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JAEA Reports

Microstructural observation of simulated fuel kernels for Pu-burner high temperature gas-cooled reactor in Japan

Aihara, Jun; Ueta, Shohei; Honda, Masaki*; Kasahara, Seiji; Okamoto, Koji*

JAEA-Research 2024-012, 98 Pages, 2025/02

JAEA-Research-2024-012.pdf:32.24MB

Concept of Pu-burner high temperature gas-cooled reactor (HTGR) was proposed for the purpose of more safely reducing amount of recovered Pu. In Pu-burner HTGR concept, coated fuel particle (CFP), with ZrC coated yttria stabilized zirconia (YSZ) containing PuO$$_{2}$$ (PuO$$_{2}$$-YSZ) small particle and with tri-structural isotropic (TRISO) coating, is employed for very high burn-up and high nuclear proliferation resistance. ZrC layer is oxygen getter. In research project of Pu-burner HTGR carried out from fiscal year of 2014 to fiscal year of 2017, simulated CFPs were fabricated using Ce to simulate Pu. Moreover, simulated fuel compacts were fabricated using fabricated simulated CFPs. In this report, results of microstructural observation of CeO$$_{2}$$-YSZ and ZrC layer at each fabrication step are reported.

Journal Articles

Martensitic transformation and shape memory effect in Mn-rich Cu-Mn-Al alloys

Ito, Tatsuya; Xu, S.*; Xu, X.*; Omori, Toshihiro*; Kainuma, Ryosuke*

Shape Memory and Superelasticity, 9 Pages, 2025/00

Journal Articles

Image selection method from image sequence to improve computational efficiency of 3D reconstruction; Application of fixed threshold to remove redundant images

Hanari, Toshihide; Nakamura, Keita*; Imabuchi, Takashi; Kawabata, Kuniaki

Journal of Robotics and Mechatronics, 36(6), p.1537 - 1549, 2024/12

This paper describes three-dimensional (3D) reconstruction processes introducing the image selection method for efficiently generating a 3D model from an image sequence. To obtain suitable images for efficient 3D reconstruction, we tried to apply the image selection method to remove the redundant images in the image sequence. By the proposed method, the suitable images were selected from the image sequence based on optical flow measures and a fixed threshold. As a result, the proposed method can reduce the computational cost for the 3D reconstruction processes based on the image sequence acquired by the camera. We confirmed that the computational cost of the 3D reconstruction processes can reduce while keeping the 3D reconstruction accuracy at a constant level.

Journal Articles

Enhanced cryogenic mechanical properties of heterostructured CrCoNi multicomponent alloy; Insights from ${it in situ}$ neutron diffraction

Naeem, M.*; Ma, Y.*; Knowles, A. J.*; Gong, W.; Harjo, S.; Wang, X.-L.*; Romero Resendiz, L.*; 6 of others*

Materials Science & Engineering A, 916, p.147374_1 - 147374_8, 2024/11

 Times Cited Count:3 Percentile:57.76(Nanoscience & Nanotechnology)

Journal Articles

Using X-ray absorption near edge structure to evaluate adsorption properties of rare earths and nitrogen by difference of their interactions

Minowa, Kazuki*; Watanabe, So; Nakase, Masahiko*; Takahatake, Yoko; Miyazaki, Yasunori; Ban, Yasutoshi; Matsuura, Haruaki*

Nuclear Instruments and Methods in Physics Research B, 556, p.165496_1 - 165496_6, 2024/11

 Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)

In this study, X-ray absorption near edge structure (XANES) spectral analysis and column experiments were used to verify the selectivity of rare earth (RE) ions by alkyl diamide amine (ADAAM) adsorbent. In addition, the interactions between the N atoms of ADAAM and RE ions were evaluated to determine whether any of the RE ions are a valid simulant for developing a mutual separation process for minor actinides (MAs) in highly radioactive liquid waste. It was confirmed that La and Ce interacted with the amine N atom of ADAAM and they showed a peak shift of the N-K edge XANES spectrum; this finding suggested that a soft interaction is an essential factor influencing ion selectivity. Therefore, the selection factor of RE ions by ADAAM adsorbent was similar to that of MAs. It was concluded that RE ions are reasonable species to simulate MAs.

