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Sasaki, Yuji; Kaneko, Masashi; Ban, Yasutoshi; Suzuki, Tatsuya*
Solvent Extraction Research and Development, Japan, 32(1), p.21 - 29, 2025/00
The magnitude of the masking effect of carboxylic, amic-acidic, and amidic compounds through Ln and Am extractions by tetraoctyl diglycolamide (TODGA) is compared. The compounds used are diglycol, ethylenediamine, diethylenetriamine-type, and two other amides (dioxaoctane diamide and nitrylotriacetamide). The results show that below pH 1.2, where carboxylic acids are less dissociated, amide O atoms have higher reactivity with lanthanides than O atoms in carboxyl groups. From observing the Ln patterns (D(Ln) vs. their atomic number), the compounds primarily show high reactivity, with middle and heavy Ln having a higher charge density than light Ln. Four amide compounds are employed in this work. Those with tertiary amine N atoms have pH dependence on D(Ln) due to protonation and dissociation from amine N atoms.
Tc separation/concentration technology from 
Mo by (n, 
) method, 2Fujita, Yoshitaka; Hu, X.*; Yang, Y.*; Kitagawa, Taiga*; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; Hori, Junichi*; Do, T. M. D.*; Suzuki, Tatsuya*; Suematsu, Hisayuki*; et al.
KURNS Progress Report 2023, P. 122, 2024/07
no abstracts in English
CNguyen, B. V. C.*; Murakami, Kenta*; Chena, L.*; Phongsakorn, P. T.*; Chen, X.*; Hashimoto, Takashi; Hwang, T.*; Furusawa, Akinori; Suzuki, Tatsuya*
Nuclear Materials and Energy (Internet), 39, p.101639_1 - 101639_9, 2024/06
Times Cited Count：1 Percentile：0.00(Nuclear Science & Technology)Hu, X.*; Fujita, Yoshitaka; Tsuchiya, Kunihiko; Fukutani, Satoshi*; Hori, Junichi*; Suzuki, Tatsuya*
Journal of Radioanalytical and Nuclear Chemistry, 333(11), p.6057 - 6063, 2024/05
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)no abstracts in English
Mo hot atoms made by a neutron capture method from 
-MoO
to waterQuach, N. M.*; Ngo, M. C.*; Yang, Y.*; Nguyen, T. B.*; Nguyen, V. T.*; Fujita, Yoshitaka; Do, T. M. D.*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Suematsu, Hisayuki*
Journal of Radioanalytical and Nuclear Chemistry, 332(10), p.4057 - 4064, 2023/10
Times Cited Count：4 Percentile：71.02(Chemistry, Analytical)Technetium-99m (Tc) is the most widely used medical radioisotope in the world and is produced from molybdenum-99 (Mo). Production of Mo via the neutron capture method draws attention as an alternative to fission-derived Mo due to non-proliferation issues, but the specific radioactivity of Mo is extremely low. In this work, a porous -MoO wire was prepared as an irradiation target in order to improve the specific activity by extracting Mo. Porous -MoO wire is synthesized from Mo metal wire by a two-step heating procedure. The hot atom effect of Mo was confirmed by activity and isotope measurements of the porous -MoO wire after neutron irradiation and the water used for extraction. In term of the extraction effectiveness, the effectiveness of Mo extraction in the porous -MoO wire was comparable to that of commercial -MoO powder.
-MoO whiskers in Mo/
Tc radioisotope production and Mo/Tc extraction using hot atomsNgo, M. C.*; Fujita, Yoshitaka; Suzuki, Tatsuya*; Do, T. M. D.*; Seki, Misaki; Nakayama, Tadachika*; Niihara, Koichi*; Suematsu, Hisayuki*
Inorganic Chemistry, 62(32), p.13140 - 13147, 2023/08
Times Cited Count：5 Percentile：60.95(Chemistry, Inorganic & Nuclear)Technetium-99m (Tc) is one of the most important radioisotopes for diagnostic radio-imaging applications. Tc is a daughter product of the Mo isotope. There are two methods used to produce Mo/Tc: the nuclear fission (n,f) and the neutron capture (n,) methods. Between them, the (n,f) method is the main route, used for approximately 90% of the world's production. However, the (n,f) method faces numerous problems, including the use of highly enriched uranium, the release of highly radioactive waste, and nonproliferation problems. Therefore, the (n,) method is being developed as a future replacement for the (n,f) method. In this work, -MoO whiskers prepared by the thermal evaporation method and -MoO particles were irradiated in a nuclear reactor to produce Mo/Tc via neutron capture. The irradiated targets were dispersed into water to extract the Mo/Tc. As a result, -MoO whisker yielded higher Mo extraction rate than that from -MoO. In addition, by comparing the dissolved 
Mo concentrations in water, we clarified a prominent hot-atom of -MoO whiskers. This research is the first demonstration of -MoO being used as an irradiation target in the neutron capture method. On the basis of the results, -MoO is considered a promising irradiation target for producing Mo/Tc by neutron capture and using water for the radioisotope extraction process in the future.
