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Ishihara, Takanori; Nishiyama, Nariaki; Kato, Yuri; Shimada, Koji
JAEA-Data/Code 2024-013, 17 Pages, 2024/12
JAEA-Data-Code-2024-013.pdf:2.8MB
JAEA-Data-Code-2024-013-appendix(DVD-ROM).zip:2305.14MB
Japan Atomic Energy Agency and Central Research Institute of Electric Power Industry conducted collaborative research as a part of "Establishment of Advanced Technology for Evaluating the Long-term Geosphere Stability on Geological Disposal Project of Radioactive Waste (Fiscal Years 2018-2022)" under a contract with the Ministry of Economy, Trade and Industry. We conducted case studies of the effects of major natural phenomena (volcanic and igneous activity, deep-seated fluid, earthquakes and faulting, and uplift and erosion) required to be investigated and evaluated in relation to the selection and modeling of geological environments suitable for geological disposal in Japan, by applying techniques based on the latest research in various academic fields. Through these studies, we accumulated the knowledge necessary to solve problems and advanced our investigation and evaluation techniques. For effectively utilization of these achievements, we organized them in a Geographic Information System (GIS) and compiled them into a dataset that can be viewed in QGIS that free GIS software. This report described the procedure for creating this dataset and how to use it. With publishing this dataset, it is expected that not only seamlessly sharing information within each research field become possible, but also facilitating access and utilization of the research results by researchers in other fields and engineers involved in the geological disposal project.
Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Hakoiwa, Hiroaki; Asamori, Koichi; Murakami, Osamu; Fukuda, Shoma; Ogita, Yasuhiro; Kagami, Saya; et al.
JAEA-Research 2024-013, 65 Pages, 2024/11
JAEA-Research-2024-013.pdf:4.22MB
This annual report documents the progress of research and development (R&D) in the 2nd fiscal year of the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.
Nishihara, Kenji; Sugawara, Takanori; Fukushima, Masahiro; Iwamoto, Hiroki; Katano, Ryota; Abe, Takumi
Proceedings of International Conference on Nuclear Fuel Cycle (GLOBAL2024) (Internet), 4 Pages, 2024/10
A pilot plant for the accelerator-driven system is proposed as a scaled-down version of a lead-bismuth cooled ADS with 800 MW thermal output for transmutation of minor actinides. In this presentation, the design policy of the pilot plant is presented.
Niwa, Masakazu; Shimada, Akiomi; Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Nakajima, Toru; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; et al.
JAEA-Review 2024-035, 29 Pages, 2024/09
JAEA-Review-2024-035.pdf:1.24MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2024. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Niwa, Masakazu; Shimada, Koji; Terusawa, Shuji*; Goto, Akira*; Nishiyama, Nariaki; Nakajima, Toru; Ishihara, Takanori; Hakoiwa, Hiroaki
Island Arc, 33(1), p.e12516_1 - e12516_16, 2024/02
Times Cited Count：1 Percentile：36.99(Geosciences, Multidisciplinary)To investigate the geological evidence of near-surface crustal deformations in a high-strain shear zone that has been geodetically identified but not associated with clear tectonic landforms, a fieldwork was conducted in E-W trending southern Kyushu high-strain shear zone, Japan. According to our study, an investigation based on the slip data from minor faults and the occurrences of fracture zones could help to identify a concealed fault that is small in terms of size to record tectonic landforms but can trigger large earthquakes.
Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Fujita, Natsuko; Yokoyama, Tatsunori; Ogita, Yasuhiro; Fukuda, Shoma; Nakajima, Toru; Kagami, Saya; Ogata, Manabu; et al.
JAEA-Review 2023-017, 27 Pages, 2023/10
JAEA-Review-2023-017.pdf:0.94MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2023. The objectives and contents in fiscal year 2023 are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Ogawa, Hiroki; Hakoiwa, Hiroaki; Watanabe, Tsuyoshi; Nishiyama, Nariaki; Yokoyama, Tatsunori; Ogata, Manabu; et al.
JAEA-Research 2023-005, 78 Pages, 2023/10
JAEA-Research-2023-005.pdf:6.51MB
This annual report documents the progress of research and development (R&D) in the 1st fiscal year of the Japan Atomic Energy Agency 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.
