• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.113-120
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• 2008

In this study, The TRITGO code was introduced, which can predict the amount of tritium production, it's transport, removal, distribution and the level of contamination for the produced hydrogen by the tritium on the VHTR (very high temperature gas cooled reactor). The TRITGO code was improved so that the permeation to the IS Iodine Sulfide) loop for producing the hydrogen can be simulated. The contamination level of the produced hydrogen by the tritium was predicted by the improved code for the VHTR with 600MW thermal power. The contamination level for the produced hydrogen by tritium was predicted as 0.055 Bq/$H_2-g$. This level is three order of lower than the regulation value of 56 Bq/$H_2-g$ from Japan. From this study, the following results were obtained. it is important that the fuel coating (SiC layer) should be kept intact to prevent the tritium from releasing. Also it is necessary that the level of impurity such as 3He and Li in the helium coolant and the reflector consisting of the graphite should be kept as low as possible. It was found that the capacity of the purification system for filtering the impurities directly from the coolant will be the important design parameter.

• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.230-234
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• 1994

The aim of the present study was to elucidate the effect of the water soluble chitosans on the removal of contaminated radiostrontium (Sr-85) from the bone of mice. The remaining radioactivities in intravenously injected controls(group 1) were higher than in intraperitoneally injected controls (group 4, P<0.01). The % retention at day 5 were $57.7{\pm}1.9%,\;54.4{\pm}1.2%$, respectively. Single intravenous injection of 0.3% water soluble chitosan and continuous oral ingestion of 10% water soluble chitosan for 15 days were' ineffective on the removal of contaminated radiostrontiums. Multiple intravenous or intraperitoneal injections of water soluble chitosan effectively removed contaminated radiostrontiums(P<0.01 vs controls). In conclusion, water soluble chitosan might remove once incorporated radiostrontium from bones of mice. Further studies were needed to elucidate the mechanism of the removal.

• Journal of Radiation Protection and Research
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• v.24 no.4
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• pp.205-213
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• 1999

Effective dose conversion coefficients from unit activity radionuclides contaminated on the ground surface were calculated by using MCNP4A rode and male/female anthropomorphic phantoms. The simulation calculations were made for 19 energy points in the range of 40 keV to 10 MeV. The effective doses E resulting from unit source intensity for different energy were compared to the effective dose equivalent $H_E$ of previous studies. Our E values are lower by 30% at low energy than the $H_E$ values given in the Federal Guidance Report of USEPA. The effective dose response functions derived by polynomial fitting of the energy-effective dose relationship are as follows: $f({\varepsilon})[fSv\;m^2]=\;0.0634\;+\;0.727{\varepsilon}-0.0520{\varepsilon}^2+0.00247{\varepsilon}^3,\;where\;{\varepsilon}$ is the gamma energy in MeV. Using the response function and the radionuclide decay data given in ICRP 38, the effective dose conversion coefficients for unit activity contamination on the ground surface were calculated with addition of the skin dose contribution of beta particles determined by use of the DOSEFACTOR code. The conversion coefficients for 90 important radionuclides were evaluated and tabulated. Comparison with the existing data showed that a significant underestimates could be resulted when the old conversion coefficients were used, especially for the nuclides emitting low energy photons or high energy beta particles.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.21-30
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• 2000

For analyzing the direct contamination pathway of radionudides in rice plants, a Solution containing $^{54}Mn,\;^{57}Co,\;^{85}Sr,\;^{103}Ru$ and $^{134}Cs$ was applied to the aboveground Parts of the between RI application and harvest. Its highest observed value was 0.94. The fractions of the initial plant deposition that remained in rice plants at harvest were in the range of $19{\sim}47%,\;17{\sim}43%,\;19{\sim}42%,\;23{\sim}61%$ and $11{\sim}69%$ for $^{54}Mn,\;^{57}Co,\;^{85}Sr,\;^{103}Ru$ and $^{134}Cs$, respectively, when no decay was assumed. The translocation factors of those radionuclides in hulled seeds were in the range of $6.9{\times}10^{-4}3.8{\times}10^{-2},\;3.6{\times}10^{-3}{\sim}1.6{\times}10^{-1},\;5.8{\times}10^{-4}{\sim}3.2{\sim}10^{-2},\;1.6{\times}10^{-4}{\sim}7.6{\times}10^{-3}$ and $3.2{\times}10^{-2}{\sim}2.0{\times}10^{-1}$, respertively, and were highest when they were applied at the stage of active seed development. It was indicated that the remaining percentage and translocation factor would not be greatly affected by the difference in the rain frequency if it is within a factor of 2. These results can be utilzed for predicting the radionuclide concentrations in rice seeds when an accidental deposition of those radionuclides occurs during the rice-growing season.

• Journal of Radiation Protection and Research
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• v.29 no.3
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• pp.165-172
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• 2004

Rice plants were exposed to $I_2$ vapor for 80 min at different growth stages in an exposure box to investigate the parameters concerning direct plant contamination. Deposition velocity $(m\;s^{-1})$ of the $I_2$ vapor for the straws was in the range of $1.4{\times}10^{-5}-1.3{\times}10^{-4}$ depending on the exposure time, being comparatively low during the earlier part of the plant growth. Ear deposition velocity was in the range of $2.5{\times}10^{-5}-6.7{\times}10^{-5}$. Whole-plant deposition velocity was in the range of $1.4{\times}10^{-5}-1.8{\times}10^{-4}$ with the highest from the exposure performed on Aug. 18 (7 d after the start of heading). The time-dependent variation generally decreased when the deposition velocity was normalized to the biomass density No noteworthy tendency in the deposition velocity was observed with regard to the temperature, sunlight and humidity. Translocation factor for the hulled seeds was $3.3{\times}10^{-5}-4.7{\times}10^{-4}$ with the highest from the Aug. 23 exposure. It was found that a leaf deposition even before the ear emergence resulted in a considerable seed translocation.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.299-302
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• 2006

