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JAEA Reports

Accident evaluation during transfer of irradiated fuel specimen

Morita, Hisashi; Iimura, Koichi; Matsui, Yoshinori; Takemoto, Noriyuki

JAEA-Technology 2022-024, 73 Pages, 2022/11

JAEA-Technology-2022-024.pdf:1.56MB

JMTR was positioned as a decommissioning facility in the facilities mid- and long-term plan (formulated in April 1, 2017) of the Japan Atomic Energy Agency. On September 18, 2019, we applied for approval of the decommissioning plan for the JMTR reactor facility, and received the approval on March 17, 2021. This made it impossible to conduct irradiation tests with nuclear fuel material at the JMTR using facility. Therefore, on August 7, 2020, in order to delete the description about irradiation test and to change accident evaluation, we applied for change of permission to use nuclear fuel material regarding JMTR facility (Facility No. 1) at the Oarai Research and Development Institute (North Area), and received the permission on May 26, 2021. As the accident evaluation, radiation exposure evaluation was performed at the boundary of the surrounding monitoring area assuming a damage accident during transfer work of the irradiated fuel specimen to the hot laboratory. As a result, it was confirmed to satisfy the standards such as the dose notification concerning about external exposure due to atmospheric diffusion, internal exposure due to atmospheric diffusion, external exposure due to direct $$gamma$$-rays and skyshine $$gamma$$-rays. This report summarizes the methods and results of the accident evaluation related to permission change of JMTR using facility.

JAEA Reports

Optimization of mercury flow with microbubbles in the target-vessel design by means of machine learning

Kogawa, Hiroyuki; Futakawa, Masatoshi; Haga, Katsuhiro; Tsuzuki, Takayuki*; Murai, Tetsuro*

JAEA-Technology 2022-023, 128 Pages, 2022/11

JAEA-Technology-2022-023.pdf:9.0MB

In a mercury target of the J-PARC (Japan Proton Accelerator Research Complex), pulsed proton beams repeatedly bombard the flowing mercury which is confined in a stainless-steel vessel (target vessel). Cavitation damage caused by the propagation of the pressure waves is a factor of the life of the target vessel. As a measure to reduce damages, we developed a bubbler to inject the gas microbubbles into the flowing mercury, which can reduce the pressure waves. To operate the mercury target vessel stably with the 1 MW high-intensity proton beams, further reduction of the damage is required. The bubbler setting position should be closer to the beam window to increase the bubble population, which could enhance the reduction effect on the pressure waves and damage. However, the space at the beam window of the target vessel is restricted. The bubbler design and setting position as well as the vane design for the mercury flowing pattern are optimized by means of a machine learning technique to get more suitable bubble distribution, increasing in bubble population and optimizing bubble size nearby the beam window of the target vessel. The results of CFD analyses performed with 1000 cases were used for machine learning. Since the flow rate of mercury affects the temperature of the target vessel, this was used for the constraint condition. As a result, we found a design of mercury target vessel that can increase the bubble population by ca. 20% higher than the current design.

JAEA Reports

Semi-autonomous remote-control technology of an articulated mobile robot to recover from stuck states (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Electro-Communications*

JAEA-Review 2022-029, 37 Pages, 2022/11

JAEA-Review-2022-029.pdf:1.89MB

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 "Semiautonomous remote-control technology of an articulated mobile robot to recover from stuck states" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. The purpose of this work is to establish a recovery method of an articulated mobile robot from stuck states. In this work, a control method of the robot to recover from stuck states by using redundancy of the system is proposed. In addition, we develop two interfaces. One is a display interface as an operator can understand the situation of the robot and surrounding terrain, and the other is a control interface to provide a target motion using the proposed control method. Finally,

JAEA Reports

Development of tailor-made adsorbents for uranium recovery from seawater on the basis of uranyl coordination chemistry (Contract research); FY2021 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2022-028, 54 Pages, 2022/11

JAEA-Review-2022-028.pdf:2.97MB

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 "Development of Tailor-made Adsorbents for Uranium Recovery from Seawater on the Basis of Uranyl Coordination Chemistry" conducted from FY2019 to FY2021. Since the final year of this proposal was FY2021, the results for three fiscal years were summarized. The present study aims to develop a new ligand class for efficient and selective capture of uranium from seawater. On the basis of deep understanding on uranyl coordination chemistry, we design molecular structures of pentadentate ligands as functional moieties for uranium adsorption from seawater and study fundamental coordination chemistry of uranyl ion with those ligands in order to resolve current problems in uranium recovery technology from seawater and

JAEA Reports

Quantitative analysis of radioactivity distribution by imaging of high radiation field environment using gamma-ray imaging spectroscopy (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Kyoto University*

