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JAEA Reports

Stable hydrogen and oxygen isotope analyses of geological samples using a thermal conversion elemental analyzer-isotope ratio mass spectrometer at Tono Geoscience Center

Yamamoto, Yusuke*; Watanabe, Takahiro; Niwa, Masakazu; Shimada, Koji

JAEA-Testing 2023-003, 67 Pages, 2024/02

JAEA-Testing-2023-003.pdf:4.63MB

A long-term geosphere stability for geological disposal is evaluated by the past geological environmental changes and modern conditions. Stable hydrogen and oxygen isotope ratios ($$delta$$D, $$delta$$$$^{18}$$O) of geological samples are useful information to estimate the past environmental changes and modern conditions. Recently, the thermal conversion elemental analyzer and isotope ratio mass spectrometer (TC-EA/IRMS) were installed in the Tono Geoscience Center for $$delta$$D and $$delta$$$$^{18}$$O measurements of geological samples. In this study, we reported analytical methods of $$delta$$D and $$delta$$$$^{18}$$O using international standard reference materials. In addition, evaluation tests of uncertainty by repeated analyses of the standards were performed using the TC-EA/IRMS. Furthermore, the $$delta$$D and $$delta$$$$^{18}$$O analyses by the TC- EA/IRMS were also applied to fault rock samples.

Journal Articles

Systematic shell-model study of $$^{99-129}$$Cd isotopes and isomers in neutron-rich $$^{127-131}$$In isotopes

Patel, D.*; Srivastava, P. C.*; Shimizu, Noritaka*; Utsuno, Yutaka

Physical Review C, 109(1), p.014310_1 - 014310_16, 2024/01

 Times Cited Count:0 Percentile:0.19(Physics, Nuclear)

no abstracts in English

JAEA Reports

Stabilization of post-experiment nuclear materials in Plutonium Fuel Research Facility

Sato, Takumi; Otobe, Haruyoshi; Morishita, Kazuki; Marufuji, Takato; Ishikawa, Takashi; Fujishima, Tadatsune; Nakano, Tomoyuki

JAEA-Technology 2023-016, 41 Pages, 2023/09

JAEA-Technology-2023-016.pdf:2.74MB

This report summarizes the results of the stabilization treatments of post-experiment nuclear materials in Plutonium Fuel Research Facility (PFRF) from August 2018 to March 2021. Based on the management standards for nuclear materials enacted after the contamination accident that occurred at PFRF on June 6, 2017, the post-experiment nuclear materials containing plutonium (Pu): samples mixed with organic substances that cause an increase in internal pressure due to radiolysis (including X-ray diffraction samples mixed with epoxy resin and plutonium powder which caused contamination accidents), carbides and nitrides samples which is reactive in air, and chloride samples which may cause corrosion of storage containers, were selected as targets of the stabilization. The samples containing organic materials, carbides and nitrides were heated in an air flow at 650 $$^{circ}$$C and 950 $$^{circ}$$C for 2 hours respectively to remove organic materials and convert uranium (U) and Pu into oxides. U and Pu chlorides in LiCl-KCl eutectic melt were reduced and extracted into liquid Cd metal by a reaction with lithium (Li) -cadmium (Cd) alloy and converted to U-Pu-Cd alloy at 500 $$^{circ}$$C or higher. All of the samples were stabilized and stored at PFRF. We hope that the contents of this report will be utilized to consider methods for stabilizing post experiment nuclear materials at other nuclear fuel material usage facilities.

Journal Articles

Current status of Toki Geochronology Research Laboratory, Tono Geoscience Center, Japan Atomic Energy Agency

Osawa, Hideaki

Gijutsushi "Chubu", (12), p.34 - 41, 2023/09

This introduces current status of Toki Geochronology Research Laboratory, Tono Geoscience Center, Japan Atomic Energy Agency.

Journal Articles

First observation of $$^{28}$$O

Kondo, Yosuke*; Achouri, N. L.*; Al Falou, H.*; Atar, L.*; Aumann, T.*; Baba, Hidetada*; Boretzky, K.*; Caesar, C.*; Calvet, D.*; Chae, H.*; et al.

