• Title/Summary/Keyword: molten salt process

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Transfer characteristics of a lithium chloride-potassium chloride molten salt

  • Mullen, Eve;Harris, Ross;Graham, Dave;Rhodes, Chris;Hodgson, Zara
    • Nuclear Engineering and Technology
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    • v.49 no.8
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    • pp.1727-1732
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    • 2017
  • Pyroprocessing is an alternative method of reprocessing spent fuel, usually involving the dissolving spent fuel in a molten salt media. The National Nuclear Laboratory designed, built, and commissioned a molten salt dynamics rig to investigate the transfer characteristics of molten lithium chloride-potassium chloride eutectic salt. The efficacy and flow characteristics of a high-temperature centrifugal pump and argon gas lift were obtained for pumping the molten salt at temperatures up to $500^{\circ}C$. The rig design proved suitable on an industrial scale and transfer methods appropriate for use in future molten salt systems. Corrosion within the rig was managed, and melting techniques were optimized to reduce stresses on the rig. The results obtained improve the understanding of molten salt transport dynamics, materials, and engineering design issues and support the industrialization of molten salts pyroprocessing.

Corrosion Behavior of Ni 200 and Ni-base Alloys in Hot Lithium Molten salt (고온 리튬용융염에서 Ni 200 및 Ni-base 합금의 부식거동)

  • Cho Soo-Hang;Lim Jong-Ho;Yun Ki-Seok;Park Seung-Won
    • Korean Journal of Materials Research
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    • v.14 no.4
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    • pp.251-259
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    • 2004
  • In the development of the advanced spent fuel management process based on the molten salt technology, it is essential to choose the optimum material for the process equipment handling molten salt. Corrosion behavior of Ni 200 and Ni-base alloys in molten salt of LiCl-$Li_2$O under oxidation atmosphere was investigated in the temperature range of $650~800^{\circ}C$ for 24~312 hrs. The order of corrosion rate was Ni 200 > Inconel 690 > Inconel 601 > Inconel 600. Inconel 600 alloy showed the highest corrosion resistance among the examined alloys, but Ni 200 exhibited the highest corrosion rate. Corrosion products of Inconel 600 and Inconel 601 were $Cr_2$$O_3$ and $NiFe_2$$O_4$. In case of Inconel 690, a single layer of $CrO_2$$O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2$O$_4$ and inner layer of $Cr_2$$O_3$ were formed with increase of corrosion time. Inconel 600 showed local corrosion behavior and Inconel 601, 690 showed uniform corrosion behavior.

Post Process Associated with the Electrochemical Reduction Process - Smelting of a Metal Product and Solidification of a Molten Salt (전해환원공정 관련 후처리공정 - 금속전환체 Smelting 및 용융염 고화)

  • 허진목;정명수;이원경;조수행;서중석;박성원
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.278-284
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    • 2004
  • The processes for the smelting of a metal product and the solidification of a molten salt were developed respectively to treat the products from the electrochemical reduction process. The method for the separation of a metal product in a magnesia container from the residual. salt and consequent smelting of it to a metal ingot by the multi step heating in vacuum was proposed. The new concept using a dual vessel and a salt valve was also suggested for the solidification of a molten salt into a regular size and shape which is suitable for the transport and measurement. The results obtained in the study will be applied to the design of the hot cell demonstration system of the Advanced Spent Fuel Conditioning Process of KAERI.

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Monitoring the Degradation Process of Inconel 600 and its Aluminide Coatings under Molten Sulfate Film with Thermal Cycles by Electrochemical Measurements

  • Take, S.;Yoshinaga, S.;Yanagita, M.;Itoi, Y.
    • Corrosion Science and Technology
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    • v.15 no.6
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    • pp.259-264
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    • 2016
  • With a specially designed electrochemical cell, the changes in impedance behavior for Inconel 600 and aluminide diffusion coatings under molten sulfate film with thermal cycles (from $800^{\circ}C$ to $350^{\circ}C$) were monitored with electrochemical impedance measurements. It was found that corrosion resistance for both materials increased with lower temperatures. At the same time, the state of molten salt was also monitored successfully by measuring the changes in impedance at high frequency, which generally represents the resistance of molten salt itself. After two thermal cycles, both Inconel 600 and aluminide diffusion coatings showed excellent corrosion resistance. The results from SEM observation and EDS analysis correlated well with the results obtained by electrochemical impedance measurements. It is concluded that electrochemical impedance is very useful for monitoring the corrosion resistance of materials under molten salt film conditions even with thermal cycles.

Formation Mechanism of Sr-Ferrite by Molten Salt Method (용융염법에 의한 Sr-ferrite의 생성기구)

  • 박준홍;신효순;이병교
    • Journal of the Korean Ceramic Society
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    • v.31 no.10
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    • pp.1181-1187
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    • 1994
  • Sr-ferrite powders were synthesized by molten salt method. The process of powder formation was investigated by controlling the size and shape (sphere and acicular) of starting materials. The morphology of resulting ferrite was plate-like regardless of the shape of starting materials, Fe2O3 powders. As a result, the formation of Sr-ferrite in the molten salt was proceeded by solution-precipitation.

