• Journal of Radiation Protection and Research
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• v.23 no.3
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• pp.175-184
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• 1998

In order to calculate dose rates from steam generators to be replaced from Kori unit 1 in 1998, radionuclide inventories inside steam generator were evaluated from smear test results and measured dose rates from S/G tubes withdrawn for the metallographical examination of damaged tubes. Based on the inventories, contact dose rates and dose rates at 1 m from the surface of a steam generator were calculated using the QAD-CG computer code. Contact dose rates ranged from 11.5 mR/hr at the bottom of channel head to 37.7 mR/hr at the middle of shell barrel, and showed no significant difference with dose rates at 1 m from the surface of steam generator. Shielding effects of lead and carbon steel were compared to provide basic shielding data. Lead shield showed excellent shielding effects. Dose rate at 1 m from the middle of S/G shell barrel decreased from 38.6 mR/hr to 15.5 mR/hr with the lead shield of 2 mm thickness. However, carbon steel showed a poor shielding effect even with the thickness of 2.0 cm. This can be explained with the great differences in the attenuation effect and buildup factor between lead and carbon steel for low energy photons.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.127-146
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• 2002

A method of more realistically, predicting radionuclide concentrations in crop plants varying with time after a nuclear accident was established to estimate 50 years' concentrations of $^{90}Sr$ and $^{137}Cs$ in polished rice seeds and Chinese cabbage for unit dry deposition. After non-growing season accidents, concentrations of both nuclides decreased gradually with time and $^{90}Sr$ concentrations were higher than those of $^{137}Cs$ throughout the whole period. Radionuclide concentrations in the 1 st year after growing season accidents were on the whole higher than those after non-growing season accidents by factors of up to 30 for $^{90}Sr$ and up to 1,000 for $^{137}Cs$. In polished rice seeds, the 50 years-integrated concentration was higher for $^{90}Sr$ than for $^{137}Cs$ after non-growing season accidents, whereas the opposite was true after growing season accidents. In Chinese cabbage. however, it was higher for $^{90}Sr$ than for $^{137}Cs$ after both types of the accident. Generally speaking, the dominant pathway for the integrated concentration after the growing season accident was root uptake for $^{90}Sr$ and direct plant contamination for $^{137}Cs$. The effect of resuspension was negligible. Based on the predicted results. the direct]on of planning countermeasures was suggested for various accident conditions.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.244-251
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• 2015

The containment filtered venting system reduces the range of the contamination area around the nuclear power plant by strengthening the integrity of the containment building. In this study, the probabilistic assessment code MACCS2 was used to assess the effect of the CFVS to off-site. The accident source term was selected from a Probabilistic Safety Analysis report of SHINKORI 1&2 Nuclear Power Plant. The three source term categories from 19 STC were chosen to evaluate the effective dose and thyroid dose of residents around the power plant and the dose with CFVS and without CFVS were compared. The dose was calculated according to the distance from the nuclear power plant, so the damage scale based on the distance that exceeds the IAEA criteria for effective dose (100 mSv per 7 days) and thyroid dose (50 mSv per 7 days) were compared. The effective dose reduction rates of the STC-3, STC-4, STC-6 were about 95-99% in the whole range (0~35 km), 96-98% for the thyroid dose. There are similar results between effective dose and thyroid dose. After applying the CFVS, the damage scale that exceeds the effective dose criteria was about 1 km (mean). Especially, the STC-4 damage scale was decreased from 26 km (mean) to 1.2 km (mean) significantly. The damage scale that exceed the thyroid dose criteria was decreased to 2~3 km (mean). The STC-4 damage scale was also decreased significantly as compared to STC-3, STC-6 in terms of effective dose.

