• Title/Summary/Keyword: eutectic penetration

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Probabilistic Estimation of LMR Fuel Cladding Performance Under Transient Conditions

  • Kwon, Hyoung-Mun;Lee, Dong-Uk;Lee, Byung-Oon;Kim, Young ll;Kim, Yong-Soo
    • Nuclear Engineering and Technology
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    • v.35 no.2
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    • pp.144-153
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    • 2003
  • The object of this paper is the probabilistic failure analysis on the cladding performance of WPF(Whole Pin Furnace) test fuel pins under transient conditions, and analysis of the KALIMER fuel pin using the preceding analysis. The cumulative damage estimation and Weibull probability estimation of WPF test are performed. The probabilistic method was adapted for these analyses to determine the effective thickness thinning due to eutectic penetration depth. In the results, it is difficult to assume that a brittle layer depth made by eutectic reaction is all of the thickness reduction due to cladding thinning. About 93% cladding thinning of the eutectic penetration depth is favorable as an effective thickness of cladding. And the unreliability of the KALIMER driver fuel pin under the same WPF test condition is lower than that of the WPF pin because of the higher plenum-fuel volume ratio and lower cladding inner radius vs. thickness ratio. KALIMER fuel pin developed from conceptual design has a more stable transient performance for a failure mechanism due to fission gas buildup than the WPF pin.

MPS eutectic reaction model development for severe accident phenomenon simulation

  • Zhu, Yingzi;Xiong, Jinbiao;Yang, Yanhua
    • Nuclear Engineering and Technology
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    • v.53 no.3
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    • pp.833-841
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    • 2021
  • During the postulated severe accident of nuclear reactor, eutectic reaction leads to low-temperature melting of fuel cladding and early failure of core structure. In order to model eutectic melting with the moving particle semi-implicit (MPS) method, the eutectic reaction model is developed to simulate the eutectic reaction phenomenon. The coupling of mass diffusion and phase diagram is applied to calculate the eutectic reaction with the uniform temperature. A heat transfer formula is proposed based on the phase diagram to handle the heat release or absorption during the process of eutectic reaction, and it can combine with mass diffusion and phase diagram to describe the eutectic reaction with temperature variation. The heat transfer formula is verified by the one-dimensional melting simulations and the predicted interface position agrees well with the theoretical solution. In order to verify the eutectic reaction models, the eutectic reaction of uranium and iron in two semi-infinite domains is simulated, and the profile of solid thickness decrease over time follows the parabolic law. The modified MPS method is applied to calculate Transient Reactor Test Facility (TREAT) experiment, the penetration rate in the simulations are agreeable with the experiment results. In addition, a hypothetical case based on the TREAT experiment is also conducted to validate the eutectic reaction with temperature variation, the results present continuity with the simulations of TREAT experiment. Thus the improved method is proved to be capable of simulating the eutectic reaction in the severe accident.

A Study on the Initial Stage of Sintering and the Grain Growth of ZnO in ZnO-Bi2O3 System (ZnO-Bi2O3계의 소결초기단계와 입자성장에 관한 연구)

  • 성건용;강을손;김종희
    • Journal of the Korean Ceramic Society
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    • v.26 no.4
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    • pp.505-513
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    • 1989
  • The sintering behavior and grain growth of ZnO in 99.0mol% ZnO-1.0mol% Bi2O3 which are the basic compositions of ZnO varistor were studied. The microstructrual observation confirmed that the final sintered density was mainly determined at the initial stage of sintering, i.e. grain rearrangement and grain growth which were induced by the penetration of eutectic melts formed at eutectic temperature(74$0^{\circ}C$). But when the liquid penetration was terminated, the grain growth did not promote further densification. Activation energy of the grain growth of ZnO in the system of 99.0mol% ZnO-1.0mol% Bi2O3 was 44.8$\pm$1.8Kcal/mol.

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Fracture simulation of SFR metallic fuel pin using finite element damage analysis method

  • Jung, Hyun-Woo;Song, Hyun-Kyu;Kim, Yun-Jae;Jerng, Dong-Wook
    • Nuclear Engineering and Technology
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    • v.53 no.3
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    • pp.932-941
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    • 2021
  • This paper suggests a fracture simulation method for SFR metallic fuel pin under accident condition. Two major failure mechanisms - creep damage and eutectic penetration - are implemented in the suggested method. To simulate damaged element, stress-reduction concept to reduce stiffness of the damaged element is applied. Using the proposed method, the failure size of cladding can be predicted in addition to the failure time and failure site. To verify the suggested method, Whole-pin furnace (WPF) test and TREAT-M test conducted at Argonne National Laboratory (ANL) are simulated. In all cases, predicted results and experimental results are overall in good agreement. Based on the simulation result, the effect of eutectic-penetration depth representing failure behavior on failure size is studied.

Microstructural Control of Al-Sn Metal Bearing Alloy with Heat Treatment (열처리에 따른 메탈베어링용 Al-Sn 합금의 미세조직 제어)

  • Kim, Jin-Soo;Park, Tae-Eun;Hahn, Chun-Feng;Sohn, Kwang-Suk;Kim, Dong-Gyu
    • Journal of Korea Foundry Society
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    • v.29 no.1
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    • pp.45-51
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    • 2009
  • Conventionally, Al-Sn bearing manufacturing involves casting the Al-Sn alloy and roll-bonding to a steel backing strip. This article will describe the microstructural control of Al-Sn metal bearing alloy following heat treatment. When the pure aluminum rod dipped in the melt of tin maintained below the melting point of aluminum, the melting of aluminum was accelerated with penetration of tin along the grain boundary of aluminum. The length of plate-shaped eutectic tin was decreased with heat treatment time. With even longer heat treatment time over 1 hour the length of eutectic tin didn't decrease any more, while resulting in coarsening of aluminum matrix. Exuded liquid of eutectic tin was formed at the surface of Al-Sn alloy after heat treatment even at below eutectic temperature.