Kawabori, Tatsuru*; Watanabe, Masashi; Imai, Yoshiyuki; Ueta, Shohei; Yan, X.; Mizoshiri, Mizue*
Applied Physics A, 129(7), p.498_1 - 498_9, 2023/07
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)We investigated a potential of femtosecond laser sintering of silicon carbide (SiC) using the nanoparticles in air. A SiC nanoparticle ink including polyvinylpyrrolidone and ethylene glycol exhibited intense absorption by SiC nanoparticles at the wavelength of 780 nm. The whole of the sintered film patterns from the surface to the bottom underwent significant oxidation at a scanning speed of 1 mm/s, suggesting that the excessive energy irradiation generated silicon oxides. In contrast, the patterns fabricated by laser scanning at a raster pitch of 30 
m at which a sintered area was observed at a scanning speed of 5 mm/s, exhibited no significant difference in oxidation of the raw SiC nanoparticles except for the surfaces from 1.72 m. These results indicate that the irradiation of femtosecond laser pulses generated the sintered SiC patterns without additional atmospheric oxidation of the raw materials because of its low heat accumulation. In additions, the dispersant of polyvinylpyrrolidone and ethylene glycol did not affect the sintering by an X-ray photoelectron spectroscopy. This vacuum-free direct printing technique has the potential for additive manufacturing.
Tc separation/concentration technology from Mo by (n, ) methodFujita, Yoshitaka; Hu, X.*; Takeuchi, Tomoaki; Takeda, Ryoma; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; Hori, Junichi*; Suzuki, Tatsuya*; Suematsu, Hisayuki*; Ide, Hiroshi
KURNS Progress Report 2022, P. 110, 2023/07
no abstracts in English
Mo/Tc generator by (n, ) method, 4Fujita, Yoshitaka; Seki, Misaki; Ngo, M. C.*; Do, T. M. D.*; Hu, X.*; Yang, Y.*; Takeuchi, Tomoaki; Nakano, Hiroko; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; et al.
KURNS Progress Report 2021, P. 118, 2022/07
no abstracts in English
Mo adsorption and Tc elution with alumina columnsFujita, Yoshitaka; Seki, Misaki; Sano, Tadafumi*; Fujihara, Yasuyuki*; Suzuki, Tatsuya*; Yoshinaga, Hisao*; Hori, Junichi*; Suematsu, Hisayuki*; Tsuchiya, Kunihiko
Journal of Physics; Conference Series, 2155, p.012018_1 - 012018_6, 2022/01
Technetium-99m (Tc), the daughter nuclide of Molybdenum-99 (Mo), is the most commonly used radioisotope in radiopharmaceuticals. The research and development (R&D) for the production of Mo by the neutron activation method ((n, ) method) has been carried out from viewpoints of no-proliferation and nuclear security, etc. Since the specific activity of Mo produced by the (n, ) method is extremely low, developing Al
O with a large Mo adsorption capacity is necessary to adapt (n, )Mo to the generator. In this study, three kinds of AlO specimens with different raw materials were prepared and compared their adaptability to generators by static and dynamic adsorption. MoO pellet pieces (1.5g) were irradiated with 5 MW for 20 min in the Kyoto University Research Reactor (KUR). Irradiated MoO pellet pieces were dissolved in 6M-NaOH aq. In dynamic adsorption, 1 g of AlO was filled into a PFA tube (
1.59 mm). The Mo adsorption capacity of AlO specimens under dynamic condition was slightly reduced compared to that under static condition. The Tc elution rate was about 100% at 1.5 mL of milking in dynamic adsorption, while it was around 56-87% in static adsorption. The Mo/Tc ratio of dynamic condition was greatly reduced compared to that of static condition. Therefore, the Tc elution property is greatly affected by the method of adsorbing Mo, e.g., the column shape, the linear flow rate, etc.
Mo/Tc generator by (n, ) method, 3Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Daigo, Fumihisa; Ide, Hiroshi; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.