• Journal of Radiation Protection and Research
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• v.39 no.2
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• pp.70-80
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• 2014

The interpretation on the diffusion of radiation contaminants in air is usually to apply a Gaussian plume equation that obtains normal distributions in stable air flow conditions to draw a conservative conclusion. In this study, a numerical study using computational fluid dynamics methods was performed to interpret the air flow pattern and the diffusion of the radiation contaminants at the Wolseong nuclear power plants, and a more detailed solution can be obtained than the Gaussian plume equation, which is difficult to use to simulate complex terrains. The results show that a significant fluctuation of air flow in the terrain appears in the case of a northwester and southeaster because of the mountain located in the northwest and the sea located in the south-east. The northwesterly air flow shows the most unstable flow in the vertical direction when it passes over the terrain of mountain. The stable southeasterly air flow enters into the nuclear power plant from the sea, but it becomes unstable rapidly because of the interference by the building and the terrain. On the other hand, in the case of a northeaster and southwester, a small interruption of air flow is caused by the terrain and wake behind the buildings of nuclear power plants.

• Nuclear industry
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• v.37 no.9
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• pp.58-90
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• 2017

'공포의 값비싼 대가(The High Cost of Fear)'는 공개된 자료 중 동료 평가를 마친 최신의 자료와 간단한 계산 방법을 통해 한국의 탈원전 정책이 가져올 경제적, 환경적 영향을 분석한 보고서이다. 우리는 탈원전 정책이 다음과 같은 영향을 미칠 것으로 예측한다. ${\cdot}$천연가스 구매에만 최소 매년 100억 달러의 비용이 들 것이다. 이는 한국 평균임금인 연소득 29,125달러를 받는 일자리 343,000개에 해당하는 금액이다. ${\cdot}$비용의 대부분은 연료 수입에 사용될 것이며, 한국의 무역 수지가 악화될 것이다. ${\cdot}$한국의 부족한 재생에너지 자원을 고려할 때, 상당한 양의 화석 연료를 추가로 사용하게 될 것이다. ${\cdot}$LNG 발전소가 석탄 발전소를 대체하지 못하고 원자력발전소를 대체하면서 대기 오염으로 인한 조기 사망자 수가 증가할 것이다. ${\cdot}$한국의 전도유망한 원전 수출 산업이 아예 붕괴되거나 큰 타격을 입을 것이다. ${\cdot}$평균적 미국 자동차의 연간 주행거리를 기준으로 150만대에서 270만대의 미국 자동차가 배출하는 배기가스의 양만큼 연간 탄소 배출이 증가할 것이고, 한국은 파리기후협정에서 약속한 탄소 배출 감축 목표를 달성할 수 없게 된다. 본 보고서는 현재 계획된 탈원전 정책의 역사적 사회적 배경을 분석하여 다음과 같은 결론을 도출하였다. ${\cdot}$'그린피스(Greenpeace)', '지구의 친구들(Friends for the Earth)' 등 막대한 자금 지원을 받는 해외 환경단체들은 탈원전 거짓 정보의 근원이며, 이들은 저렴하고 풍부한 에너지라는 개념을 반대한다. ${\cdot}$후쿠시마 원전 사고와 그 여파의 주된 원인은 일본 원자력산업계의 오만과 원자력에 대한 과장된 집단 공포이다. ${\cdot}$반핵 진영의 논리에는 산업계와 정부에 대한 불신과 원자력, 방사선에 대한 몰이해가 반영되어 있다. ${\cdot}$반핵 진영은 후쿠시마 사고를 2014년 한수원 납품 비리 사태의 심각성을 과장하는 데 사용하고 있다. 2014년의 비리 사태는 한국 원자력 규제기관의 독립성을 증명했으며, 2016년의 경주 지진은 2011년 후쿠시마에서 쓰나미와 노심 용융을 초래한 동일본 대지진의 1/350,000의 크기밖에 되지 않는다. 본 보고서는 한국과 타국가의 반핵 운동이 주는 교훈을 다음과 같이 정리하였다. ${\cdot}$어떠한 국가도 에너지 자원 최빈국인 프랑스나 한국 같은 국가조차도 탈원전 '전쟁'에서 자유롭지 않으며, 이는 전 세계적으로 원자력산업이 쇠퇴하는 원인이다. ${\cdot}$원자력산업계, 정부, IAEA 등은 한국과 세계 여러 국가에서- 문화적, 제도적, 재정적 원인으로 원자력산업의 보호와 확대라는 목표를 달성할 수 없다. ${\cdot}$원자력산업을 구하기 위해서는 새로운 비전과 새로운 제도, 그리고 새로운 리더십이 필요하다. ${\cdot}$원자력의 근원적이고 혁신적인 비전 원자력 인본주의(atomic humanism)에 대한 재조명이 필요하다. ${\cdot}$원자력을 지키고 대중과 소통하기 위해 과학 연구단체, 대학교, 사단법인, NGO 등의 새로운 기관들을 후원해야 한다. ${\cdot}$공포를 조장하는 반원전 세력에 맞서 공포를 극복해야 하고, 대중의 공포를 극복해왔던 다른 기술들의 사례에서 교훈을 얻어야 한다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.441-454
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• 2018