JAEA-Review 2022-027, 85 Pages, 2022/11

JAEA-Review-2022-027.pdf:5.72MB

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 (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 FY2018, this report summarizes the research results of the "Quantitative analysis of radioactivity distribution by imaging of high radiation field environment using gamma-ray imaging spectroscopy" 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. In this study, ETCC, a gamma-ray imaging system, was modified to be a portable device that can be used in 1F decommissioning project and can operate in high-dose environments. ETCC is the world's first gamma-ray camera capable of complete bijective imaging, the same as an optical camera. Therefore, ETCC can make general quantitative image analysis methods applicable to radiation, and will bring innovative

JAEA Reports

Horonobe Underground Research Laboratory Project; Investigation program for the 2022 fiscal year

Nakayama, Masashi

JAEA-Review 2022-026, 66 Pages, 2022/11

JAEA-Review-2022-026.pdf:12.31MB

The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies for geological disposal of High-level Radioactive Waste through investigations of the deep geological environment within the host sedimentary rock at Horonobe Town in Hokkaido, north Japan. In fiscal year 2022, we continue to conduct research on "Study on near-field system performance in geological environment", "Demonstration of repository design options", and "Understanding of buffering behaviour of sedimentary rocks to natural perturbations", which are the important issues shown in the Horonobe underground research plan from fiscal year 2020. The main studies to be conducted in fiscal year 2022 are as follows. As "Study on near-field system performance in geological environment", we will continue to the test under the simulated condition in which the heat generation by the high-level radioactive waste has subsides in the full-scale engineered barrier system (EBS) performance experiment. We will also conduct solute transport experiment with model testing that take into account the effects of organic matter, microbes, and colloids, and initiate borehole investigation to evaluate solute transport experiments on fractures distribute in Koetoi formation. As "Demonstration of repository design concept", we will continue experiment and analysis of concrete deterioration in the underground environment as a demonstration of remote technique for emplacement and retrievable. As a demonstration of the closure techniques, laboratory tests will be continued to investigate the mechanism of bentonite runoff behaviour, which could be a factor in changing the performance of backfill material, and to expand data on swelling and deformation behaviour. In addition, in-situ borehole closure tests will be conducted to evaluate the applicability of the closure method. As "Understanding of buffering behaviour of

JAEA Reports

Horonobe Underground Research Laboratory Project; Investigation report for the 2021 fiscal year

Nakayama, Masashi

JAEA-Review 2022-025, 164 Pages, 2022/11

JAEA-Review-2022-025.pdf:12.25MB

The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA). The main aim of this project is to enhance the reliability of relevant disposal technologies for geological disposal of high-level radioactive waste through a comprehensive research and development (R&D) program in the deep geological environment within the host sedimentary rock at Horonobe in Hokkaido, north Japan. In fiscal year 2021, we continued R&D on three important issues specified in the "Horonobe Underground Research Plan from Fiscal Year 2020", which involve "Study on near-field system performance in geological environment", "Demonstration of repository design options", and "Understanding of buffering behaviour of sedimentary rock to natural perturbations". Specifically, "full-scale engineered barrier system (EBS) performance experiment" and "solute transport experiment with model testing" were carried out as part of "Study on near-field system performance in geological environment". "Demonstration of engineering feasibility of repository technology" and "evaluation of EBS behaviour over 100$$^{circ}$$C' were addressed for "Demonstration of repository design options". A study on "Understanding of buffering behaviour of sedimentary rock to natural perturbations" was also implemented in two areas, "evaluation of intrinsic buffering against endogenic and exogenic processes" and "development of techniques for evaluating excavation damaged zone (EDZ) self-sealing behaviour after backfilling". The results of the R&D, along with those obtained in other departments of JAEA, will reinforce the technical basis for both repository implementation and safety regulation. For the sake of this, we will steadily proceed with this project in collaboration with relevant organizations and universities both domestically and internationally and also widely publish the plans and results of the R&D to ensure their transparency and technical reliability.

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

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.