JAEA Reports

Heat transfer coefficients model for SIMMER-III and SIMMER-IV

Brear, D. J.*; Kondo, Satoru; Sogabe, Joji; Tobita, Yoshiharu*; Kamiyama, Kenji

JAEA-Research 2024-009, 134 Pages, 2024/10

JAEA-Research-2024-009.pdf:2.45MB

The SIMMER-III/SIMMER-IV computer codes are being used for liquid-metal fast reactor (LMFR) core disruptive accident (CDA) analysis. The sequence of events predicted in a CDA is often influenced by the heat exchanges between LMFR materials, which are controlled by heat transfer coefficients (HTCs) in the respective materials. The mass transfer processes of melting and freezing, and vaporization and condensation are also controlled by HTCs. The complexities in determining HTCs in a multi-component and multi-phase system are the number of HTCs to be defined at binary contact areas of a fluid with other fluids and structure surfaces, and the modes of heat transfer taking into account different flow topologies representing flow regimes with and without structure. As a result, dozens of HTCs are evaluated in each mesh cell for the heat and mass transfer calculations. This report describes the role of HTCs in SIMMER-III/SIMMER-IV, the heat transfer correlations implemented and the calculation of HTCs in all topologies in multi-component, multi-phase flows. A complete description of the physical basis of HTCs and available experimental correlations is contained in Appendices to this report. The major achievement of the code assessment program conducted in parallel with code development is summarized with respect to HTC modeling to demonstrate that the coding is reliable and that the model is applicable to various multi-phase problems with and without reactor materials.

Journal Articles

Development of failure mitigation technologies for improving resilience of nuclear structures

Kasahara, Naoto*; Yamano, Hidemasa; Nakamura, Izumi*; Demachi, Kazuyuki*; Sato, Takuya*; Ichimiya, Masakazu*

International Journal of Pressure Vessels and Piping, 211, p.105298_1 - 105298_6, 2024/10

 Times Cited Count:1 Percentile:0.00(Engineering, Multidisciplinary)

JAEA Reports

Research and development of the sample-return technique for fuel debris using the unmanned underwater vehicle (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; National Institute of Maritime, Port and Aviation Technology*

JAEA-Review 2024-020, 77 Pages, 2024/09

JAEA-Review-2024-020.pdf:3.34MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Research and development of the sample-return technique for fuel debris using the unmanned underwater vehicle" conducted from FY2020 to FY2022. The present study aims to develop a fuel debris sampling device that comprises a neutron detector with radiation resistance and enhanced neutron detection efficiency, an end-effector with powerful cutting and collection capabilities, and a manipulator under the Japan-UK joint research team. We will also develop a fuel debris sampling system that can be mounted on an unmanned vehicle.

Journal Articles

Enhancing mechanical properties of medium Mn steel by warm rolling based on laminated elemental segregation

Chen, H. F.*; Liu, B. X.*; Xu, P. G.; Fang, W.*; Tong, H. C.*; Yin, F. X.*

Journal of Materials Research and Technology, 32, p.3060 - 3069, 2024/09

 Times Cited Count:1 Percentile:0.00(Materials Science, Multidisciplinary)

JAEA Reports

Clarification of debris formation conditions on the basis of the sampling data and experimental study using simulated fuel debris and reinforcement of the analytical results of severe accident scenario (Contract Research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; University of Fukui*

JAEA-Review 2024-014, 112 Pages, 2024/08

JAEA-Review-2024-014.pdf:8.22MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Clarification of debris formation conditions on the basis of the sampling data and experimental study using simulated fuel debris and reinforcement of the analytical results of severe accident scenario" conducted in FY2022. The present study aims to clarify the debris formation mechanism and utilize the results to refine the accident scenario. In the backward analysis of oxide debris formation, we succeeded in the formation of simulated fuel particle by the aerodynamic levitation method and ejection of melted oxides from tungsten pipe with a small hole. And we demonstrated the formation of simulated fuel debris of U1-No.15 obtained by the sampling in 1F.

JAEA Reports

Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies (Contract research); FY2022 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*

JAEA-Review 2023-048, 151 Pages, 2024/05

JAEA-Review-2023-048.pdf:8.48MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Development of a hybrid method for evaluating the long-term structural soundness of nuclear reactor buildings using response monitoring and damage imaging technologies" conducted in FY2022. The present study aims to develop an evaluation method necessary to obtain a perspective on the long term structural soundness of accident-damaged reactor buildings, where accessibility to work sites is extremely limited due to high radiation dose rate and high contamination. In FY2022, the second year of the three-year plan, some tests and other activities on the following research items were conducted following FY2021, based on the specific research methods and research directions clarified in FY2021.

Journal Articles

Existence of local polar domains in perovskite oxyfluoride, BaFeO$$_2$$F

Katsumata, Tetsuhiro*; Suzuki, Ryo*; Sato, Naoto*; Oda, Ryoya*; Motoyama, Shingo*; Suzuki, Shumpei*; Nakashima, Mamoru*; Inaguma, Yoshiyuki*; Mori, Daisuke*; Aimi, Akihisa*; et al.

Chemistry of Materials, 36(8), p.3697 - 3704, 2024/04

 Times Cited Count:1 Percentile:30.18(Chemistry, Physical)

A perovskite-type oxynitride BaFeO$$_2$$F was prepared by high-pressure synthesis. Since the SHG signal was observed in the obtained material, suggesting the existence of spontaneous polarization, the mechanism of polarization was investigated by synchrotron high-energy X-ray diffraction. The obtained pair distribution functions were fitted, and a local polarization mechanism with different orientations was found. Since BaFeO$$_2$$F is also a magnetic material, a magnetic domain and a ferroelectric domain are considered to coexist.

