Chelating agents in low and intermediate radioactive wastes can form complexes with radionuclides and increase the mobility of the radionuclides. According to the Korea Radioactive Waste Agency (Acceptance criteria for low and intermediate radioactive waste, WAC-SIL-2022-1), if the amount of residual chelating agents in the waste are greater than 0.1%, the chemical names and residual amounts should be specified; if greater than 1%, the waste must be solidified and contain no more than 8%. The existing method for analyzing chelates in radioactive waste was based on UV–Visible spectrophotometry (UV-Vis), but the new method is based on liquid chromatography/mass spectrometry (LC-MS). The analysis was performed in aqueous solution before applying to real samples. Since the real sample may contain several heavy metals, it is expected that the chelates will exist as complexes. Therefore, 1.0×10-4 mol L-1 of EDTA (Ethylenediaminetetraacetic acid), DTPA (Diethylenetriaminepentaacetic acid), NTA (Nitrilotriacetic acid), and excess metals in aqueous solution were analyzed using HPLC using RP (Reverse Phase) column and HILIC (Hydrophilic interaction) column. When the RP column was used, each substance eluted without separation at the beginning of the analysis. However, when analyzed using a HILIC column, the peaks of each substance were separated. LC-MS measurements using HILIC conditions resulted in separations with better sensitivity.

As existing nuclear power plants reach the end of their lifespan, 22 nuclear power plants in korea are scheduled to be permanently shut down and decommissioned by 2050. Chelates are used as decontamination agents during nuclear power plant operation and decommissioning, and as a result, decommissioning waste contains chelates. Chelates contained in radioactive waste are complexed with radionuclides and increases their mobility. So, qualitative and quantitative analysis of chelates contained in radioactive waste is necessary. However, the spectroscopic method (UVVis), previously used for chelate analysis in Korea takes too much time for analysis and cannot analyze two or more chemically similar chelates at the same time. Due to these problems, new methods for analyzing chelate must be developed. Overseas, many cases of chelate analysis using advanced analysis equipment have been reported. CEA in France has developed a chelate analysis method for application to radioactive waste using HPLC-MS (J. Chromatogram. A, 1276, 20-25, 2013). In this method, the existing method of measuring EDTA using a complex of Fe and EDTA was improved to measuring a complex of Ni and EDTA. Based on such overseas cases, we would like to develop an analysis method for chelates in radioactive waste. For this purpose, we will verify similar overseas papers and develop pretreatment methods for mixtures of chelates (EDTA, DTPA, NTA) and metals (Fe, Ni, Cu, etc.) in various media. Finally, we will develop a separation analysis technology for multi-component chelates in nuclear decommissioning waste based on LCMS.

This study presents distribution of naturally occurring radioactive materials in groundwater in Jeju island. Radon (222Rn) and potassium (40K) concentrations were performed by using Liquid Scintillation Counter and Ion Chromatograph respectively. In addition, the activities of uranium and thorium nuclides were analyzed by Inductively Coupled Plasma Mass Spectroscopy. Groundwater samples were collected from 9 sites of water intake facilities for wide area supply in Jeju island from September 2022 to September 2023. The 40K concentrations of groundwater ranged between 0.050 and 0.400 Bq·L-1. The radon concentrations in groundwater were in the range of 0 to 60 Bq L-1, and there was no groundwater exceeding the range of 148 Bq L-1 proposed by the US EPA. The distribution of uranium and thorium in groundwater varied from 0 to 500 ng L-1 and 0 to 2.4 ng L-1, respectively. The concentrations of uranium did not exceed 30 μg L-1, thresholds indicated by the US EPA. By analyzing the concentrations of 40K, 222Rn, 238U and 232Th, the annual effective dose of residents can be assessed. The evaluated residents’ effective dose from natural radionuclides due to intake of drinking water is less than the recommended value of 100 μSv y-1. Consequently, this study indicates that the cancer risks of the residents in Jeju island from naturally occurring radioactive materials ingested with water is insignificant.

This study presents distribution of naturally occurring radioactive materials in groundwater in Jeju island. Radon (222Rn) and potassium (40K) concentrations were performed by using RAD H2O of RAD7 and 940 Professional IC Vario, respectively. In addition, the activities of uranium and thorium nuclides were analyzed by ICP-MS. All of the groundwater samples were collected from 29 sites from August to October 2022. The radon concentrations in groundwater were in the range of 0 to 60 Bq L-1, and there was no groundwater exceeding the range of 148 Bq L-1 proposed by the US EPA. The distribution of uranium in groundwater varied from 0 to 0.6 μg L-1 and did not exceed 30 μg L-1, thresholds indicated by the US EPA.

본 연구의 목적은 에너지 소비 및 심폐 능력 향상을 위한 고강도 유산소 운동, 근력 및 근지구력 강화를 위한 서킷 트레이닝, 생활 습관 변화 교육으로 구성된 4주간의 건강증진 중재 프로그램이 과체중 또는 비만 초등학생의 비만도, 체력수준, 인슐린 저항성 및 대사증후군 미치는 영향을 조사하는데 있다. 과체중 또는 비만 아동 23명을 비만군으로, 정상체중 아동 15명을 정상군으로 선발하였다. 건강증진 프로그램은 총 4주간, 주 3일, 1일 2시간의 운동시간과 1시간의 교육으로 구성되었다. 비만도 (체질량지수, 허리둘레, 체지방률), 체력(근력, 근지구력, 유연성, 심폐체력), 인슐린 저항성 및 대사증후 군 위험요인(혈압, 공복 혈당, 중성지방, 고밀도 지단백 콜레스테롤)을 측정하였다. 프로그램 참여 후, 비 만도의 유의미한 감소는 없었지만, 비만 아동의 체력수준, 인슐린 저항성 및 대사 증후군 위험 요인은 상당한 개선이 있었다. 결과적으로 여름캠프 참여를 통해 비만 초등학생의 체력수준 향상, 인슐린 저항 성 감소 및 대사증후군 위험요인의 빈도 감소에 효과가 있는 것으로 밝혀졌다.

Quality characteristics such as texture and sensory properties of garaetteok(Korean rice cake)made with organic rice flour treated withcitric acid were investigated. Compared to rice flour without addition of citric acid,rice flour treated with citric acid showed a significantly lower viscosity and viscoelasticity level as the concentration of citric acid increased. Hardness of garaetteokmade with citric acid showed a similar trend in viscoelasticity changes, whereas cohesiveness was not significantly affected by the pretreatment of citric acid.Garaetteok of 0.5% citric acid pretreatment showed the highest scores in hardness, springiness, chewiness and overall acceptability.However,flavor and taste of garaetteokof citric acid pretreatment were lower than those of the control.