Sato, Rika*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Hayashi, Hirokazu; Sugawara, Takanori; Nishihara, Kenji
Dai-43-Kai Nihon Netsu Bussei Shimpojiumu Koen Rombunshu (CD-ROM), 3 Pages, 2022/10
no abstracts in English
Yee-Rendon, B.; Meigo, Shinichiro; Kondo, Yasuhiro; Tamura, Jun; Nakano, Keita; Maekawa, Fujio; Iwamoto, Hiroki; Sugawara, Takanori; Nishihara, Kenji
Journal of Instrumentation (Internet), 17(10), p.P10005_1 - P10005_21, 2022/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)To reduce the hazard of minor actinides in nuclear waste, JAEA proposed an accelerator-driven subcritical system (JAEA-ADS). The JAEA-ADS drives a subcritical reactor 800-MWth by 30-MW proton linac delivering the beam to the spallation neutron target inside the reactor. The beam transport to the target (BTT) is required for high-beam power stability and low peak density to ensure the integrity of the beam window. Additionally, the design should have compatible with the reactor design for the maintenance and replacement of the fuel and the beam window. A robust-compact BTT design was developed through massive multiparticle simulations. The beam optics was optimized to guarantee beam window feasibility requirements by providing a low peak density of less than 0.3 
A/mm
. Beam stability was evaluated and improved by simultaneously applying the linac's input beam and element errors. The input beam errors to the reactor were based on the beam degradation obtained by implementing fast fault compensation in the linac. Those results show that the BTT fulfills the requirements for JAEA-ADS.
Sasao, Eiji; Ishimaru, Tsuneari; Niwa, Masakazu; Shimada, Akiomi; Shimada, Koji; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; Ogita, Yasuhiro; et al.
JAEA-Review 2022-022, 29 Pages, 2022/09
JAEA-Review-2022-022.pdf:0.97MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2022. The objectives and contents in fiscal year 2022 are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques
Nakano, Keita; Iwamoto, Hiroki; Nishihara, Kenji; Meigo, Shinichiro; Sugawara, Takanori; Iwamoto, Yosuke; Takeshita, Hayato*; Maekawa, Fujio
JAEA-Research 2021-018, 41 Pages, 2022/03
JAEA-Research-2021-018.pdf:2.93MB
Neutronic analysis of beam window of the Accelerator-Driven System (ADS) proposed by Japan Atomic Energy Agency (JAEA) has been conducted using PHITS and DCHAIN-PHITS codes. We investigate gas production of hydrogen and helium isotopes in the beam window, displacement per atom of beam window material, and heat generation in the beam window. In addition, distributions of produced nuclides, heat density, and activity are derived. It was found that at the maximum 12500 appm H production, 1800 appm He production, and damage of 62.1 DPA occurred in the beam window by the ADS operation. On the other hand, the maximum heat generation in the beam window was 374 W/cm
. In the analysis of LBE, 
Bi and 
Po were found to be the dominant nuclides in decay heat and radioactivity. Furthermore, the heat generation in the LBE by the proton beam was maximum around 5 cm downstream of the beam window, which was 945 W/cm.
Sugawara, Takanori; Watanabe, Nao; Ono, Ayako; Nishihara, Kenji; Ichihara, Kyoko*; Hanzawa, Kohei*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 10 Pages, 2022/03
Japan Atomic Energy Agency (JAEA) has investigated an accelerator-driven system (ADS) to transmute minor actinides (MAs) included in high level wastes discharged from nuclear power plants. The ADS is a lead-bismuth cooled tank-type reactor with 800 MW thermal power. It is supposed that the ADS is safer than conventional critical reactors because it is operated in a subcritical state. The previous study performed the transient analyses for the typical ADS accidents such as unprotected loss of flow or beam overpower. It was shown that all calculation cases except loss of heat sink (LOHS) satisfied the no-damage criteria. To avoid the damage by LOHS, the ADS equips Direct Reactor Auxiliary Cooling System (DRACS) to remove the decay heat. The most important points of a DRACS operation are its reliability and to ensure the flowrate in a natural circulation state. This study aims to perform the CFD analysis of the natural circulation to clarify the flowrate in the ADS reactor vessel.