KURNS Progress Report 2020, P. 136, 2021/08
no abstracts in English
Mo-adsorption/Tc-elution properties of alumina with different surface structuresFujita, Yoshitaka; Seki, Misaki; Sano, Tadafumi*; Fujihara, Yasuyuki*; Kitagawa, Tomoya*; Matsukura, Minoru*; Hori, Junichi*; Suzuki, Tatsuya*; Tsuchiya, Kunihiko
Journal of Radioanalytical and Nuclear Chemistry, 327(3), p.1355 - 1363, 2021/03
Times Cited Count：4 Percentile：39.96(Chemistry, Analytical)We prepared three types of AlO with different surface structures and investigated Mo-adsorption/Tc-elution properties using [Mo]MoO that was irradiated in the Kyoto University Research Reactor. AlO adsorbed [Mo]molybdate ions in solutions at different pH; the lower was the pH, the higher was the Mo-adsorption capacity of AlO. The Tc-elution properties of molybdate ion adsorbed AlO were elucidated by flowing saline. Consequently, it was suggested that Mo-adsorption/desorption properties are affected by the specific surface of AlO and Tc-elution properties are affected by the crystal structure of AlO.
for production of Tc radioactive isotopeSuematsu, Hisayuki*; Sato, Soma*; Nakayama, Tadachika*; Suzuki, Tatsuya*; Niihara, Koichi*; Nanko, Makoto*; Tsuchiya, Kunihiko
Journal of Asian Ceramic Societies (Internet), 8(4), p.1154 - 1161, 2020/12
Times Cited Count：4 Percentile：17.02(Materials Science, Ceramics)Pulsed electric current sintering of molybdenum trioxide (MoO) was carried out by one- and two-step pressuring methods for fabrication of irradiation target using production of Mo and Tc nuclear medicine. At 550C by the two-step pressurizing method, a relative density of 93.1% was obtained while, by the one-step pressurization method, the relative density was 76.9%. Direct sample temperature measurements were conducted by inserting a thermocouple in a punch. By the two-step pressurizing method, the sample temperature was higher than that by the one-step pressurizing method even almost the same die temperature. From voltage and current waveforms, it was thought that the conductivity of the sample increased by the two-step pressurizing method to increase the sample temperature and the relative density. The two-step pressurization method enables us to prepare dense targets at a low temperature from recycled and coarse-grained Mo enriched MoO powder.
Li, Y.; Hirota, Takatoshi*; Itabashi, Yu*; Yamamoto, Masato*; Kanto, Yasuhiro*; Suzuki, Masahide*; Miyamoto, Yuhei*
JAEA-Review 2020-011, 130 Pages, 2020/09
JAEA-Review-2020-011.pdf:9.31MB
For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in Japan Atomic Energy Agency based on the latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressure thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to perform verification activities, and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL module and the source program of PASCAL was released to the members of working group. This report summarizes the activities of the working group on the verification of PASCAL in FY2016 and FY2017.
Mo/Tc generator by (n,) method, 2Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kato, Yoshiaki; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.
KURNS Progress Report 2019, P. 157, 2020/08
no abstracts in English
Lu, K.; Katsuyama, Jinya; Li, Y.; Miyamoto, Yuhei*; Hirota, Takatoshi*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Mechanical Engineering Journal (Internet), 7(3), p.19-00573_1 - 19-00573_14, 2020/06
Kim, J.*; Yamanaka, Satoru*; Murayama, Ichiro*; Kato, Takanori*; Sakamoto, Tomokazu*; Kawasaki, Takuro; Fukuda, Tatsuo; Sekino, Toru*; Nakayama, Tadachika*; Takeda, Masatoshi*; et al.
Sustainable Energy & Fuels (Internet), 4(3), p.1143 - 1149, 2020/03
Times Cited Count：22 Percentile：63.45(Chemistry, Physical)Suzuki, Masahide*; Murakami, Kenta*; Suzuki, Takashi*; Okayama, Ryuta*; Katsuyama, Jinya; Li, Y.
E-Journal of Advanced Maintenance (Internet), 11(4), p.172 - 178, 2020/02
no abstracts in English
Nancekievill, M.*; Espinosa, J.*; Watson, S.*; Lennox, B.*; Jones, A.*; Joyce, M. J.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; et al.
Sensors (Internet), 19(20), p.4602_1 - 4602_16, 2019/10
Times Cited Count：9 Percentile：44.74(Chemistry, Analytical)In order to contribute to fuel debris search at the Fukushima Daiichi Nuclear Power Station, we developed a system to search for submerged fuel debris by mounting a sonar on the remotely operated vehicle (ROV). The system can obtain 3D images of submerged fuel debris in real time by using the positioning system, depth sensor, and collected sonar data. As a demonstration test, a simulated fuel debris was installed at the bottom of the water tank facility at the Naraha Center for Remote Control Technology Development, and a 3D image was successfully obtained.
Mo/Tc generator by (n,) methodFujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kimura, Akihiro; Shibata, Akira; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.
KURNS Progress Report 2018, P. 155, 2019/08
no abstracts in English
