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(001)Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
Times Cited Count：2 Percentile：62.71(Physics, Applied)Tanida, Hajime; Tsuji, Takuya; Kobata, Masaaki
JAEA-Technology 2021-031, 25 Pages, 2022/02
JAEA-Technology-2021-031.pdf:2.3MB
In the decommissioning of the Tokyo Electric Power Company Holdings Fukushima Daiichi Nuclear Power Station, analysis of fuel debris to understand its characteristics is very important. The fuel debris removed for testing and analyzing will be fine particulates. Non-destructive analytical methods using X-rays are effective for such samples, but in order to apply them to fine particles, the X-rays must be focused to the micrometer order. For this purpose, the Kirkpatrick-Baez (KB) mirror was introduced. In this paper, we record the selection, specification, adjustment of the mirror, and write down the example of mapping of elements and evaluation of their valence by this mirror.
Miwa, Kazuji; Obata, Hajime*; Suzuki, Takashi
Journal of Nuclear Science and Technology, 57(5), p.537 - 545, 2020/05
Times Cited Count：2 Percentile：17.45(Nuclear Science & Technology)This study investigated the vertical distribution of Iodine-129 (
I) which is mainly produced by European nuclear reprocessing plants in the Chukchi Sea and Bering Sea. I was found to be distributed almost uniformly in fallout level, and an increasing in I concentration levels caused by high I water inflow from the Atlantic Ocean was not observed. Additionally, we revealed the vertical distribution of iodide, one chemical form of iodine, from the Bering Shelf area to the Chukchi Sea for the first time. The increasing tendency of iodide near sea bottom was observed.
Okubo, Ayako; Obata, Hajime*; Magara, Masaaki; Kimura, Takaumi; Ogawa, Hiroshi*
Analytica Chimica Acta, 804, p.120 - 125, 2013/12
Times Cited Count：2 Percentile：6.98(Chemistry, Analytical)This work introduces a novel method of recovery of iron hydroxide using a DIAION CR-20 chelating resin column to determine Th isotopes in seawater with a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). Thorium isotopes in seawater were coprecipitated with iron hydroxide, and this precipitate was sent to chelating resin column. The chelating column quantitatively collected 
Th with iron hydroxide in seawater at flow rates of 20-25 mL/min. Based on this flow rate, a 5 L sample was processed within 3-4 h.
Okubo, Ayako; Takeda, Shigenobu*; Obata, Hajime*
Atmospheric Research, 129-130, p.20 - 32, 2013/07
Times Cited Count：41 Percentile：69.93(Meteorology & Atmospheric Sciences)To understand the atmospheric input of trace metals to surface seawaters, the total deposition samples were collected simultaneously from three coastal station in Japan. The observed flux was within the lower limit of the previous estimation based on a model. Except for Sc and Fe, all the elements showed a increasing tendency toward dissolution with decreasing the pH. We calculated the Sc-normalized enrichment factors. The increasing tendency toward dissolution with decreasing the pH was higher for Al than that of Fe.
Th and Th distributions in mid-latitudes of the North Pacific Ocean; Effect of bottom scavengingOkubo, Ayako; Obata, Hajime*; Gamo, Toshitaka*; Yamada, Masatoshi*
Earth and Planetary Science Letters, 339-340, p.139 - 150, 2012/07
Times Cited Count：43 Percentile：72.23(Geochemistry & Geophysics)Vertical distributions of total Th and dissolved Th were determined in the mid-latitudes of the North Pacific Ocean. Th in the Pacific Ocean have been described well using the reversible-scavenging model. However, we observed the depletion of total Th. The enhanced vertical eddy diffusion derived from the complex topography of the western Pacific Ocean might promote bottom scavenging and transport of the low Th in deep water to the upper layers.
Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kamiya, Junichiro; Morohashi, Yuko; Yamada, Ippei; Abe, Kazuhide
no journal, ,
The mechanism of how the substrate titanium contributes to the advanced getter performance has not been elucidated. In this study, NEG/Ti interface analysis was performed using HAXPES at BL22XU to clarify the effect of Ti substrate on NEG performance.
