Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2021

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.

Petrology and mineralogy of an igneous clast in the Northwest Africa 1685 (LL4) chondrite; Comparison with alkali-rich igneous clasts in LL-chondritic breccias

Niihara, Takafumi*; Yokoyama, Tatsunori; Arai, Tomoko*; Misawa, Keiji*

Meteoritics & Planetary Science, 56(8), p.1619 - 1625, 2021/08

https://doi.org/10.1111/maps.13719

We have conducted petrological and mineralogical studies on an igneous clast in the Northwest Africa (NWA) 1685 (LL4) chondrite. In an earlier description, the meteorite contained similar clasts in the LL chondritic breccias Yamato (Y)-74442 (LL4), Bhola (LL3-6), and Kraehenberg (LL5). We carefully compared their textures as well as mineral and matrix compositions with those of alkali-rich clasts in the LL chondritic breccias. Olivine grains are embedded in glassy matrix and have no chemical. Shock melt veins and fractures were observed only in olivine grains and did not continue to matrix. Major and minor element compositions of olivine grains in the clast are homogeneous. Potassium abundance of matrix glasses of the NWA 1685 clast is lower than those of alkali-rich igneous clasts in Y-74442, Bhola, and Kraehenberg, indicating that the igneous clasts in NWA 1685 are different from the alkali-rich clasts previously reported in the LL chondritic breccias and that they could have formed during an impact melting event, quenched on the LL-chondrite parent body, and finally incorporated into breccia.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2018

Nakano, Masanao; Fujii, Tomoko; Nemoto, Masashi; Tobita, Keiji; Kono, Takahiko; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Maehara, Yushi; Narita, Ryosuke; et al.

JAEA-Review 2019-048, 165 Pages, 2020/03

JAEA-Review-2019-048.pdf:2.69MB

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 2018 to March 2019. 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.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2016

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Hosomi, Kenji; Nagaoka, Mika; Hokama, Tomonori; Nishimura, Tomohiro; Koike, Yuko; et al.

JAEA-Review 2017-028, 177 Pages, 2018/01

JAEA-Review-2017-028.pdf:3.61MB

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 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. 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 were exceeded the normal range of fluctuation in the monitoring, were evaluated.

Effects of the radial electric field on the confinement of fast ions in ITER

Tani, Keiji*; Honda, Mitsuru; Oikawa, Toshihiro*; Shinohara, Koji; Kusama, Yoshinori; Sugie, Tatsuo

Nuclear Fusion, 55(5), p.053010_1 - 053010_15, 2015/05

AA2014-0355.pdf:2.0MB

https://doi.org/10.1088/0029-5515/55/5/053010

The effects of a radial electric field (EF) on the losses of alpha particles and NBI fast ions in typical ITER operation scenarios for both error fields due to test blanket modules (TBMs) and toroidal field (TF) ripple were evaluated using an iterative method to execute an orbit-following Monte-Carlo code and a one-dimensional transport code. The EF effect on the loss of fast ions strongly depends on the operation scenario as well as on the error field. The electric field is very significant in the loss of fast ions in a 9MA ITER operation scenario with a higher safety factor and in the error field associated with TBMs. The EF effect in the error field of TF-ripple is very small in any operation scenario. The radial electric field changes the toroidal precession of fast ions and consequently alter their condition of resonance with the error field, which may account for the EF effect on the loss of fast ions in ITER with TBMs.

Hydrogeomechanical investigation of an excavation damaged zone in the Horonobe Underground Research Laboratory

Aoyagi, Kazuhei; Tsusaka, Kimikazu*; Nohara, Shintaro*; Kubota, Kenji*; Tokiwa, Tetsuya*; Kondo, Keiji*; Inagaki, Daisuke*

Proceedings of 8th Asian Rock Mechanics Symposium (ARMS-8) (USB Flash Drive), 8 Pages, 2014/10

Horonobe Underground Research Laboratory Project; Investigation report for the 2011 fiscal year

Nakayama, Masashi; Amano, Kenji; Tokiwa, Tetsuya; Yamamoto, Yoichi; Oyama, Takuya; Amano, Yuki; Murakami, Hiroaki; Inagaki, Daisuke; Tsusaka, Kimikazu; Kondo, Keiji; et al.

JAEA-Review 2012-035, 63 Pages, 2012/09

JAEA-Review-2012-035.pdf:12.23MB

The Horonobe Underground Research Laboratory Project is planned to extend over a period 20 years. The investigations will be conducted in three phases, namely "Phase 1: Surface-based investigations", "Phase 2: Construction Phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase"(research in the underground facilities). This report summarizes the results of the investigations for the 2011 fiscal year (2011/2012). The investigations, which are composed of "Geoscientific research" and "R&D on geological disposal technology", were carried out according to "Horonobe Underground Research Laboratory Project Investigation Program for the 2011 Fiscal year". The results of these investigations, along with the results which were obtained in other departments of Japan Atomic Energy Agency (JAEA), are properly offered to the implementations and the safety regulations. For the sake of this, JAEA has proceeded with the project in collaboration with experts from domestic and overseas research organisations.

Effects of ELM mitigation coils on energetic particle confinement in ITER steady-state operation

Tani, Keiji*; Shinohara, Koji; Oikawa, Toshihiro*; Tsutsui, Hiroaki*; Miyamoto, Seiji; Kusama, