• Progress in Medical Physics
• /
• v.9 no.1
• /
• pp.55-64
• /
• 1998

In recent, the demand of development of the high dose rate brachytherapy source increased for substitute for Co-60 source by iridium source, since the supplying Co-60 source is very depressed and the high dose rate brachytherapy sources are entirely imported from the abroad. This study investigated the exposure rates and isotropic dose distributions for the Ir-192 source produced from $\^$191/Ir(n,r)$\^$192/Ir by nuclear reactor in Korea Atomic Energy Research Institute. The activity of source was obtained an 1.012 Ci (the initial activity without encapsulation was 2,87Ci) by measurement with encapsuled stainless steel. The exposure rate of provided Ir-192 source was determined on 6.36 ${\pm}$ 0.147 Rm$^2$/h-GBq (2.350 ${\pm}$ 0.054 Rcm$^2$/mCi-hr) within ${\pm}$ 2.2% discrepancy with IC-10 ion chamber (0.14 cc) which was mounted on the acrylic jig to 5, 10 and 20 cm from the center of source. The calculated doses with 22 most significant spectrum lines were corrected with intrinsic efficiency of the germanium detector were compared to measured exposure dose rates within ${\pm}$3.8 % discrepancy. The authors confirmed the high dose rate Ir-192 source could be replaced the long decayed Co-60 source via investigation of the isotropic dose distributions in lateral, source axis and diagonal direction of source center are very closed to within 3% uncertainties. Especially, this exposure rate constant and isotropic dose distribution will be fundamental to build the high dose rate source and develop the computed therapy planning system.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2009.06a
• /
• pp.35-36
• /
• 2009

지속가능 에너지원인 원자력은 또한 글로벌 에너지원의 특성을 갖추고 있다 핵연료는 원자로에 장전되는 신규 핵연료를 구성하고 있는 우라늄 채광 단계에서부터 연소 후에 발생하는 사용후 핵연료 (SNF 또는 SF) 관리 단계에 이르는 전과정에 걸쳐 핵연료 사이클로 파악되고 있다. 이러한 전과정 관점에서 볼 때, 핵연료 사이클에 관여하는 이해관계자는 자국뿐만 아니라 다국가 (multination)를 포함하고 있다. 특히, 후행 핵연료 사이클인 사용후 핵연료의 저장, 처리, 처분 단계에서는 다국가 시나리오를 배제하지 않는 사용후 핵연료 관리 전략의 도입이 고려될 수 있다. 여기서 다국가는 접경 국가, 인접 국가, 핵연료 공급 국가, 재처리 제공 국가, 재처리 위탁 국가, SNF 통과 허용 국가, SNF 저장 부지 제공 국가, SNF 향후 이용 국가 등이 될 수 있다 [김성호 2006]. 현재 우리나라에서는 여러 국가로부터 수입되고 있는 신규 핵연료 물질을 연소시켜 나온 사용후 핵연료를 부지내에 임시 저장하고 있다. 사용후 핵연료 발생량의 추산에 따르면, 2016년쯤에 현재 임시저장 용량이 포화될 예정이다 이러한 상황에서 다국가 시나리오를 포함한 관리 전략은 다국가 시나리오를 배제한 관리 전략과 다각적인 측면 에서 비교 검토될 필요성이 있다. 사용후 핵연료의 영구 처분장 부지 확보를 해결하기 위한 선행 단계로 공론화 단계가 지금 준비되고 있다. 예컨대, 단기 공론화 관리 방안의 하나로 비록 소극적인 입장이지만 타국 위탁 재처리 방식이 고려되고 있다 [KRS 2009] 이 연구에서는 단기적인 사용후 핵연료 관리 전략으로 여러 가지 다국가 수준의 저장, 처리, 처분 방식으로 바탕으로 다국가 시나리오들을 제안하려고 한다. 이들 다국가 시나리오를 포함한 관리 전략은 현재 다국가 시나리오를 배제한 국내 사용후 핵연료 처분장 부지 선정이 정치적/사회적 수용성 문제로 어려운 상황에 처할 경우에 해결책을 찾는 데에 기여하리라 본다. 또한, 부지 선정 단계에서 바라지 않는 난항이 나타나는 경우에 국가 차원의 한 대비책으로 다음을 제안한다: 한편으로는 자국 저장 시설이 추진되면서, 다른 편으로는 타국 저장 부지를 확보하는 전략이 검토되어야 한다. 이러한 이중 노선 (dual track) 전략은 여러 유럽 국가에서 이미 고려되고 있는 방안이다 [Greenpeace 2005] 다양한 다국성 정도 (a degree of multinationality) 의 저장, 처리, 처분 방식을 연결하는 가능한 다국가 시나리오 구조가 Fig.1에 제시되어 있다. 다국가 시나리오를 구성하는 기본 요소는 다음과 같다’ 1) 자국 임시 저장; 2) 자국 재처리; 3) 자국 중간 저장; 4) 자국 영구 처분; 5) 다국가 중간 저장; 6) 다국가 재처리; 7 ) 다국가 영구 처분. 이들 기본 요소들을 다국성 정도에 따라 결합하면 다양한 다국가 시나리오들이 얻어진다. 이들을 포함한 SNF 관리 전략은 크게는 1) 다국가 재처리 전략， 2) 다국가 저장 및 재처리 전략， 또는 3) 다국가 처분 전략 등으로 분류될 수 있다.

