배관류 폐기물의 베타선 오염도 측정용 플라스틱 검출기 제작 및 특성평가

김계홍,오원진,이근우,서범경,Kim Gye-Hong,Oh Won-Zin,Lee Kune-Woo,Seo Bum-Kyoung 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.3

The characterization of radiological contamination inside pipes generated during the decommission of a nuclear facility is necessary before pipes can be recycled or disposed. But, existing direct measurements of radioactive contamination level using the survey-meter can not estimate the characteristic of contamination on a local area such as the pipe inside. Moreover, the measurement of surface contamination level using the indirect methods has many problems of an application because of the difficulty of collecting sample and contamination possibility of a worker when collecting sample. In this work, plastic scintillator was simulated by using Monte Carlo simulation method for detection of beta radiation emitted from internal surfaces of small diameter pipe. Simulation results predicted the optimum thickness and geometry of plastic scintillator at which energy absorption for beta radiation was maximized. In addition, the problem of scintillator processing and transferring the detector into the pipe inside was considered when fabricating the plastic detector on the basis of simulation results. The characteristic of detector fabricated was also estimated. As a result, it was confirmed that detector capability was suitable for the measurement of contamination level. Also, the development of a detector for estimating the radiological characteristic of contamination on a local area such as the pipe inside was proven to be feasible.

방사성 금속폐기물의 용융시 방사성 핵종(⁶⁰Co, ¹³⁷Cs)의 분배특성

민병연,최왕규,오원진,정종헌,강용,Min, Byung Youn,Choi, Wang Kyu,Oh, Won Zin,Jung, Chong Hun,Kang, Yong 한국화학공학회 2007 Korean Chemical Engineering Research(HWAHAK KONGHA Vol. No.

원자력 시설 해체시 발생되는 금속성 폐기물의 용융 제염을 위한 기초 연구를 위해 아크 용융로를 사용하여 스테인레스강과 탄소강의 금속 폐기물 용융시 슬래그 종류, 농도, 염기도에 따라 $^{60}Co$, $^{137}Cs$ 핵종의 주괴, 슬래그, 분진 상으로 분배 특성을 살펴보았다. $^{60}Co$은 90% 이상 주괴상에 균질하게 분포되었으며, 슬래그 상에는 약 10% 미만으로 잔존하며 슬래그 조성에 따라 분배특성이 크게 영향을 받지 않았으나, 유동성이 좋은 염기성 슬래그 형성제가 포함된 슬래그에서는 영향을 받음을 알 수 있었다. $^{137}Cs$는 스테인레스강과 탄소강의 용융체로부터 완전히 제거되어 슬래그상과 분진상 상으로 분배됨을 알 수 있었다. A fundamental study on the melt decontamination of metal wastes generated by dismantling the nuclear facility, the melting of metal wastes such as stainless steel and carbon steel have been carried out to investigate the distribution phenomena of the radioisotopes such as $^{60}Co$ and $^{137}Cs$ into the ingot, slag and dust phases by using the various slag types, slag concentration and basicity in an arc furnace. The $^{60}Co$ remained homogeneously in the ingot phase above 90 % and it was barely present in the slag below 10 %. The effect of the slag composition on the distribution for Co-60 was not considerable, but a basic slag former with high fluidity showed effective. $^{137}Cs$ was completely eliminated from the melt of the stainless steel as well as the carbon steel and distributed to the slag and the dust phase.

Hot Cell 내의 고방사능 분진 제거를 위한 사이클론 적용 실험

김계남,이성열,원휘준,정종헌,오원진,Kim Gye Nam,Lee Sung Yeol,Won Hui Jun,Jung Chong Hun,Oh Won Zin 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.1

원자력시설 핫셀 (Hot Cell)내에서 핵종실험 시 발생하는 고방사능 분진(Hot Particulate)의 크기는 0.5300 ${\mu}m$이고 주 핵종은 UO$_2$였다. 핫셀 내의 고방사능 분진을 제거하기 위해 사이클론과 Bag/HEPA필터로 구성된 장치를 고안하였고, 이 장치의 사이클론에 의해 고방사능 분진을 최대로 포집할 수 있는 실험조건을 제시했다. 모의입자의 크기가 클수록 입자의 포집효율은 높았다. 모의 입자의 크기가 5${\mu}m$ 이상일 때, 입자의 포집효율은 $80\%$보다 높았다. 모의 입자의 크기가 1.0 ${\mu}m$ 보다 작을 때, 포집효율은 $70\%$ 보다 작았다. 모의 입자의 유입속도가 12 m/sec보다 클 때, 포집효율은 $70\%$보다 높았다. 그러나 유입속도가 17 m/sec 보다 클 때 포집효율의 증가율은 크지 않았다. 모의입자의 포집효율은 Vortex Finder의 길이가 7.2 cm이하일 때, 길이의 증가와 함께 높아졌지만 7.2 cm 이상일 때는 낮아지기 시작했다. 그러므로 Vortex Finder의 길이가 7.2 cm 일 때, 최대포집효율을 나타냈다. 사이클론 밑에 보조콘 부착 시 모든 속도 범위에서 약 평균 $2\%$ 정도 포집효율이 증가하므로 보조콘 부착효과가 크지 않았다.

