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

• 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.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.201-209
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• 2016

The object of this study was to evaluate the separation distance from a temporary storage facility satisfying the dose criteria. The calculation of ambient dose rates took into account cover soil thickness, facility size, and facility type by using MCNPX code. Shielding effects of cover soil were 68.9%, 96.9% and 99.7% at 10 cm, 30 cm and 50 cm respectively. The on-ground type of storage facility had the highest ambient dose rate, followed by the semi-ground type and the underground type. The ambient dose rate did not vary with facility size (except $5{\times}5{\times}2m\;size$) due to the self-shielding of decontamination waste in temporary storage. The separation distances without cover soil for a $50{\times}50{\times}2m\;size$ facility were evaluated as 14 m (minimum radioactivity concentration), 33 m (most probably radioactivity concentration), and 57 m (maximum radioactivity concentration) for on-ground storage type, 9 m, 24 m, and 45 m for semi-underground storage type, and 6 m, 16 m, and 31 m for underground storage type.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.35-41
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• 2010

The effect of combination of chitosan coating and gamma irradiation on Escherichia coli inactivation and nutritional properties of shell egg was investigated. The E. coli inoculated on shell egg was not detected by 2 kGy of gamma irradiation at day 0 and/or chitosan coating (1%, pH 5.0) after 3 days of storage. There was no E. coli detected thereafter. In the contents of moisture, crude fat, crude protein, ash, retinol, phospholipid, and minerals, no difference was found by treatment combination. However, the contents of cholesterol and carotenoids were reduced by irradiation of 2 kGy (P<0.05). Results suggest that the combination of gamma irradiation (2 kGy) and chitosan coating (1%) can be a good method to improve the safety and prolonged shelf-life of egg because of effective pathogen inactivation without significant adverse changes in nutritional quality.

• Korean Journal of Clinical Laboratory Science
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• v.53 no.1
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• pp.1-10
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• 2021

Radiopharmaceuticals are drugs that contain radioisotopes and are used in the diagnosis, treatment, or investigation of diseases. Radiopharmaceuticals must be manufactured in compliance with good manufacturing practice regulations and subjected to quality control before they are administered to patients to ensure the safety of the drug. Radiopharmaceuticals for administration to humans need to be sterile and pyrogen-free. Hence, sterility tests and membrane filter integrity tests are carried out to confirm the asepticity of the finished drug product, and a bacterial endotoxin test conducted to assess contamination, if any, by pyrogens. The physical appearance and the absence of foreign insoluble substances should be confirmed by a visual inspection. The chemical purity, residual solvents, and pH should be evaluated because residual by-products and impurities in the finished product can be harmful to patients. The half-life, radiochemical purity, radionuclidic purity, and strength need to be assessed by analyzing the radiation emitted from radiopharmaceuticals to verify that the radioisotope contents are properly labeled on pharmaceuticals. Radiopharmaceuticals always carry the risk of radiation exposure. Therefore, the time taken for quality control tests should be minimized and care should be taken to prevent radiation exposure during handling. This review discusses the quality control procedures and acceptance criteria for a diagnostic radiopharmaceutical.

• Journal of Food Hygiene and Safety
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• v.2 no.1
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• pp.21-27
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• 1987

ABS1'RACT-Comparative effects of gamma irradiation and ethylene oxide treatment on the sterilization, and physicochemical and sensory quality of dried marine products(shrimp, anchovy) were investigated. Population of mesophilic total bacteria, aerobic spores and tolerant bacteria of samples were $10^{3}-10^{7}/g,\;10^{7}\;to \;10^{4}/g\;and\;10^{2}\;to\;10^{6}/g$, respectively. Coliforms and molds were found only in dried shrimp as $10^{2}/g$. Mesophilic total bacteria, aerobic spores and acid tolerant bacteria were reduced by over 2 to 4 log cycles with irradiation of 5 to 7 kGy and they were completely sterilized by irradiation dose of 7 to 10 kGy. $D_{10}$ value of mesophilic total bacteria of samples ranged from 1.53 to 2.73 kGy. Coliforms and molds were sterilized at 5 to 7 kGy irradiation but ethylene oxide treatment proved insufficient to eliminate the microorgainsms. An optimum dose of irradiation was less detrimental than ethylene oxide treatment to phpicochemical properties of the samples, such as the pH, TBA value, TMA-N, amino acids, minerals and color difference. Sensory quality after three months of storage showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as ethylene oxide treated samples.amples.