Iwamoto, Hiroki; Meigo, Shinichiro; Nakano, Keita; Yee-Rendon, B.; Katano, Ryota; Sugawara, Takanori; Nishihara, Kenji; Sasa, Toshinobu; Maekawa, Fujio
JAEA-Research 2021-012, 58 Pages, 2022/01
JAEA-Research-2021-012.pdf:7.23MB
A radiation shielding analysis was performed for the structure located above the spallation target of an accelerator-driven system (ADS), assuming one cycle of an 800 MW thermal and 30 MW beam power operation. In this analysis, the Monte Carlo particle transport code PHITS and the activation analysis code DCHAIN-PHITS were used. The structures to be analyzed are a beam duct above the target, a beam transport room located above the ADS reactor vessel, beam transport equipment, and the room ceiling. For each structure, the radiation doses and radioactivities during and after the operation were estimated. Furthermore, the shielding structure of the ceiling was determined. As a result, it was found that the radiation dose at the site boundary would be sufficiently lower than the legal limit by applying the determined shielding structure. Moreover, under the condition of this study, it was shown that the effective dose rate around the beam transport equipment positioned above the target after the operation exceeded 10 mSv/h, and that the maintenance and replacement of the equipment in the room would require remote handling.
Sugawara, Takanori; Moriguchi, Daisuke*; Ban, Yasutoshi; Tsubata, Yasuhiro; Takano, Masahide; Nishihara, Kenji
JAEA-Research 2021-008, 63 Pages, 2021/10
JAEA-Research-2021-008.pdf:4.43MB
This study aims to perform the neutronics calculations for accelerator-driven system (ADS) with a new fuel composition based on the SELECT process developed by Japan Atomic Energy Agency because the previous studies had used the ideal MA (minor actinide) fuel composition without uranium and rare earth elements. Through the neutronics calculations, it is shown that two calculation cases, with/without neptunium, satisfy the design criteria. Although the new fuel composition includes uranium and rare earth elements, the ADS core with the new fuel composition is feasible and consistent with the partitioning and transmutation (P&T) cycle. Based on the new fuel composition, the heat removal during fuel powder storage and fuel assembly assembling is evaluated. For the fuel powder storage, it is found that a cylindrical tube container with a length of 500 [mm] and a diameter of 11 - 21 [mm] should be stored under water. For the fuel assembly assembling, CFD analysis indicates that the cladding tube temperature would satisfy the criterion if the inlet velocity of air is larger than 0.5 [m/s]. Through these studies, the new fuel composition which is consistent with the P&T cycle is obtained and the heat removal with the latest conditions is investigated. It is also shown that the new fuel composition can be practically handled with respect to heat generation, which is one of the most difficult points in handling MA fuel.
Watanabe, Nao; Sugawara, Takanori; Okubo, Nariaki; Nishihara, Kenji
JAEA-Technology 2020-026, 59 Pages, 2021/03
JAEA-Technology-2020-026.pdf:3.95MB
As a part of partitioning and transmutation technology development to reduce the burden of radioactive disposal, an investigation of Accelerator-Driven System (ADS) has been performed by Japan Atomic Energy Agency. A beam window, which is an inherent structure of the ADS, is planned to be made from T91 steel and its shape is a thin hemisphere shell. However, it had never been tried to manufacture it out of T91 steel. In this investigation, we tried to manufacture miniature beam windows by cutting T91 steel, and to discuss the process, manufacturing accuracy and geometry measurement methods. As a result, considering a real scale ADS beam window, a figure error between designing and machining ones is estimated to be about 5%. Its effect would be very small to the structural strength.
Watanabe, Nao; Obayashi, Hironari; Sugawara, Takanori; Sasa, Toshinobu; Nishihara, Kenji; Castelliti, D.*
Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.248 - 261, 2019/08
For the R&D for lead-bismuth eutectic alloy (LBE) cooled Accelerator Driven System (ADS), installation of experimental facility using LBE spallation target dedicated for ADS materials irradiation under flowing high temperature LBE environment is planned within the J-PARC project. JAEA has recently finalized the construction of "IMMORTAL", a demonstrative test loop representing a 1:1 model of the above LBE spallation target system. Such facility pursues several different objectives such as studies on the thermal-hydraulic behavior of the target, and validation of the LBE physical properties, the pressure drops and the heat transfer correlations. These results will be useful for design of the facility and LBE target/cooled ADS. In the frame of a bi-lateral collaboration between JAEA and SCK-CEN, a benchmark exercise on the experimental results from IMMORTAL has been carried out. The calculations have been performed with RELAP5-3D System Thermal-Hydraulic code. To assess and predict the thermal-hydraulic behavior of its primary loop, RELAP5-3D calculation models have been configured. The calculated results from these models represented that a valid contribution towards the validation of the LBE properties and empirical correlations present in RELAP5-3D code.
