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Asahi, Yoshimitsu; Fukuda, Shigeki; Shiramizu, Daiki; Miyata, Koshi; Tone, Masaya; Katsuoka, Nanako; Maeda, Yuta; Aoyama, Yusuke; Niitsuma, Koichi; Kobayashi, Hidekazu; et al.
JAEA-Technology 2024-024, 271 Pages, 2025/03
JAEA-Technology-2024-024.pdf:33.98MB
JAEA-Technology-2024-024-hyperlink.zip:31.96MB
A glass melter for the vitrification process of highly active liquid waste in the Tokai Reprocessing Plant, TVF's 3rd melter, was built, and the glass of 18 vitrified waste canisters in weight was melted and poured through a cold test operation. The molten glass surface was covered by a cold cap from feeding fiberglass cartridges saturated with non-radioactive simulant liquid waste as raw material, whose components are equivalent to actual waste. Differences in inherent characteristics of the thermal behavior between the 2nd and the 3rd melter due to the difference in design were considered to establish the procedure to control the new melter. The melter's condition was stabilized at a higher glass temperature and the cooling of 1 kW less in each of the two main electrodes, compared to the 2nd one. Under 39 kW joule heating of the main electrodes with 26 Nm3/h coolant flow rate, it showed the capability to finish heating the bottom furnace in 5 hours before pouring, 2 hours shorter than the 2nd melter. Measurements of the temperature distributions in molten glass and casing surface yielded data that is efficient for developing a simulation model. After Platinum Group Elements (PGE) concentration saturates in the molten glass, feeding raw material and discharging glass were suspended to examine a holding state, indicating PGE settling could retard. During the holding test, observation of the melting process of the cold cap declared that the surface was covered by a thin layer with almost non-fluidity. It will be a reason for choosing the no-slip condition of a fluid calculation, even in the hot-top condition. The investigation of PGE discharging behavior by analyzing the elemental composition of poured glass showed the accumulated PGE amount in the 3rd melter is small compared to the 2nd melter. Inspection of the melter inside after draining out concluded that there were neither significant residual glass nor refractory fragments.
Tokai Reprocessing Technology Development Center
JAEA-Evaluation 2015-012, 83 Pages, 2015/12
JAEA-Evaluation-2015-012.pdf:6.67MB
Japan Atomic Energy Agency (hereafter referred as "JAEA") consulted the "Evaluation Committee of Research and Development Activities for Fast Reactor Cycle" to assess the issue on "Research and Development on Reprocessing of Nuclear Fuel Materials" conducted by JAEA during the period from FY2010 to FY2014. In response to the JAEA's request, the committee assessed the R&D programs and the activities of JAEA related to the issue and concluded the mission was accomplished. This evaluation was performed based on the "General guideline for the evaluation of government R&D activities", the "Guideline for evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology (MEXT)" and the "Operational rule for evaluation of R&D activities" by JAEA.
Aoshima, Atsushi; Ueno, Tsutomu; Shiotsuki, Masao
Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 9 Pages, 2008/05
In TVF, concentrated high radioactive liquid waste produced in TRP has been vitrified since 1995. Because of very corrosive condition of melting glass, design life of a melter is limited five years and it requires interruption of plant operation and generation of high radioactive solid waste for melter change. To improve this situation, prolongation of melter design life time by increasing corrosion resistance of structural material is required strongly. Effective removal of noble metal from a melter is also required because accumulated noble metal cause shortening lifetime of a melter. So, JAEA tried to develop a melter which equipped with ability of high corrosion resistance and control temperature distribution for noble metal easy drain out. Mechanical removal technology of remained noble metal rich glass also used if necessary. Low temperature glassing technology and advance removal of noble metal from concentrated high radioactive liquid are also be studying.
Aoshima, Atsushi; Ueno, Tsutomu; Shiotsuki, Masao
Proceedings of European Nuclear Conference 2007 (ENC 2007) (CD-ROM), 5 Pages, 2007/09
Tokai Vitrification Facility (TVF) started hot operation in 1996 and produced 241 canisters as of June 2007. Through TVF operation, JAEA had much experience and accumulated much technical know-how which indicated that management for noble metal accumulation in a melter was key technology for smooth plant operation. JAEA should continue service operation based on a vitrification contract with the Japanese utilities because there remains about two third of High Active Liquid Waste (HALW) produced in the reprocessing service operation of Tokai Reprocessing Plant (TRP). TVF melter is designed in condition of five years life time because of very corrosive characteristic of melted glass. Five years design life time is equivalent to 500 canisters production in TVF. Because estimated number of canisters which will be produced in the future is over 500 canisters, exchange of the present melter is necessary. From these situations, JAEA decided basic strategy to increase stability of the existing melter operation and develop an advanced new melter for replacement in future which has largely prolonged life time and high noble metal drain ability. To attain these targets, JAEA extracted necessary key technologies to assemble into a ten years road map and started development. This development has been progressing on schedule.
