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Murakami, Kenta*; Onizawa, Kunio; Yamamoto, Akio*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 66(4), p.199 - 202, 2024/04
The Standards Committee of Atomic Energy Society of Japan has been leading activities related to long-term operation through the revision of the Code of Practice for Aging Management, and we believe that we must continue to make important contributions in light of recent changes in laws and regulations. This paper recapitulates the discussions in the special session conducted at the 2023 fall meeting, and describes the efforts toward safe long-term operation and the points to keep in mind in the standardization of such activities. The important points are (1) to make effective use of knowledge found over time, (2) not to overlook new knowledge that has a significant impact on safety, including obsolescence, (3) to assign a level of importance to the response based on the impact on safety and the likelihood of its occurrence, and (4) to contribute to the establishment of an international knowledge base.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2023-030, 80 Pages, 2024/03
JAEA-Review-2023-030.pdf:4.96MB
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 cooperative operation robot system for radiation source exploration" conducted in FY2022. The present study aims to develop a Cooperative Operation Robot system for RAdiation Source Exploration (CORRASE). The multiple robot system provides radiation source exploration with wide field of view, rapidity, and low cost. The radiation source exploration is realized with multiple robots carrying directional gamma-ray detectors determining the incident direction of the incoming gamma-rays. We will develop the system by the final year of this proposal aiming for application in the Fukushima Daiichi Nuclear Power Station.
Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2023-023, 99 Pages, 2024/03
JAEA-Review-2023-023.pdf:6.0MB
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 FY2019, this report summarizes the research results of the "Human Resource Development Related to Remote Control Technology for Monitoring Inside RPV Pedestal during Retrieval of Fuel Debris" conducted in FY2022. The present study aims to construct a monitoring platform for understanding the status inside a reactor during fuel debris removal, and measurement and visualization by sensors moving on the platform. In addition, to develop research personnel through research education by participating in such research projects, classroom lectures, and facility tours is also a goal of this project. In FY2022, each system was improved and expanded toward the final year, and verification experiments were conducted in simulated environments.
Murakami, Kenta*; Arai, Taku*; Yamada, Koji*; Momma, Kensuke*; Tsuji, Takashi*; Nakagawa, Nobuyuki*; Onizawa, Kunio
Transactions of the 27th International Conference on Structural Mechanics in Reactor Technology (SMiRT 27) (Internet), 3 Pages, 2024/03
This paper studied the future vision of codes and standards in Japan by systematically comparing Japanese regulatory rules, standards, and industry guides related to long term operation with international safety standards, and confirmed that the Japanese standard system generally meets their recommendations. The recommendation for the future improvements of Japanese codes and standards were summarized into five items.
Oizumi, Akito; Akie, Hiroshi
JAEA-Technology 2023-017, 93 Pages, 2023/12
JAEA-Technology-2023-017.pdf:8.45MB
After the decision of decommissioning JMTR (Japan Materials Testing Reactor), Japan Atomic Energy Agency investigated the possibility to construct a new irradiation test reactor to succeed JMTR (post-JMTR), and the final report of the investigated result was submitted to the Ministry of Education, Culture, Sports, Science and Technology on March 30th 2021. This investigation was carried out in 4 steps of (1) selection of reactor type, (2) reactor core plans studies, (3) neutronic studies, (4) thermal studies, and was finally (5) considered and evaluated. This JAEA-Technology report summarizes the process and the results of (3) neutronic studies. Neutron fluxes were calculated at irradiation sample positions in the investigated cores, the standard core and the compact core, and the calculated fluxes satisfied the required irradiation capability. It was also evaluated the two investigated cores' continuous reactor operation time in days in one refueling cycle, and the results guaranteed an operation days equality with that of existing JMTR. In addition, neutronic characteristics of the cores were estimated, such as power distribution in the core, control rod reactivity worth, reactivity coefficients, distribution of fuel burnup rate of each fuel element, and kinetics parameters. The evaluated neutronic characteristics were used in the post-JMTR final investigation report to confirm the neutronic feasibility by comparing with the neutronic limiting values of existing JMTR, and to estimate the cooling capability to make the core thermally feasible.
