• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.199-208
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• 1994

The derived intervention levels in Korean foodstuffs were estimated using the dynamic ingestion pathway model which was developed considering Korean environment. The derived intervention levels were estimated from the intervention level of dose based on the thyroid committed dose equivalent of infant in the case of I-131, and the whole body committed dose equivalent for age groups and 13 kinds foodstuffs in the cases of Cs-137 and Sr-90. The derived intervention levels were shown as a considerable variation with deposition time and radionuclide. The adult was the most important age group in the estimation of derived intervention levels for Cs-137 and Sr-90. In the adult, the derived intervention levels for rice were 2390 and 47 Bq/kg for Cs-137 and Sr-90 in the case of deposition in summer, respectively, and 198 and 79 Bq/kg in the case of deposition in winter, respectively.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.911-918
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• 1995

동적섭식경로모델을 사용하여 "목초$\longrightarrow$우유$\longrightarrow$사람"의 핵종이동 경로에 대해 침적시점에 따른 입력변수의 민감도와 결과에 대한 불확실성분석을 수행하였다. Cs-137과 Sr-90의 경우 모든 침적시점에 대해 재부유인자가 가장 높은 중요도를 보였다. 두 핵종에 대해 침적시점에 따른 입력변수의 중요도의 변화는 비슷한 유형을 보였다. 목초의 성장기에서 전이율이 상대적으로 중요도가 높았고, Cs-137의 전이율은 Sr-90의 경우보다 높은 중요도를 나타냈다. 목초의 비성장기에서 Sr-90에 대한 농축인자의 중요도는 매우 높았다. Cs-137과 Sr-90에 의한 피폭선량의 95% 신뢰도구간은 약 1 $\times$ $10^1$, 5 $\times$ $10^1$ 범위를 나타냈다. 범위를 나타냈다.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.11-19
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• 2000

The sensitivity analysis of input parameters for a dynamic food chain model DYNACON was conducted as a function of deposition date for the long-lived radionuclides $(^{137}Cs,\;^{90}Sr)$. Also, the influence of input parameters for the short and long-terms contamination of selected foodstuffs (cereals, leafy vegetables, milk) was investigated. The input parameters were sampled using the LHS technique, and their sensitivity indices represented as PRCC. The sensitivity index was strongly dependent on contamination period as well as deposition date. In case of deposition during the growing stages of plants, the input parameters associated with contamination by foliar absorption were relatively important in long-term contamination as well as short-term contamination. They were also important in short-term contamination in case of deposition during the non-growing stages. In long-term contamination, the influence of input parameters associated with foliar absorption decreased, while the influence of input parameters associated with root uptake increased. These phenomena were more remarkable in case of the deposition of non-growing stages than growing stages, and in case of $^{90}Sr$ deposition than $^{137}Cs$ deposition. In case of deposition during growing stages of pasture, the input parameters associated with the characteristics of cattle such as feed-milk transfer factor and daily intake rate of cattle were relatively important in contamination of milk.

• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.9-24
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• 1993

The time-dependent radioecological model applicable to Korean environment has been developed in order to assess the radiological consequences following the short-term deposition of radionuclides in an accident of nuclear power plant. Time-dependent radioactivity concentrations in foodstuffs can be estimated by the model called 'KORFOOD' as well as time-dependent and time-integrated ingestion doses. Three kinds of critical radionuclides and thirteen kinds of foodstuffs were considered in this model. Dynamic variation of radioactivities were simulated by considering several effects such as deposition, weathering and washout, resuspension, root uptake, translocation, leaching, senescence, intake and excretion of soil by animals, intake and excretion of feedstuffs by animals, etc. The input data to the KORFOOD are the time of the year when the deposition occurs, the kinds of radionuclides and foodstuffs for estimation. The time-dependent specific activities in rice and the ingestion doses due to the consumption of all considered foodstuffs were calculated with deposition time using agricultural data-base in Kori region. In order to validate results of KORFOOD, the calculated results were compared with those by a leading German model, ECOSYS-87. The comparison of results shows good agreements within a factor of ten.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.243-249
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• 1998

The methodology for justification and optimization of the countermeasures related with contamination management of milk was designed based on the cost and benefit analysis. The application results were discussed for the deposition on August 15, when pasture is fully developed in Korean agricultural conditions. A dynamic food chain model DYNACON was used to estimate the time-dependent radioactivity of milk after the deposition. The considered countermeasures are (1) the ban of milk consumption (2) the substitution of clean fodder, which are effective in reducing the ingestion dose as well as simple and easy to carry out in the first year after the deposition. The total costs of the countermeasures were quantitatively estimated in terms of cost equivalent of doses and monetary costs. It is obvious that a fast reaction after the deposition is an important factor in cost effectiveness of the countermeasures. In most cases, the substitution of clean fodder was more effective countermeasure than the ban of consumption. A fast reaction after the deposition made longer justifiable/optimal duration of the countermeasure.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.165-170
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• 2002

Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than thy deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.181-188
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• 2004

The contaminative influence of beef due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was comprehensively investigated with the improvement of the Korean food chain model DYNACON. As the results, it was found that both pathways can not be neglected at all in the contamination of beef in the case of an accidental release during the non-grazing period of livestock. The ingestion of soil was more influential in the contamination of beef than the inhalation of air over most time following an release. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was far greater compared with the cases of no precipitation. This fact was more distinct for a long-lived radionuclide $^{l37}Cs$ than a short-lived radionuclide $^{131}I$ (elemental iodine). Compared with the results for milk performed prior to this study, the contaminative pathways due to the inhalation of air and the ingestion of soil were more important in beef because of longer biological half-lives. On the other hand, in the case of an accidental release during the grazing period of livestock, radioactive contamination due to the ingestion of pasture was dominant irrespective of the existence of precipitation during an accidental release. It means that contaminative influence due to the inhalation of air and the ingestion of soil is negligible, like the cases of milk.

• Journal of Radiation Protection and Research
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• v.28 no.4
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• pp.299-309
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• 2003

In an accidental release of radioactive materials to the environment the contaminative influence of animal products due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was investigated with the improvement of the Korean dynamic food chain model DYNACON Although mathematical models for both contaminative pathways have been established for considering all animal products and incorporated into the model, investigation was limited to milk. As a result, it was found that both pathways are influential in the contamination of milk in the case of an accidental release during the non-grazing period of dairy cows. In the case of an accidental release during the non-grazing period, the inhalation of air was more influential than the ingestion of soil in the early days following an accidental release. While, it was the opposite with the lapse of time. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was greater compared with the cases of no precipitation, in general, because of a stealer deposition of radionuclides onto the ground. Precipitation during an accidental release was a less influential factor in $^{131}I$ (elemental iodine) contamination compared with the $^{137}Cs\;and\;^{90}Sr$ contaminations. In the case of an accidental release during the grazing period of dairy cows, the contaminative influence due to the inhalation of air was negligible.

• Journal of Radiation Protection and Research
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• v.19 no.3
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• pp.209-221
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• 1994

In the case of a severe accident of a nuclear power plant, the whole body dose and the relative importance of the radionuclides during the lifetime of an exposed person were estimated for each exposure pathway with distances from the release point. The external exposure pathways due to immersion of radioactive cloud and deposition of radioactive materials on the ground, and the internal exposure pathways due to inhalation and ingestion of contaminated foodstuffs were considered. The effects due to the ingestion of contaminated foodstuffs were estimated considering the variation of radioactive concentration in the foodstuffs according to deposition time and elapsed time after deposition using a dynamic ingestion pathway model applicable to Korean environment, named 'KORFOOD'. As the results up to 80 km from the release point, the effects due to ingestion of contaminated foodstuffs showed the highest contribution to total exposure dose. The contribution of I isotopes was the highest in the case of the external dose due to immersion of radioactive cloud and internal dose due to inhalation. The contribution of Cs isotopes was highest in the case of the external dose due to deposition of radioactive materials on the ground. In the case of the internal dose due to ingestion of contaminated foodstuffs, Cs deposition in summer and Sr deposition in winter, respectively, were the most dominant radionuclide to whole body.

• Journal of Radiation Protection and Research
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• v.24 no.2
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• pp.65-72
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• 1999

A methodology for determining the optimal durations of the use of contaminated crops as feedstuffs of cattle was designed based on the cost-benefit analysis method. The results of application for pigs, an omnivorous cattle, were discussed for the hypothetical deposition of radionuclides on August 15 when a number of crops are fully developed in Korean agricultural conditions. For investigating the relative cost-effectiveness of the use of contaminated crops as feedstuffs, the net benefit was compared with the case of the direct disposal of contaminated crops. The time-dependent radionuclide concentration in crops after the deposition was predicted using a dynamic food chain model DYNACON. The net benefit from the actions was quantitatively evaluated in terms of cost equivalent of doses and monetary costs of implementing the action. It depended on a number of factors such as radionuclides, variety of crops supplied as feedstuffs and duration of the actions. The use of contaminated crops as feedstuffs was more cost effective for $^{90}Sr\;or\;^{131}I$ deposition than for $^{137}Cs$ deposition.