Sugawara, Takanori; Ban, Yasutoshi; Katano, Ryota; Tateno, Haruka; Nishihara, Kenji
Proceedings of International Conference on the Management of Spent Fuel from Nuclear Power Reactors 2019 (Internet), 9 Pages, 2019/06
The JAEA has proposed the double-strata strategy which will introduce a dedicated minor actinide (MA) transmutation cycle using an accelerator-driven system (ADS). In the previous study, the ideal fuel condition was supposed in the neutronics design of the ADS. For example, impurities such as rare earth (RE) nuclides which would accompany with MA, were not assumed. However, these nuclides would accompany with the ADS fuel and the capture reaction of these nuclides deteriorates the neutron economy of the ADS core. This study investigates a new fuel composition based on the SELECT (Solvent Extraction from Liquid-waste using Extractants of CHON-type for Transmutation) process proposed by JAEA. By performing the neutronics calculation of the ADS with the new fuel composition, a feasibility of the new fuel composition will be investigated.
Eguchi, Yuta; Sugawara, Takanori; Nishihara, Kenji; Tazawa, Yujiro; Tsujimoto, Kazufumi
Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07
In order to investigate the basic neutronics characteristics of the accelerator-driven subcritical system (ADS), JAEA has a plan to construct a new critical assembly in the J-PARC project, Transmutation Physics Experimental Facility (TEF-P). This study aims to evaluate the natural cooling characteristics of TEF-P core which has large decay heat by minor actinide (MA) fuel, and to achieve a design that does not damage the core and the fuels during the failure of the core cooling system. In the evaluation of the TEF-P core temperature, empty rectangular lattice tube outer of the core has a significant effect on the heat transfer characteristics. The experiments by using the mockup device were performed to validate the heat transfer coefficient and experimental results were obtained. By using the obtained experimental results, the three-dimensional heat transfer analysis of TEF-P core were performed, and the maximum core temperature was obtained, 294
C. This result shows TEF-P core temperature would be less than 327C that the design criterion of temperature.
Sugawara, Takanori; Takei, Hayanori; Iwamoto, Hiroki; Oizumi, Akito; Nishihara, Kenji; Tsujimoto, Kazufumi
Progress in Nuclear Energy, 106, p.27 - 33, 2018/07
Times Cited Count：19 Percentile：84.57(Nuclear Science & Technology)The Japan Atomic Energy Agency (JAEA) has investigated an accelerator-driven system (ADS) to transmute minor actinides which will be partitioned from the high level waste. There are various inherent issues for the research and development on the ADS. The recent two activities to realize a feasible and reliable ADS concept are introduced in this paper. For the feasibility, the design of a beam window which is a boundary of the accelerator and the subcritical core, is one of the most important issues. To mitigate the design condition of the beam window, namely to reduce the proton beam current, the subcritical core concept with subcriticality adjustment rods were investigated. For the reliability, the beam-trip is the inherent and serious issue for the ADS design because it induces rapid temperature change to coolant and structures in the subcritical core. To improve the beam-trip frequencies, a double-accelerator concept was proposed and its beam-trip frequency was estimated.
Pyeon, C. H.*; Vu, T. M.*; Yamanaka, Masao*; Sugawara, Takanori; Iwamoto, Hiroki; Nishihara, Kenji; Kim, S. H.*; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 55(2), p.190 - 198, 2018/02
Times Cited Count：16 Percentile：79.90(Nuclear Science & Technology)At the Kyoto University Critical Assembly, a series of reaction rate experiments is conducted on the accelerator-driven system (ADS) with spallation neutrons generated by the combined use of 100 MeV protons and a lead and bismuth target in the subcritical state. The reaction rates are measured by the foil activation method to obtain neutron spectrum information on ADS. Numerical calculations are performed with MCNP6.1 and JENDL/HE-2007 for high-energy protons and spallation process, JENDL-4.0 for transport and JENDL/D-99 for reaction rates. The reaction rates depend on subcriticality is revealed by the accuracy of the C/E (calculation/experiment) values. Nonetheless, the accuracy of the reaction rates at high-energy thresholds remains an important issue in the fixed-source calculations.