Since the permanent shutdown of Kori Unit 1 in 2017, a full-scale decommissioning project for a commercial nuclear reactor has been approaching. It is estimated that about 160,000 t of low-activity concrete waste will be produced from decommissioning of one unit of this commercial nuclear power reactor. Accordingly, it is necessary to review whether the effectiveness of the current regulatory framework for clearance waste (i.e. waste stream that meets activity concentration guidelines or dose criteria for clearance set forth in NSSC Notice No. 2017-65) can be maintained for the clearance of a bulk amount of concrete waste. In this regard, the IAEA SRS No. 44, which was used as a basis for revision of the Korean clearance regulations, is thoroughly analyzed and the radiological effects from four different clearance scenarios, along with input values and parameters derived from industrial practices in Korea, were evaluated. Though it is shown that the maximum annual dose from most recycling scenarios will be less than the clearance dose criterion for the normal scenario (i.e. an order of magnitude of $0.01mSv{\cdot}y^{-1}$), the radiation dose, estimated with conservative assumptions for the banking scenario, may exceed the above clearance dose criteria. Therefore, for safe and sustainable clearance of the bulk amount of concrete waste, it is required to diversify the concrete waste processors, perform more detailed site-specific assessment, and apply limiting conditions to the banking scenario.

• Science of Emotion and Sensibility
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• v.25 no.2
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• pp.79-86
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• 2022

With external air pollution forcing many people indoors, new methods of facilitating healthier indoor life are necessary. This study, therefore, investigates the effects of indoor oxygen concentration and respiration methods on biosignals and cognitive ability. The study included twenty healthy subjects who inhaled air through a mask from a gas delivery system. All subjects were asked to perform three types of breathing (nasal, oral, and oral breathing with high oxygenation) and respond to cognitive stimuli (rest close eye, rest open eye, 1-back and 2-back working memory tasks). The changes in cognitive load according to respiration were analyzed by measuring response time, accuracy, and biosignals to stimuli. The result showed that, in all three respirations, heart rate significantly increased with the increase in cognitive load. Also, in oral respiration, the airway respiration rate significantly increased according to the increase in cognitive load. The change appeared to compensate for insufficient oxygen supply in oral respiration during cognitive activity. Conversely, there was no significant change in airway respiration rate during oral respiration with a high concentration oxygen supply as in nasal respiration. This result suggests that a high concentration oxygen supply might play a role in compensating for insufficient oxygen concentration or inefficient oxygen inhalation, such as oral respiration. Based on the results of this study, a follow-up study is necessary to determine the impact of changes in the autonomic nervous system, such as stress and emotions, to find out more precise and comprehensive effects of oxygen concentration and breathing type.

• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.429-434
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• 2009