Journal Articles

Field-induced insulator-metal transition in EuTe$$_2$$

Takeuchi, Tetsuya*; Honda, Fuminori*; Aoki, Dai*; Haga, Yoshinori; Kida, Takanori*; Narumi, Yasuo*; Hagiwara, Masayuki*; Kindo, Koichi*; Karube, Kosuke*; Harima, Hisatomo*; et al.

Journal of the Physical Society of Japan, 93(4), p.044708_1 - 044708_10, 2024/04

 Times Cited Count:0 Percentile:0.00(Physics, Multidisciplinary)

Journal Articles

Uniaxial magnetic anisotropy of L1$$_{0}$$-FeNi films with island structures on LaAlO$$_{3}$$(110) substrates by nitrogen insertion and topotactic extraction

Nishio, Takahiro*; Ito, Keita*; Kura, Hiroaki*; Takanashi, Koki; Yanagihara, Hideto*

Journal of Alloys and Compounds, 976, p.172992_1 - 172992_8, 2024/03

 Times Cited Count:3 Percentile:34.67(Chemistry, Physical)

Journal Articles

A Study on the effects of photogrammetry by the camera angle of view using computer simulation

Nakamura, Keita; Hanari, Toshihide; Matsumoto, Taku; Kawabata, Kuniaki; Yashiro, Hiroshi*

Journal of Robotics and Mechatronics, 36(1), p.115 - 124, 2024/02

Journal Articles

Quantum critical behavior of the hyperkagome magnet Mn$$_3$$CoSi

Yamauchi, Hiroki; Sari, D. P.*; Yasui, Yukio*; Sakakura, Terutoshi*; Kimura, Hiroyuki*; Nakao, Akiko*; Ohara, Takashi; Honda, Takashi*; Kodama, Katsuaki; Igawa, Naoki; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

Journal Articles

Impact of interatomic structural characteristics of aluminosilicate hydrate on the mechanical properties of metakaolin-based geopolymer

Kim, G.*; Cho, S.-M.*; Im, S.*; Suh, H.*; Morooka, Satoshi; Shobu, Takahisa; Kanematsu, Manabu*; Machida, Akihiko*; Bae, S.*

Construction and Building Materials, 411, p.134529_1 - 134529_18, 2024/01

 Times Cited Count:10 Percentile:67.40(Construction & Building Technology)

Journal Articles

Characteristic microstructural phase evolution and the compressive strength development mechanisms of tricalcium silicate pastes under various initial carbonation curing environments

Cho, S.*; Suh, H.*; Im, S.*; Kim, G.*; Kanematsu, Manabu*; Morooka, Satoshi; Machida, Akihiko*; Shobu, Takahisa; Bae, S.*

Construction and Building Materials, 409, p.133866_1 - 133866_20, 2023/12

 Times Cited Count:13 Percentile:83.68(Construction & Building Technology)

Journal Articles

Upgrade of seismic design procedure for piping systems based on elastic-plastic response analysis

Nakamura, Izumi*; Otani, Akihito*; Okuda, Yukihiko; Watakabe, Tomoyoshi; Takito, Kiyotaka; Okuda, Takahiro; Shimazu, Ryuya*; Sakai, Michiya*; Shibutani, Tadahiro*; Shiratori, Masaki*

Dai-10-Kai Kozobutsu No Anzensei, Shinraisei Ni Kansuru Kokunai Shimpojiumu (JCOSSAR2023) Koen Rombunshu (Internet), p.143 - 149, 2023/10

In 2019, the JSME Code Case for seismic design of nuclear power plant piping systems was published. The Code Case provides the strain-based fatigue criteria and detailed inelastic response analysis procedure as an alternative design rule to the current seismic design, which is based on the stress evaluation by elastic response analysis. In 2022, it was approved to revise the Code Case with improving the cycle counting method for fatigue evaluation to the Rain flow method. In addition, the discussion to incorporate the elastic-plastic behavior of support structures is now in progress for the next revision of the Code Case. This paper discusses the contents and background of the 2022 revision, the progress of the next revision, and future tasks.

Journal Articles

Spontaneous topological Hall effect induced by non-coplanar antiferromagnetic order in intercalated van der Waals materials

Takagi, Hirotaka*; Takagi, Rina*; Minami, Susumu*; Nomoto, Takuya*; Oishi, Kazuki*; Suzuki, Michito*; Yanagi, Yuki*; Hirayama, Motoaki*; Khanh, N.*; Karube, Kosuke*; et al.

Nature Physics, 19(7), p.961 - 968, 2023/07

 Times Cited Count:55 Percentile:99.13(Physics, Multidisciplinary)

471 (Records 1-20 displayed on this page)