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Li, X.; Yamaji, Akifumi*; Sato, Ikken*; Yamashita, Takuya
Annals of Nuclear Energy, 214, p.111217_1 - 111217_13, 2025/05
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Miwa, Kenta*; Kakino, Ryo*; Sato, Tatsuhiko; Furuta, Takuya; Miyaji, Noriaki*; Yamao, Tensho*; Yamashita, Kosuke*; Terauchi, Takeshi*
Physical and Engineering Sciences in Medicine, 9 Pages, 2025/00
Times Cited Count:0Radiotherapy package based on Particle and Heavy Ion Transport code System (RT-PHITS) enables to calculate the 3-dimensional dose distribution inside patients using their individual SPECT/CT images coupled with the Monte Carlo radiation transport simulation. The objective of this study is to evaluate the feasibility of individual dosimetry based on RT-PHITS for patients after Lu-DOTATATE peptide receptor radionuclide therapy.
Yamashita, Takuya
Fukushima Daiichi Nuclear Power Station Accident Information Collection and Evaluation (FACE) Project Annual Report 2023, p.55 - 62, 2024/11
Yamada, Takeshi*; Li, X.; Yamashita, Takuya; Yamaji, Akifumi*
Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 10 Pages, 2024/11
In this study, a new crust model is being developed to analyze MCCI, which involves continuous concrete ablation with presence of the crust layer between the corium and the concrete walls, which may gradually move with the slow concrete wall ablation process over long time. The new crust model must enable accumulation of physical displacement of the crust particle over long time (i.e., enable physical creeping) while preventing accumulation of numerical displacement of the crust particles over long time (i.e., preventing numerical creeping), Hence, in the new crust model, the PS has been effectively disabled for the crust particles. Qualitative validity of such numerical modeling was confirmed through some trial analyses of VULCANO-VBS test using a set of tentative calculation conditions and parameters, which should be carefully revised for future quantitative discussions including validation of the analysis results with experimental results.
Nakamura, Yuki*; Kojima, Yoshihiro*; Yamashita, Takuya; Shimomura, Kenta; Mizokami, Shinya
Proceedings of 14th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation, and Safety (NTHOS-14) (Internet), 12 Pages, 2024/08
Sato, Ikken; Yoshikawa, Shinji; Yamashita, Takuya; Shimomura, Kenta; Cibula, M.*; Mizokami, Shinya*
Nuclear Engineering and Design, 422, p.113088_1 - 113088_24, 2024/06
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Li, X.; Yamaji, Akifumi*; Sato, Ikken*; Yamashita, Takuya; Nagae, Yuji
Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 12 Pages, 2024/05
Shimomura, Kenta; Yamashita, Takuya; Nagae, Yuji
Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 12 Pages, 2024/05
Yamashita, Takuya; Shimomura, Kenta; Nagae, Yuji; Nagai, Eiichi*; Yasumatsu, Tomohiro*; Nakashima, Satoru*; Ogino, Shoya*; Mizokami, Shinya*
Proceedings of 11th European Review Meeting on Severe Accident Research Conference (ERMSAR 2024) (Internet), 11 Pages, 2024/05
Sato, Ikken; Yoshikawa, Shinji; Yamashita, Takuya; Shimomura, Kenta; Cibula, M.*; Mizokami, Shinya*
Nuclear Engineering and Design, 414, p.112574_1 - 112574_20, 2023/12
Koyama, Shinichi; Ikeuchi, Hirotomo; Mitsugi, Takeshi; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Tsai, T.-H.; Takano, Masahide; Fukaya, Hiroyuki; Nakamura, Satoshi; et al.
Hairo, Osensui, Shorisui Taisaku Jigyo Jimukyoku Homu Peji (Internet), 216 Pages, 2023/11
In FY 2021 and 2022, JAEA perfomed the subsidy program for "the Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy, Thermal Bahavior Estimation, and Simplified Analysis of Fuel Debris)" started in FY 2021. This presentation material summarized the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning, Contaminated Water and Treated Water Management.
Yamashita, Takuya; Shimomura, Kenta; Nagae, Yuji; Yamaji, Akifumi*; Mizokami, Shinya; Mitsugi, Takeshi; Koyama, Shinichi
Hairo, Osensui, Shorisui Taisaku Jigyo Jimukyoku Homu Peji (Internet), 53 Pages, 2023/10
JAEA performed the subsidy program for the "Project of Decommissioning, Contaminated Water and Treated Water Management (Development of Analysis and Estimation Technologies for Characterization of Fuel Debris (Development of Estimation Technologies of RPV Damaged Condition, etc.) in 2022JFY. This presentation summarized briefly the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning, Contaminated Water and Treated Water Management.
