고리 및 영광 논토양에 대한 ^137Cs의 모의 사고 침적시 토양-벼 전이계수

최용호,임광묵,박효국,최희주,이한수 대한방사선 방어학회 2002 방사선방어학회지 Vol.27 No.4

고리 및 영광 원전 반경 5km 내 11곳의 논토양을 원상대로 재배상자에 채취하여 실험 온실로 운반한 후 벼의 이식 전과 생육중에 ^137Cs을 담수의 표면에 처리하였다. 이식전 처리시 ^137Cs의 토양-작물체 전이계수(m²kg^-1-dry plant)는 토양에 따라 8배 정도의 변이를 보였고 평균은 지역간 차이가 거의 없이 쌀알의 경우 1.1 x 10^-4 , 볏짚의 경우 2.7 x 10^-4 이었다. 분얼초기 처리와 수잉기 처리시 전이계수는 이식전 처리에 비해 대체로 2∼3 배 및 15∼30 배 정도 높았다. 토양 유기물 함량과 전이계수 간에는 정의 상관이 있었다. 본 실험결과에 입각하여 우리나라 논에 대한 일회성 사고침적시 적용할 수 있는 ^137Cs 전이계수의 대표치를 침적시기별로 제안하였다. Undisturbed soil blocks were taken into culture boxes from 11 paddy fields within 5 km radii of Kori and Yonggwang NPPs and carried to a greenhouse where ^137Cs was applied to the surface of standing water before rice transplanting and during its growth. Transfer factors (m²kg^-1-dry plant) of ^137Cs applied before transplanting varied with soils by a factor of about 8. The mean was 1.1 x 10^-4 for hulled rice seeds and 2.7 x 10^-4 for straw without significant regional differences. The ^137Cs applications at the early tillering stage and booting stage resulted in, on the whole, 2∼3 and 15∼30 times, respectively, higher transfer factors than the application before transplanting. A positive correlation was found between soil organic matter and transfer factor. Generic values of transfer factors were proposed for an acute accidental deposition of ^137Cs onto Korean paddy fields in different times of the year.

소수성 촉매를 이용한 수소동위원소 교환 반응 측정을 위한 순환 반응기

최희주,이한수,안도희,강희석,김광락 한국공업화학회 2002 응용화학 Vol.6 No.2

The catalytic rate constants of hydrophobic catalysts developed for the removal of tritium mainly generated in the pressurized heavy water reactors should be measured. A recycle reactor was designed and built for characterzing the long-term behavior of the catalyst performance at the various temperatures and gas velocities.The catalytic rate constants were measured at the apparent gas velocity of 0.5 m/s and the temperature of 60℃. The initial catalytic constant was 8.44×10^-4mol/g.sec. This value is much greater than that considered in the design of Wolsong Tritium Removal Facility.

Streptomyces thermocyaneoviolaceus의 Xylanase 생산조건 및 Xylooligo당의 생산

주길재,박희동,최준호,이인구,이오석,권달호 慶北大學校農業科學技術硏究所 1998 慶北大農學誌 Vol.16 No.-

농산폐자원으로부터 기능성물질인 xylooligo당을 생산하기 위해서 내열성 균주인 S.thermocyaneoviolaceus가 생산하는 xylanase의 생산최적조건을 검토한 결과 0.8% 밀기울, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.005% FeSO₄·7H₂O, 0.05% KH₂PO₄및 0.2% K₂HPO₄를 함유한 배지(pH7.0)에서 50℃, 24시간 배양시 최고효소활성(2.47 unit/ml)의 배양상징액을 얻을 수 있었다. 효소의 최적반응조건은 pH5.5, 65℃였다. 또한 pH안정성을 조사한 결과 pH4.5∼9.5사이에서 4℃에서 12시간후에도 80% 이상의 효소활성을 유지하였고, 열 안정성은 60℃에서 1시간 처리후 94%이상의 효소활성을 유지하는 내열성이 있는 효소였다. 생산된 xylanase birchwood xylan 반응생성물을 TLC 및 HPLC로 확인해 본 결과, pH가 낮을수록(pH 5.0∼6.0) xylobiose와 xylotriose및 소량의 xylose의 양이 증가하였고, pH가 높을수록 (pH8.0∼9.0) X₄이상의 각종 xylooligo당의 양이 상대적으로 증가하였다. 또한 24 시간후에는 xylan의 상대량이 25% 이하로 감소하면서 주분해산물로 xylobiose가 생산되었으며 xylotriose와 xylose 및 X₄이상의 각종 xylooligo당이 생산되었다. A thermotolerant bacterium, Streptomyces thermocyaneoviolaceus which produced xylan-degrading enzymes, utilized excellently xylan of wheat bran by producing the enzymes in comparison with that of birchwood or oat spelts. Optimal enzyme production was achieved in WB medium containing 0.8% wheat bran, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.05% FeSO₄·7H₂O, 0.05% KH₂PO₄ and, 0.2% K₂HPO₄(pH 7.0) at 50℃ for 24 hrs. The optimal pH and temperature for the hydrolysis of xylan were pH 5.5 and 65℃, respectively. The enzyme activity was retained more than 80% at the range from pH 4.5 to pH 9.5 at 4℃ for 12 hrs and 94% on the heat-treatment at 65℃ for 1 hr. Xylobiose, xylotriose, xylose, and other xylooligosaccharides were produced as end products from hydrolysis of birchwood xylan by the xylanase of S. thermocyaneoviolceus.

