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Journal Articles

Effect of seawater components on corrosion rate of steel in air/solution alternating condition

Otani, Kyohei; Tsukada, Takashi; Ueno, Fumiyoshi; Kato, Chiaki

Zairyo To Kankyo, 69(9), p.246 - 252, 2020/09

The purpose of this study was to investigate the effect of artificial sea water concentration on the corrosion rate of carbon steel under air/solution alternating condition, and to clarify the corrosion mechanism of carbon steel that changes with artificial seawater concentration. Mass measurements showed that the corrosion rate of carbon steel in the alternating condition accelerates with increasing concentration in the concentration region between deionized water to 200 times diluted artificial seawater (ASW), and the corrosion rate decreases with increasing concentration in the concentration region between 20 times diluted ASW to undiluted ASW. It can be considered that the reason why the carbon steel corrosion was suppressed in highly concentrated artificial seawater would Mg ions and Ca ions in the artificial seawater precipitate and cover on the surface due to the increase in pH near the surface by oxygen reduction reaction.

Journal Articles

Analysis for the mechanism of accelerated corrosion on low alloy steel in air-solution alternating condition

Otani, Kyohei; Tsukada, Takashi; Ueno, Fumiyoshi

Zairyo To Kankyo, 68(8), p.205 - 211, 2019/08

In the present study, the iron rust layer formed on the low ally steel in air-solution alternating condition was investigated by cross-sectional observation and analysis, and the mechanism of accelerated corrosion of the steel in the alternating condition was clarified. Observation and analysis showed that the multi-layered iron rust layer composed of red rust layer (FeOOH), rust crust layer (Fe$$_{3}$$O$$_{4}$$), inner crystal (Fe$$_{3}$$O$$_{4}$$), and inner rust layer was formed on the low alloy steel. It can be considered that the multi-layered iron rust layer accelerated the cathodic reaction rate of the steel in the alternating condition. This acceleration would be the reason why the corrosion rate of the low alloy steel in the alternating condition was accelerated.

Journal Articles

Development of radiation resistant monitoring camera system

Takeuchi, Tomoaki; Otsuka, Noriaki; Watanabe, Takashi*; Tanaka, Shigeo*; Ozawa, Osamu*; Komanome, Hirohisa*; Ueno, Shunji*; Tsuchiya, Kunihiko

Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11

no abstracts in English

JAEA Reports

Development of $$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd and $$^{126}$$Sn analytical methods for radioactive waste from Fukushima Daiichi Nuclear Power Station

Aono, Ryuji; Sato, Yoshiyuki; Shimada, Asako; Tanaka, Kiwamu; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Technology 2017-025, 32 Pages, 2017/11

JAEA-Technology-2017-025.pdf:1.45MB

We have developed analytical methods for $$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd and $$^{126}$$Sn, which are considered important in terms of the safety assessment of radioactive waste disposal. The methods are specialized for the wastes left after Fukushima accident. As the main analytical sample, we assumed accumulated water / treated water collected at Fukushima Daiichi Nuclear Power Station. As for $$^{93}$$Zr, $$^{93}$$Mo, $$^{107}$$Pd and $$^{126}$$Sn contained in this accumulated water / treated water, we have worked on the development of separation and purification method of target nuclide and improvement of recovery, and summarized these results in this report.

Journal Articles

New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

 Times Cited Count:3 Percentile:6.76

Journal Articles

Radiolysis of mixed solutions of Cl$$^{-}$$ and Br$$^{-}$$ and its effect on corrosion of a low-alloy steel

Hata, Kuniki; Inoue, Hiroyuki*; Kojima, Takao*; Kasahara, Shigeki; Hanawa, Satoshi; Ueno, Fumiyoshi; Tsukada, Takashi; Iwase, Akihiro*

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.304 - 314, 2017/09

A model simulation of $$gamma$$ radiolysis of mixed solutions of NaCl and NaBr was carried out. The simulation result agreed well with the experimental result, and Br$$^{-}$$ played an important role in determining the amounts of products from water radiolysis. The simulation result also showed that, in highly pure NaCl solutions, the steady-state concentration of a radolytic product, H$$_{2}$$O$$_{2}$$, was mainly controlled by three reactions (Cl$$^{-}$$ + $$^{.}$$OH $$rightarrow$$ ClOH$$^{.-}$$, ClOH$$^{.-}$$ $$rightarrow$$ Cl$$^{-}$$ + $$^{.}$$OH, and ClOH$$^{.-}$$ + H$$^{+}$$ $$rightarrow$$ Cl$$^{.}$$ + H$$_{2}$$O), which indicated that accurate evaluation of the rate constants of these reactions was very important in improving the radiolysis simulation of solutions containing Cl$$^{-}$$. An immersion test using a low-alloy steel, SQV2A, in the mixed solutions was also carried out under irradiation. The corrosion rate increased or decreased depending on the pH or the concentrations of the halide ions in a similar way to the change in concentration of H$$_{2}$$O$$_{2}$$ produced from water radiolysis, which is affected by the presence of Cl$$^{-}$$ and Br$$^{-}$$. However, at high pH values ($$>$$12), the corrosion rate was almost zero even though the concentration of H$$_{2}$$O$$_{2}$$ was high. This could be attributed to enhancement of the passivity of test specimens at higher pH values.