• Analytical Science and Technology
• /
• v.16 no.6
• /
• pp.443-449
• /
• 2003

Thermal neutron irradiation experiment of boric acid solution was carried out using HANARO in following three conditions: (A) $^{10}B$ concentration = $203.0{\mu}g/mL$, irradiation time = 1 hr; (B) $^{10}B$ concentration = $381.4{\mu}g/mL$, irradiation time = 1 hr; (C) $^{10}B$ concentration = $381.4{\mu}g/mL$, irradiation time = 0.5 hr. The amount of lithium produced from $^{10}B(n{\cdot}{\alpha})^7Li$ reaction which was generated on neutron irradiation, was measured by flameless atomic absorption spectroscopy. The concentration of $^7Li$ measured in the three experiments was $0.18{\mu}g/mL$ (78.3% of theoretical value, $0.23{\mu}g/mL$) in (A), $0.31{\mu}g/mL$ (70.5% of theoretical value, $0.44{\mu}g/mL$) in (B) and $0.16{\mu}g/mL$ (71.6% of theoretical value, $0.22{\mu}g/mL$) in (C). The pH value of irradiated boric acid was shifted to considerably low. It is estimated that boric acid would be transformed into the polyborate fonn, by radiolysis products of water, which has high dissociation constant.

• Journal of the Korean Chemical Society
• /
• v.37 no.8
• /
• pp.711-716
• /
• 1993

The mechanism for electrochemical oxidation of natural alkaloid, ${\iota}$-sparteine (SP) was studied in acetonitrile solvent. The cyclic voltammogram of SP shows two irreversible anodic peaks at +0.75 V and +1.45 V vs. Ag/AgCl (0.1M AgNO$_2$ in acetonitrile) electrode. Coulometry reveals that the number of electrons involved in each oxidation peaks is in the range of 1.2∼1.3 respectively. Neutral imine radical was produced by fast deprotonation of SP radical cation formed by oxidation of one nitrogen atom in SP. Two pathways are possible for the reaction of the neutral radical: Due to the disproportionation of the radical, SP and enamine were mainly produced. Also, the 1,2-dehydrosparteinium cation was formed as minor product through the second one electron transfer oxidation of this radical. The (+)-lupanine was produced by treatment of sparteinium cation with potassium hydroxide. We have isolated and confirmed the electrolysis products using IR, GC-MS, UV-Vis, and thin-layer spectroelectrochemical method.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.6
• /
• pp.632-637
• /
• 2001

Components of polysaccharides isolated from ascidian tunic were measuerd by gel filtration, electrophoresis and chemical analyses. The sulfated polysaccharides consisted in sulfate, protein, uronic acid and amino sugars. Hexosamines were composed of arabinose, xylose, glucose, galactose, glucuronic acid, N-acetylgalactosamine and N-acetylglucosamine by gas chromatography analysis. The galactose was predominant hexose after autoclave and nutrase digestion followed by DEAE-cellulose ion exchange chromatography and gel-permeation chromatography on Sephadex G-100 and G-25. FT-IR spectra of isolated polysaccharides from ascidian tunic and standard chondroitin sulfates have similar functional groups of the type of vibration and frequency. Molecular weight of isolated polysaccharides by autoclave represented more than 40 kDa by polyacrylamide gel electrophoresis. But the neutrase treatment group divided into three band. The highest molecular band group was shown more than 100 kDa, and the two low molecular band group were shown about 22 kDa and 5 kDa, respectively, compare to standard materials.