Department of HTTR
JAEA-Review 2023-016, 82 Pages, 2023/09
JAEA-Review-2023-016.pdf:2.31MB
The High Temperature Engineering Test Reactor (HTTR) is the first Japanese High Temperature Gas-cooled Reactor (HTGR) with 30MW in thermal power and 950
C of maximum outlet coolant temperature that is constructed by the Japan Atomic Energy Agency located at Oarai-machi, Higashiibaraki-gun, Ibaraki-ken, Japan. The purpose of the HTTR is establishment of basic HTGR technologies, demonstration of HTGR safety characteristics and so on. The HTTR has had a lot of experience of HTGRs' operation and maintenance throughout rated power operations, safety demonstration tests, long-term high temperature operations and demonstration tests relevant to HTGRs' R&Ds. In the fiscal year 2021, as the HTTR completed activities to conform to the New Regulatory Requirements of Nuclear Regulation Authority, The HTTR restarted since the 2011 off the Pacific coast of Tohoku Earthquake and carried out the Loss-of-forced cooling test without Vessel Cooling System (VCS) operational at 9MW (Three gas circulators trip and VCS is stopped.) as the safety demonstration test. This report summarizes the activities carried out in the fiscal year 2021, which were the situation of the New Regulatory Requirements screening of the HTTR, the operation and maintenance of the HTTR, R&Ds relevant to commercial-scale HTGRs, the international cooperation on HTGRs and so on.
Togawa, Orihiko; Okura, Takehisa; Kimura, Masanori
JAEA-Review 2022-049, 76 Pages, 2023/01
JAEA-Review-2022-049.pdf:3.74MB
Before construction and after operation of nuclear facilities, environmental consequence assessments are conducted for normal operation and an emergency. These assessments mainly aim at confirming safety for the public around the facilities and producing relief for them. Environmental consequence assessments are carried out using observations/ measurements by environmental monitoring and/or model predictions by calculation models, sometimes using either of which and at other times using both them, according to the situations and necessities. First, this report investigates methods, roles, merits/demerits and relationship between observations/measurements and model predictions which are used for environmental consequence assessments of nuclear facilities, especially holding up a spent nuclear fuel reprocessing plant at Rokkasho, Aomori as an example. Next, it explains representative examples of utilization of data on observations/measurements and results on model predictions, and considers points of attention at using them. Finally, the report describes future direction, for example, improvements of observations/measurements and model predictions, and fusion of both them.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2022-041, 76 Pages, 2023/01
JAEA-Review-2022-041.pdf:3.27MB
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 FY2021. 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 cooperative operation robot system for radiation source exploration" conducted in FY2021. The present study aims to develop a Cooperative Operation Robot system for RAdiation Source Exploration (CORRASE). The multiple robot system provides radiation source exploration with wide field of view, rapidity, and low cost. The radiation source exploration is realized with multiple robots carrying directional gamma-ray detectors determining the incident direction of the incoming gamma-rays. We will develop the system by the final year of this proposal aiming for application in the Fukushima Daiichi Nuclear Power Station.
Saha, P. K.; Okabe, Kota; Nakanoya, Takamitsu; Shobuda, Yoshihiro; Harada, Hiroyuki; Tamura, Fumihiko; Okita, Hidefumi; Yoshimoto, Masahiro; Hotchi, Hideaki*
Journal of Physics; Conference Series, 2420, p.012040_1 - 012040_7, 2023/01
Takei, Hayanori
Journal of Nuclear Science and Technology, 14 Pages, 2023/00
Times Cited Count：0 Percentile：0.18(Nuclear Science & Technology)In the proton linear accelerator (linac), the proton beam is unexpectedly interrupted due to the electrical discharge originating from the radio frequency, failure of the device/equipment, or other factors. Do these beam trips occur randomly? Conventionally, it has been implicitly assumed that beam trips occur randomly. In this study, we investigated whether beam trips in the linac of the Japan Proton Accelerator Research Complex (J-PARC) occur randomly to estimate the beam trip frequency in a superconducting proton linac for an accelerator-driven nuclear transmutation system. First, the J-PARC linac was classified into five subsystems. Then, the reliability function for the operation time in each subsystem was obtained using the Kaplan--Meier estimation, a reliability engineering methods. Using this reliability function, the randomness of beam trips was examined. Analysis of five-year operational data for five subsystems of the J-PARC linac showed that beam trips occurred randomly in some subsystems. However, beam trips did not occur randomly in many subsystems of the proton linac, including the ion source and the acceleration cavity, the primary subsystems of the proton linac.
Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2022-032, 102 Pages, 2022/12
JAEA-Review-2022-032.pdf:9.83MB
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 FY2021. 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 FY2019, this report summarizes the research results of the "Human resource development related to remote control technology for monitoring inside RPV pedestal during retrieval of fuel debris" conducted in FY2021. The present study aims to construct a monitoring platform for understanding the status inside a reactor during fuel debris removal, and measurement and visualization by sensors moving on the platform. In addition, to develop research personnel through research education by participating in such research projects, classroom lectures, and facility tours is also a goal of this project. In FY2021, we mainly worked on improving the base design and technology development that we had worked on in the previous year, and we also prepared for integration experiments.
Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Polytechnic University*
JAEA-Review 2022-011, 80 Pages, 2022/07
JAEA-Review-2022-011.pdf:5.42MB
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 FY2020. 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 FY2018, this report summarizes the research results of the "Development of semantic survey map building system using semi-autonomous mobile robots for surveying of disaster area and gathering of information in nuclear power station" conducted from FY2018 to FY2021 (this contract was extended to FY2021). Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study aims to research and develop semi-autonomous mobile robot systems (multi-sensor fusion system, semantic simultaneous localization and mapping (SLAM), system for traversable-route learning and safe traversable-route presentation, etc.) that simply, safely, and rapidly make semantic survey maps …
Engineering Services Department
JAEA-Review 2021-054, 85 Pages, 2022/01
JAEA-Review-2021-054.pdf:95.12MB
The Engineering Services Department is in charge of operation and maintenance of utility facilities (water distribution systems, electricity supply systems, steam generation systems and drain water systems etc.) in whole of the institute. And also is in charge of operation and maintenance of specific systems (power receiving and transforming facilities, an emergency electric power supply system, an air/liquid waste treatment system, a compressed air supply system) in nuclear reactor facilities, nuclear fuel treatment facilities and usual facilities or buildings. In addition, the department is in charge of maintenance of buildings, design and repair of electrical/mechanical equipments. This annual report describes summary of activities, operation and maintenance data and technical developments of the department carried out in JFY 2020. We hope that this report may help to future work.
Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*
JAEA-Review 2021-030, 79 Pages, 2021/12
JAEA-Review-2021-030.pdf:3.82MB
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 FY2020. 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 FY2019, this report summarizes the research results of the "Human resource development related to remote control technology for monitoring inside RPV pedestal during retrieval of fuel debris" conducted in FY2020. This study deals with construction of a monitoring platform for understanding the status inside a reactor during fuel debris removal, and measurement and visualization by sensors moving on the platform. In addition, to develop research personnel through research education by participating in such research projects, classroom lectures, and facility tours is also a goal of this project. In FY2020, the main activities were base design and underlying technology development.
Engineering Services Department
JAEA-Review 2021-011, 86 Pages, 2021/08
JAEA-Review-2021-011.pdf:5.35MB
The Engineering Services Department is in charge of operation and maintenance of utility facilities (water distribution systems, electricity supply systems, steam generation systems and drain water systems etc.) in whole of the institute. And also is in charge of operation and maintenance of specific systems (power receiving and transforming facilities, an emergency electric power supply system, an air/liquid waste treatment system, a compressed air supply system) in nuclear reactor facilities, nuclear fuel treatment facilities and usual facilities or buildings. In addition, the department is in charge of maintenance of buildings, design and repair of electrical/mechanical equipments. This annual report describes summary of activities, operation and maintenance data and technical developments of the department carried out in JFY 2019. We hope that this report may help to future work.
Okita, Hidefumi; Tamura, Fumihiko; Yamamoto, Masanobu; Nomura, Masahiro; Shimada, Taihei; Yoshii, Masahito*; Omori, Chihiro*; Sugiyama, Yasuyuki*; Hasegawa, Katsushi*; Hara, Keigo*; et al.
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.3020 - 3022, 2021/08
In the J-PARC RCS, the dual-harmonic operation, in which each RF cavity is driven by superposition of the fundamental accelerating voltage and the second harmonic voltage, are employed. The dual-harmonic-operation significantly improves the bunching factor and is indispensable for acceleration of the high intensity beams. The original LLRF control system was replaced with the new system in 2019, which can control the amplitudes of the higher harmonics as well as the fundamental and second harmonics. Therefore we consider to use additionally the third harmonic voltage for further improvement of the bunching factor during acceleration. By the triple-harmonic operation, the flat RF bucket can be realized and beam simulation results indicate that the bunching factor can be improved about 30% at maximum. In this presentation, we describe the longitudinal simulation studies of the triple-harmonic operation. Also the preliminary test results are presented.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-074, 105 Pages, 2021/03
JAEA-Review-2020-074.pdf:3.72MB
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and TPL (Tritium Process Laboratory). This annual report describes the activities of our department in fiscal year of 2018. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-073, 113 Pages, 2021/03
JAEA-Review-2020-073.pdf:3.87MB
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and Tritium Process Laboratory. This annual report describes the activities of our department in fiscal year of 2017. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2020-072, 102 Pages, 2021/03
JAEA-Review-2020-072.pdf:3.86MB
The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility and Tritium Process Laboratory). This annual report describes the activities of our department in fiscal year of 2016. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.
