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Journal Articles

Decommissioning program and future plan for Research Hot Laboratory, 3

Shiina, Hidenori; Ono, Katsuto; Nishi, Masahiro; Uno, Kiryu; Kanazawa, Hiroyuki; Oi, Ryuichi; Nihei, Yasuo

Dekomisshoningu Giho, (61), p.29 - 38, 2020/03

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) was constructed in 1961, as the first one in Japan, to perform the examinations of irradiated fuels and materials. RHL consists of 10 heavy concrete cells and 38 lead cells. RHL contributed to research and development program in or out of JAEA for the investigation of irradiation behavior for fuels and nuclear materials. However, RHL is the one of target as the rationalization program for decrepit facilities in former Tokai institute. Therefore the decommissioning works of RHL started on April 2003. The dismantling of 12 lead cells has been progressing since 2010. The dismantling procedure of lead cells was performed in the following order. The peripheral equipment in lead cells were removed and contamination survey of the inner surface of the cells. Then, the backside shield doors were extracted. The lifting frame for the isolation tent was set on the cells. After that, the ceiling plates, isolation walls and lead blocks were removed. The strippable paint was used to remove permeable contamination on the inner surface of structural steel of the cells. The dismantling work will be continued to mention the efficiency of decommissioning works and reduction of radioactive waste with ensuring safety.

Journal Articles

Treatment technology of highly radioactive solid waste generated by experimental tests and sample analysis in reprocessing facilities

Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko; Mori, Eito*

Nippon Hozen Gakkai Dai-16-Kai Gakujutsu Koenkai Yoshishu, p.221 - 224, 2019/07

Test equipment, containers, and analytical wastes, generated by experiments using spent fuel pieces in hot cell of Operation Testing Laboratory and by analysis of highly active liquid wastes in hot analytical cell line of Tokai Reprocessing Plant, are treated as highly radioactive solid wastes. These wastes are stored in specific shielded containers called waste cask and then transport to the storage facility. The treatment of these highly radioactive solid wastes have been carried out for 40 years with upgrading waste taking out system and transportation device. As a results, automation of several procedures have been achieved utilizing conventional equipment, and work efficiency and safety have been improved.

Journal Articles

Physical property evaluation of valve seal material at analytical radioactive liquid waste storage tanks in reprocessing facility

Goto, Yuichi; Yamamoto, Masahiko; Kuno, Takehiko; Inada, Satoshi

Nippon Hozen Gakkai Dai-15-Kai Gakujutsu Koenkai Yoshishu, p.489 - 492, 2018/07

Radioactive liquid waste from the Tokai Reprocessing Facility Analytical Laboratory is temporarily stored in intermediate waste storage tank by using receiving valves. Then, the liquid waste is transferred to liquid treatment facility by using liquid feed valves. The deterioration of the gasket part of these valves (leakage of waste liquid) was confirmed in 2004. Since then, the material of gaskets was changed from polyethylene to Teflon. In 2016, the gaskets were replaced by periodical update. Therefore, physical properties of used gaskets were investigated, and the relevance between radioactive level and degradation degree was evaluated.

Journal Articles

Replacement of the glove port equipped with glove box in Nuclear Fuel Reprocessing Facility

Horigome, Kazushi; Taguchi, Shigeo; Nishida, Naoki; Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko

Nippon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.381 - 384, 2017/08

no abstracts in English

Journal Articles

Design and application of greenhouse on the maintenance of analytical machineries in Tokai Reprocessing Plant

Suzuki, Yoshimasa; Tanaka, Naoki; Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko

Nippon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.385 - 389, 2017/08

Greenhouse is used in order to prevent diffusion of radioactive materials on the maintenance of machineries and decomposition of the analytical equipment such as glove box in Tokai Reprocessing Plant (TRP). The specifications of the greenhouse change depending on a risk of the radiation exposure, operation and environment. Design and application of original greenhouses in the analytical laboratory of TRP is summarized.

Journal Articles

High-precision quadrupole moment reveals significant intruder component in $$^{33}_{13}$$Al$$_{20}$$ ground state

Heylen, H.*; De Rydt, M.*; Neyens, G.*; Bissell, M. L.*; Caceres, L.*; Chevrier, R.*; Daugas, J. M.*; Ichikawa, Yuichi*; Ishibashi, Yoko*; Kamalou, O.*; et al.