Journal Articles

2016 Professional Engineer (PE) test preparation course; Nuclear and radiation technical disciplines

Takahashi, Naoki; Suzuki, Soju; Saito, Hiroto; Ueno, Takashi; Abe, Sadayoshi; Yamanaka, Atsushi; Tanigawa, Masafumi; Nakamura, Daishi; Sasaki, Shunichi; Mine, Tadaharu

Nippon Genshiryoku Gakkai Homu Peji (Internet), 20 Pages, 2017/05

no abstracts in English

Journal Articles

Radiochemical analysis of rubble collected from around and inside reactor buildings at Units 1 to 4 in Fukushima Daiichi Nuclear Power Station

Sato, Yoshiyuki; Aono, Ryuji; Konda, Miki; Tanaka, Kiwamu; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 13 Pages, 2017/00

no abstracts in English

Journal Articles

Radiochemical analysis of rubble collected from Fukushima Daiichi Nuclear Power Station

Sato, Yoshiyuki; Tanaka, Kiwamu; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

Hoken Butsuri, 51(4), p.209 - 217, 2016/12

A large amount of contaminated rubbles were generated by the accident at the Fukushima Daiichi Nuclear Power Station (F1NPS). For safe decommissioning of F1NPS, it is important to evaluate the composition and concentration of radionuclides in the rubbles. In this paper, to characterize the rubbles collected at F1NPS in Unit-1, Unit-2 and Unit-3, radiochemical analysis was operated. As a result of radiochemical analysis, $$gamma$$-ray-emitting nuclides $$^{60}$$Co, $$^{137}$$Cs and $$^{152,154}$$Eu, $$beta$$-ray-emitting nuclides $$^{3}$$H, $$^{14}$$C, $$^{90}$$Sr and $$^{99}$$Tc, and $$alpha$$-particle-emitting nuclides $$^{238,239+240}$$Pu, $$^{241}$$Am and $$^{244}$$Cm were detected. In contrast, $$^{94}$$Nb and $$^{152}$$Eu concentrations were below the detection limit. Measured radioactive concentrations implied that $$^{3}$$H, $$^{14}$$C, $$^{60}$$Co and $$^{90}$$Sr concentrations depended on $$^{137}$$Cs concentration respectively. This analysis was characterized the radioactivity concentrations of the rubbles.

Journal Articles

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

 Times Cited Count:5 Percentile:7.43

Journal Articles

Simulation for radiolytic products of seawater; Effects of seawater constituents, dilution rate, and dose rate

Hata, Kuniki; Sato, Tomonori; Motooka, Takafumi; Ueno, Fumiyoshi; Hanawa, Satoshi; Kasahara, Shigeki; Tsukada, Takashi

Journal of Nuclear Science and Technology, 53(8), p.1183 - 1191, 2016/08

 Times Cited Count:5 Percentile:38.13(Nuclear Science & Technology)

JAEA Reports

Study on radionuclide analysis of rubble and plants for decommissioning of Fukushima Daiichi Nuclear Power Station

Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka

JAEA-Technology 2016-013, 37 Pages, 2016/07

JAEA-Technology-2016-013.pdf:2.09MB

In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as $$^{90}$$Sr and $$^{137}$$Cs.

Journal Articles

Gamma irradiation effects of image sensor for radiation-resistant camera

Takeuchi, Tomoaki; Otsuka, Noriaki; Tsuchiya, Kunihiko; Tanaka, Shigeo*; Ozawa, Osamu*; Komanome, Hirohisa*; Watanabe, Takashi*; Ueno, Shunji*

Nippon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.391 - 394, 2016/07

no abstracts in English

Journal Articles

Development of radiation resistant camera system

Takeuchi, Tomoaki; Otsuka, Noriaki; Watanabe, Takashi*; Kamiyanagi, Tomohiro*; Komanome, Hirohisa*; Ueno, Shunji*; Tsuchiya, Kunihiko

Proceedings of Decommissioning and Remote Systems 2016 (D&RS 2016) (CD-ROM), p.263 - 264, 2016/07

