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Suzuki, Yuri*; Hiradate, Shuntaro*; Koarashi, Jun; Atarashi-Andoh, Mariko; Yomogida, Takumi; Kanda, Yuki*; Nagano, Hirohiko*
Soil (Internet), 11(1), p.35 - 49, 2025/01
Times Cited Count:0Takahashi, Yoshio*; Yamaguchi, Akiko; Yomogida, Takumi
Treatise on Geochemistry, 3rd edition, Vol.6, 46 Pages, 2025/00
With the recent development of measurement techniques, new approaches to the environmental geochemistry of radionuclides have been applied for various research targets. In this review article, several topics within the last 10-15 years in the field of environmental geochemistry of radionuclides have been discussed. In particular, this article mainly focused on two topics, (i) studies on the migration of radionuclides emitted by the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in 2011 and (ii) the development of X-ray absorption fine structure (XAFS) spectroscopy and its application to the geochemical processes of radionuclides.
Shimokita, Keisuke*; Yamamoto, Katsuhiro*; Miyata, Noboru*; Shibata, Motoki*; Nakanishi, Yohei*; Arakawa, Masato*; Takenaka, Mikihito*; Kida, Takumitsu*; Tokumitsu, Katsuhisa*; Tanaka, Ryo*; et al.
Langmuir, 40(30), p.15758 - 15766, 2024/07
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Aoyagi, Noboru; Motokawa, Ryuhei; Okumura, Masahiko; Ueda, Yuki; Saito, Takumi*; Nishitsuji, Shotaro*; Taguchi, Tomitsugu*; Yomogida, Takumi; Sazaki, Gen*; Ikeda, Atsushi
Communications Chemistry (Internet), 7, p.128_1 - 128_13, 2024/06
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Yomogida, Takumi; Ouchi, Kazuki; Morii, Shiori; Oka, Toshitaka; Kitatsuji, Yoshihiro; Koma, Yoshikazu; Konno, Katsuhiro*
Scientific Reports (Internet), 14, p.14945_1 - 14945_11, 2024/06
Times Cited Count:0 Percentile:0.00(Multidisciplinary Sciences)Particles containing alpha () nuclides were identified from sediment in stagnant water in the Unit 3 reactor building of the Fukushima Dai-ichi Nuclear Power Station (FDiNPS). We analyzed different concentrations of alpha nuclides samples collected at two sampling sites, torus room and Main steam isolation valve (MSIV) room. Most of the
-nuclides in the stagnant water samples of the torus room and the MSIV room were present in particle fractions larger than 10
m. We detected uranium-bearing particles in
m-size by scanning electron microscopy-energy dispersive X-Ray (SEM-EDX) observation. Other short lived
-nuclides were detected by alpha track detection. The
-nuclide-containing particles with several tens to several hundred
m in size were mainly comprised iron (Fe) by SEM-EDX analysis. This study clarifies that the morphologies of U and other
-nuclides in the sediment of stagnant water in the FDiNPS's Unit 3 reactor building.
Kato, Masato; Oki, Takumi; Watanabe, Masashi; Hirooka, Shun; Vauchy, R.; Ozawa, Takayuki; Uwaba, Tomoyuki; Ikusawa, Yoshihisa; Nakamura, Hiroki; Machida, Masahiko
Journal of the American Ceramic Society, 107(5), p.2998 - 3011, 2024/05
Times Cited Count:2 Percentile:30.59(Materials Science, Ceramics)Yomogida, Takumi; Hashimoto, Tadashi; Okumura, Takuma*; Yamada, Shinya*; Tatsuno, Hideyuki*; Noda, Hirofumi*; Hayakawa, Ryota*; Okada, Shinji*; Takatori, Sayuri*; Isobe, Tadaaki*; et al.
Analyst, 149(10), p.2932 - 2941, 2024/03
Times Cited Count:1 Percentile:63.46(Chemistry, Analytical)In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source to determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from the U mine. It is difficult to separate the fluorescent X-ray of the U L line at 13.615 keV from that of the Rb K
line at 13.395 keV in the X-ray fluorescence spectrum with an energy resolution of approximately 220 eV of the conventional silicon drift detector (SDD). Meanwhile, the fluorescent X-rays of U L
and Rb K
were fully separated by TES with 50 eV energy resolution at the energy of around 13 keV. The successful peak separation by TES led to an accurate mapping analysis of trace U in micro-X-ray fluorescence measurements and a decrease in the signal-to-background ratio in micro-X-ray absorption near edge structure spectroscopy.
