Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kokubun, Yuji; Nakada, Akira; Seya, Natsumi; Koike, Yuko; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; Nagai, Shinji; et al.
JAEA-Review 2023-046, 164 Pages, 2024/03
JAEA-Review-2023-046.pdf:4.2MB
The Nuclear Fuel Cycle Engineering Laboratories conducts environmental radiation monitoring around the reprocessing plant in accordance with the "Safety Regulations for Reprocessing Plant of JAEA, Part IV: Environmental Monitoring". This report summarizes the results of environmental radiation monitoring conducted during the period from April 2022 to March 2023 and the results of dose calculations for the surrounding public due to the release of radioactive materials into the atmosphere and ocean. In the results of the above environmental radiation monitoring, many items were affected by radioactive materials emitted from the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company, Incorporated (changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016), which occurred in March 2011. Also included as appendices are an overview of the environmental monitoring plan, an overview of measurement methods, measurement results and their changes over time, meteorological statistics results, radioactive waste release status, and an evaluation of the data which deviated of the normal range.
Nakahara, Masaumi; Watanabe, So; Takeuchi, Masayuki; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yamada, Naoto*; Koka, Masashi*; Kada, Wataru*; et al.
Nuclear Instruments and Methods in Physics Research B, 542, p.144 - 150, 2023/09
Times Cited Count：1 Percentile：63.33(Instruments & Instrumentation)The structures of Eu complexes in the adsorbents prepared with various extractants were evaluated by ion beam induced luminescence analysis in an extraction chromatography for minor actinides recovery. The luminescence of Eu was measured with a proton beam obtained from the single-ended accelerator and an argon ion beam obtained from the azimuthally varying field cyclotron in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In this study, it was confirmed that the spectral shape of Eu complexes in the adsorbents varied depending on the kinds of extractants, and the correlation between the change in the spectra and the structures of Eu complexes was investigated.
Nakada, Akira; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Futagawa, Kazuo; Nemoto, Masashi; Tobita, Keiji; Yamada, Ryohei*; Uchiyama, Rei; Yamashita, Daichi; et al.
JAEA-Review 2022-078, 164 Pages, 2023/03
JAEA-Review-2022-078.pdf:2.64MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2021 to March 2022. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Nakada, Akira; Nakano, Masanao; Kanai, Katsuta; Seya, Natsumi; Nishimura, Shusaku; Nemoto, Masashi; Tobita, Keiji; Futagawa, Kazuo; Yamada, Ryohei; Uchiyama, Rei; et al.
JAEA-Review 2021-062, 163 Pages, 2022/02
JAEA-Review-2021-062.pdf:2.87MB
Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2020 to March 2021. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Co., Inc. (the trade name was changed to Tokyo Electric Power Company Holdings, Inc. on April 1, 2016) in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and exceeded the normal range of fluctuation in the monitoring, were evaluated.
Shobu, Takahisa; Shiro, Ayumi*; Kono, Fumiaki*; Muramatsu, Toshiharu; Yamada, Tomonori; Naganuma, Masayuki; Ozawa, Takayuki
Quantum Beam Science (Internet), 5(2), p.17_1 - 17_9, 2021/06
The automotive industries employ laser beam welding because it realizes a high energy density without generating irradiation marks on the opposite side of the irradiated surface. Typical measurement techniques such as strain gauges and tube X-rays cannot assess the localized strain at a joint weld. Herein high-energy synchrotron radiation X-ray diffraction was used to study the internal strain distribution of laser lap joint PNC-FMS steels (2- and 5-mm thick) under loading at a high temperature. As the tensile load increased, the local tensile and compressive strains increased near the interface. These changes agreed well with the finite element analysis results. However, it is essential to complementarily utilize internal defect observations by X-ray transmission imaging because the results depend on the defects generated by laser processing.
Isobe, Kanetsugu; Kawamura, Yoshinori; Iwai, Yasunori; Oyaizu, Makoto; Nakamura, Hirofumi; Suzuki, Takumi; Yamada, Masayuki; Edao, Yuki; Kurata, Rie; Hayashi, Takumi; et al.