JAEA Reports

Assessment report on research and development activities in post-evaluation of third medium-/long-term plan and in pre-evaluation of the fourth medium-/long-term plan on "Research and Development on High Temperature Gas-cooled Reactor and Related Heat Application Technology"

Shinohara, Masanori; Sumita, Junya; Shibata, Taiju; Hirata, Masaru

JAEA-Evaluation 2022-006, 198 Pages, 2022/11

Japan Atomic Energy Agency (JAEA) received a post-evaluation of the third medium-/long-term plan (from FY2015 to FY2021) and pre-evaluation of the fourth medium-/long-term plan (from FY2022 to FY2028) from the "Evaluation Committee of Research Activities for High Temperature Gas-cooled Reactor (hereinafter referred to as "HTGR") and Related Hydrogen Production Technology" (hereinafter referred to as "Evaluation Committee") which consists of specialists in the fields of evaluation subjects of HTGR and related heat application technologies. As a result, for the post-evaluation of the third medium-/ long-term plan, two of the ten technical committee members concluded a score of "S", seven members concluded "A" and one member concluded "B". The comprehensive evaluation concluded a score of "A". On the other hand, one of the two humanities and social sciences members concluded a score of "B", one members concluded "C". The comprehensive evaluation concluded a score of "B". For the pre-evaluation of the fourth medium-/long-term plan, although there were some items that several evaluation committee members rated as "needs improvement," the majority of the committee members judged the plan to be appropriate. This report describes the members of the Evaluation Committee, assessment items, assessment results and JAEA's measures following the assessment.

JAEA Reports

Assessment report on research and development activities in FY2021 Activity "Research and Development on Fast Reactor and Fuel Cycle Technologies" (Post- and pre-review peport)

Konishi, Kensuke; Kunogi, Kosuke

JAEA-Evaluation 2022-005, 106 Pages, 2022/11

Japan Atomic Energy Agency (hereafter referred to as "JAEA") consulted with the "Evaluation Committee of Research and Development Activities for Fast Reactor and Fuel Cycle" (hereinafter referred to as "Committee"), which consists of specialists in the fields of the evaluation subjects of fast reactor cycle technologies, for post-review and pre-review assessment of Research and Development (R&D) activities of fast reactor cycle in accordance with "General Guideline for the Evaluation of Government R&D Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and Regulation on Conduct for Evaluation of R&D Activities" by JAEA. In response to JAEA's request, the Committee assessed mainly the progress of the R&D project according to guidelines, which addressed the rationale behind the R&D project, the relevance of the project outcome and the efficiency of the project implementation during the period of the current and next plan. This report is issued for the purpose of actively disseminate evaluation information to the people of Japan (based on General Guideline), which lists the members of the Committee and outlines the assessment items and the review process for procedure of the assessment. The assessment reports which were issued by the Committee is attached.

JAEA Reports

Review of research on Advanced Computational Science in FY2021

Center for Computational Science & e-Systems

JAEA-Evaluation 2022-004, 38 Pages, 2022/11

JAEA-Evaluation-2022-004.pdf:1.38MB

Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid- and long-term goal of the Japan Atomic Energy Agency", has been performed by Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of external experts and authorities which evaluates and advises toward the future research and development. This report summarizes the results of the R&D performed by CCSE in FY2021 (April 1st, 2021 - March 31st, 2022) and their evaluation by the committee.

JAEA Reports

Assessment report of research on development activities in FY 2021 Activity; "Computational Science and Technology Research" (Result and in-advance evaluation)

Center for Computational Science & e-Systems

JAEA-Evaluation 2022-003, 61 Pages, 2022/11

JAEA-Evaluation-2022-003.pdf:1.42MB
JAEA-Evaluation-2022-003-appendix(CD-ROM).zip:6.16MB

Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consults an assessment committee, "Evaluation Committee of Research Activities for Computational Science and Technology Research" (hereinafter referred to as "Committee") for result and in-advance evaluation of "Computational Science and Technology Research", in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by the JAEA. In response to the JAEA's request, the Committee assessed the research program of the Center for Computational Science and e-Systems (hereinafter referred to as "CCSE"). The Committee evaluated the management and research activities of the CCSE based on explanatory documents prepared by the CCSE, and oral presentations with questions-and answers.

JAEA Reports

Assessment report of research and development activities in FY2021; Activity "Implementation and technological development of decommissioning of nuclear facilities" and "Implementation and technological development of radioactive waste processing" (Result evaluation, in-advance evaluation)

Sector of Nuclear Fuel, Decommissioning and Waste Management Technology Development

JAEA-Evaluation 2022-002, 172 Pages, 2022/11

Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consulted the "Evaluation Committee on Research and Development Activities for Decommissioning" (hereinafter referred to as "Committee") about the ex-post evaluation result for the implementation of the 3rd mid- and long-term objectives period and the ex-ante evaluation of R&D plan for the 4th mid- and long-term objectives period concerning "Decommissioning of nuclear facilities and development of technologies for the treatment of related radioactive waste" project in accordance with the "Guideline for evaluation of government R&D activities", the "Guideline for evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology (MEXT)" and the "Operational rule for evaluation of R&D activities" by JAEA. In response, the Committee evaluated the results of research and development during the 3rd mid- and long-term objectives period (April 2015 to March 2022) and the research and development plan for the 4th mid- and long-term objectives period (April 2022 to March 2029) according to the evaluation method established by the committee.