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Electrical and Optical Properties of PLZT Ceramics Prepared by Flux Method (용융염 합성법에 의한 PLZT 세라믹스의 제작과 그 전기적.광학적 특성)

  • 남효덕
    • Journal of the Korean Ceramic Society
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    • v.23 no.4
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    • pp.62-68
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    • 1986
  • $(Pb_{1-x} La_x)(Zr_{0.65} Ti_{0.35})_{1-x/4}O_3$ (PLZT X/65/35) powders were prepared by molten salt synthesis using NaCl-K Cl and conventional calcining of oxides. The effects of molten salt on formation and charactrization of PLZT powder and on dielectric piezolectric and optical properties of PLZT ceramics were studied, The completed PLZT powder formation in the presence of fused salt was attained at 50-10$0^{\circ}C$ lower temperature than that in solid state reaction and the particle size of the powder made by molten salt synthesis was markedly increased with increasing calcining temperature. The substitution of Na and/or K ions in NaCl-KCl for Pb ion in process of molten salt synthesis was increased with increasing La concentration Z. These substituted Na and/or K ions were identified as the origins of decreasing coupl-ing factor and optical transmittance of PLZT ceramics.

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A Study on the Fabrication Process and Melt Infiltration of Salt Core in Squeeze Casting Method (스퀴즈캐스팅용 Salt Core의 제조 및 용탕침투성에 관한 연구)

  • Kim, Ki-Bae;Noh, Sang-Woo;Lee, Ho-In;Nam, Tae-Woon
    • Journal of Korea Foundry Society
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    • v.17 no.4
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    • pp.402-410
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    • 1997
  • Developing a salt core for squeeze casting process, two different salt cores(pure salt core and mixed salt core) were fabricated and investigated. Pure salt core was composed of 100% NaCl and mixed salt core was made by mixtures of NaCl with MgO(1%), $Na_2B_4O_7$(2%), and talc(1%) as a binder or a strengthening agent. Salt cores were compacted to various theoretical density, heat treated, and then squeeze-cast with molten Al alloy(AC8A). The compression strength of salt cores were measured and the squeeze-cast products were examined for shape retention, infiltration of molten metal into the cores, and microstructures. The shape of salt core compacted at above 75% of the theoretical density was maintained stably. The higher theoretical density of salt cores gave higher compression strength, and the compression strength of mixed salt core was higher than that of pure salt core. Namely at 90% theoretical density, the compression strength of mixed salt core was $6.3 kg/mm^2$, compared to $4.6 kgmm^2$ for pure salt core. At a squeeze casting pressure of $1000 kg/cm^2$, molten Al alloy was infiltrated into pure salt core of under 85% of the theoretical density. At squeeze casting pressure of $1000 kg/cm^2$, only mixed salt core above 90% of the theoretical density were valid, but the shape of the core was altered in the case of pure salt core at 90% of theoretical density. A key factor for developing a salt core for squeeze casting process was estimated as the ultimate compressive strength of salt core.

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Crystal Phase Changes of Zeolite in Immobilization of Waste LiCI Salt

  • KIM Jeong-Guk;LEE Jae-Hee;Lee Sung-Ho;KIM In-Tae;KIM Joon-Hyung;KIM Eung-Ho
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11b
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    • pp.176-181
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    • 2005
  • The electrolytic reduction process and the electrorefining process, which are being developed at the Korea Atomic Energy Research Institute (KAERI), are to generate molten waste salts such as LiCI salt and LiCI-KCI eutectic salt, respectively. Our goal in waste salt management is to minimize a total waste generation and fabricate a very low­leaching waste form such as a ceramic waste form. Zeolite has been known to one of the most desirable media to immobilize waste salt, which is water soluble and easily radiolyzed. Zeolite can be also used to the removal of fission products from the spent waste salt. Molten LiCI salt is mixed with zeolite A at $650^{\circ}C$ to form a salt-loaded zeolite, and then thermally treated in above $900^{\circ}C$ to become an immobilized product with crystal phase of $Li_{8}Cl_{2}$-Sodalite. In this work, a crystal phase changes of immobilization medium, zeolite, during immobilization of molten LiCI salt using zeolite A is introduced.

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Molten Salt-Based Carbon-Neutral Critical Metal Smelting Process From Oxide Feedstocks

  • Wan-Bae Kim;Woo-Seok Choi;Gyu-Seok Lim;Vladislav E. Ri;Soo-Haeng Cho;Suk-Cheol Kwon;Hayk Nersisyan;Jong-Hyeon Lee
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.1
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    • pp.9-22
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    • 2023
  • Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO2) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.

Corrosion Behavior of Pyro-Carbon in Hot Lithium Molten Salt Under an Oxidation Atmosphere (산화성 고온 리튬용융염계 분위기에서 Pyro-Carbon의 부식거동)

  • Lim, Jong-Ho;Choi, Jeong-Mook
    • Korean Journal of Materials Research
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    • v.23 no.2
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    • pp.123-127
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    • 2013
  • The electrolytic reduction of a spent oxide fuel involves liberation of the oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is too crosive for typical structural materials. Therefore, it is essential to choose the optimum material for the process equipment for handling a molten salt. In this study, the corrosion behavior of pyro-carbon made by CVD was investigated in a molten LiCl-$Li_2O$ salt under an oxidation atmosphere at $650^{\circ}C$ and $750^{\circ}C$ for 72 hours. Pyro-carbon showed no chemical reactions with the molten salt because of its low wettability between pyro-carbon and the molten salt. As a result of XRD analysis, pyro-carbon exposed to the molten salt showed pure graphite after corrosion tests. As a result of TGA, whereas the coated layer by CVD showed high anti-oxidation, the non-coated layer showed relatively low anti-oxidation. The stable phases in the reactions were $C_{(S)}$, $Li_2CO_{3(S)}$, $LiCl_{(l)}$, $Li_2O$ at $650^{\circ}C$ and $C_{(S)}$, $LiCl_{(l)}$, $Li_2O_{(S)}$ at $750^{\circ}C$. $Li_2CO_{(S)}$ was decomposed at $750^{\circ}C$ into $Li_2O_{(S)}$ and $CO_{2(g)}$.