Nature, 620(7976), p.965 - 970, 2023/08

 Times Cited Count:6 Percentile:93.26(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Thermal stability of non-collinear antiferromagnetic Mn$$_3$$Sn nanodot

Sato, Yuma*; Takeuchi, Yutaro*; Yamane, Yuta*; Yoon, J.-Y.*; Kanai, Shun*; Ieda, Junichi; Ohno, Hideo*; Fukami, Shunsuke*

Applied Physics Letters, 122(12), p.122404_1 - 122404_5, 2023/03

 Times Cited Count:2 Percentile:49.29(Physics, Applied)

Journal Articles

Large collectivity in $$^{29}$$Ne at the boundary of the island of inversion

Revel, A.*; Wu, J.*; Iwasaki, Hironori*; Ash, J.*; Bazin, D.*; Brown, B. A.*; Chen, J.*; Elder, R.*; Farris, P.*; Gade, A.*; et al.

Physics Letters B, 838, p.137704_1 - 137704_7, 2023/03

 Times Cited Count:1 Percentile:64.66(Astronomy & Astrophysics)

no abstracts in English

JAEA Reports

Assessment report of research and development activities in FY2021; Activity of "Research and Development on Geological Disposal of High-level Radioactive Waste" (Post- and pre-review report)

Geological Disposal Research and Development Department

JAEA-Evaluation 2022-007, 81 Pages, 2022/11

JAEA-Evaluation-2022-007.pdf:2.06MB
JAEA-Evaluation-2022-007-appendix(CD-ROM).zip:37.06MB

Japan Atomic Energy Agency (JAEA) consulted the advisory committee, "Evaluation Committee on Research and Development (R&D) Activities for Geological Disposal of High-Level Radioactive Waste", for post- and pre-review assessment of R&D activities on high-level radioactive waste disposal in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by the Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and JAEA's "Regulation on Conduct for Evaluation of R&D Activities". In response to JAEA's request, the Committee reviewed mainly the progress of the R&D project on geological disposal, the relevance of the project outcome and the efficiency of the project implementation during the period of the current and next plan. This report summarizes the results of the assessment by the Committee with the Committee report attached.

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

JAEA Reports

Stabilization treatment of nuclear fuel material contained with organic matter

Senzaki, Tatsuya; Arai, Yoichi; Yano, Kimihiko; Sato, Daisuke; Tada, Kohei; Ogi, Hiromichi*; Kawanobe, Takayuki*; Ono, Shimpei; Nakamura, Masahiro; Kitawaki, Shinichi; et al.

JAEA-Testing 2022-001, 28 Pages, 2022/05

JAEA-Testing-2022-001.pdf:2.33MB

In preparation for the decommissioning of Laboratory B of the Nuclear Fuel Cycle Engineering Laboratory, the nuclear fuel material that had been stored in the glove box for a long time was moved to the Chemical Processing Facility (CPF). This nuclear fuel material was stored with sealed by a polyvinyl chloride (PVC) bag in the storage. Since it was confirmed that the PVC bag swelled during storage, it seems that any gas was generated by radiolysis of the some components contained in the nuclear fuel material. In order to avoid breakage of the PVC bag and keep it safety for long time, we began the study on the stabilization treatment of the nuclear fuel material. First, in order to clarify the properties of nuclear fuel material, radioactivity analysis, component analysis, and thermal analysis were carried out. From the results of thermal analysis, the existence of organic matter was clarified. Then, ion exchange resin with similar thermal characteristics was selected and the thermal decomposition conditions were investigated. From the results of these analyzes and examinations, the conditions for thermal decomposition of the nuclear fuel material contained with organic matter was established. Performing a heat treatment of a small amount of nuclear fuel material in order to confirm the safety, after which the treatment amount was scaled up. It was confirmed by the weight change after the heat treatment that the nuclear fuel material contained with organic matter was completely decomposed.

Journal Articles

A First glimpse at the shell structure beyond $$^{54}$$Ca; Spectroscopy of $$^{55}$$K, $$^{55}$$Ca, and $$^{57}$$Ca

Koiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navr$'a$til, P.*; Ogata, Kazuyuki*; et al.

Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04

 Times Cited Count:4 Percentile:74.12(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

In-beam $$gamma$$-ray spectroscopy of $$^{32}$$Mg via direct reactions

Kitamura, Noritaka*; Wimmer, K.*; Miyagi, Takayuki*; Poves, A.*; Shimizu, Noritaka*; Tostevin, J. A.*; Bader, V. M.*; Bancroft, C.*; Barofsky, D.*; Baugher, T.*; et al.