Purpose : Severe aspiration of the amniotic fluid is known to cause fatal respiratory distress in neonates. We conducted this study to investigate the clinical findings of severe amniotic fluid aspiration pneumonia (AFAP) in neonates and the effect of pulmonary surfactant replacement therapy (SRT). Methods : Retrospective analysis of medical records was conducted on 28 patients who received ventilator care due to severe AFAP in a neonatal intensive care unit over a 7-year period (2000-2006). Patients whose amniotic fluid was contaminated with meconium were excluded. Results : A large number of cases were term infants (82.1%) and infants born by caesarean section (85.7%), and the 1- and 5-min Apgar scores of these patients were $6.5{\pm}1.2$ and $7.5{\pm}1.3$, respectively. Soon after birth, the amount of amniotic fluid sucked out from airway below the vocal cord was $16.0{\pm}10.1$ mL. All patients received SRT with a modified bovine-derived surfactant (120 mg/kg/dose), and one dose was administered in most cases (75%). Compared with pre-SRT, the oxygenation index ($8.0{\pm}9.6$ vs. $18.9{\pm}7.3$) according to ventilator care was a significant improvement at 12 h after SRT (P<0.001). Furthermore, most cases showed radiological improvement for aeration at 12 h post-treatment. Many cases (46.4%) had cardiorespiratory complications, but their final outcomes were excellent (survival rate, 96.4%). Conclusion : AFAP may be an important cause of serious respiratory distress in near-term and term infants, and SRT seems to be an effective adjuvant therapy in mechanically ventilated neonates with severe AFAP.

• Journal of Radiation Protection and Research
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• v.10 no.1
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• pp.50-63
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• 1985

A derivation of new release limit, named Derived Release Limit(DRL), into the atomsphere from a reference nuclear power plant has been performed on the basis of the new system of dose limitation recommended by the ICRP, instead of the (MPC)a limit which has been currently used until now as a general standard for radioactive effluents in Korea. In DRL Calculation, a Concentration Factor Method was applied, in which the concentrations of long-term routinely released radionuclides were in equilibrium with dose in environment under the steady state condition. The analytical model used in the exposure pathway analysis was the one which has been suggested by the USNRC and the exposure limits applied in this analysis were those recommended by the USEPA lately. In the exposure pathway analysis, all of the pathways are not considered and some may be excluded either because they are not applicable or their contribution to the exposure is insignificant compared with other pathways. In case, the environmental model developed in this study was applied to the Kori nuclear power plant as the reference power plant, the highest DRL value was calculated to be as $9.10{\times}10^6Ci/yr$ for Kr-85 in external whole body exposure from the semi-infinite radioactive cloud, while the lowest DRL value was observed 3.64Ci/yr for Co-60 in external whole body exposure from the contaminated ground, by the radioactive particulates. The most critical exposure pathway to an individual in the unrestricted area of interest (Kilchun-Ri, 1.3 km to the north of the release point) seems to be the exposure pathway from the contaminated ground and the most critical radionuclide in all pathways appears to be Co-60 in the same pathway. When comparing the actual release rate from KNU-l in 1982 with the DRL's obtained here the release of radionuclides from KNU-1 were much lower than the DRL's and it could be conclued that the exposure to an individual had been kept below the exposure limits recommended by the USEPA.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.31-39
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• 2016

Background: It is necessary to consider the overall countermeasure for analysis of nuclear activities according to the increase of the nuclear facilities like nuclear power and reprocessing plants in the neighboring countries including China, Taiwan, North Korea, Japan and South Korea. South Korea and comprehensive nuclear-test-ban treaty organization (CTBTO) are now operating the monitoring instruments to detect radionuclides released into the air. It is important to estimate the origin of radionuclides measured using the detection technology as well as the monitoring analysis in aspects of investigation and security of the nuclear activities in neighboring countries. Materials and methods: A three-dimensional forward/backward trajectory model has been developed to estimate the origin of radionuclides for a covert nuclear activity. The developed trajectory model was composed of forward and backward modules to track the particle positions using finite difference method. Results and discussion: A three-dimensional trajectory model was validated using the measured data at Chernobyl accident. The calculated results showed a good agreement by using the high concentration measurements and the locations where was near a release point. The three-dimensional trajectory model had some uncertainty according to the release time, release height and time interval of the trajectory at each release points. An atmospheric dispersion model called long-range accident dose assessment system (LADAS), based on the fields of regards (FOR) technique, was applied to reduce the uncertainties of the trajectory model and to improve the detective technology for estimating the radioisotopes emission area. Conclusion: The detective technology developed in this study can evaluate in release area and origin for covert nuclear activities based on measured radioisotopes at monitoring stations, and it might play critical tool to improve the ability of the nuclear safety field.