• Title/Summary/Keyword: atomic processes

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Employing high-temperature gas flux in a residual salt separation technique for pyroprocessing

  • Kim, Sung-Wook;Heo, Dong Hyeon;Kang, Hyun Woo;Hong, Sun-Seok;Lee, Sang-Kwon;Jeon, Min Ku;Hur, Jin-Mok;Choi, Eun-Young
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1866-1870
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    • 2019
  • Residual salt separation is an essential step in pyroprocessing because its reaction products, as prepared by electrochemical unit processes, contain frozen residual electrolyte species, which are generally composed of alkali-metal chloride salts (e.g., LiCl, KCl). In this study, a simple technique that utilizes high-temperature gas flux as a driving force to melt and push out the residual salt in the reaction products was developed. This technique is simple as it only requires the use of a heating gun in combination with a gas injection system. Consequently, $LiNO_3-ZrO_2$ and $LiCl-ZrO_2$ mixtures were successfully separated by the high-temperature gas injection (separation efficiency > 93%), thereby demonstrating the viability of this simple technique for residual salt separation.

Simulation Methods for Prediction of Membrane Protein Structure

  • Son, Hyeon-S.
    • Proceedings of the Korean Biophysical Society Conference
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    • 1998.06a
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    • pp.10-10
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    • 1998
  • IMPs are important to cells in functions such as transport, energy transduction and signalling. Three dimensional molecular structures of such proteins at atomic level are needed to understand such processes. Prediction of such structures (and functions) is necessary especially because there are only a small number of membrane protein structures determined in atomic resolution.(omitted)

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Treatment of Hydrogen Fluoride Generated from the F-gases Decomposition Processes

  • Park, Jun-Hyeong;Choi, Chang Yong;Kim, Tae-Hun;Shin, InHwan;Son, Youn-Suk
    • Asian Journal of Atmospheric Environment
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    • v.10 no.4
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    • pp.190-196
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    • 2016
  • The objective of this study is to obtain the optimal conditions to remove hydrogen fluoride (HF) generated from a variety of F-gas treatment processes. First, we selected $Ca(OH)_2$ and $CaCO_3$ as a reactant among the various alkali salts which have a high removal efficiency and a competitive price by forming a calcium fluoride precipitate. Additionally, various factors were investigated to improve the removal efficiency of HF. The conditions such as the settling time, agitating time and intensity, reaction temperature, and pH were considered as main factors. As a result, in the treatment process to remove HF through Ca-based alkali salts, the optimal conditions were a 120 min settling time, 30 min of agitation at 100 rpm, a pH of 4-8, and a reaction temperature of $40^{\circ}C$.

Fabrication of Nanostructured Alumina by the Combined Processes of Magnetic Pulsed Compaction (MPC) and Spark Plasma Sintering (SPS) (자기펄스성형법 및 통전가압소결법의 연속공정을 이용한 고밀도 나노 알루미나 세라믹의 제조)

  • Lee, J. K.;Hong, S. J.;Lee, M. K.;Rhee, C. K.
    • Journal of Powder Materials
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    • v.12 no.5 s.52
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    • pp.345-350
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    • 2005
  • In this study the nanostructured ${\alpha}-Al_{2}O_3$ ceramics have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent spark plasma sintering (SPS), and their density and hardness properties were investigated. The ${\alpha}-Al_{2}O_3$ prepared by the combined processes showed an increase by $8.4\%$ in density, approaching the value close to the true density, and an enhancement by $210\~400\;Hv$ in hardness, compared to those fabricated by MPC or static compaction method followed by sintering treatment.

Preliminary Study on the Development of Alternative Methods for the Treatment of TRISO Fuels (TRISO 연료 대체 처리방법 개발에 관한 선행연구)

  • Lee Jong-Hyeon;Shim Joon-Bo;Ahn Byung-Gil;Kwon Sang-Woon;Kim Eung-Ho;Yoo Jae-Hyung;Park Seong-Won;Snyder Christine T.;Leibowitz Leonard
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.3 no.3
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    • pp.201-211
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    • 2005
  • In this study, conventional head-end processes of spent TRISO fuel have been reviewed to develope more effective treatment methods. The main concerns in the TRISO treatment are to effectively separate the carbon and SiC contained in the TRISO particles. The crush-burn scheme which was considered in the early stages of the development has been replaced by the crush-leach process because of $^{14}C$ problems as a second waste being generated during the process. However, there are still many obstacles to overcome in the reported processes. Hence, innovative thermomechanical concepts and a molten salt electrochemical approach to breach the coating layers of the TRISO particle with a minimized amount of second waste are proposed in this paper and their principles are described in detail.