Physical Review C, 105(3), p.034318_1 - 034318_17, 2022/03

 Times Cited Count:2 Percentile:49.92(Physics, Nuclear)

no abstracts in English

Journal Articles

Probing different characteristics of shell evolution driven by central, spin-orbit, and tensor forces

Utsuno, Yutaka

Physics (Internet), 4(1), p.185 - 201, 2022/03

no abstracts in English

Journal Articles

Moments and radii of exotic Na and Mg isotopes

Otsuka, Takaharu*; Shimizu, Noritaka*; Tsunoda, Yusuke*

Physical Review C, 105(1), p.014319_1 - 014319_8, 2022/01

 Times Cited Count:5 Percentile:80.72(Physics, Nuclear)

no abstracts in English

Journal Articles

Coexisting normal and intruder configurations in $$^{32}$$Mg

Kitamura, Noritaka*; Wimmer, K.*; Poves, A.*; Shimizu, Noritaka*; Tostevin, J. A.*; Bader, V. M.*; Bancroft, C.*; Barofsky, D.*; Baugher, T.*; Bazin, D.*; et al.

Physics Letters B, 822, p.136682_1 - 136682_7, 2021/11

AA2021-0459.pdf:1.01MB

 Times Cited Count:6 Percentile:70.39(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

Prediction of stability constants for novel chelates design in minor actinides partitioning over lanthanides using density functional theory calculation

Kaneko, Masashi; Sasaki, Yuji; Wada, Eriko*; Nakase, Masahiko*; Takeshita, Kenji*

Chemistry Letters, 50(10), p.1765 - 1769, 2021/10

 Times Cited Count:0 Percentile:0(Chemistry, Multidisciplinary)

Density functional theory calculation is applied to predict the stability constants for Eu$$^{3+}$$ and Am$$^{3+}$$ complexes in aqueous solution for molecular modelling of novel separation agents for minor actinides over lanthanides. Logarithm of experimental stability constants correlates with calculated complex formation enthalpies with high reproducibility (R$$^{2}$$ $$>$$ 0.98). Prediction of stability constants of novel chelates is demonstrated and indicates a potential availability of the derivatives of diethylenetriaminepentaacetic acid type chelate in acidic condition and enhancement of Am$$^{3+}$$ selectivity over Eu$$^{3+}$$.

Journal Articles

Investigation of the ground-state spin inversion in the neutron-rich $$^{47,49}$$Cl isotopes

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; G$'o$mez-Ramos, M.*; et al.

Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10

AA2021-0468.pdf:1.29MB

 Times Cited Count:6 Percentile:63.69(Physics, Nuclear)

no abstracts in English

Journal Articles

Cross-shell excitations in $$^{46}$$Ca studied with fusion reactions induced by a reaccelerated rare isotope beam

Ash, J.*; Iwasaki, Hironori*; Mijatovi$'c$, T.*; Budner, T.*; Elder, R.*; Elman, B.*; Friedman, M.*; Gade, A.*; Grinder, M.*; Henderson, J.*; et al.

Physical Review C, 103(5), p.L051302_1 - L051302_6, 2021/05

 Times Cited Count:3 Percentile:45.55(Physics, Nuclear)

no abstracts in English

Journal Articles

Transfer of $$^{137}$$Cs to web-building spiders, ${it Nephila clavata}$, and its pathways; A Preliminary study using stable carbon and nitrogen isotope analyses

Tanaka, Sota; Kakinuma, Hotaru*; Adachi, Taro*; Atarashi-Andoh, Mariko; Koarashi, Jun

Journal of Nuclear Science and Technology, 58(4), p.507 - 514, 2021/04

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Understanding the pathways of $$^{137}$$Cs transfer to predatory spiders is useful to assess long-term behavior of $$^{137}$$Cs in the environment, because spiders obtain food resources from both the grazing and detritus food chains in terrestrial-aquatic linking forest ecosystems. In the present study, we collected spider samples at forest interior and riverside. The sample collection was approximately 6.5 years after the FDNPP accident. Moreover, a transfer factor value (T$$_{ag}$$) for $$^{137}$$Cs in spiders was quantified. Stable carbon and nitrogen isotope ratios ($$delta$$$$^{13}$$C and $$delta$$$$^{15}$$N) of the spiders were also investigated to estimate the transfer pathways of $$^{137}$$Cs to the spiders.

Journal Articles

Gamow-Teller transitions of neutron-rich $$N$$ = 82, 81 nuclei by shell-model calculations

Shimizu, Noritaka*; Togashi, Tomoaki*; Utsuno, Yutaka

Progress of Theoretical and Experimental Physics (Internet), 2021(3), p.033D01_1 - 033D01_15, 2021/03

AA2020-0889.pdf:1.07MB

 Times Cited Count:4 Percentile:48.26(Physics, Multidisciplinary)

no abstracts in English

606 (Records 1-20 displayed on this page)