to prevent future legacy site occurrences.

• Korean Journal of Veterinary Research
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• v.41 no.4
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• pp.571-578
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• 2001

To evaluate if the apoptotic fragment assay could be used to estimate the dose prediction after radiation exposure, we examined apoptotic mouse crypt cells per 1,000 cells after whole body $^{60}Co$ $\gamma$-rays and 50MeV ($p{\rightarrow}Be^+$) cyclotron fast neutron irradiation in the range of 0.25 to 1 Gy, respectively. The incidence of apoptotic cell death rose steeply at very low doses up to 1 Gy, and radiation at all doses tigger rapid changes in crypt cells in stem cell region. These data suggest that apoptosis may play an important role in homeostasis of damaged radiosensitive target organ by removing damaged cells. The curve of dose-effect relationship for the data of apoptotic fragments was obtained by the linear-quadratic model $y=0.18+(9.728{\pm}0.887)D+(-4.727{\pm}1.033)D^2$ ($r^2=0.984$) after $\gamma$-rays irradiation, while $y=0.18+(5.125{\pm}0.601)D+(-2.652{\pm}0.7000)D^2$ ($r^2=0.970$) after neutrons in mice. The dose-response curves were linear-quadratic, and a significant dose-response relationship was found between the frequency of apoptotic cell and dose. These data show a trend towards increase of the numbers of apoptotic crypt cells with increasing dose. Both the time course and the radiation dose-response curve for high and low linear energy transfer (LET) radiation modalities were similar. The relative biological effectiveness (RBE) value for crypt cells was 2.072. In addition, there were significant peaks on apoptosis induction at 4 and 6h after irradiation, and the morpholoigcal findings of the irradiated groups were typical apoptotic fragments in crypt cells that were hardly observed in the control group. Thus, apoptosis in crypt cells could be a useful in vivo model for studying radio-protective drug sensitivity or screening test, microdosimetric indicator and radiation-induced target organ injury. Since the apoptotic fragment assay is simple, rapid and reproducible in the range of 0.25 to 1 Gy, it will also be a good tool for evaluating the dose response of radiation-induced organ damage in vivo and provide a potentially valuable biodosimetry for the early dose prediction after accidental exposure.