• Analytical Science and Technology
• /
• v.17 no.4
• /
• pp.355-362
• /
• 2004

Fission products and Inter reaction layer of $U_3Si-Al$ dispersion fuel, irradiated in HANARO research reactor with 121 kW/m of maximum liner power and 63 at% of average burn-up, was characterization by EPMA (Electron Probe Micro Analyzer). The fuel punching system developed by Irradiated Materials Examination Facility (IMEF) has used to make these samples for the EPMA. With this system a very small and thin specimen which is 1.57 mm in diameter and 2 mm in thickness respectively has been fabricated to protect the EPMA operator from high radioactive fuel and to mini-mize the equivalent dose rate less than 150 mSv/h. EPMA was performed to observe layers of sectional, Inter-reaction and oxide with specimens of cutting and polished. Stoichiometry in the Inter-reaction layer with $16{\mu}m$ of thickness was $U_{2.84}$ Si $Al_{14}$ with calibration of $UO_2$ and $U_{3.24}$ Si $Al_{14.1}$ with calibration of standard specimen. metallic precipitates in this layer were not observed using fission products examination.

• Journal of Radiation Protection and Research
• /
• v.7 no.1
• /
• pp.34-48
• /
• 1982

The prime purpose of this study is to realize an index quantity, absorbed dose index, defined by the ICRU for the characterization of ambient radiation level at any location for the purpose of radiation protection. The experiment has been designed to be carried out in two phases, namely, preliminary and main experiment. In the primary study a 30cm diameter sphere of polyethylene was used, while in the main experiment that of tissue equivalent material was fabricated and used. Both experiments were performed in the gamma-ray fields of $^{137}Cs\;and\;^{60}Co$, and in a neutron beam of thermal column of the TRIGA MARK-II research reactor. In the measurement of gamma-ray absorbed dose TLD-700 $(^{7}LiF)$ chips were used, and for the neutron dose both Au activation foils and TLD chips (TLD-600 $(^{6}LiF)$ and TLD-700 for the discrimination of gamma-ray contribution) were used. Theoretical assessment of the absorbed dose in the sphere phantom has been carried out in accordance with the Ehrlich's idea that deduced on the basis of Burlin's cavity theory in the case of gamma-ray irradiation. For the analysis of neutron dose fluence-KERMA rate conversion method was used. The explanation on the dose assessment is given in detail. Results obtained were numerically and statistically analyzed and the depth dose distributions are presented in the graphic forms with normalized values. In the concluding remarks, the possibility and difficulty of realizing the index quantity, including questions and problems to be solved are mentioned.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.8 no.4
• /
• pp.347-353
• /
• 2010

Source terms of metal waste comprising a spent fuel assembly are relatively important when the spent fuel is pyroprocessed, because cesium, strontium, and transuranics are not a concern any more in the aspect of source term of permanent disposal. In this study, characteristics of radiation source terms for each structural component in spent fuel assembly was analyzed by using ORIGEN-S with a assumption that 10 metric tons of uranium is pyroprocessed. At first, mass and volume for each structural component of the fuel assembly were calculated in detail. Activation cross section library was generated by using KENO-VI/ORIGEN-S module for top-end piece and bottom-end piece, because those are located at outer core with different neutron spectrum compared to that of inner core. As a result, values of radioactivity, decay heat, and hazard index were reveled to be $1.40{\times}10^{15}$ Bequerels, 236 Watts, $4.34{\times}10^9m^3$-water, respectively, at 10 years after discharge. Those values correspond to 0.7 %, 1.1 %, 0.1 %, respectively, compared to that of spent fuel. Inconel 718 grid plate was shown to be the most important component in the all aspects of radioactivity, decay heat, and hazard index although the mass occupies only 1 % of the total. It was also shown that if the Inconel 718 grid plate is managed separately, the radioactivity and hazard index of metal waste could be decreased to 20~45 % and 30~45 %, respectively. As a whole, decay heat of metal waste was shown to be negligible in the aspect of disposal system design, while the radioactivity and hazard index are important.

