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Journal Articles

Present status of the JAEA-AMS-TONO (2022FY)

Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Kimura, Kenji; Shimada, Akiomi; et al.

Dai-35-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.17 - 19, 2024/03

The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.

Journal Articles

Effect of dissolved oxygen concentration on dynamic strain aging and stress corrosion cracking of SUS304 stainless steel under high temperature pressurized water

Hirota, Noriaki; Nakano, Hiroko; Fujita, Yoshitaka; Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Demura, Masahiko*; Kobayashi, Yoshinao*

The IV International Scientific Forum "Nuclear Science and Technologies"; AIP Conference Proceedings 3020, p.030007_1 - 030007_6, 2024/01

Dynamic strain aging (DSA) and intergranular stress corrosion cracking (intragranular SCC) occur in high temperature pressurized water simulating a boiling water reactor environment due to changes in dissolved oxygen (DO) content, respectively. In order to clearly understand the difference between these phenomena, the mechanism of their occurrence was summarized. As a result, it was found that DSA due to intragranular cracking occurred in SUS304 stainless steel at low DO $$<$$ 1 ppb, while DSA was suppressed at DO 100 to 8500 ppb due to the formation of oxide films on the surface. On the other hand, when DO was increased to 20000 ppb, the film was peeled from the matrix, O element diffused to the grain boundary of the matrix, resulting in intergranular SCC. These results are indicated that the optimum DO concentration must be adjusted to suppress crack initiation due to DSA and intergranular SCC.

Journal Articles

Study on $$^{rm 99m}$$Tc separation/concentration technology from $$^{99}$$Mo by (n, $$gamma$$) method

Fujita, 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

Journal Articles

Status report of JAEA-AMS-TONO; Research and technical development in the last four years

Kokubu, Yoko; Fujita, Natsuko; Watanabe, Takahiro; Matsubara, Akihiro; Ishizaka, Chika; Miyake, Masayasu*; Nishio, Tomohiro*; Kato, Motohisa*; Ogawa, Yumi*; Ishii, Masahiro*; et al.

Nuclear Instruments and Methods in Physics Research B, 539, p.68 - 72, 2023/06

 Times Cited Count:0 Percentile:0.02

The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has an accelerator mass spectrometer (JAEA-AMS-TONO-5MV). The spectrometer enabled us to use a multi-nuclide AMS of carbon-14 ($$^{14}$$C), beryllium-10, aluminium-26 and iodine-129, and we have recently been proceeding test measurement of chlorine-36. In response to an increase of samples, we installed a state-of-the-art multi-nuclide AMS with a 300 kV Tandetron accelerator in 2020. Recently, we are driving the development of techniques of isobar separation in AMS and of sample preparation. Ion channeling is applied to remove isobaric interference and we are building a prototype AMS based on this technique for downsizing of AMS. The small sample graphitization for $$^{14}$$C has been attempted using an automated graphitization equipment equipped with an elemental analyzer.

Journal Articles

Present status of the JAEA-AMS-TONO (2021)

Matsubara, Akihiro*; Fujita, Natsuko; Miyake, Masayasu; Ishii, Masahiro*; Watanabe, Takahiro; Kokubu, Yoko; Nishio, Tomohiro*; Ogawa, Yumi; Jinno, Satoshi; Kimura, Kenji; et al.

JAEA-Conf 2022-002, p.55 - 62, 2023/03

We report the present status of the JAEA-AMS-TONO. Particularly, the destructions of varistors used in the beamline equipment will be presented. The cause of the destruction as well as implementation of the safety measures are mentioned.

Journal Articles

Present status of the JAEA-AMS-TONO (2022FY)

Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Yamamoto, Yusuke; Kimura, Kenji; et al.

Dai-23-Kai AMS Shimpojiumu Hokokushu, p.1 - 4, 2022/12

The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.