연구로 및 원자력 시설의 해체 공정 절차 수립과 해체 시나리오 선정에 기초 자료를 제공하고자 컴퓨터 그래픽스를 응용한 방사화 분포 가시화 연구가 수행되었다. 해체 전 시료 채취와 핵종 분석을 통해 방사능 자료가 확보된 연구로 2 호기 조사실(Exposure Room)과 조사실 주변의 콘크리트 차폐체(Concrete Shielding)를 대상으로 방사화 분포 가시화 실험이 이루어졌다. $^{60}Co$에 오염된 조사실의 벽면과 콘크리트 차폐체의 깊이 별로 조사된 방사능 농도 값을 기초로하여 이들 구조물을 3 차원으로 모델링 한 후 Contour mapping을 수행하여 방사화 분포 가시화를 완료하였다. 방사능 정도를 가시화 한 결과와 콘크리트 차폐체 깊이에 따라 지수 함수적으로 감소하고 있었던 결과가 잘 일치하고 있음을 확인할 수 있었다. 연구 결과 자료는 향후 해체 활동 중 방사선에 노출되는 작업자의 피폭선량 평가 모델에 중요한 역할을 수행할 것이다.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.293-297
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• 1989

Electron contamination due to the interaction between radiation beam and material was analyzed for the factors such as source-skin distance (SSD), field size, tray characteristics and position of filter, which can affect the surface dose in Cobalt teletherapy. Surface dose in open beam was more influenced by SSD with increasing field size. Relative surface charge (RSC) increased with the use of tray (solid, circular hole, slotted), compared with open beam, which is thought to be due to increased electron contamination of the tray. To reduce the surface dose, 0.4mm thick Lipowitz metal filter was used. Compared with open beam, RSC decreased by 8.8%, 11.3%, 13.3%, 16.6%, 19.3% and 21.7% for the field size of $5{\times}5$, $10{\times}10$, $15{\times}15$, $20{\times}20$, $25{\times}25$ and $30{\times}30cm^2$, respectively. On the contrary, use of Lipowitz metal filter increased RSC at 60cm or less SSD. Surface dose was effectively reduced with Lpowitz metal filter placed right below solid tray in Cobalt teletherapy.

• Journal of Veterinary Clinics
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• v.19 no.1
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• pp.7-13
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• 2002

This study was examined the microbiological adequacy of fish feed treated with high-dose irradiation (5 kGy). 125 flounder (Paralichthys olivaceus) were grouped into 5 and then the fishes were fed the following feeds for 28 days: (1)standard feed; (2)standard feed, inoculated with Edwardsiella tarda ($1{\times}10^8-1{\times}10^9CFU/g$ of feed); (3)standard feed, inoculated with Vibrio anguilarum ($1{\times}10^8-1{\times}10^9CFIT/g$ of feed); (4)standard feed, inoculated with Streptococcus faecalis ($1{\times}10^8-1{\times}10^9CFU/g$ of feed); (5)standard feed, inoculated with Edwardsiella tarda, Vibrio anguillarum and Streptococcus faecalis, and then irradiated the mixed feed to 5 kGy. The flounders feed the mixed diet with Edwardsiella tarda, Wbrio anguillarum or Streptococcus faecalis inoculated feed were showed severe cumulative mortalities of 60, 48 and 52% respectively. The gross and histological changes were observed on the fishes. However, fishs fed with the feed of bacteria inoculation before irradiation demonstrated excellent protection against the bacteria-related disease. The results from experiments with bacteria inoculated feed indicated that the irradiation methods employed were capable of preventing contamination of the fishs with pathogenic bacteria.

• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.75-82
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• 1998

Tritium concentration in the atmosphere during HTO exposure was different between two experiments due to different velocity of HTO evaporation. Assimilation rate of the rice plant was considered to be higher than that of Chinese cabbage The uptake of atmospheric HTO into tissue free water tritium(TFWT) was higher in rice plants than in Chinese cabbage. However, organically bound tritium(OBT) concentration is relatively higher in Chinese cabbage than in rice. The specific activity ratio(SAR) increased slowly after HTO exposure and decreased gradually with time. The behaviour of HTO in the soil was affected by the environmental conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1781-1786
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• 2011

This study was conducted to investigate the cause of microbiological contamination in yogurt and evaluate the effect of physicochemical treatment on the growth inhibition of Hanseniaspora uvarum isolated from yogurt. The yeast strain Hanseniaspora uvarum Y1 was subjected to heat and pH treatments. H. uvarum Y1 was killed at $70^{\circ}C$ and $80^{\circ}C$ after 15 min and survived in a wide pH range from pH 2 to 9. However, it did not survive under pH 1 and over pH 10. In a disk diffusion susceptibility test on H. uvarum Y1, a clear zone (5 mm) of growth inhibition was observed upon treatment with electrolyzed water. The effect of ozone gas on the growth of H. uvarum Y1 was evaluated by viable cell count. Initial cell numbers of $10^2$ and $10^3$ CFU/mL of H. uvarum Y1 were completely killed by treatment for 10 and 30 min, respectively. H. uvarum Y1 was also sterilized by microwave treatment for 1 min. When treated with gamma-irradiation, the rate of killing of H. uvarum Y1 was proportional to the irradiation dose. and complete killing occurred at a dose of 50 kGy.