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Suhyun Choi,Cheolhyun Kang,Jongil Lee,Insu Chang 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2
Kr-85 has a half-life of 10.7 years and it stays in the atmosphere for a long time. However it does not accumulate as an noble gas but only emits beta particles. Therefore its contribution to environmental radiation dose is lower than any other radionuclides. Kr-85 is one of the main fission products produced by nuclear fission reaction and artificial radionuclide that does not exist in nature. For these reasons, monitoring Kr-85 from the atmosphere is meaningful so that the nuclear-related facilities are recommended to control and regulate environmental emissions. Post Irradiation Examination Facility (PIEF) which located in KAERI is a facility that conducts various material and chemical experiments using the irradiated nuclear fuels. Therefore, various radionuclides can present in gaseous effluent including Kr-85. To prevent the environmental hazards and guarantee the radiation safety of the public, nuclear facilities are recommended to be equipped with stack radiation/radioactivity monitoring system, so that the Kr-85 concentration in gaseous effluent is controlled within the regulatory criteria. Particularly, the Kr-85 concentration of gaseous effluent is commonly monitored by the stack monitoring system connected to the process ventilation system from the hot cell. The monitoring system supply the information such as beta count rate, dose rate and flow rate, etc. Due to the concentration of Kr-85 in gaseous effluent is subject to regulatory guide lines, a systemized procedure for calculating Kr-85 concentration of the stack exhaust is necessary. Furthermore, the emission should be monitored whether it satisfies the regulatory standard or does not. This paper performed discussion on the process of calculating the concentration of Kr-85 in the gaseous effluent of PIEF stack from the monitoring system (NGM209, MGP), and the amount of Kr- 85 over the last 2 years emissions was calculated. In addition to calculating effluent rate of radioactive Kr-85, the Minimum Detectable Concentration (MDC) and Decision Threshold (SD) were calculated. As a result, the calculated Kr-85 concentration was below the SD during the entire period. It is considered that there are no environmental emissions of Kr-85.
염전 병행 태양광 발전 시스템 타당성 검토를 위한 기초연구
강성현(Seong-hyun Kang),김봉석(Bong-suck Kim),김근호(Geun Ho GIM),박종성(Jongsung Park),김덕성(Deok Sung Kim),임철현(Cheolhyun Lim) 한국태양광발전학회 2021 Current Photovoltaic Research Vol.9 No.1
In this study, the effect of water level and temperature on the power generation was investigated in a water tank with an aquavoltaic PV module to perform feasibility research for the development of salt farm aquavoltaic system. The silicon solar cell attached to the bottom of each water tank is a 1-cell mini module, and the underwater effects of the crystal phase (19.0~19.9% of single- & 17.9~19.9% of poly-crystalline) of the PV module were investigated, and power generation characteristics for water level (0~10 cm) and temperature (10~40°C) were analyzed. The deterioration coefficients according to the water level and temperature of each single- and poly-crystalline module were investigated at very similar levels such as, –2.01 %/cm and –2.02 %/cm, –0.50 %/°C and –0.48 %/°C, respectively. Therefore, in salt farm aquavoltaic system, water levels need to maintain as low as possible, and heat-induced degradation is similar to those shown in general land, and no factors have been found to be affected by the underwater environment depending on the determination.
Development and Application Cases of Clearance Procedures for Special Waste Type
Jihye Son,TaeHyoung Kim,Cheolhyun Kang 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
The radioactive waste generated within radiation-controlled areas is classified and processed according to relevant laws and regulations based on contamination levels. In cases where such radioactive waste complies with the legally defined clearance concentration or dose criteria, it is disposed of as non-radioactive waste by means of incineration, reclamation, recycling, etc. Within radiation controlled areas, various consumables are periodically replaced to ensure the proper operation of the area. It is necessary to have appropriate disposal methods for these consumables. In particular, waste items such as fire extinguishers, fluorescent lamps, batteries, and pressure vessels (hereinafter referred to as “Special Waste Type”), which may contain hazardous substances within their internal components and contents, should be considered for appropriate disposal methods that comply with nuclear safety and environmental laws. In the present case, the specified special waste type do not come into direct contact with radiation sources, and they have impermeable surfaces, which significantly reduces the risk of external contamination infiltrating the interior. However, the current method of clearance is not suitable for these items (Typically, nuclear energy-related business operators are required to classify clearance target waste based on internal and external components and demonstrate compliance with the criteria. Nevertheless, for special waste type, it is difficult to separate and measure internal and external components within the radiation-controlled area). In this case, the Clearance Procedure for special waste type applied to Korea Atomic Energy Research Institute was introduced. Additionally, we have extracted considerations for future domestic clearance of the type.
