• 방사성폐기물학회지
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• 제12권2호
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• pp.171-178
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• 2014

원전 해체 시 원자력설비는 안전하게 해체되어야 한다. 고리 1호기나 월성 1호기와 같은 노후화된 원전의 경우 곧 원전 해체를 계획하고 있는 대상 원전이지만, 이 원전들의 가동 중단 후 해체 시 선원항 평가 기준, 제염 및 해체 기술 등의 독자적인 국내 기술 확보는 미흡한 실정이다. 본 연구의 목적은 원전 선원항 평가 기술 중 하나로 In-Situ 기법을 이용하여 대형 원전 기기를 직접 측정하여 측정대상체에 대한 선원항 평가방법을 개발하는 것이다. 원자로 헤드를 별도의 해체 없이 이동형 감마핵종분석기를 이용하여 직접 측정법으로 분석하고 간접 측정을 병행하여 측정 결과를 보완하였다. 그리고, 표면오염시료는 방사화학분석을 수행하였다. 분석 결과를 확장하여 원자로의 핵종 재고량을 계산하였다. 본 연구 결과를 토대로 각 핵종별 방사능량 변화에 따라 해체 시점을 결정할 수 있으며, 원전 해체 시 작업자의 피폭 저감에 도움이 될 것으로 기대한다.

• 대한임상독성학회지
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• 제3권2호
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• pp.86-92
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• 2005

Purpose: The main cause of death due to acute organophosphate (OP) poisoning is believed acute respiratory failure caused by cholinergic reactions. Recently, advances in respiratory and intensive care make it possible to maintain the respiratory function of patients with OP poisoning, but the mortality rates remain high. The present study clarified the hemodynamics of patients with acute lethal OP poisoning. The purpose of this study was to analyse the outcomes and predictors of mortality in patients with acute OP poisoning requiring intensive care. Methods: We reviewed medical and intensive care records of patients with acute OP poisoning admitted to emergency department and ICU between March 1998 and Aug 2005. We collected patient information regarding poisoning, clinical, and demographic features. Results: During the study period, 67 subjects treated with intensive care and ventilator management in addition to gastric decontamination standard therapy with atropine and 2-PAM. Of 67 patients, 13 died. Kaplan-Meier survival analysis demonstrated a steep decline in the cumulative survival to $86.6\%$ during the first week. Mean arterial pressure < 60 mmHg within the first 24 hours was recognized as a poor prognostic indicators among mechanical ventilated patients. Conclusion: Most OP poisoning-related deaths occurred within the first week of poisoning. Mean arterial pressure lower than 60 mmHg might be the best predictor of poor outcome. We speculated that the refractory hypotension is the leading cause of death in patients with lethal OP poisoning that receiving mechanical ventilation and maximal supportive care.

• Journal of Radiation Protection and Research
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• 제28권2호
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• pp.127-135
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• 2003

The primary contributors to the total occupational radiation exposure in operating nuclear power plants are operation and maintenance activities doting refueling outages. The Advanced Power Reactor 1400 (APR1400) includes a number of design improvements and plans to utilize advanced maintenance methods and robotics to minimize the annual collective dose. The major radiation exposure reduction features implemented in APR1400 are a permanent refueling pool seal, quick opening transfer tube blind flange, improved hydrogen peroxide injection at shutdown, improved permanent steam generator work platforms, and more effective temporary shielding. The estimated average annual occupational radiation exposure for APR1400 based on the reference plant experience and an engineering judgment is determined to be in the order of 0.4 man-Sv, which is well within the design goal of 1 man-Sv. The basis of this average annual occupational radiation exposure estimation is an eighteen (18) month fuel cycle with maintenance performed to steam generators and reactor coolant pumps during refueling outage. The outage duration is assumed to be 28 days. The outage work is to be performed on a 24 hour per day basis, seven (7) days a week with overlapping twelve (12) hour work shifts. The occupational radiation exposure for APR1400 is also determined by an alternate method which consists of estimating radiation exposures expected for the major activities during the refueling outage. The major outage activities that cause the majority of the total radiation exposure during refueling outage such as fuel handling, reactor coolant pump maintenance, steam generator inspection and maintenance, reactor vessel head area maintenance, decontamination, and ICI & instrumentation maintenance activities are evaluated at a task level. The calculated value using this method is in close agreement with the value of 0.4 man-Sv, that has been determined based on the experience aid engineering judgement. Therefore, with the As Low As Reasonably Achievable (ALARA) advanced design features incorporated in the design, APR1400 design is to meet its design goal with sufficient margin, that is, more than a factor of two (2), if operated on art eighteen (18) month fuel cycle.