Physical Review C, 94(3), p.034312_1 - 034312_5, 2016/09

AA2016-0115.pdf:0.4MB

 Times Cited Count:27 Percentile:6.99(Physics, Nuclear)

no abstracts in English

Journal Articles

Physical property of seal-gasket for glove box panel in reprocessing facilities

Goto, Yuichi; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki

Nippon Hozen Gakkai Dai-13-Kai Gakujutsu Koenkai Yoshishu, p.31 - 34, 2016/07

Chloroprene rubber gaskets are often used to seal the glove box body and its panels. Such gaskets are deformed with compressive pressure and its elastic restoring force keeps sealing property. Therefore, gaskets play an important role in glove box sealing. However, physical properties of those used in glove box have not reported so far. In this study, hardness, elongation, tensile strength and compression set are investigated and its sealing performances are evaluated. The gaskets samples are taken from the glove box, which is used for 37 years. It is found that hardness, elongation and tensile strength of gaskets are changed due to the aging but its values are within the specification of chloroprene rubber. Also, the compression-set is less than the value that sealing performance is decreased. The results show that even the gaskets are used for long time, it has the property to keep sealing performances of glove box.

Journal Articles

Radionuclide release to stagnant water in the Fukushima-1 Nuclear Power Plant

Nishihara, Kenji; Yamagishi, Isao; Yasuda, Kenichiro; Ishimori, Kenichiro; Tanaka, Kiwamu; Kuno, Takehiko; Inada, Satoshi; Goto, Yuichi

Journal of Nuclear Science and Technology, 52(3), p.301 - 307, 2015/03

 Times Cited Count:11 Percentile:18.6(Nuclear Science & Technology)

After the severe accident at the Fukushima-1 nuclear power plant, large amounts of contaminated stagnant water have accumulated in turbine buildings and their surroundings. This rapid communication reports calculation of the radionuclide inventory in the core, collection of measured inventory in the stagnant water, and estimation of radionuclide release ratios from the core to the stagnant water. This evaluation is based on data obtained before June 3, 2011. The release ratios of tritium, iodine, and cesium were several tens of percent, whereas those of strontium and barium were smaller by one or two orders of magnitude. The release ratios in the Fukushima accident were equivalent to those in the TMI-2 accident.

Journal Articles

Status report on technical developments of electrostatic accelerators

Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Matoba, Shiro; Chiba, Atsuya; Yokoyama, Akihito; Usui, Aya; Sato, Takahiro; Okubo, Takeru; Uno, Sadanori

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 159, 2014/03

no abstracts in English

Journal Articles

Operation of electrostatic accelerators

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; et al.

JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 179, 2014/03

Three electrostatic accelerators at TIARA were operated on schedule in fiscal year 2012 except changing its schedule by cancellations of users. The yearly operation time of the 3 MV tandem accelerator, the 400 kV ion implanter and the 3MV single-ended accelerator were in the same levels as the ordinary one, whose operation time totaled to 2,073, 1,847 and 2,389 hours, respectively. The tandem accelerator had no trouble, whereas the ion implanter and the single-ended accelerator stopped by any troubles for one day and four days, respectively. The molecular ion beam of helium hydride was generated by the ion implanter, because the users required irradiation of several cluster ions in order to study the effect of irradiation. As a result, its intensity of beam was 50 nA at 200 kV. The ion beam of tungsten (W) at 15 MeV was accelerated by the tandem accelerator, whose intensity was 20 nA at charge state of 4+, because of the request from a researcher in the field of nuclear fusion.

Journal Articles

Development of beam generation and irradiation technology for electrostatic accelerators

Yamada, Keisuke; Chiba, Atsuya; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Uno, Sadanori

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 155, 2013/01

no abstracts in English

Journal Articles

Operation of electrostatic accelerators

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; Kitano, Toshihiko*; et al.

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 173, 2013/01

The three electrostatic accelerators at the TIARA had no mechanical damage when the Tohoku earthquake happened on March 11, 2011. But, they could not be operated during April, due to the influence of planned power outage by TEPCO. These accelerators additionally operated on Saturday for ten days in order to compensate for the lost experiment time. As a result, the yearly operation time had kept the same level as the ordinary one. The ion beam of erbium (Er) with 11.7MeV was accelerated newly by the tandem accelerator, whose intensity was 20nA at charge state of 3+. The sequential generation/irradiation of two different kinds of fullerene ions was achieved at the ion implanter by a mixed powder method without exchange of the Freeman type ion source by the user's request.

Journal Articles

Operation of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Nara, Takayuki; Kitano, Toshihiko*; et al.