In response to the lesson of the accident at the Fukushima Dai-ichi Nuclear Power Plant, we started a development of a radiation resistant monitoring camera system. In this study, improvement of radiation resistance of the imaging sensor was addressed as the main target. Three different types of CMOS image sensors with field plate structure and three transistors (3TPD), photogate structure and three (3TPG) or four transistors (4TPG) were designed and fabricated. The sensors were irradiated up to 70 kGy at the $$^{60}$$Co $$gamma$$-ray irradiation facility at Takasaki Advanced Radiation Research Institute in Japan Atomic Energy Agency. After irradiation, the dark current of the 4TPG rapidly increased and excessed that of the 3T types at least by 50 kGy. The large increase of the dark current of the 4TPG resulted in almost no sensitivity at least by 50 kGy. On the other hand, the sensitivities of the 3T types remained usable values and 3TPG had larger sensitivity than 3TPD after 50 kGy. As the results, the 3TPG sensor was revealed to be the most advantageous one in terms of dark current and sensitivity among the fabricated three sensors.

Journal Articles

Hydrogen peroxide production by $$gamma$$ radiolysis of sodium chloride solutions containing a small amount of bromide ion

Hata, Kuniki; Inoue, Hiroyuki*; Kojima, Takao*; Iwase, Akihiro*; Kasahara, Shigeki; Hanawa, Satoshi; Ueno, Fumiyoshi; Tsukada, Takashi

Nuclear Technology, 193(3), p.434 - 443, 2016/03

 Times Cited Count:5 Percentile:38.13(Nuclear Science & Technology)

Journal Articles

2016 Professional Engineer (PE) test preparation course "Nuclear and Radiation Technical Disciplines"

Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.

Nippon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00

no abstracts in English

JAEA Reports

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2014

Hama, Katsuhiro; Mikake, Shinichiro; Ishibashi, Masayuki; Sasao, Eiji; Kuwabara, Kazumichi; Ueno, Tetsuro; Onuki, Kenji*; Beppu, Shinji; Onoe, Hironori; Takeuchi, Ryuji; et al.

JAEA-Review 2015-024, 122 Pages, 2015/11

JAEA-Review-2015-024.pdf:80.64MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technical basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase III, as the Phase II was concluded for a moment with the completion of the excavation of horizontal tunnels at GL-500m level in February 2014. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2014.

Journal Articles

Study of corrosion rate of carbon steel in diluted artificial seawater under simulated irradiation condition

Komatsu, Atsushi; Tsukada, Takashi; Ueno, Fumiyoshi; Yamamoto, Masahiro

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 4 Pages, 2015/05

Effect of oxygen and hydrogen peroxide on corrosion rate of carbon steel in diluted artificial seawater was investigated by electrochemical methods. Diffusion coefficient and thickness of diffusion layer for oxygen and hydrogen peroxide were measured to estimate the diffusion limiting current density. Corrosion tests of carbon steel were also conducted in diluted artificial seawater containing oxygen and/or hydrogen peroxide at 323K. The diffusion coefficient of hydrogen peroxide was about 0.8 times lower than that of oxygen, and the thickness of diffusion layer was almost equivalent between oxygen and hydrogen peroxide. Diffusion limiting current density of hydrogen peroxide was estimated to be 0.4 times lower than that of oxygen in the same concentration at 323K. Plot of corrosion rate with the addition of concentration of oxygen and 0.4 times concentration of hydrogen peroxide showed good correlation.

Journal Articles

Beam test of a new radio frequency quadrupole linac for the Japan Proton Accelerator Research Complex

Kondo, Yasuhiro; Morishita, Takatoshi; Yamazaki, Saishun; Hori, Toshihiko; Sawabe, Yuki; Chishiro, Etsuji; Fukuda, Shimpei; Hasegawa, Kazuo; Hirano, Koichiro; Kikuzawa, Nobuhiro; et al.

Physical Review Special Topics; Accelerators and Beams, 17(12), p.120101_1 - 120101_8, 2014/12

 Times Cited Count:5 Percentile:54.9(Physics, Nuclear)

We performed a beam test of a new radio frequency quadrupole linac (RFQ III) for the beam current upgrade of the Japan Proton Accelerator Research Complex. First, the conditioning of RFQ III was conducted, and after 20 h of conditioning, RFQ III became very stable with a nominal peak power and duty factor of 400 kW and 1.5%, respectively. An off-line beam test was subsequently conducted before installation in the accelerator tunnel. The transmission, transverse emittance, and energy spread of the 50-mA negative hydrogen beam from RFQ III were measured and compared with simulation results. The experiment and simulation results showed good agreement; therefore, we conclude that the performance of RFQ III conforms to its design.

Journal Articles

Present status of J-PARC linac

Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10

no abstracts in English

118 (Records 1-20 displayed on this page)