PFC제염폐액 내의 미립자 제거를 위한 여과막의 특성 연구

김계남,이성열,원휘준,정종헌,오원진,박진호,Kim Gye-Nam,Lee Sung-Yeol,Won Hui-Jun,Jung Chong-Hun,Oh Won-Zin,Park Jin-Ho 한국방사성폐기물학회 2005 방사성폐기물학회지 Vol.3 No.2

PFC(Perfluorocarbon) decontamination process is one of best methods to remove hot particulate adhered at inside surface of hot cell and surface of equipment in hot cell. It was necessary to develop a particulate filtration equipment to reuse PFC solution used on PFC decontamination due to its high cost and to minimize the volume of second wastewater. Contamination characteristics of hot particulate were investigated and then a filtration process was presented to remove hot particulate in PFC solution generated through PFC decontamination process. The removal efficiency of PVDF(Poly vinylidene fluoride), PP(Polypropylene), Ceramic(Al$_{2}$O$_{3}$ filter showed more than 95$\%$. The removal efficiency of PVDF filter was a little lower than those of other kiters at same pressure(3psi). A ceramic filter showed a higher removal efficiency with other filters, while a little lower flux rate than other filters. Due to inorganic composition, a ceramic filter was highly stable against radio nuclides in comparison with PVDF and PP membrane, which generate H$_{2}$ gas in e-radioactivity atmosphere. Therefore, the adoption of ceramic filter is estimated to be suitable for the real nitration process.

유해가스 제거용 첨착활성탄의 이용

이후근(Hoo Kun Lee),오원진(Won Zin Oh),박현수(Hyun Soo Park),박영태(Young Tae Park) 한국고분자학회 1997 고분자 과학과 기술 Vol.8 No.2

초산완충액에 으한 동전기적 토양복원 효과 증진 연구

김계남(Gye Nam Kim),오원진(Won Zin Oh) 大韓環境工學會 2000 대한환경공학회지 Vol.22 No.11

원자력연구시설 해체비용 산정 구조

정관성,이동규,이근우,오원진,정종헌,박진호,Jeong Kwan-Seong,Lee Dong-Gyu,Lee Kune-Woo,Oh Won-Zin,Jung Chong-Hun,Park Jin-Ho 한국방사성폐기물학회 2006 방사성폐기물학회지 Vol.4 No.2

Decommissioning cost estimation is a very important technique in designing and planning of nuclear facilities' decommissioning. Decommissioning cost estimation should be made according to the phases of decommissioning activities and installed components of nuclear facilities. In this paper, the basic framework necessary for decommissioning cost estimation is completed so that it could be used as a technique for decommissioning costs estimation by specifying cost items and group components and unit cost factors on which work time is calculated. Also, factors to be considered for decommissioning cost estimation of major activities and tasks are reviewed. Afterwards, these techniques will be utilized as a basic technology to establish methodology of decommissioning cost estimation and evaluation.

고농도 질산용액에서 Ag(I) 이온의 확산계수 측정

박상윤,최왕규,이근우,문제권,오원진,Park Sang Yoon,Choi Wang Kyu,Lee Kune Woo,Moon Jei Kwon,Oh Won Zin 한국전기화학회 1999 한국전기화학회지 Vol.2 No.2

유해성 유기물을 효과적으로 분해시키는데 이용되는 Ag(II)이온에 의한 전기화학적 매개산화 공정의 한계전류밀도를 예측하기 위하여 질산전해질의 농도, Ag(I) 이온의 농도 및 온도변화에 따른 Ag(I)/Ag(II) 이온쌍의 cyclic voltammogram을 백금전극에서 얻었으며, 피크전류로부터 Ag(I) 이온의 확산계수를 구하였다. Ag(I)/Ag(II) 이온쌍의 산화환원 반응은 물 분해 반응에 의해 크게 영향을 받았으며 백그라운드 보정을 통하여 정확한 피크전류를 측정할 수 있었다. Ag(I) 이온의 확산계수를 질산용액의 점도 및 온도의 함수로 나타냄으로써 전기화학적 매개산화공정의 한계전류밀도를 용이하게 예측할 수 있는 실험식을 제시하였다. From the anodic peak currents of cyclic voltammograms for Ag(I)/Ag(II) couple obtained with the variation of nitric acid concentration, Ag(I) concentration and solution temperature at a Pt electrode in concentrated nitric acid solutions, the diffusion coefficients of Ag(I) ion were evaluated to estimate the limiting current density of Ag(II)-mediated electrochemical oxidation (MEO) process, which has been effectively used for the complete destruction of hazardous organic materials. The results showed that, due to the water decomposition reaction which occurred simultaneously with the Ag(I) ion oxidation, background subtractions for the cyclic voltammograms were required to estimate the correct peak currents. The empirical relationship for the diffusion coefficient of Ag(I) was suggested as a function of solution viscosity and temperature.