Kato, Junya; Miura, Akihiko; Yamashita, Teruo; Shiotsuki, Masao
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Miura, Akihiko; Kobayashi, Hidekazu; Ayame, Yasuo; Shiotsuki, Masao; Weisenburger, S.*; Roth, G.*
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Sato, Hideo; Kurosawa, Akira; Nagaishi, Ryuji; Yamada, Reiji; Watahiki, Masaru
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Nakazaki, Katsutoshi; Takaya, Akikazu; Kato, Junya; Kobayashi, Masahiro; Matsumura, Tadayuki; Niitsuma, Koichi; Fujiwara, Koji
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Nakayama, Jiro; Sumi, Hirotaka; Kuboki, Michikatsu; Kodaka, Akira; Fujiwara, Koji
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Asahi, Yoshimitsu; Kodaka, Akira
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In the glass production of TVF melter, as raw material, fiberglass frit cartridges saturated with HAW are supplied to the melter. A lot of in-melting cartridges float on the molten glass surface and form a layer called cold-cap. A simulation model of the cold-cap, which enables reproduction of temperature distribution was developed. The cold-cap was modeled as a two-phase flow of cartridges and molten glass with fluid-particle interaction. The increasing of the apparent viscosity and the decreasing of joule heat current and thermal conductivity caused by floating cartridges are defined as a function of the concentration of solid particles. By involving these models simultaneously, a simulation in regard to an operation during glass production for the 2nd melter in TVF yields a slow fluid velocity at the cold-cap region and reproduced a thermally isolated layer, and the change of temperature observed at the bottom side of the cold-cap.
Suzuki, Seima; Otaka, Hikaru; Usui, Yasufumi*; Morigaki, Yoshin*; Ito, Ryosuke*
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Suzuki, Seima; Otaka, Hikaru; Fukuda, Shigeki; Miyauchi, Atsushi; Sumi, Hirotaka
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Yamauchi, Sho; Tokoro, Takeshi; Kuboki, Michikatsu; 9 of others*
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Yamashita, Teruo; Masaki, Toshio; Nakajima, Masayoshi; Shiotsuki, Masao; Kojima, Keizo; Toyoshima, Mikihiro; Matsumoto, Shiro*
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Miyauchi, Atsushi; Morikawa, Yo; Sasage, Kenichi; Yamashita, Teruo; Shiotsuki, Masao
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Sasage, Kenichi; Miyauchi, Atsushi; Morikawa, Yo; Yamashita, Teruo; Shiotsuki, Masao
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Viscosity and specific resistivity of simulated waste glass was measured to investigate characterization of waste glass processed by the long-life vitrification melter. The composition of the simulated waste glass was varied based on 8 cases of assumed spent fuel conditions and reprocessing flows including reprocessing of FBR fuel with minor actinides separation. The viscosity of the sample glasses was from 0.5 to 1.8 times that of waste glass with standard composition. The specific resistivity of the sample glasses was from 0.5 to 1.5 times that of standard waste glass.
Nakajima, Masayoshi; Oeda, Mikihiro; Yamashita, Teruo; Shiotsuki, Masao; Kawahara, Hitoshi*; Sato, Akihiro*
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Miura, Akihiko; Kato, Junya; Yamashita, Teruo; Shiotsuki, Masao; Matsumoto, Shiro*
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Kobayashi, Hidekazu; Sasage, Kenichi; Usui, Yasufumi; Ayame, Yasuo; Shiotsuki, Masao
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Kato, Junya; Miura, Akihiko; Shiotsuki, Masao; Yamashita, Teruo
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To examine long-life vitrification melter, static corrosion tests of electrode materials are conducted to measure corrosion rate. Samples taken from the tests are observed and analyzed using SEM/EDX. As a result, NCF690 and RS311 which are the nickel based alloy show the high corrosion resistance in molten glass because high dense CrO
layer is observed at the glass contact surface.