An Evaluation on the Weldability of Al-Li Alloys by Varestraint Testing Method (Varestraint Test법에 의한 Al-Li합금의 용접성 평가)

  • 김형태;이창배;신현식;서창제
    • Journal of Welding and Joining
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    • v.14 no.6
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    • pp.48-57
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    • 1996
  • The weldability of high purity aluminum-lithium binary alloys has been investigated using the Varestraint test. Autogenous GTAW (gas-tungsten-arc-welds) were run along specimens of different lithium concentration using three sets of welding parameters. Welding voltage was held constant at 10 volts. Welding current (70∼100 amps) and travel speed (23∼33 cm/min) were the parameter varied. Hot-tearing susceptibility varied with lithium content and exhibited a steep peak at 2.6 weight percent lithium. Depth of penetration increased with increasing heat input and lithium concentration. The susceptibility is influenced by the wettability of dendrites by the interdendritic eutectic liquid as well as the time available for back-Siting by eutectic liquid. The welding condition of welding current 70A and travel speed 23 cm/min was showed good resistance to cracking in aluminum-lithium alloys. Suggestions for improving weld cracking resistance are also provided.

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Non-aqueous Zinc(Zn) Plating to Prevent Hydrogen Release from Test Specimens in Hydrogen Embrittlement Test (수소 취성 시험 평가를 위한 수소 방출 방지용 비수계 아연(Zn) 도금)

  • Jeon, Jun-Hyuck;Jang, JongKwan
    • Journal of the Korean Institute of Gas
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    • v.26 no.3
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    • pp.21-26
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    • 2022
  • Zinc is emerging as a environment-friendly plating material to replace cadmium, which is harmful to the human body, to prevent hydrogen gas penetration or release from metal materials. Electroplating of Zn and Zn alloys, which is usually performed in an aqueous acidic atmosphere, has disadvantages such as low coulombic efficiency, corrosion, and hydrogen release, resulting in industrial use difficult. In this study, a deep-eutectic solvent was synthesized using choline chloride and ethylene glycol. Using this as a solvent, an electrolyte for Zn plating was prepared, and then zinc was plated on the STS 304 substrate. The surface microstructure and roughness were observed using SEM and AFM. The crystal structure of the electro-plated film was analyzed using XRD. Finally, the preventing effects of hydrogen release through Zn-based deep-eutectic plating on the STS 304 substrate were compared with the uncoated substrate.

Effects of GMA Welding Conditions on the Bead Shape of Hardfacing Overlay Welding (하드페이싱 오버레이용접 비드형상에 미치는 GMA 용접조건의 영향)

  • Han, Kyu-Ho;Kim, Jun-Ki;Kim, Cheol-Hee;Kim, Jeong-Han;Nam, See-Hwan;Jeon, Chi-Jung
    • Journal of Welding and Joining
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    • v.25 no.5
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    • pp.58-63
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    • 2007
  • The relationship between GMA welding conditions and the bead shape of overlay weld was studied by using ${\Phi}1.6mm$ hypo-eutectic metal-cored wire designed for hardfacing against the severe metal-to-metal wear. As the welding voltage increased, the dilution also increased but the sudden drop of dilution was observed at $30{\sim}33V$. It was considered to be due to the decrease of penetration resulting from the change of transfer mode, from short circuit to spray. It was also found that the behavior of penetration with welding current was dependant on the transfer mode. The short circuit mode exerted the penetration to decrease while the spray mode did it to increase with increase of welding current. The former was considered to be responsible for the remarkable decrease in dilution at low welding voltage region. The change of transfer mode also had an effect on the behavior of bead width with welding current but it did not on the bead spreadability defined as W/H ratio. It was considered that the optimal welding conditions for multi-pass overlay welding could be obtained from the bead spreadability suitable for bead lapping and the dilution as low as possible in the spray transfer mode.

Deicing Performance with Deicer Types (제설제 종류에 따른 제설성능 평가)

  • Lee, Byung-Duck;Lee, Chan-Young;Yun, Byung-Sung;Lee, Joo-Kwang;Chung, Young-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.371-374
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    • 2005
  • In this study, calcium chloride($CaCl_2$), sodium chloride (NaCl), organic acids-containing deicer(NS 40, NS 100), mixed deicier($NaCl\;70\%\;+\;CaCl_{2}\;30\%,\;NS\;40\;70\%\;+\;CaCl_{2}\;30\%,\;NaCl\;70\%\;+\;NS\;40\;30\%,\;NS\;40\;70\%\;+\;NaCl\;30\%$) is investigated based on the laboratory test for deicing performance. Test items for deicing performance were ice melting and ice penetration, freezing point depressions and eutectic points, pH, thermal properties for selected deicing chemicals. As a test results, in case of the use chloride-containing deicier in area that concrete structures has subjected to freez-thaw reaction in winter season, it showed desirable method that use deicing chemicals mixed with optimum ratio rather than use one deicing chemicals when is consider to deicing performance and effects, corrosion of steel materials, freez-thaw resistance of concrete. When use various deicing chemicals mixed, NS40($70\%$)+Calcium chloride($30\%$) showed the best effective method.

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