Dai-7-Kai Takasaki Oyo Kenkyu Shimpojiumu Yoshishu, P. 119, 2012/10

The three electrostatic accelerators at TIARA had no damage when the Tohoku earthquake happened on March 11, 2011. But, they could not be operated until end of April, due to the influence of planned power outage and keep out into the controlled area for radiation. These accelerators additionally operated on Saturday for twelve days in order to compensate for the lost experiment time. Therefore, the yearly operation time had kept the same level as the ordinary one. The tandem accelerator has stopped leakage of the SF$$_{6}$$ gas from the base flange on the tank by the Viton gasket of rectangular cross section at the new type.

Journal Articles

Erosion of $$N$$=20 shell in $$^{33}$$Al investigated through the ground-state electric quadrupole moment

Shimada, Kenji*; Ueno, Hideki*; Neyens, G.*; Asahi, Koichiro*; Balabanski, D. L.*; Daugas, J. M.*; Depuydt, M.*; De Rydt, M.*; Gaudefroy, L.*; Gr$'e$vy, S.*; et al.

Physics Letters B, 714(2-5), p.246 - 250, 2012/08

 Times Cited Count:6 Percentile:58.11(Astronomy & Astrophysics)

no abstracts in English

Journal Articles

Current status of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Kitano, Toshihiko*; Takayama, Terumitsu*; Orimo, Takao*; Kanai, Shinji*; Aoki, Yuki*; Yamada, Naoto*; et al.

Dai-25-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.64 - 66, 2012/07

The three electrostatic accelerators at the TIARA had no damage when the Tohoku earthquake happened on March 11, 2011. But, they could not be operated until end of April, due to the influence of planned power outage and keep out into the controlled area for radiation. These accelerators additionally operated on Saturday for twelve days in order to compensate for the lost experiment time. Therefore, the yearly operation time had kept the same level as the ordinary one. The tandem accelerator has stopped leakage of the SF$$_{6}$$ gas from the base flange on the tank by the Viton gasket of rectangular cross section at the new type. The ion implanter could generate two kinds of fullerene ions by a mixed material of ions and a controlled temperature of the oven without exchange of ion source.

Journal Articles

Radionuclide release to stagnant water in Fukushima-1 Nuclear Power Plant

Nishihara, Kenji; Yamagishi, Isao; Yasuda, Kenichiro; Ishimori, Kenichiro; Tanaka, Kiwamu; Kuno, Takehiko; Inada, Satoshi; Goto, Yuichi

Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.13 - 19, 2012/03

After the severe accident in the Fukushima-1 Nuclear Power Plant, large amount of contaminated stagnant water has been produced in turbine buildings and those surroundings. This rapid communication reports calculation of radionuclide inventory in the core, collection of measured inventory in the stagnant water, and estimation of radionuclide release ratios from the core to the stagnant water. The present evaluation is based on data obtained before June 3, 2011.

Journal Articles

Development of beam generation and irradiation technology for electrostatic accelerators

Yokoyama, Akihito; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Agematsu, Takashi

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 158, 2012/01

no abstracts in English

Journal Articles

Operation of the electrostatic accelerators

Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Yokota, Wataru; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 173, 2012/01

Three electrostatic accelerators of TIARA were operated smoothly in FY 2010, and all the planned experiments were carried out except those canceled by users or the impact of Great East Japan Earthquake on March 11, 2011. On the other hand, Saturday operation for experiments was carried out after October on the Global Nuclear-Human Resource Development Initiative. The yearly operation time of the tandem accelerator, the single-ended accelerator and the ion implanter amounted to 2116, 2367 and 1800 hours, respectively, which were similar to those of usual years. Regarding the single-ended accelerator, the generator in the high-voltage terminal failed and was replaced with new one. A switching magnet was installed for a new branch beam line of the ion implanter. As to the tandem accelerator, In ion was generated and accelerated at intensity of 500 nA.

Journal Articles

Status of TIARA facility

Yamada, Keisuke; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08

no abstracts in English

Journal Articles

Current status of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Agematsu, Takashi; Kitano, Toshihiko*; Takayama, Terumitsu*; Orimo, Takao*; Kanai, Shinji*; Aoki, Yuki*; et al.

Dai-24-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.125 - 128, 2011/07

The yearly operation time of three electrostatic accelerators at TIARA of Japan Atomic Energy Agency is keeping the same level since 2000, the tandem accelerator, the ion implanter and the single-ended accelerator amounted to about 2000, 1900 and 2500 hours, respectively. Three electrostatic accelerators did not have damage when the Tohoku Earthquake occurred on March 11, 2011. However, these accelerators were not able to operate during the planned power outage by Tokyo Electric Power Company (TEPCO). The tandem accelerator accelerated ion beam of In, which gave intensity of 500nA with stability. Additionally, the ion implanter generated maximum 400nA at ion beam of Gd, which was used in experiments for the users.

116 (Records 1-20 displayed on this page)