Chansong Kim,Jin Woong Lee,허준혁,Cheolhyun Park,Dai-Hwan Kim,Gyu Sung Yi1,Ho Chang Kang,Hyun Suk Jung,Hyunjung Shin,Jung Heon Lee 한국생체재료학회 2022 생체재료학회지 Vol.26 No.1
Background: A considerable number of studies has been carried out to develop alloplastic bone graft materials such as hydroxyapatite (HAP) that mimic the hierarchical structure of natural bones with multiple levels of pores: macro-, micro-, and nanopores. Although nanopores are known to play many essential roles in natural bones, only a few studies have focused on HAPs containing them; none of those studies investigated the functions of nanopores in biological systems. Method: We developed a simple yet powerful method to introduce nanopores into alloplastic HAP bone graft materials in large quantities by simply pressing HAP nanoparticles and sintering them at a low temperature. Results: The size of nanopores in HAP scaffolds can be controlled between 16.5 and 30.2 nm by changing the sintering temperature. When nanopores with a size of ~ 30.2 nm, similar to that of nanopores in natural bones, are introduced into HAP scaffolds, the mechanical strength and cell proliferation and differentiation rates are significantly increased. The developed HAP scaffolds containing nanopores (SNPs) are biocompatible, with negligible erythema and inflammatory reactions. In addition, they enhance the bone regeneration when are implanted into a rabbit model. Furthermore, the bone regeneration efficiency of the HAP-based SNP is better than that of a commercially available bone graft material. Conclusion: Nanopores of HAP scaffolds are very important for improving the bone regeneration efficiency and may be one of the key factors to consider in designing highly efficient next-generation alloplastic bone graft materials.
Electroacupuncture for migraine protocol for a systematic review of controlled trials
Chu, Hongmin,Seo, Jihye,Kim, Cheolhyun,Moon, Yeonju,Kang, Dae Gill,Lee, Ho Sub,Sung, Kang-Keyng,Lee, Sangkwan Williams & Wilkins Co 2018 Medicine Vol.97 No.17
<P><B>Abstract</B></P><P><B>Background and Objective:</B></P><P>A migraine is one of the primary headache disorders. Acupuncture has been widely used to treat migraine. Furthermore, electroacupuncture (EA) treatment has been also used to treat migraine. However, there has been no systematic review by assessing efficacy and safety of EA on migraine. This protocol is developed to conduct a systematic review and meta-analysis to evaluate the evidences related to the effectiveness and safety of EA on migraine.</P><P><B>Methods and analysis:</B></P><P>This protocol follows the guideline according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis Protocol and registered on the International Prospective Register of Systematic Reviews (PROSPERO). The following seven databases will be searched from their inception to September 2016: Medline, the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, OASIS, the Korean Traditional Knowledge Portal, the Korean Medical Database and the China National Knowledge Infrastructure (CNKI). This Systemic review will include only the randomized controlled clinical trials (RCTs) of acupuncture therapy on migraine. We will perform data extraction, study selection, assessment with risk of bias and data analysis. The primary outcomes of this study are headache pain intensity and the total treatment effective rate. And this protocol study for systematic reviews, the approval of IRB was not required.</P><P><B>Ethics and dissemination:</B></P><P>This systematic review will not need ethical approval, because it doesn’t involve human beings. We will publish this systematic review electronically in a peer-reviewed journal. This systematic review will give healthcare practitioners good practical guide and information for treating migraine.</P><P><B>Systematic review registration:</B></P><P>PROSPEROCRD42018085099</P>