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Review on Discontinuum-based Coupled Hydro-Mechanical Analyses for Modelling a Deep Geological Repository for High-Level Radioactive Waste (고준위방사성폐기물 심층처분장 모델링을 위한 불연속체 기반 수리-역학 복합거동 해석기법 현황 분석)

  • Kwon, Saeha;Kim, Kwang-Il;Lee, Changsoo;Kim, Jin-Seop;Min, Ki-Bok
    • Tunnel and Underground Space
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    • v.31 no.5
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    • pp.309-332
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    • 2021
  • Natural barrier systems surrounding the geological repository for the high-level radioactive waste should guarantee the hydraulic performance for preventing or delaying the leakage of radionuclide. In the case of the behavior of a crystalline rock, the hydraulic performance tends to be decided by the existence of discontinuities, so the coupled hydro-mechanical(HM) processes on the discontinuities should be characterized. The discontinuum modelling can describe the complicated behavior of discontinuities including creation, propagation, deformation and slip, so it is appropriate to model the behavior of a crystalline rock. This paper investigated the coupled HM processes in discontinuum modelling such as UDEC, 3DEC, PFC, DDA, FRACOD and TOUGH-UDEC. Block-based discontinuum methods tend to describe the HM processes based on the fluid flow through the discontinuities, and some methods are combined with another numerical tool specialized in hydraulic analysis. Particle-based discontinuum modelling describes the overall HM processes based on the fluid flow among the particles. The discontinuum methods that are currently available have limitations: exclusive simulations for two-dimension, low hydraulic simulation efficiency, fracture-dominated fluid flow and simplified hydraulic analysis, so it could be improper to the modelling the geological repository. Based on the concepts of various discontinuum modelling compiled in this paper, the advanced numerical tools for describing the accurate coupled HM processes of the deep geological repository should be developed.

A Communication Method Between Distributed Control System and Function Test Facility Using TCP/IP and Shared Memory

  • Kim, Jung-Soo;Jung, Chul-Hwan;Kim, Jung-Taek;Lee, Dong-Young;Ham, Chang-Sik
    • Nuclear Engineering and Technology
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    • v.30 no.4
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    • pp.298-307
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    • 1998
  • In order to design mutual communication between a distributed control system and a function test facility, we used the Inter-Process Communication(IPC) in two systems and Transmission Control Protocol/Internet Protocol(TCP/IP) protocol. The data from the function test facility are put in the shared memory using an IPC, which is then accessed by the distributed control system through an Application Program Interface(API). The server in the function test facility includes two processes(one for sending and one for receiving), which are generated by the fork function from the client signal. The client in the distributed control system includes two separate programs(one for receiving and one for sending).

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Characteristics of Reduced Metal from Spent Oxide Fuel by Lithium

  • Kim Ik-Soo;Seo Chung-Seok;Shin Hee-Sung;Hwang Yong-Soo;Park Seong-Won
    • Nuclear Engineering and Technology
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    • v.35 no.4
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    • pp.309-317
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    • 2003
  • The mass balance of the unit processes of the Advanced spent fuel Conditioning Process was calculated to obtain basic information. Based on this mass balance, the changes in decay heat and radioactivity of the spent fuel due to the metallization in the high temperature molten salt system were estimated. The decay heat and the radioactivity were calculated by using the ORIGEN2 computer code, and the result showed that the decay heat and the radioactivity of the metallized spent fuel ingot were $24.27\%\;and\;24.24\%$, respectively, compared to those of oxide spent fuel.

Recent Developments in Radiationless Transitions

  • Hayashi, M.;Liang, K.K.;Chang, C.H.;Mebel, A.;Lin, S.H.
    • Journal of Photoscience
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    • v.6 no.3
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    • pp.97-102
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    • 1999
  • In this paper, the historicla development of radiationless transitions will be briefly reviewed. The paper will then focus on the ab inition calculations of internal conversion rate constants with emphasis on the case of small polyatomic molecules where the Duschinsky effect is important . As an example, we have chosen the new expressions for singlevibronic level rate constants of radiationless transitions. This type of rate constants is important in femto-second processes.

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