Okane, Tetsuo; Kobayashi, Toru; Kobata, Masaaki; Tanida, Hajime; Fujimori, Shinichi; Takeda, Yukiharu; Tsuji, Takuya; Fukuda, Tatsuo; Shibata, Goro; Kawasaki, Ikuto; et al.
no journal, ,
no abstracts in English
Kobata, Masaaki; Morohashi, Yuko; Abe, Kazuhide; Yamada, Ippei; Fukuda, Tatsuo; Koarai, Kazuma; Tanida, Hajime; Kamiya, Junichiro
no journal, ,
This study aimed to improve non-evaporable getter (NEG) coating technology on titanium substrates, focusing on lowering activation temperatures and enhancing repeatability. Using Hard X-ray Photoelectron Spectroscopy (HAXPES) and Secondary Ion Mass Spectrometry (SIMS), we analyzed NEG activation and degradation mechanisms. The effects of titanium, stainless steel (SUS316), and beryllium copper (BeCu) substrates on NEG properties were compared. Results suggested that the BeCu substrate had the lowest activation temperature, indicating its potential advantage for low-temperature NEG activation.
Okubo, Ayako; Obata, Hajime*; Magara, Masaaki; Kimura, Takaumi; Ogawa, Hiroshi*
no journal, ,
This work introduces a novel method of recovery of iron hydroxide with thorium using a DIAION CR-20 chelating resin column to determine Th isotopes in seawater with a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). Thorium isotopes in seawater were co-precipitated with iron hydroxide, and this precipitate was sent to chelating resin column. The chelating column quantitatively collect Th with iron hydroxide in seawater at flow rate of 20-25 mL/min. Based on this flow rate, 5 L sample was processed within 3-4 h. The aging of iron hydroxide tends to reduce the recovery of Th. The rapid collection method was successfully applied to the determination of Th and Th in open-ocean seawater samples.
Obata, Hajime*; Miwa, Kazuji*; Kondo, Yoshiko*; Gamo, Toshitaka*; Otosaka, Shigeyoshi; Suzuki, Takashi
no journal, ,
Distributions chemical species of iodine (iodide, iodate and organic iodine) in seawater were investigated in the Chukchi Sea and Bering Sea, Arctic northern marginal seas. I, which is a good tracer for anthropogenically released iodine to the marine environments, were also revealed by this study. Iodide concentrations in seawater often increased toward the seafloor. This tendency was remarkable with iodide and organic iodine, indicating that these iodine species are released from the sediments of the continental shelf. Concentrations of I ranged from 0.79 to 2.89
10
atom/L. While this level was several times higher than those in the North Pacific, significant increase of I concentration due to seawater inflow from the North Atlantic was not observed. Considering latitudinal range of this study area, it can be estimated that most I detected by this study was derived by atmospheric deposition of I originates from Europe.
Cs on the continental shelf off FukushimaOtosaka, Shigeyoshi*; Misono, Toshiharu; Dohi, Terumi; Tsuruta, Tadahiko; Takahashi, Yoshio*; Sugihara, Naoko*; Obata, Hajime*; Ikenoue, Takahito*; Jimi, Naoto*; Hookabe, Natsumi*
no journal, ,
no abstracts in English
Otosaka, Shigeyoshi*; Aono, Tatsuo*; Fukuda, Miho*; Kambayashi, Shota*; Misono, Toshiharu; Dohi, Terumi; Tsuruta, Tadahiko; Suzuki, Takashi; Takahashi, Yoshio*; Sugihara, Naoko*; et al.
no journal, ,
While the amount of cesium-137 (Cs: half-life 30.1 years) accumulated on the seabed due to the accident of the Fukushima Daiichi Nuclear Power Plant (0.1-0.2 PBq) is only about 1 to 2% of the total amount of Cs transported to the ocean, it has been reported that it will remain for a long time in the coastal areas. On the other hand, long-term migration process of the sedimentary radiocesium and the impact on the ecosystem near the seafloor remain unknown. In this presentation, we will give an overview of the distribution and behavior of Cs, especially on the seafloor along the coast of Fukushima, and report the latest results on the processes I the seafloor that should be considered on decadal timescale.