• 한국포장학회지
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• 제19권1호
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• pp.11-15
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• 2013

도서관 등에서의 책의 위생적 유통과 관리를 위한 방안을 찾기 위하여 보관되는 책 및 관련된 환경 오염원에서의 미생물 오염도를 측정하였고, 미생물 부하를 저감시키는 방안에 대하여 연구하였다. 일반적으로 책 내부 표면의 오염도는 매우 낮으며 부주의한 취급으로 침 등과 같은 액체에 의해서 오염되는 경우에 미생물 부하가 증가될 수 있었다. 그리고 책 내부 표면에 비해서 먼지가 축적되기 쉬운 옆끝면에서 미생물 오염부하가 높았다. 책에서의 미생물적 오염의 다양성을 고려할 때, 책의 청결도 유지를 위한 조작으로서는, 미생물 부하가 많은 먼지 등의 건조 분체 오염은 공기와류 장치를 사용하고, 습윤상태의 오염은 280 nm UV LED를 사용하는 것이 적절한 것으로 나타났다. UV LED에 의한 미생물 사멸에서는 2 cm 정도의 가까운 거리에서 약 5분 정도 이상의 조사가 효과적이었고, 공기 와류에 의한 건조 분체 오염부하을 저감시키는 조건으로는 풍속 5.5 m/s에서 30초~1분의 처리가 적절하였다.

• Journal of Periodontal and Implant Science
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• 제51권4호
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• pp.276-284
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• 2021

Purpose: The aim of this randomized clinical trial was to assess whether chemical cleansing using a sulfonic/sulfuric acid gel solution (HBX) as an adjunct to scaling and root planing (SRP) resulted in a decrease in residual plaque and calculus in deep periodontal pockets compared to SRP alone. Methods: Fifty-six patients with 56 hopeless posterior teeth, scheduled for extraction due to severe periodontitis, were enrolled in this study. Each tooth was randomly assigned to 1 of the 2 experimental procedures. The test teeth were subjected to the irrigation of the subgingival area with HBX for 2 minutes, followed by SRP with hand and ultrasonic instruments for 14 minutes, and then extracted. The control teeth received only mechanical instrumentation before extraction. Residual biofilm was evaluated on photographs and measured as total area and percentage of root surface covered by remaining plaque (RP) or calculus (RC) after treatment. Results: The initial pocket depth (PD) and total subgingival root surface area were similar between the 2 treatment groups. After treatment, the total subgingival root area covered by RP and RC was statistically significantly larger (P<0.001) in the control group than in the test group. The test teeth showed a lower percentage of RP, but a higher percentage of RC than the control teeth (both P<0.001). Complete calculus removal was achieved in 42% of the control teeth surfaces and in 25% of the test teeth surfaces for a PD of 4 mm. Conclusions: The additional chemical cleansing with HBX resulted in a statistically significant improvement in bacterial plaque removal during SRP of deep pockets, but it was not effective in reducing calculus deposits.

• 방사성폐기물학회지
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• 제17권2호
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• pp.203-212
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• 2019

처분 부적합 폐기물이란 원전운영이나 해체 시 처리, 고화 및 포장이 요구되는 방사성폐기물 등을 일컬으며, 대표적으로 분산 특성을 갖는 입자성 방사성폐기물을 예로 들 수가 있다. 이들 폐기물에는 원전 운영과정에서 발생되는 농축폐액의 건조분말, 슬러리 및 슬러지, 향후 원전 해체과정에서 발생되는 온갖 분말 상태의 폐기물(콘크리트 파쇄물, 제염 슬러지 등), 그리고 제염이 용이치 못한 미세 크기의 방사능오염 토양 등이 있다. 입자성 폐기물을 기존의 고화방식으로 처리할 경우에는 최종 폐기물의 부피가 증가하는 단점을 갖게 되어 처분 비용의 증가 및 처분장의 수용성을 감소하는 결과를 야기할 수가 있다. 따라서 이들 문제를 해결하고자 본 연구에서는 최종 폐기물 부피의 감용화를 위해 롤 압축 기술을 이용하여 분말의 펠렛화 연구를 수행하였다.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1210-1217
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• 2021