회귀분석(regression analysis)을 이용한 개인별 혈중알콜농도의 감소율 계산

홍성욱,권미아,최혜진,박용훈,인상환,김동우,정주연,우상희,박혜성 內務部 國立科學搜査硏究所 2002 國立 科學 搜査 硏究所 年報 Vol.34 No.-

상용 소수성 백금촉매의 제조비용 절감

안도희,백승우,강희석,최희주,정흥석 한국공업화학회 2003 응용화학 Vol.7 No.2

Wolsong Tritium Removal Facility(WTRF) is being constructed at Wolsong Nuclear Power Plant for reduction of the radiation hazards from tritium. The Liqiud Phase Catalytic Exchange (LPCE) process developed by KAERI and KEPRI was selected for the transfer process in WTRF. Approximately 2,000 litres of the hydrophobic platinum catalyst will be charged in the LPCE column. It was estimated that more than half of material cost for the catalyst preparation arised from H₂PtCl-(6) as a platinum precursor and high purity hydrogen gas as a reducing agent. In order to reduce material costs for the catalyst preparation, various catalysts were prepared and characterized using three kinds of H-(2)PtCl-(6) and two kinds of high purity hydrogen gas. It appears from the experiment that characteristics of the catalyst does not depend on both a kind of H₂PtCl_(6) and purity of hydrogen in the experimental conditions.

Preliminary conceptual design of a geological disposal system for high-level wastes from the pyroprocessing of PWR spent fuels

Choi, Heui-Joo,Lee, Minsoo,Lee, Jong Youl Elsevier 2011 Nuclear engineering and design Vol.241 No.8

<P><B>Highlights</B></P><P>► A geological disposal system consists of disposal overpacks, a buffer, and a deposition hole or a disposal tunnel for high-level wastes from a pyroprocessing of PWR spent fuels is proposed. The amount and characteristics of high-level wastes are analyzed based on the material balance of pyroprocessing. ► Four kinds of deposition methods, two horizontal and two vertical, are proposed. Thermal design is carried out with ABAQUS program. The spacing between the disposal modules is determined for the peak temperature in buffer not to exceed 100°C. ► The effect of the double-layered buffer is compared with the traditional single-layered buffer in terms of disposal density. Also, the effect of cooling time (aging) is illustrated. ► All the thermal calculations are represented by comparing the disposal area of PWR spent fuels with the same cooling time.</P> <P><B>Abstract</B></P><P>The inventories of spent fuels are linearly dependent on the production of electricity generated by nuclear energy. Pyroprocessing of PWR spent fuels is one of promising technologies which can reduce the volume of spent fuels remarkably. The properties of high-level wastes from the pyroprocessing are totally different from those of spent fuels. A geological disposal system is proposed for the high-level wastes from pyroprocessing of spent fuels. The amount and characteristics of high-level wastes are analyzed based on the material balance of pyroprocessing. Around 665kg of monazite ceramic wastes are expected from the pyroprocessing of 10MtU of PWR spent fuels. Decay heat from monazite ceramic wastes is calculated using the ORIGEN-ARP program. Disposal modules consisting of storage cans, overpacks, and a deposition hole or a disposal tunnel are proposed. Four kinds of deposition methods are proposed. Thermal design is carried out with ABAQUS program and geological data obtained from the KAERI Underground Research Tunnel. Through the thermal analysis, the spacing between the disposal modules is determined for the peak temperature in buffer not to exceed 100°C. Thermal analysis shows that the optimum spacing between the vertical deposition holes with 4 overpacks is 8m when the disposal tunnel spacing is 40m and optimum spacing of 2m for horizontal disposal tunnel with 25m tunnel spacing. Also, the spacing reduces to 6m for vertical deposition when the double-layered buffer is used, which reduces the disposal area to one-sixty fifth (1/65th) compared with the direct disposal of spent fuels. Finally, the effect of cooling time on the disposal area is illustrated.</P>

Long Terminal Repeat of an Endogenous Retrovirus HERV-K Family from Human Liver and Kidney cDNA

Joo Young Choi,Joo Mi Lee,Seung Heui Jeon,Young Choon Lee,Won Ho Lee,Kyung Lib Jang,Heui Soo Kim 한국생명과학회 2000 Journal of Life Science Vol.10 No.2

Review of Instant Release Fractions of CANDU and PWR Spent Nuclear Fuels for a Safety Case

Heui-Joo Choi,In Young Kim,Youn-Myoung Lee,Dong-Keun Cho 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.06

Derivation of the Cathodic Current Density around the HLW Canister Due to the Radiolysis of Groundwater

Heui-Joo Choi,Dong-Keun Cho,Jongwon Choi,Pil Soo Hahn 대한방사선방어학회 2006 방사선방어학회지 Vol.31 No.2

PREDICTION OF THE TRITIUM CONCENTRATION IN THE SOIL WATER AFTER THE OPERATION OF WOLSONG TRITIUM REMOVAL FACILITY

CHOI HEUI-JOO,LEE HANSOO,SUH KYUNG SUK,KANG HEE SUK Korean Nuclear Society 2005 Nuclear Engineering and Technology Vol.37 No.4

The effect of the Wolsong Tritium Removal Facility on the change of tritium concentration in the soil water was assessed by introducing a dynamic compartment model. For the mathematical modeling, the tritium in the environment was thought to come from two different sources. Three global tritium cycling models were compared with the natural background concentration. The dynamic compartment model was used to model the behavior of the tritium from the nuclear power plants at the Wolsong site. The source term for the dynamic compartment model was calculated with the dry and wet deposition rates. The area around the Wolsong nuclear power plants was represented by the compartments. The mechanisms considered in deriving the transfer coefficients between the compartments were evaporation, runoff, infiltration, hydrodynamic dispersion, and groundwater flow. We predicted what the change of the tritium concentration around the Wolsong nuclear power plants would be after future operation of the tritium removal facility to show the applicability of the model. The results showed that the operation of the tritium removal facility would reduce the tritium concentration in topsoil water quickly.