Bando, Yamato*; Yamaji, Akifumi*; Yamashita, Takuya
Proceedings of International Conference on Environmental Remediation and Radioactive Waste Management (ICEM2023) (Internet), 9 Pages, 2023/10
Yamashita, Takuya; Honda, Takeshi*; Mizokami, Masato*; Nozaki, Kenichiro*; Suzuki, Hiroyuki*; Pellegrini, M.*; Sakai, Takeshi*; Sato, Ikken; Mizokami, Shinya*
Nuclear Technology, 209(6), p.902 - 927, 2023/06
Times Cited Count:5 Percentile:80.64(Nuclear Science & Technology)Sato, Ikken; Yoshikawa, Shinji; Yamashita, Takuya; Cibula, M.*; Mizokami, Shinya*
Nuclear Engineering and Design, 404, p.112205_1 - 112205_21, 2023/04
Times Cited Count:10 Percentile:95.46(Nuclear Science & Technology)Based on updated knowledge from plant-internal investigations, experiments and model simulations until now, the in-vessel phase of Fukushima-Daiichi Nuclear Power Station Unit 2 was analyzed using the MAAP code. In Unit 2, it is considered that the core material enthalpy was relatively low when it relocated to the lower plenum of the pressure vessel, then, cooled by the coolant and solidified there. Although the MAAP code tended to underestimate the degree of core-material oxidation during the relocation, this probable underestimation was compensated for by an existing study that was considered more reliable, so that more realistic debris conditions in the lower plenum could be obtained. Basic validity of the former prediction of the Unit 2 accident progression behavior was confirmed and detailed boundary condition for the later phase was provided. This boundary condition should be utilized for future studies addressing debris reheating process leading to lower head failure and debris relocation toward the pedestal.
Shimomura, Kenta; Yamashita, Takuya; Nagae, Yuji
JAEA-Data/Code 2022-012, 270 Pages, 2023/03
In a light water reactor, which is a commercial nuclear power plant, a severe accident such as loss of cooling function in the reactor pressure vessel (RPV) and exposure of fuel rods due to a drop in the water level in the reactor can occur when a trouble like loss of all AC power occurs. In the event of such a severe accident, the RPV may be damaged due to in-vessel conditions (temperature, molten materials, etc.) and leakage of radioactive materials from the reactor may occur. Verification and estimation of the process of RPV damage, molten fuel debris spillage and expansion, etc. during accident progression will provide important information for decommissioning work. Possible causes of RPV failure include failure due to loads and restraints applied to the RPV substructure (mechanical failure), failure due to the current eutectic state of low-melting metals and high-melting oxides with the RPV bottom members (failure due to inter-material reactions), and failure near the melting point of the structural members at the RPV bottom. Among the failure factors, mechanical failure is verified by numerical analysis (thermal hydraulics and structural analysis). When conducting such a numerical analysis, the heat transfer properties (thermal conductivity, specific heat, density) and material properties (thermal conductivity, Young's modulus, Poisson's ratio, tensile, creep) of the materials (zirconium, boron carbide, stainless steel, nickel-based alloy, low alloy steel, etc.) constituting the RPV and in-core structures to near the melting point are required to evaluate the creep failure of the RPV. In this document, we compiled data on the properties of base materials up to the melting point of each material constituting the RPV and in-core structures, based on published literature. In addition, because welds exist in the RPV and in-core structures, the data on welds are also included in this report, although they are limited.
Madokoro, Hiroshi; Yamashita, Takuya; Gaus-Liu, X.*; Cron, T.*; Fluhrer, B.*; Sato, Ikken; Mizokami, Shinya*
Nuclear Technology, 209(2), p.144 - 168, 2023/02
Times Cited Count:2 Percentile:29.47(Nuclear Science & Technology)Yamashita, Takuya; Sato, Takumi; Madokoro, Hiroshi; Nagae, Yuji
Annals of Nuclear Energy, 173, p.109129_1 - 109129_15, 2022/08
Times Cited Count:5 Percentile:61.74(Nuclear Science & Technology)Yamashita, Takuya; Madokoro, Hiroshi; Sato, Ikken
Journal of Nuclear Engineering and Radiation Science, 8(2), p.021701_1 - 021701_13, 2022/04
Pshenichnikov, A.; Shibata, Hiroki; Yamashita, Takuya; Nagae, Yuji; Kurata, Masaki
Journal of Nuclear Science and Technology, 59(3), p.267 - 291, 2022/03
Times Cited Count:3 Percentile:31.52(Nuclear Science & Technology)