• Journal of Yeungnam Medical Science
• /
• v.15 no.2
• /
• pp.224-236
• /
• 1998

A study was conducted to investigate the blood lead and zinc protoporphyrin(ZPP) concentrations of the underground parking lot workers who exposed to vehicular exhaust aerosols which contained lead. The blood samples were collected from 25 study subjects of underground parking lot and from 33 controls in Taegu, from July to October, 1997. And also the related factors to the blood lead and ZPP concentrations were investigated. Blood lead concentration and ZPP concentration were measured by flameless furnace atomic absorption spectrophotometer (1L.551) and hemetofluorometer, respectively. The mean blood lead concentrations of study subjects and controls were $23.10{\pm}20.77{\mu}g/dl$ and $12.99{\pm}12.71{\mu}g/dl$, respectively(p<0.05), and the mean blood ZPP concentrations of study subjects and controls were $40.72{\pm}9.46{\mu}g/dl$ and $38.21{\pm}10.97{\mu}g/dl$, respectively. No significant correlations were observed between the blood lead concentration of the study subjects and their job duration and between blood ZPP concentration of the study subjects and their job duration. There were no statistically significant differences in the blood lead concentration and the blood ZPP concentration of smokers and nonsmokers. In multiple regression analysis on blood lead concentration of the study subjects and controls, occupation was a only significant dependent variable. In case of bood ZPP concentration, age was a only significant dependent variable in the study subjects and controls.

• Journal of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.18-24
• /
• 1989

Two crystal structures of dehydrated $Ag^+$ and $Rb^+$ exchanged zeolite A, stoichiometries of $Ag_{9}Rb_{3}-A$ (a = 12.278(2)${\AA}$) and $Ag_{10}Rb_{2}-A$ (a = 12.286(2)${\AA}$) per unit cell, have been determined by single crystal x-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at 21(1)$^{\circ}$C. The crystals of $Ag_{10}Rb_{2}-A$ and $Ag_{10}Rb_{2}-A$ were prepared by flow methods using exchanged solution in which mole ratios of AgNO$_3$ and RbNO$_3$ were 1:5 and 1:50, respectively, with the total concentration of 0.05 M. The structures of the dehydrated $Ag_{9}Rb_{3}-A$ and the $Ag_{10}Rb_{2}-A$ were refined to the final error indices, $R_1$ = 0.064 and $R_2$ = 0.060 with 291 reflections, and $R_1$ = 0.063 and $R_2$ = 0.080 with 416 reflections respectively, for which I >3${\sigma}$(I). In both structures, one reduced silver atom per unit cell was found inside the sodalite cavity. It may be present as a hexasilver cluster in 1/6 of the sodalite units or as an isolated Ag atom coordinated to 4 $Ag^+$ ions in each sodalite unit to give $(Ag_5)^{4+}$, symmetry 4 mm. In the structure of dehydrated $Ag_{9}Rb_{3}-A$, 8 $Ag^+$ ions lie on the threefold axis and each is nearly at the center of the 8-rings at the sites of $D_{4h}$ symmetry. In the structure of dehydrated $Ag_{10}Rb_{2}-A$, two crystallographically different eight 6-ring $Ag^+$ ions were found; $7Ag^+$ ions in the (111) planes of their O(3) framework oxygens and one $Ag^+$ ion inside of sodalite cavity. Two crystallographically different 8-ring cations were also found; two $Rb^+$ ions at the centers of the 8-oxygen rings and one $Ag^+$ ion into the large cavity. Both structures indicate that $Rb^+$ ions prefer to occupy the 8-ring sites, while $Ag^+$ ions prefer to occupy the 6-ring sites.