Experimental verification of operational conditions for the 3rd glass melter in TVF

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.

Synchrotron analysis of coagulated surface of simulated waste glasses

Nagai, Takayuki; Katsuoka, Nanako; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*

Photon Factory Activity Report 2023 (Internet), 3 Pages, 2024/00

https://pfwww.kek.jp/acr/2023pdf/u_reports/pf23b0063.pdf

no abstracts in English

Synchrotron analysis of simulated waste glasses different in boron isotope ingredient

Nagai, Takayuki; Tone, Masaya; Katsuoka, Nanako; Okamoto, Yoshihiro; Baba, Yuji*; Akiyama, Daisuke*

Photon Factory Activity Report 2022 (Internet), 3 Pages, 2023/00

https://pfwww.kek.jp/acr/2022pdf/u_reports/pf22b0056.pdf

no abstracts in English

Study on vitrification plan of high level liquid waste in the TVF, 9; Consideration of operating parameters for the new glass melter

Tone, Masaya; Shiramizu, Daiki; Katsuoka, Nanako; Aoyama, Yusuke; Miyata, Koshi; Fukuda, Shigeki; Otaka, Hikaru; Kobayashi, Hidekazu; Kodaka, Akira

no journal, , 

The replacement of existing 2nd glass melter with the 3rd glass melter is scheduled from 2025 to 2026 in Tokai Vitrification Facility, TVF. The bottom shape of 3rd melter was changed from the square pyramid of 2nd melter to a cone to improve ability to discharge platinum group elements. Therefore, it is necessary to confirm operational parameters appropriate for the 3rd melter with cone shaped bottom. Operational test using non-radioactive simulant of liquid waste was carried out to ensure the appropriate operational parameters that accommodate key control values such as glass temperature.

Investigation of chemical state of uranium in borosilicate glass containing decontamination waste

Katsuoka, Nanako

no journal, , 

no abstracts in English

Investigation of chemical state of uranium contained borosilicate glass, 2; Uranium reduction using graphite crucible

Katsuoka, Nanako; Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Sato, Nobuaki*; Kirishima, Akira*

no journal, , 

no abstracts in English

Investigation of chemical state of uranium contained in borosilicate glass

Katsuoka, Nanako; Nagai, Takayuki; Okamoto, Yoshihiro; Akiyama, Daisuke*; Kirishima, Akira*; Sato, Nobuaki*

no journal, , 

no abstracts in English

Basic Research Programs of Vitrification Technology for Waste Volume Reduction, 126; Examination of YP formation mechanisms by experiments using zirconium molybdate as a starting material, 3

Okamoto, Yoshihiro; Nagai, Takayuki; Katsuoka, Nanako; Akiyama, Daisuke*; Kirishima, Akira*

no journal, , 

XAFS analysis of heat-treated samples under various conditions using zirconium molybdate as starting material was performed to compare the formation of calcium molybdate. It was found that zirconium molybdate decomposes by heat treatment at 1073K to form zirconium oxide, but the zirconium immediately dissolves into the glass. On the other hand, after decomposition, the molybdenum continued to maintain the form of molybdate ions, eventually becoming calcium molybdate. However, it was found that calcium molybdate was formed at a lower temperature in the latter case when sodium was present in the raw glass from the beginning or when it was supplied as sodium nitrate without being included in the raw glass.