JAEA Reports

Analysis of the radioactivity concentrations in radioactive waste generated from JRR-3, JRR-4 and JRTF facilities

Tobita, Minoru*; Konda, Miki; Omori, Takeshi*; Nabatame, Tsutomu*; Onizawa, Takashi*; Kurosawa, Katsuaki*; Haraga, Tomoko; Aono, Ryuji; Mitsukai, Akina; Tsuchida, Daiki; et al.

JAEA-Data/Code 2022-007, 40 Pages, 2022/11

JAEA-Data-Code-2022-007.pdf:1.99MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until the beginning of disposal. In order to contribute to this work, we collected and analyzed concrete, ash, ceramic and brick samples generated from JRR-3, JRR4 and JRTF facilities. In this report, we summarized the radioactivity concentrations of 24 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{41}$$Ca, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{99}$$Tc, $$^{rm 108m}$$Ag, $$^{129}$$I, $$^{137}$$Cs, $$^{133}$$Ba, $$^{152}$$Eu, $$^{154}$$Eu, $$^{rm 166m}$$Ho, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of the samples in fiscal years 2020-2021.

JAEA Reports

Proceedings of the 2021 Symposium on Nuclear Data; November 18-19, 2021, On-line Connection Conference

Yamaguchi, Yuji; Meigo, Shinichiro

JAEA-Conf 2022-001, 226 Pages, 2022/11

JAEA-Conf-2022-001.pdf:17.97MB

The 2021 Symposium on Nuclear Data was held as an online connection conference on November 18-19, 2021. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan (AESJ) in cooperation with the Sigma Investigative Advisory Committee of AESJ, J-PARC Center, Nuclear Science and Engineering Center of Japan Atomic Energy Agency (JAEA), and High Energy Accelerator Research Organization (KEK). In the symposium, tutorials "New Developments in TALYS and TENDL-2021" and "Role of ADS and its Development Issues" were proposed and held. Three sessions of lectures and discussions were held: "J-PARC and JAEA Facilities", "Current Status and Future Prospects of Nuclear Data Research", and "Medical, Isotope Production, and Analysis". In addition, recent research progress on experiments, nuclear theory, evaluation, benchmark, and applications were presented in the poster session. The total number of participants was 132 participants. Each oral and poster presentation was followed by an active question and answer session. This report consists of a total of 36 papers including 14 oral and 22 poster presentations.

JAEA Reports

Demonstration of the groundwater observation network system in backfilled underground facility

Murakami, Hiroaki; Takeuchi, Ryuji; Iwatsuki, Teruki

JAEA-Technology 2022-022, 34 Pages, 2022/10

JAEA-Technology-2022-022.pdf:3.47MB

Japan Atomic Energy Agency (JAEA) has been conducting the hydro-pressure and hydrochemical monitoring for more than two decades to understand the hydrochemical disturbance due to the excavation of tunnels at Mizunami Underground Research Laboratory (MIU). To understand the environmental influence due to the backfilling of research tunnels that started in 2019, environmental monitoring of groundwater has been performed and recovery status of groundwater is being confirmed. In order to observe the deep-groundwater environment from the ground, the groundwater pressure monitoring and sampling, which have been performed in the research tunnel, are to be performed from the ground. However, backfilling of a large-scale underground facilities such as MIU is globally unprecedented, thus it was necessary to develop a new observation system. Accordingly, we developed a new observation network to observe the environment around the research tunnels of the MIU. This system enables monitoring of groundwater pressure and water sampling of the backfilled tunnel from the ground while utilizing the existing-monitoring system installed in the tunnels. Accordingly, we demonstrated its technology through the environmental monitoring of groundwater. The results of the environmental monitoring and the existing groundwater data of MIU indicate that this system is able to monitor the groundwater environment in the backfilled tunnels.

JAEA Reports

Development of technologies for enhanced analysis accuracy of fuel debris; Summary results of the 2020 fiscal year (Subsidy program for the project of decommissioning and contaminated water management)

Ikeuchi, Hirotomo; Koyama, Shinichi; Osaka, Masahiko; Takano, Masahide; Nakamura, Satoshi; Onozawa, Atsushi; Sasaki, Shinji; Onishi, Takashi; Maeda, Koji; Kirishima, Akira*; et al.