• Journal of radiological science and technology
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• v.11 no.1
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• pp.71-77
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• 1988

To improve the storage method for kimchi, optimal ripening kimchi was irradiated with doses of 1, 3, 5kGy Co-60gamma radiation, followed by the microbiological, physicochemical and senosory evaluations during storage at $5^{\circ}C$. 1. Total aerobic count increased in the beginning of storage and then decreased slowly as the number of total lactobacilli (anaerobe) increased. The above, total aerobic and lactobacilli were reduced by 1 to 3 log cycles with irradiation and at the 90th day after storage the number of total lactobacilli remained $1.30{\times}10^{8}$ per ml in 3 kGy irradiated group. Irradiation treatment at 3 kGy sterilized coliforms and molds contaminating the sample as the level of $2.0{\times}10^{4}$ per ml and $5.4{\times}10^{2}$ per ml respectively and no apparent growth was observed in both control and 1 kGy irradiated groups after 20 days of storage. The population of yeast, $3.5{\times}10^{3}$ per ml initially, increased steadily during kimchi storage and at 90 days of storage the number was shown to be $5.6{\times}10^{4}$ per ml and $6.5{\times}10^{2}$ per ml in control and 3 kGy irradiated groups, respectively. 2. In the physicochemical changes during kimchi storage, pH, acidity and volatile acid of non-irradiated control at the 45th day after storage were 4.0, 0.7% and 0.066%, while those of 3 kGy irradiated group were 4.2, 0.59 and 0.06% at the 90th day of storage, respectively. The reducing sugar content of all stored samples changed inversely total acidity content, indicating irradiation delayed the changes of them. The amount of ascorbic acid decreased gradually with the storage time and irradiation dose increase. Textural parameters of 3 kGy irradiated group were superior to those of other groups at the latter stage of storage. 3. Sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend the shelf-life of kimchi more than two months as compared to control.

• Food Science and Preservation
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• v.16 no.2
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• pp.160-165
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• 2009

Microbiological and sensory qualities of Musaengchae prepared with gamma-irradiated red pepper powder were investigated during storage at $4^{\circ}C$. Total aerobic bacteria in non-irradiated raw materials prior to Musangchae preparation were 6.71 log CFU/g in red pepper powder, 3.39 log CFU/g in radish, 2.21 log CFU/g in scallion, and 2.10 log CFU/g in garlic, respectively. Coliforms(2.15 log CFU/g) were detected only in red pepper powder, and not in Musangchae to which gamma-irradiated red pepper powder. None of pH, Hunter's color value, or sensory properties were significantly affected by addition of irradiated red pepper powder. These results suggest that addition of such powder, after irradiation with less then 10 kGy, could improve Musangchae microbiological safety without changing the sensory or physical qualities.

• Journal of Food Hygiene and Safety
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• v.3 no.4
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• pp.225-232
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• 1988

To improve the storage method for Kimchi, optimal ripening Kimchi was irradiated with doses of 1,3,5 kGy Co-GO gamma radiation, followed by the microbiological, physicochemical and sensory evaluations during storage at $5^{\circ}C$. 1. Total aerobic count increased in the beginning of storage and then decreased slowly as the number of total lactobacilli (anaerobe) increased. The above total aerobic and lactobacilli were reduced by 1 to 3 log cycles with irradiation and at the 90th day after storage the number of total lactobacilli remained $1.30{\times}10^{8}\;per\;ml$ in3 kGy irradiated group. Irradiation treatment at 3 kGy sterilized coli forms and molds contaminating the sample as the level of $2.0{\times}10^{4}\;per\;ml\;and\;5.4{\times}10^{2}\;per\;ml$, respectively and no apparent growth was observed in both control and 1 kGy irradiated groups after 20 days of storage. The population.of yeast, $3.5{\times}10^{3}\;per\;ml$ initially, in, creased steadily during Kimchi storage and at 90 days of storage the number was shown to be $5.6{\times}10^{4}\;per\;ml\;and\;6.5{\times}10^{2}\;per\;ml$ in control and 3 kGy irradiated groups, respectively. 2. In the physicochemical changes during Kimchi storage, pH, acidity and volatile acid of non-irradiated control at the 45th day after storage were 4.0,0.7% and 0.066%, while those of 3 kGy irradiated group were 4.2, 0.59 and 0.06% at the 90th day of storage, respectively. The reducing sugar content of all stored samples changed inversely total acidity content, indicating irradiation delayed the changes of them. The amount of aseorbic acid decreased gradually with the storage time and irradiation dose increase. Textural parameters of 3 kGy irradiated group were superior to those of other groups at the latter stage of storage. 3. Sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend tite shelf-life of Kimchi more than two months as compared to control.