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.

Dust behavior during laser cutting and water quality during muddy water cleaning in huge water tank

Miyamoto, Yuta; Uemura, Masaru*; Igarashi, Masahiro*; Maeda, Hideo*

Reiwa-3-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 24, P. 36, 2022/11

The laser cutting of test pieces which simulated the structural materials of the Advanced Thermal Reactor "FUGEN" was performed at a water depth of 10 m. During the cutting process, we obtained data on the behavior of particulate matter such as dust and dross generated by underwater laser cutting, and changes in water quality related to the cleaning of water in test tank that became muddy after cutting.

Feasibility study of PGAA for boride identification in simulated melted core materials

Tsuchikawa, Yusuke; Abe, Yuta; Oishi, Yuji*; Kai, Tetsuya; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Kimura, Atsushi; Nakamura, Shoji; Harada, Masahide; et al.

JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011074

In the decommissioning of the Fukushima-Daiichi (1F) Nuclear Power Plant, it is essential to understand characteristics of the melted core materials. The estimation of boride in the real debris is of great importance to develop safe debris removal plans. Hence, it is required to investigate the amount of boron in the melted core materials with nondestructive methods. Prompt gamma-ray activation analysis (PGAA) is one of the useful techniques to determine the amount of borides by means of the 478 keV prompt gamma-ray from neutron absorption reaction of boron. Moreover, it is well known that the width of the 478 keV gamma-ray peak is typically broadened due to the Doppler effect. The degree of the broadening is affected by coexisting materials, and can be recognized by the width of the prompt gamma-ray peak. As a feasibility study, the prompt gamma-ray from boride samples were measured using the ANNRI, NOBORU, and RADEN beamlines at the Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Complex (J-PARC).

Electrochemical corrosion tests for core materials utilized in BWR under conditions containing seawater

Shizukawa, Yuta; Sekio, Yoshihiro; Sato, Isamu*; Maeda, Koji

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 5 Pages, 2017/00

http://hotlab.sckcen.be/proceedings

Electrochemical corrosion behavior under salt water in a type 304L stainless steel used to a part of BWR core materials was investigated to evaluate the possibility of crevice corrosion occurrence for the fuel assemblies which experienced seawater exposure in Fukushima Daiichi Nuclear Power Plant (1F) accident. Especially, focusing on the upper end plug part having the 304L SS crevice structure, measurement of repassivation potential for crevice corrosion () were carried out using the crevice test pieces fabricated by 304L SS plates. From the results, was lower than the spontaneous potential () when the conditions of 2500 ppm chloride ion concentration at over 50 C or that of 2500 ppm at over 80 C, which are included in the SFP water quality conditions. Therefore, in the 304L SS parts of the 1F fuel assemblies that experienced seawater exposure, there is a possibility of crevice corrosion occurrence.

Does Gd@C have an anomalous endohedral structure? Synthesis and single crystal X-ray structure of the carbene adduct

Akasaka, Takeshi*; Kono, Takayoshi*; Takematsu, Yuji*; Nikawa, Hidefumi*; Nakahodo, Tsukasa*; Wakahara, Takatsugu*; Ishitsuka, Midori*; Tsuchiya, Takahiro*; Maeda, Yutaka*; Liu, M. T. H.*; et al.

Journal of the American Chemical Society, 130(39), p.12840 - 12841, 2008/10

https://doi.org/10.1021/ja802156n

We report here the results on single crystal X-ray crystallographic analysis of the Gd@C carbene adduct (Gd@C(ad), Ad=adamantylidene). The Gd atom in Gd@C(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C cage, as found for M@C (M = Sc and La) and La@C(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure.

Irradiation effects on MgB bulk samples and formation of columner defects on high-Tc supercoductor

Okayasu, Satoru; Sasase, Masato; Hojo, Kiichi; Chimi, Yasuhiro; Iwase, Akihiro; Ikeda, Hiroshi*; Yoshizaki, Ryozo*; Kambara, Tadashi*; Sato, H.*; Hamatani, Yutaro*; et al.

Physica C, 382(1), p.104 - 107, 2002/10

https://doi.org/10.1016/S0921-4534(02)01206-6

no abstracts in English

Investigation of causality in the H-L transition on the JFT-2M tokamak

; ; ; ; ; ; ; Oikawa, Toshihiro; ; ; et al.

Fusion Energy 1996, p.885 - 890, 1997/05

no abstracts in English

Integration study (IV) for performance assessment system of geological disposal

Yanagisawa, Ichiro*; Ezaki, Masahiro*; Ishihara, Yoshinao*; Fusaeda, Shigeki*; Mukai, Satoru*; Doi, Hideo*; Maeda, Kazuto*; Nakahara, Yutaka*

PNC TJ1214 93-001, 544 Pages, 1993/03

PNC-TJ1214-93-001.pdf:16.47MB

None

Investigation of development condition with novel nuclear emulsion for neutron measurement under high -ray background

Ishihara, Kohei*; Sakai, Yosuke*; Kawarabayashi, Jun*; Tomita, Hideki*; Naka, Ryuta*; Asada, Takashi*; Morishima, Kunihiro*; Nakamura, Mitsuhiro*; Maeda, Shigetaka; Iguchi, Tetsuo*

no journal, , 

In order to measure neutron spectrum in high -ray field, a new nuclear emulsion and its data-processing system are developed. This report examined the optimal development conditions about the new nuclear emulsion NGITA (Neutron-Gamma Image TrAcker). By lowering developing solution temperature to 10 C from 20 C, the sensitivity to a ray was able to be controlled to the abbreviation 1/10, with the sensitivity to a neutron maintained.

Measurement of electron spectrum generated by irradiating thin-Foil target with Ultra-intense Ultra-short pulse laser

Maeda, Shota; Nishiuchi, Mamiko; Sakaki, Hironao; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T. A.; Faenov, A. Ya.*; Ogura, Koichi; Fukuda, Yuji; Matsukawa, Kenya*; et al.

no journal, , 

In JAEA, the high energy ions generated by the interaction between Ultra-intense Ultra-Short pulse laser and thin-foil target is being studied. Irradiating condition must be optimized to generate higher energy ions while suppress the becoming gigantic of laser. It is necessary to know the physical phenomenon in plasma to determine the parameter to optimize from the information on the electron and neutron, X-rays, which are generated simultaneously with ion. In this study, in order to measure electron temperature accurately, an electron spectrometer was developed which have broad range (1-200 MeV). The detector is comprised of permanent magnets and a fluorescent plate, CCD camera. In the presentation, the result of the calibration experiment carried out using 4, 9, 12, 15 MeV quasi-monoenergetic electron beam in HIBMC will be reported. Moreover, response analysis method was inspected using PHITS which is particle transporting Monte Carlo simulation code, and will also report the result.