Fusion Engineering and Design, 98-99, p.1792 - 1795, 2015/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Activities on Broader Approach (BA) were started in 2007 on the basis of the Agreement between the Government of Japan and the EURATOM. The period of BA activities consist of Phase1 and Phase2 dividing into Phase 2-1 (2010-2011), Phase 2-2 (2012-2013) and Phase 2-3 (2014-2016). Tritium technology was chosen as one of important R&D issues to develop DEMO plant. R&D activities of tritium technology on BA consist of four tasks. Task-1 is to prepare and maintain the tritium handling facility in Rokkasho BA site in Japan. Task 2, 3 and 4 are main R&D activities for tritium and these are focused on: Task-2) Development of tritium accountancy technology, Task-3) Development of basic tritium safety research, Task-4) Tritium durability test. R&D activities of tritium technology in Phase 2-2 were underway successfully and closed in 2013.
Kono, Fumiaki; Sogame, Motomu; Yamada, Tomonori; Shobu, Takahisa; Naganuma, Masayuki; Ozawa, Takayuki; Muramatsu, Toshiharu
JAEA-Technology 2015-004, 57 Pages, 2015/03
JAEA-Technology-2015-004.pdf:20.87MB
Laser welding of ferritic/martensitic steel (PNC-FMS) sheets with different thicknesses (2 mm and 5 mm) was examined to investigate the weldability between the inner and outer duct in fast reactor fuel assemblies with inner duct structure (FAIDUS); the objective of the inner duct is to avoid the re-criticality in case of the core melting accident. Laser-spot and melt-run welding was performed at various laser powers, welding times and velocities to find out the appropriate welding conditions with few defects and enough penetration depth. As for the spot welding, furthermore, slow cooling rate or pulsed laser irradiation could reduce the crack and porosity in the welded zone. The strain of the welded zone almost disappeared and the hardness was comparable with that of the base metal by applying post welding heat treatment at 690 
C for 103 min. In addition, the shear strength of welded joints was confirmed to be sufficiently higher than the provisional allowance shear stress. These results indicate that laser welding would be probably applied to the PNC-FMS inner and outer ducts.
Hayashi, Takumi; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Oyaizu, Makoto; Edao, Yuki; et al.
Fusion Science and Technology, 67(2), p.365 - 370, 2015/03
Times Cited Count：1 Percentile：9.61(Nuclear Science & Technology)Yamanishi, Toshihiko; Nakamura, Hirofumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Oyaizu, Makoto; Yamada, Masayuki; Suzuki, Takumi; Hayashi, Takumi
Fusion Engineering and Design, 87(5-6), p.890 - 895, 2012/08
Times Cited Count：1 Percentile：10.02(Nuclear Science & Technology)In JAEA, the tritium processing and handling technologies have been studied at TPL. The main basic R&D activities in this field are: the tritium processing technology for the blanket recovery system; the tritium behavior in a confinement; and detritiation and decontamination. The R&D for tritium processing and handling technologies to a demonstration reactor (DEMO) are also planned to be carried out in the Broader Approach (BA) program in Japan by JAEA with Japanese universities. The ceramic electrolysis cell has been studied as a tritium processing method for the blanket system. The permeation behavior of tritium through pure iron into the gas containing water vapor has been studied. As for the behavior of high concentration tritium water, it was observed that the formation of the oxidized layer was prevented by the presence of tritium in water. Tritium durability tests were also carried out for the electrolysis cell of the chemical exchange column.
Yamanishi, Toshihiko; Yamada, Masayuki; Suzuki, Takumi; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Inomiya, Hiroshi; Hayashi, Takumi
Fusion Science and Technology, 60(3), p.1083 - 1087, 2011/10
Times Cited Count：2 Percentile：18.18(Nuclear Science & Technology)Tritium Process Laboratory (TPL) in Japan Atomic Energy Agency has been established as the only test facilities to handle over 1 gram of in Japan. From March 1988, TPL has been operated with tritium, and no tritium release accident has been observed. The average tritium concentration in a stream from a stack of the TPL to environment was 71 Bq/m
, and was 1/70 of the Japanese regulation value for HTO. The failure data have been analyzed for several main components of the safety systems such as pumps, valves, and monitors. The data on the tritium waste and accountancy has also been accumulated. As a study of the Grants-in-Aid for Scientific Research, these data are analysed and are reported.