JAEA-Technology 2022-021, 224 Pages, 2022/10

JAEA-Technology-2022-021.pdf:12.32MB

A set of technology, including acid dissolving, has to be established for the analysis of content of elements/nuclides in the fuel debris samples. In this project, a blind test was performed for the purpose of clarifying the current level of analytical accuracy and establishing the alternative methods in case that the insoluble residue remains. Overall composition of the simulated fuel debris (homogenized powder having a specific composition) were quantitatively determined in the four analytical institutions in Japan by using their own dissolving and analytical techniques. The merit and drawback for each technique were then evaluated, based on which a tentative flow of the analyses of fuel debris was constructed.

JAEA Reports

Experiment of incineration for Trans-Uranic (TRU) wastes containing chlorides

Yamashita, Kiyoto; Yokoyama, Aya*; Takagai, Yoshitaka*; Maki, Shota; Yokosuka, Kazuhiro; Fukui, Masahiro; Iemura, Keisuke

JAEA-Technology 2022-020, 106 Pages, 2022/10

JAEA-Technology-2022-020.pdf:4.77MB

Radioactive solid wastes generated by Fukushima Daiichi Nuclear Power Station disaster may contain high levels of salt from the tsunami and seawater deliberately released into the area. It is assumed that polyvinyl chloride (PVC) products may be used for decommissioning work and for containment of radioactive wastes in the future. Among the method of handling them, incineration is one method that needs to be investigated as it is good method for reduction and stabilization of wastes. But in order to dispose of Trans-Uranic (TRU) solid waste containing chlorides, it is necessary to select the structure and materials of the facility based on the information such as the movement of nuclides and chlorides in the waste gas treating system and the corrosion of equipment due to chlorides. Therefore, we decided to get various data necessary to design a study of the incineration facilities. And we decided to examine the transfer behavior of chlorides to the waste gas treatment system, the corrosion-resistance of materials in the incineration facilities, and the distribution survey of plutonium in them obtained using the Plutonium-contaminated Waste Treatment Facility (PWTF), Nuclear Fuel Cycle Engineering Laboratories, which is a unique incinerating facility in Japan. This report describes the transfer behavior of chlorides in the waste gas treatment system, the evaluation of corrosion-resistance materials and the distribution survey of plutonium in the incineration facilities obtained by these tests using the Plutonium-contaminated Waste Treatment Facility, Nuclear Fuel Cycle Engineering Laboratories.

JAEA Reports

Annual report of Nuclear Human Resource Development Center (April 1, 2020 - March 31, 2021)

Nuclear Human Resource Development Center

JAEA-Review 2022-024, 60 Pages, 2022/10

JAEA-Review-2022-024.pdf:2.48MB

This annual report summarizes the activities of Nuclear Human Resource Development Center (NuHRDeC) of Japan Atomic Energy Agency (JAEA) in the fiscal year (FY) 2020. In FY 2020, in addition to the regular training programs at NuHRDeC, we actively organized special training courses responding to the external training needs, cooperated with universities, offered international training courses for Asian countries and promoted activities of the Japan Nuclear Human Resource Development Network (JN-HRD.net). In FY2020, due to the spread of the new coronavirus infection over the world, some training courses were conducted online using web conference systems. Regular national training programs; training courses for radioisotopes and radiation engineers, nuclear energy engineers and national qualification examinations, were conducted as scheduled in the annual plan. We also delivered training for prefectural and municipal officials in Fukushima meeting their training needs. We continued cooperative activities with universities, such as acceptance of postdoctoral researchers, and activities in line with the cooperative graduate school system, including the acceptance of students from Nuclear Professional School, the University of Tokyo. Furthermore, joint course among seven universities was successfully held by utilizing remote education system. The joint course and the intensive summer course were conducted as part of the collaboration network with universities. The Instructor Training Program (ITP) under contract with Ministry of Education, Culture, Sports, Science and Technology, was continually offered to the ITP participating countries. As part of the ITP, the Instructor Training Courses such as "Reactor Engineering Course" and the Nuclear Technology Seminar "Basic Radiation Knowledge for School Education Seminar" were conducted online at NuHRDeC. As secretariat of JN-HRD.net, we steadily facilitated the network and conducted webinar and online training despite circulat

JAEA Reports

Structural investigation of borosilicate glasses by using XAFS measurement in soft X-ray region, 2 (Joint research)

Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*

JAEA-Research 2022-008, 37 Pages, 2022/10

JAEA-Research-2022-008.pdf:5.27MB

The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M$$_{5}$$, M$$_{4}$$-edge XANES spectra disappeared and the Fe L$$_{3}$$, L$$_{2}$$-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different Na$$_{2}$$O content were measured, and following was confirmed. (1) As the Na$$_{2}$$O concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the Na$$_{2}$$O content in glass frits was about 7wt%.

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