Hot Cell 내에 오염된 고방사능분진 제거를 위한 사이클론 개발 및 성능평가

김계남,원휘준,최왕규,정종헌,오원진,박진호,Kim Gye-Nam,Won Hui-Jun,Choi Wang-Kyu,Jung Chong-Hun,Oh Won-Zin,Park Jin-Ho 한국방사성폐기물학회 2006 방사성폐기물학회지 Vol.4 No.3

The structural and contamination characteristics of hot cells at KAERI were investigated. The SEM results showed that the size of the hot particulate on the inner surface of the hot cell ranged from 0.2 to $10{\mu}m$. It was found that an inlet flow rate of 15 m/sec was suitable for this developed cyclone with a 49 mm optimum vortex finder length. The results showed that the collection efficiency was about 85% for $3{\mu}m$ particles. The collection efficiency didn't show a sharp increase when the inlet flow rate was faster than 15m/sec. When the temperature of the inlet flow gas was increased, the collection efficiency of the cyclone was slightly decreased. The larger the vortex finder length was, the higher the pressure drop in the cyclone was. The cut size diameter decreased with an increment of the Reynolds number. It was established that the flow in the cyclone was a turbulent flow on the basis of the Reynolds number and this turbulent flow caused a pressure drop in the cyclone. $Stk^{1/2}_{50}$ decreased with increasing values of the Reynolds number and it gradually approached a constant value at a higher value of the Reynolds number Namely, $Stk^{1/2}_{50}$ approached approximately 0.045 between 6000 and 8000 of the Reynolds number.

Ag(II)매개산화에 의한 폐 유기이온교환수지의 분해

최왕규,남혁,박상윤,이근우,오원진,Choi Wang-Kyu,Nam Hyeog,Park Sang-Yoon,Lee Kune-Woo,Oh Won-Zin 한국전기화학회 1999 한국전기화학회지 Vol.2 No.4

원자력 시설의 가동 및 유지보수 중에 중$\cdot$저준위 방사성폐기물로 다량 생성되는 폐 유기이온교환수지를 상온의 수용 상 내에서 분해 처리하는 공정을 개발할 목적으로, 전기화학적으로 생성되는 Ag(II)를 매개산화제로 사용하여 양이온 및 음이온교환수지의 분해 연구를 수행하였다. Ag(II) 매개산화 공정에서 제어 가능한 인자인 전류, 온도 및 전해질 농도가 이온교환수지의 분해거동에 미치는 영향을 고찰하였다. 양이온교환수지는 거의 대부분 $CO_2$로 분해되었으며, 전류밀도가 감소할수록 전류효율이 증가됨을 보인 반면에 양극전해질로 사용된 질산의 농도 및 온도가 증가하더라도 분해거동에는 영향을 미치지 않았다. 양이온교환수지와는 달리 음이온교환수지의 분해시에는 온도와 무관하게 약 $10\%$ 정도가 CO로 분해되었고, $CO_2$로의 분해효율은 온도에 의존하는 경향을 보였으며, $60^{\circ}C$ 이상에서 효과적으로 분해가 가능하였다. A study on the destruction of organic cation and anion exchange resins by electro-generated Ag(II) as a mediator was carried out to develop the ambient-temperature aqueous process, known as Ag(II)-mediated electro-chemical oxidation (MEO) process, for the treatment of a large quantity of spent organic ion exchange resins as the low and Intermediated-level radioactive wastes arising from the operation, maintenance and repairs of nuclear facilities. The effects of controllable process parameters such as applied current density, temperature, and nitric acid concentration on the MEO of organic ion exchange resins were investigated. The cation exchange resin was completely decomposed to $CO_2$. The current efficiency increased with a decrease in applied current density while nitric acid concentration and temperature on the MEO of cation exchange resin did not affect the MEO. On the other hand, anion exchange resins were decomposed to CO and $CO_2$. The ultimate conversion to CO was about $10\%$ regardless of temperature. The destruction efficiencies to $CO_2$ were dependent upon temperature and the effective destruction of anion exchange resin could be obtained above $60^{\circ}C$.