Hayashi, Takumi; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko
Fusion Science and Technology, 60(3), p.1101 - 1104, 2011/10
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Yamanishi, Toshihiko; Hayashi, Takumi; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Suzuki, Takumi; Yamada, Masayuki
Fusion Engineering and Design, 85(7-9), p.1002 - 1006, 2010/12
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The R&D for tritium technologies to a demonstration reactor (DEMO) is planned to be carried out in the Broader Approach (BA) program in Japan by JAEA with Japanese universities: (1) tritium analysis technology; (2) basic tritium safety research; and (3) tritium durability test. A multi-purpose RI facility is under construction at Rokkasho in Aomori to carry out the above R&D subjects. A preliminary safety study has been carried out for the amount of tritium released to the environment and for the radiation dose of workers. The main subjects of the R&D of tritium analysis are the technologies for real-time analysis for hydrogen isotopes, gas, liquid and solid. The materials of interest include F82H, SiC, ZrCo, solid and liquid advanced breeder and multipliers. In the tritium durability tests, organic materials and metals are studied for the radiation and the corrosion damage. A series of preliminary studies for the above subjects has been started.
Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru; Kutsukake, Chuzo; Oginuma, Yoshikazu; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko; Konno, Chikara
Journal of Plasma and Fusion Research SERIES, Vol.9, p.338 - 341, 2010/08
We have conducted a small tritium target production R&D for FNS inside JAEA. The tritium target is produced by adsorbing tritium in a thin titanium layer. Since titanium is very active to oxygen, glow discharge cleaning was carried out to remove an oxidation film of the titanium surface. Through many tests with deuterium, we found out that it was not an oxidation film but humidity to disturb tritium absorption. The following procedures were necessary; (1) to outgas the inside of an absorption chamber, (2) to keep environmental humidity under 3% in handling the titanium-deposited substrate, (3) to keep the titanium-deposited target substrate in the vacuum. The DT neutron generation performance of the tritium target produced with the above procedures was the same as that with discharge cleaning. The manufacture condition of the small target was established.
Hatano, Yuji*; Yamada, Masayuki; Hayashi, Takumi
Purazuma, Kaku Yugo Gakkai-Shi, 86(3), p.173 - 184, 2010/03
DT fusion reactor has been studied. In this type of fusion reactor, about 500 g of tritium should be burned and produced every day in the 100 MWe class of reactor. Fusion reactor has itself the potential safety, however, the most important safety point of the DT fusion reactor is tritium confinement. In this report, large amount of tritium safety handling experiences, accumulated in the Hydrogen Isotope Research Center, University of Toyama, and in the Tritium Process Laboratory, Japan Atomic Energy Agency, are summarized and its accomplishments of the related safety studies are also reviewed.
Yamanishi, Toshihiko; Hayashi, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Arita, Tadaaki; Hoshi, Shuichi; et al.
Fusion Engineering and Design, 83(10-12), p.1359 - 1363, 2008/12
Times Cited Count：4 Percentile：29.38(Nuclear Science & Technology)At TPL (Tritium Process Laboratory) of JAEA, ITER relevant tritium technologies have been studied. The design studies of Air Detritiation System have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the research of the tritium recovery system of ITER test blanket system. A ceramic proton conductor has been studied as an advanced blanket system. A series of fundamental studies on tritium safety technologies not only for ITER but also for fusion DEMO plants has also been carried out at TPL of JAEA. The main research activities in this field are the tritium behavior in a confinement and its barrier materials; monitoring; accountancy; detritiation and decontamination etc. In this paper, the results of above recent activities at TPL of JAEA are summarized from viewpoint of ITER relevant and future fusion DEMO reactors.