Journal Articles

Event report of JHPS Symposium 2022

Yasuoka, Yumi*; Fujita, Hiroki; Tsuji, Tomoya; Tsujiguchi, Takakiyo*; Sasaki, Michiya*; Miyazaki, Tomoyuki*; Hashima, Shun*; Yasuda, Hiroshi*; Shimada, Kazumasa; Hirota, Seiko*

Hoken Butsuri (Internet), 57(3), p.146 - 155, 2022/12

no abstracts in English

Journal Articles

X ray spectroscopy on $$Xi$$$$^-$$ atoms (J-PARC E03, E07 and future)

Yamamoto, Takeshi; Fujita, Manami; Gogami, Toshiyuki*; Harada, Takeshi*; Hayakawa, Shuhei*; Hosomi, Kenji; Ichikawa, Yudai; Ishikawa, Yuji*; Kamata, K.*; Kanauchi, H.*; et al.

EPJ Web of Conferences, 271, p.03001_1 - 03001_5, 2022/11

Journal Articles

Radiochemical research for the advancement of $$^{99}$$Mo/$$^{rm 99m}$$Tc generator by (n, $$gamma$$) method, 4

Fujita, 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

Journal Articles

Development of stabilization treatment technology for radioactive aluminum waste

Seki, Misaki; Fujita, Yoshitaka; Fujihara, Yasuyuki*; Zhang, J.*; Yoshinaga, Hisao*; Sano, Tadafumi*; Hori, Junichi*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; et al.

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 29(1), p.2 - 9, 2022/06

no abstracts in English

Journal Articles

Present status of the JAEA-AMS-TONO (2019-2020)

Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Watanabe, Takahiro; Kokubu, Yoko; Nishio, Tomohiro*; Ogawa, Yumi*; Kato, Motohisa*; Shimada, Akiomi; Ogata, Nobuhisa

Dai-33-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, P. 48, 2022/04

no abstracts in English

Journal Articles

Estimation of creep behavior of thick rubber bearings from 47 years observation in an actual building

Masaki, Nobuo*; Kato, Koji*; Yamamoto, Tomohiko; Miyagawa, Takayuki*; Fujita, Satoshi*; Okamura, Shigeki*

Nihon Kenchiku Gakkai Gijutsu Hokokushu, 28(68), p.81 - 84, 2022/02

no abstracts in English

Journal Articles

Mechanisms responsible for adsorption of molybdate ions on alumina for the production of medical radioisotopes

Fujita, Yoshitaka; Niizeki, Tomotake*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; Yamauchi, Yusuke*; Malgras, V.*; Kaneti, Y. V.*; Liu, C.-H.*; Hatano, Kentaro*; Suematsu, Hisayuki*; et al.

Bulletin of the Chemical Society of Japan, 95(1), p.129 - 137, 2022/01

 Times Cited Count:5 Percentile:78.23(Chemistry, Multidisciplinary)

In this work, the mechanisms responsible for the adsorption of molybdate ions on alumina are investigated using in-depth surface analyses carried out on alumina specimens immersed in solutions containing different molybdate ions at different pH values. The obtained results reveal that when alumina is immersed in an acidic solution containing molybdate ions, the hydroxyl groups present on the surface are removed to generate positively charged sites, and molybdate ions (MoO$$_{4}$$$$^{2-}$$ or AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMo$$_{6}$$O$$_{24}$$H$$_{6}$$$$^{3-}$$, which is more easily desorbed than MoO$$_{4}$$$$^{2-}$$. Furthermore, the enhancement in the Mo adsorption or desorption property may be achieved by enriching the surface of the alumina adsorbent with many -OH groups and optimizing Mo solution to adsorb molybdate ions on alumina as MoO$$_{4}$$$$^{2-}$$ ions. These findings will assist researchers in engineering more efficient and stable alumina-based adsorbents for molybdenum adsorption used in medical radioisotope ($$^{99}$$Mo/$$^{99m}$$Tc) generators.