Tanida, Hajime; Tsuji, Takuya; Kobata, Masaaki; Kitagaki, Toru
no journal, ,
In the decommissioning of Fukushima Daiichi Nuclear Power Plant, analysis of fuel debris is extremely important to understand its properties. The fuel debris to be removed on a trial basis and the samples available for analysis are expected to be fine particles. In the case of relatively large samples, handling becomes difficult due to the dose problem. Non-destructive X-ray analysis using X-rays is an effective analysis method for such samples, but in order to apply it to fine particles, X-rays must be focused to the micrometer order. For this purpose, a Kirkpatrick-Baez (KB) mirror was installed in the experimental hutch 3 of the RI building of the JAEA beamline BL22XU, which has a hard X-ray undulator as a light source, at SPring-8.
O Schottky junction from gamma ray regionFukuda, Tatsuo; Fukada, Yukimasa; Kobata, Masaaki; Yoshii, Kenji; Shobu, Takahisa; Tominaga, Aki; Yamashita, Yoshiyuki*; Tanida, Hajime; Yaita, Tsuyoshi
no journal, ,
no abstracts in English
Kobayashi, Toru; Kobata, Masaaki; Tanida, Hajime; Fujimori, Shinichi; Tsuji, Takuya; Fukuda, Tatsuo; Shibata, Goro; Kawasaki, Ikuto; Doi, Reisuke; Okamoto, Yoshihiro; et al.
no journal, ,
Tanida, Hajime; Kobayashi, Toru; Kobata, Masaaki; Fujimori, Shinichi; Okamoto, Yoshihiro; Okane, Tetsuo; Yaita, Tsuyoshi; Satou, Yukihiko; Suzuki, Shingo; Maeda, Koji
no journal, ,
no abstracts in English
Yomogida, Takumi; Kobata, Masaaki; Watanabe, Yusuke; Fujimori, Shinichi; Kirihara, Yoichi; Yaita, Tsuyoshi; Okamoto, Yoshihiro; Doi, Reisuke; Kobayashi, Toru; Tsuji, Takuya; et al.
no journal, ,
We detected particles containing Uranium(U) in stagnant water of Fukushima Daiichi Nuclear Power Station building and analyzed by synchrotron microbeam X-ray spectroscopy. We found two different types of U-containing particles: fine U particles (a few micrometers in diameter) and Fe particles with adsorbed U (tens to hundreds of micrometers in diameter). The X-ray absorption fine structure (XAFS) spectra of these particles showed that the U distributed on the Fe particles was in a more oxidized states than the fine U particles, which suggested these U had migrated to the stagnant water through a different formation process.
Kobayashi, Toru; Kobata, Masaaki; Tanida, Hajime; Fujimori, Shinichi; Tsuji, Takuya; Fukuda, Tatsuo; Shibata, Goro; Kawasaki, Ikuto; Matsuda, Shohei; Doi, Reisuke; et al.
no journal, ,
no abstracts in English
Kobayashi, Toru; Yaita, Tsuyoshi; Tanida, Hajime; Kobata, Masaaki; Fukuda, Tatsuo; Ito, Ayumi*; Konashi, Kenji*; Arita, Yuji*
no journal, ,
XAFS-XRD simultaneous measurement system to observe the reactions of nuclear fuel under ultra-high temperatures was developed. In this presentation, we will introduce the overview and performance of the measurement system installed at JAEA beamline BL22XU of SPring-8. We will also report the results of the simultaneous measurement of Zr and Y-K edge XAFS spectra and X-ray diffraction pattern of Zr-YO mixture under ultra-high temperature by using the heating equipment reported in series presentation (2).