Hayashi, Takumi; Suzuki, Takumi; Yamada, Masayuki; Shu, Wataru; Yamanishi, Toshihiko
Fusion Engineering and Design, 83(10-12), p.1429 - 1432, 2008/12
Times Cited Count：30 Percentile：86.16(Nuclear Science & Technology)In ITER facility, about 3 kg of tritium will be stored in more than 30 ZrCo hydride beds, as a reference design. The safe design and operation of tritium storage beds will be one of the most important points to enhance total safety of the facility. In the Tritium Process Lab. in Japan Atomic Energy Agency, many tritium storage beds with ZrCo have been used with/without self-accountancy measure, and the safe handling experiences have been accumulated for almost 20 years. From these experiences, the key issues to be considered for the safety design are the effect of tritium decay, such as decay heat transfer and He behavior with the normal protection of over temperature, over pressure and leak for a metal-hydride bed. Concerning the safety operation, the key issues are the procedure of hydrogenation-dehydrogenation cycle under the requirements of the storage system and the emergency performances, such as a rapid hydrogen recovery and loss of normal cooling function.
Yamanishi, Toshihiko; Yamada, Masayuki; Suzuki, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Hoshi, Shuichi; et al.
Fusion Science and Technology, 54(1), p.315 - 318, 2008/07
Times Cited Count：11 Percentile：58.97(Nuclear Science & Technology)The construction of the building and safety systems of the TPL was completed until 1985. The operations of the safety systems with tritium have been started from March 1988. The amount of tritium held at the TPL was 13 PBq at March 2007. The average tritium concentration in a stream from a stack of the TPL to environment was 6.0
10
Bq/cm
; and is 1/100 smaller than that of the regulation value for the concentration of HTO in the air in Japan. The safety operation results with tritium have thus been obtained. A set of failure data of several main components of the TPL was also obtained as the valuable data for fusion tritium facilities.
Hayashi, Takumi; Kobayashi, Kazuhiro; Iwai, Yasunori; Isobe, Kanetsugu; Nakamura, Hirofumi; Kawamura, Yoshinori; Shu, Wataru; Suzuki, Takumi; Yamada, Masayuki; Yamanishi, Toshihiko
Fusion Science and Technology, 54(1), p.319 - 322, 2008/07
Times Cited Count：2 Percentile：16.93(Nuclear Science & Technology)Kobayashi, Kazuhiro; Hayashi, Takumi; Iwai, Yasunori; Isobe, Kanetsugu; Nakamura, Hirofumi; Kawamura, Yoshinori; Shu, Wataru; Suzuki, Takumi; Yamada, Masayuki; Yamanishi, Toshihiko
Proceedings of 2nd Japan-China Workshop on Blanket and Tritium Technology, p.74 - 78, 2008/05
In order to accumulate the tritium behavior in the future fusion reactor included ITER, intentional tritium release experiments have been carried out using Caisson Assembly for Tritium Safety study (CATS) at Tritium Process Laboratory (TPL) in Japan Atomic Energy Agency (JAEA). Main objectives of CATS are (1) to demonstrate the initial tritium behavior in the room and to develop 3D simulation code of tritium behavior in the room. (2) to demonstrate the performance of integrated system for tritium confinement after intentional tritium release accident, (3) to accumulate the data for the detritiation behavior and the interaction between various materials and tritium (tritiated water) in the confinement. The study using CATS has been continued for about 10 yeas in TPL/JAEA.
Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; et al.
Nuclear Fusion, 47(12), p.1645 - 1651, 2007/12
Times Cited Count：4 Percentile：14.97(Physics, Fluids & Plasmas)The confinement and removal of tritium are the key subjects for safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell building, tritium is often released, as vapor and is in contact with the inner walls. Also those of an ITER tritium plant building will be exposed to tritium in an accident. However, the data are scarce, especially on the penetration of tritium into the concrete of the wall materials. The tritium released in the buildings is removed by the Atmosphere Detritiation Systems (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF
is used in ITER, and is expected to be released in an accident such as fire. Although the SF gas has the potential as a catalyst poison, the performance of ADS with the existence of SF has not been confirmed yet. Tritiated water is produced in the regeneration process of ADS, and is subsequently processed by the ITER Water Detritiation System (WDS). One of the key components of WDS is an electrolysis cell. The electrolysis cell is made of organic compounds, and there is no data on the durability of the cell exposed to tritium. To overcome these issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behavior in concrete; (2) effect of SF on performance of ADS; and (3) tritium durability of electrolysis cell of ITER-WDS.