Journal Articles

Development of emergency monitoring system for alpha-particle-emitting radionuclides in the air

Hokama, Tomonori; Fujita, Hiroki; Nakano, Masanao; Iimoto, Takeshi*

Radiation Protection Dosimetry, 196(3-4), p.136 - 140, 2021/11

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

During the early phase of a nuclear accident, major radioactive materials are released into the environment, necessitating the prompt deployment of various protective actions to avoid or reduce radiation exposure. To implement these actions, the levels of radioactivity in the environment should be determined. However, the radioactivity concentrations of artificial alpha-particle-emitting radionuclides such as plutonium are difficult to measure in airborne samples, because they are interfered with natural radionuclides such as uranium decay products. Therefore, chemical separation is required to measure the concentrations. This study presents a new emergency monitoring system for airborne samples, which performs multiple-pulse time-interval analysis (MTA) without chemical separation. The system is used in conjunction with an alpha/beta-particle survey meter and adopted an analysis method focusing on the detected time interval of each particle. Its features are that a short time to output measurement result, easy handling and nondestructive. The estimated detection limit of the system was 9.5$$times$$10$$^{-2}$$ Bq m$$^{-3}$$. The MTA-based monitoring system could be useful in situations requiring prompt measurement and screening of samples.

Journal Articles

Research and examination of seismic safety evaluation and function maintenance for important equipment in nuclear facilities

Furuya, Osamu*; Fujita, Satoshi*; Muta, Hitoshi*; Otori, Yasuki*; Itoi, Tatsuya*; Okamura, Shigeki*; Minagawa, Keisuke*; Nakamura, Izumi*; Fujimoto, Shigeru*; Otani, Akihito*; et al.

Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 6 Pages, 2021/07

Since the Fukushima accident, with the higher safety requirements of nuclear facilities in Japan, suppliers, manufacturers and academic societies have been actively considering the reconstruction of the safety of nuclear facilities from various perspectives. The Nuclear Regulation Authority has formulated new regulatory standards and is in operation. The new regulatory standards are based on defense in depth, and have significantly raised the levels of natural hazards and have requested to strengthen the countermeasures from the perspective of preventing the simultaneous loss of safety functions due to common factors. Facilities for dealing with specific serious accidents are required to have robustness to ensure functions against earthquakes that exceed the design standards to a certain extent. In addition, since the probabilistic risk assessment (PRA) and the safety margin evaluation are performed to include the range beyond the design assumption in the safety improvement evaluation, it is very important to extent the special knowledge in the strength of important equipment for seismic safety. This paper summarizes the research and examination results of specialized knowledge on the concept of maintaining the functions of important seismic facilities and the damage index to be considered by severe earthquakes. In the other paper, the study on reliability of seismic capacity analysis for important equipment in nuclear facilities will be reported.

Journal Articles

Fundamental study on seismic safety margin for seismic isolated structure using the laminated rubber bearings

Fukasawa, Tsuyoshi*; Miyagawa, Takayuki*; Uchita, Masato*; Yamamoto, Tomohiko; Miyazaki, Masashi; Okamura, Shigeki*; Fujita, Satoshi*

Nihon Kikai Gakkai Rombunshu (Internet), 87(898), p.21-00007_1 - 21-00007_17, 2021/06

This paper describes a fundamental study on the seismic safety margin for the isolated structure using laminated rubber bearings. The variation of the seismic response assumed in the isolated structure will occur under the superposition of "Variations in seismic response due to input ground motions" and "Error with design value accompanying manufacture of the isolation devices ". The seismic response analysis which allows to their conditions is important to assess the seismic safety margin for the isolated structure. This paper clarifies that the seismic safety margin of the isolated structure, which consists of rubber bearings, for Sodium-cooled Fast Reactor (SFR) is ensured against the basis ground motions of Japan Electric Association Guide 4601 (JEAG4601) and SFR through the seismic response analysis considering the variation factors of seismic response. In addition, a relationship between the seismic safety margin and the excess probability of linearity limits is discussed using the results of seismic response analysis.