Yamazaki, Takumi*; Hirai, Takamasa*; Yagi, Takashi*; Yamashita, Yuichiro*; Uchida, Kenichi*; Seki, Takeshi*; Takanashi, Koki
Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02
Times Cited Count:2 Percentile:80.53(Physics, Applied)Morii, Shiori; Yomogida, Takumi; Asai, Shiho*; Ouchi, Kazuki; Oka, Toshitaka; Kitatsuji, Yoshihiro
KEK Proceedings 2023-2, p.132 - 137, 2023/11
New analytical method of a combination of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and isotope dilution mass spectrometry (IDMS) for quantification of Zr isotopes in a solid sample was investigated. Solid Zr-isotope reference was added to a simulated radioactive waste sample as a spike, then Zr isotope ratio was measured by LA-ICP-MS. As a result, we successfully quantify Zr isotopes in the simulated radioactive waste sample by new IDMS. There is a possibility that this new method can be applied for quantification of Zr-93 in difficult to dissolve radioactive wastes.
Morii, Shiori; Yomogida, Takumi; Asai, Shiho*; Ouchi, Kazuki; Oka, Toshitaka; Kitatsuji, Yoshihiro
Bunseki Kagaku, 72(10.11), p.441 - 448, 2023/10
Rapid analytical method for the determination of Zr-93 in radioactive wastes has been developed. Laser ablation (LA)-ICP-MS was applied to the analysis of Zr isotopes in simulated high-level radioactive waste (HLW). Sample preparation time was dramatically reduced by using a DGA resin as the adsorbent for Zr. Direct quantification of Zr isotopes in this resin sample was carried out by LA-ICP-MS. Laser settings were optimized to obtain a reliable isotope ratio of the sample by LA-ICP-MS. Quantification of Zr isotopes in the simulated HLW solution by isotope dilution mass spectrometry (IDMS) was examined. The amount of Zr-90 in the sample obtained by IDMS corresponded to a value calculated from the given concentration of Zr in the sample within uncertainty. Thus, this method can be applied for the quantification of Zr-93 in radioactive wastes.
Yamashita, Susumu; Sato, Takumi; Nagae, Yuji; Kurata, Masaki; Yoshida, Hiroyuki
Journal of Nuclear Science and Technology, 60(9), p.1029 - 1045, 2023/09
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Li, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
Times Cited Count:10 Percentile:64.21(Chemistry, Analytical)no abstracts in English
Nagano, Hirohiko*; Atarashi-Andoh, Mariko; Tanaka, Sota*; Yomogida, Takumi; Kozai, Naofumi; Koarashi, Jun
Frontiers in Forests and Global Change (Internet), 6, p.1228053_1 - 1228053_9, 2023/00
Times Cited Count:2 Percentile:26.05(Ecology)Yomogida, Takumi; Akiyama, Daisuke*; Ouchi, Kazuki; Kumagai, Yuta; Higashi, Kotaro*; Kitatsuji, Yoshihiro; Kirishima, Akira*; Kawamura, Naomi*; Takahashi, Yoshio*
Inorganic Chemistry, 61(50), p.20206 - 20210, 2022/12
Times Cited Count:5 Percentile:52.06(Chemistry, Inorganic & Nuclear)FeUO was studied to clarify the electronic structure of U(V) in a metal monouranate compound. We obtained the peak splitting of HERFD-XANES spectra utilizing high-energy-resolution fluorescence detection-X-ray absorption near edge structure (HERFD-XANES) spectroscopy at the U L
-edge, which is a novel technique in the U(V) compounds. Theoretical calculations revealed that the peak splitting was caused by splitting the 6d orbital of U(V). Such distinctive electronic states are of major interest to researchers and engineers working in various fields, from fundamental physics to the nuclear industry and environmental sciences for actinide elements.
Yomogida, Takumi; Kitatsuji, Yoshihiro; Miyamoto, Yutaka
KEK Proceedings 2022-2, p.148 - 153, 2022/11
The Research Group for Safeguards Analytical Chemistry is currently developing a method to analyze the chemical state of uranium particles in environmental samples collected at nuclear facilities using micro-Raman spectroscopy. The chemical state of uranium particles in environmental samples can be partially oxidized by long-term exposure to air. It is necessary to develop a method to analyze the chemical state of the entire particle. In this study, uranium dioxide stored under atmospheric conditions was analyzed by micro-Raman mapping. The Raman spectra showed that uranium peroxide was locally present in the UO particle. The Raman peaks originating from the structure of UO
around 570 cm
and 1150 cm
could not be observed in the point analysis of the particle center. On the other hand, in mapping analysis, Raman peaks originating from the structure of UO
can be observed from the same particle, demonstrating that Raman mapping analysis is an effective method for analyzing the chemical state of the entire particle.
Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka
KEK Proceedings 2022-2, p.108 - 113, 2022/11
Automated Particle Measurement (APM) is the first measurement of environmental sample for safeguard purpose. APM tells us the number of particles in sample, their enrichment and their location. Precision and accuracy of APM is easily affected by particle condition. We have investigated how influential baking temperature in sample preparation are for uranium secondary ion quantity, uranium hydride generation and particle crystallinity. Our experimental results showed that baking temperature of 800C reduced uranium secondary ion quantity to 33% compared with baking at 350
C. Uranium hydride generation ratio of the sample baked at 850
C was also 4 times higher than the sample baked at 350
C. Baking at 850
C raised only crystallinity of uranium particles. Baking sample at too high temperature caused less uranium secondary ion generation and much more uranium hydride generation. It made precision and accuracy of APM worse. In our experiment, baking at 350
C is suitable for uranium particles in the safeguards sample.
Yomogida, Takumi; Ouchi, Kazuki; Oka, Toshitaka; Kitatsuji, Yoshihiro; Koma, Yoshikazu; Konno, Katsuhiro*
Scientific Reports (Internet), 12(1), p.7191_1 - 7191_10, 2022/05
Times Cited Count:8 Percentile:53.61(Multidisciplinary Sciences)Particles containing alpha () nuclides were identified from sediment in stagnant water at the torus room of the Fukushima Dai-ichi Nuclear Power Station (FDiNPS)'s Unit 2 reactor. Several uranium-bearing particles were identified by SEM observation. These particles contained Zr and other elements which constituted fuel cladding and structural materials. The
U/
U isotope ratio in the solid fractions that included U particles was consistent with the nuclear fuel in the Unit 2 reactor, which indicated that the U particles had been derived from nuclear fuel. The particles with alpha-emitters detected by alpha track analysis were several tens to several hundred
m in size. The EDX spectra showed that these particles mainly comprised iron, which indicated Pu, Am, and Cm were adsorbed on the Fe-baring particles. This study clarifies that the major morphologies of U and other
-nuclides were differed in the sediment of stagnant water in the torus room of FDiNPS's Unit 2 reactor.
Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*
Journal of Physical Chemistry C, 126(12), p.5607 - 5616, 2022/03
Times Cited Count:2 Percentile:15.58(Chemistry, Physical)The reaction mechanism of the direct photoreduction of a Rh ion complex to a Rh
species induced by pulsed ultraviolet laser irradiation was studied using dispersive X-ray absorption fine structure (DXAFS) spectroscopy. The time-resolved X-ray absorption near edge structure (XANES) showed the absence of isosbestic points and suggested that more than two Rh
species contribute toward the direct photoreduction of Rh
. Analysis of the time-resolved XANES data by singular value deposition showed that the direct photoreduction involves three Rh
species. Multivariate curve resolution by alternating least-squares analysis (MCR-ALS) of the time-resolved XANES data gave pure spectra and concentration profiles of the three Rh
species. The Rh
species were assigned to Rh
, Rh
, and Rh
species based on the features of the pure XANES spectra. The concentration profiles suggested that the direct photoreduction proceeds in the order of Rh
Rh
Rh
. A reaction mechanism, which was proposed involving photoreductions of Rh
and Rh
, photoinduced autocatalytic reductions of Rh
and Rh
, and photooxidation of Rh
, well reproduced the concentration profiles of three Rh
species.
Yomogida, Takumi; Saeki, Morihisa*; Morii, Shiori; Oba, Hironori*; Kitatsuji, Yoshihiro
Analytical Sciences, 37(12), p.1843 - 1846, 2021/12
Times Cited Count:1 Percentile:4.42(Chemistry, Analytical)In this study, we developed a simple and one-step Pd separation technique based on photoreduction with Xe lamp irradiation for the determination of Pd in highly radioactive samples. A simulated high-level radioactive liquid wastes (HLLW) solution, which consists of 14 major elements (Rb, Sr, Zr, Mo, Ru, Rh, Pd, Cs, Ba, La, Ce, Pr, Nd, Sm) in a 3 mol L
HNO
solution, was used to evaluate the separation performance. The Pd precipitate were formed by Xe lamp irradiation and recovered by centrifugation. The results showed that the recovery of Pd from a simulated HLLW solution depend on the irradiation time and concentration of ethanol. By optimizing the conditions at photo irradiation, the Pd recovery from the simulated HLLW solution reached up to 50 %, while 99.5 % of the other 13 elements were separated. The Pd precipitate could be separated from the elements that are the main source of radioactivity (Sr, Cs, and Ba) and the source of spectral interference for the determination of
Pd (Zr, and Ru). These results indicate that selective separation of Pd is achieved with the proposed method, showing the applicability of the proposed separation technique to HLLW samples.
Tomita, Ryohei; Tomita, Jumpei; Yomogida, Takumi; Suzuki, Daisuke; Yasuda, Kenichiro; Esaka, Fumitaka; Miyamoto, Yutaka
KEK Proceedings 2021-2, p.146 - 150, 2021/12
no abstracts in English