The analysis of ⁴¹Ca in concrete generated from the nuclear facilities decommissioning is critical for ensuring the safe management of radioactive waste. An analytical method for the determination of ⁴¹Ca in concrete is described. ⁴¹Ca is a neutron-activated long radionuclide, and hence, for accurate analysis, it is necessary to completely extract Ca from the concrete sample where it exists as the predominant element. The decomposition methods employed were the acid leaching, microwave digestion, and alkali fusion. A comparison of the results indicated that the alkali fusion is the most suitable way for the separation of Ca from the concrete sample. Several processes of hydroxide and carbonate precipitation were employed to separate ⁴¹Ca from interferences. The method relies on the differences in the solubility of the generated products. The behavior of Ca and the interfering elements such as Fe, Ni, Co, Eu, Ba, and Sr is examined at each separation step. The purified ⁴¹Ca was measured by a liquid scintillation counter, and the quench curve and counting efficiency were determined by using a certified reference material of known ⁴¹Ca activity. The recoveries in this study ranged from 56 to 68%, and the minimum detectable activity was 50 mBq g^-1 with 0.5 g of concrete sample.

• 한국산업보건학회지
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• 제32권2호
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• pp.182-194
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• 2022

Objectives: This study evaluates and recommends the priority of policy implementation to improve the fire protection clothing management system used by firefighters and the reduction of cross-contamination from contaminated clothing at the scene of a fire. Methods: It consisted of 7 experts and conducted three interviews and two modified Delphi surveys. Through the results of previous research and interviews with experts, a plan to reduce cross-contamination of fire suits and improve the management system was first derived. An improvement plan was presented in the four areas including resources, management, fire protection related work, and laws and regulations, and the priority of policy implementation was derived by analyzing the importance and practicality of the policy at the same time. Results: As a result of the analysis, the first priority was education on the health effects of pollutants at the disaster scene for firefighters, and the second priority was the addition of SOP for the primary decontamination of on-scene personal protective equipment in preparation for the health effects of the disaster scene, and education for fire suppression and rescue workers. The next step was to improve the management system of personal protective equipment such as fire suits and develop a training course for systematic operation. Conclusions: This findings could be used in the implementation of mid- to long-term firefighting policies for the systematic operation and establishment of a systematic management system for personal protective equipment such as fire protective suits.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제29권3호
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• pp.37-44
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• 2023

Purpose: To decrease cross-infection, it's essential to analyze the spatial composition of the 'PPE doffing area'. Instead of solely relying on manpower standards, we should focus on responding to infectious diseases within the context of space planning. By doing so, we can lower the risk for healthcare workers' infection and ensure a level of safety in various environmental changes or new manpower input situations. Methods: This analysis is conducted specifically for facilities with negative pressure isolation wards. Additionally, interview surveys to obtain feedback from healthcare workers and incorporate their expertise into the design of the 'PPE doffing area' have been carried. Results: In a PPE doffing area, the standard spaces include a PPE doffing room, a shower room, and a clothing room. Depending on the facility environment or the level of infectious diseases, a Decontamination room or Anteroom can be optionally added. Healthcare workers who remove their PPE in the PPE doffing room should avoid re-entering the Negative pressure room. The shower room is often underutilized. When planning for a future PPE doffing area, an aisle space or passageway must be included even if a shower room is planned. Implications: This study examined the space used by healthcare workers rather than patients, with a focus on infection prevention through architectural planning rather than individual efforts. However, the investigation was limited to facilities that have been converted from general wards to negative pressure isolation wards, so it cannot be generalized to all infectious disease facilities.

• Journal of Radiation Protection and Research
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• 제48권1호
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• pp.44-51
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• 2023

Background: Aptamers are currently being used in various fields including medical treatments due to their characteristics of selectively binding to specific molecules. Due to their special characteristics, the aptamers are expected to be used to remove radionuclides from a large amount of liquid radioactive waste generated during the decommissioning of nuclear power plants. The radiological effects on the aptamers should be evaluated to ensure their integrity for the application of a radionuclide removal technique. Materials and Methods: In this study, Monte Carlo N-Particle transport code version 6 (MCNP6) and Monte Carlo damage simulation (MCDS) codes were employed to evaluate the radiological effects on the aptamers. MCNP6 was used to evaluate the secondary electron spectrum and the absorbed dose in a medium. MCDS was used to calculate the DNA damage by using the secondary electron spectrum and the absorbed dose. Binding experiments were conducted to indirectly verify the results derived by MCNP6 and MCDS calculations. Results and Discussion: Damage yields of about 5.00×10^-4 were calculated for 100 bp aptamer due to the radiation dose of 1 Gy. In experiments with radioactive materials, the results that the removal rate of the radioactive ⁶⁰Co by the aptamer is the same with the non-radioactive ⁵⁹Co prove the accuracy of the previous DNA damage calculation. Conclusion: The evaluation results suggest that only very small fraction of significant number of the aptamers will be damaged by the radioactive materials in the liquid radioactive waste.