Journal Articles

Effect on $$^{99}$$Mo-adsorption/$$^{99m}$$Tc-elution properties of alumina with different surface structures

Fujita, 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

AA2020-0805.pdf:0.77MB

 Times Cited Count:1 Percentile:47.54(Chemistry, Analytical)

We prepared three types of Al$$_{2}$$O$$_{3}$$ with different surface structures and investigated $$^{99}$$Mo-adsorption/$$^{99m}$$Tc-elution properties using [$$^{99}$$Mo]MoO$$_{3}$$ that was irradiated in the Kyoto University Research Reactor. Al$$_{2}$$O$$_{3}$$ adsorbed [$$^{99}$$Mo]molybdate ions in solutions at different pH; the lower was the pH, the higher was the Mo-adsorption capacity of Al$$_{2}$$O$$_{3}$$. The $$^{99m}$$Tc-elution properties of molybdate ion adsorbed Al$$_{2}$$O$$_{3}$$ were elucidated by flowing saline. Consequently, it was suggested that $$^{99}$$Mo-adsorption/desorption properties are affected by the specific surface of Al$$_{2}$$O$$_{3}$$ and $$^{99m}$$Tc-elution properties are affected by the crystal structure of Al$$_{2}$$O$$_{3}$$.

Journal Articles

Preliminary report on small-mass graphitization for radiocarbon dating using EA-AGE3 at JAEA-AMS-TONO

Watanabe, Takahiro; Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Nishio, Tomohiro*; Ishizaka, Chika; Kokubu, Yoko

Geochemical Journal, 55(4), p.277 - 281, 2021/00

 Times Cited Count:2 Percentile:22.73(Geochemistry & Geophysics)

Small-mass radiocarbon dating less than 0.1 mg carbon has been developed by Accelerator mass spectrometry (AMS) and manual preparation techniques using the vacuum glass lines. Because geological samples are limited for the dating in many cases, preparation techniques should be improved for small samples and high efficiency analysis. For radiocarbon dating of geological and other organic samples, small-mass graphitization of international standard reference materials (ca. 0.1 and 0.05 mg carbon) was evaluated using the elemental analyzer and automated graphitization equipment 3 (EA-AGE3; IonPlus AG) in our study. Additionally, this paper presents the first data for the small samples by the EA-AGE3. The average radiocarbon concentration of the small-mass international standards (NIST-SRM4990C, IAEA-C5, and C7) prepared by the EA-AGE3 were agreement with the consensus values within $$pm$$ 2$$sigma$$. Therefore, small-mass graphitization using the EA-AGE3 can be adapted for AMS radiocarbon measurements in our case (down to ca. 0.05 mg carbon).

Journal Articles

Radiocarbon dating of a shrine pavilion and offerings at Abushina shrine in Gifu prefecture, Japan

Kokubu, Yoko; Nishio, Tomohiro; Fujita, Natsuko; Matsubara, Akihiro

Proceedings of the 8th East Asia Accelerator Mass Spectrometry Symposium and the 22nd Japan Accelerator Mass Spectrometry symposium (EA-AMS 8 & JAMS-22), p.91 - 93, 2020/00

no abstracts in English

Journal Articles

Present status of the JAEA-AMS-TONO in 2019

Fujita, Natsuko; Matsubara, Akihiro; Miyake, Masayasu*; Watanabe, Takahiro; Kokubu, Yoko; Kato, Motohisa*; Okabe, Nobuaki*; Isozaki, Nobuhiro*; Ishizaka, Chika*; Nishio, Tomohiro; et al.

Proceedings of the 8th East Asia Accelerator Mass Spectrometry Symposium and the 22nd Japan Accelerator Mass Spectrometry symposium (EA-AMS 8 & JAMS-22), p.34 - 36, 2020/00

no abstracts in English

446 (Records 1-20 displayed on this page)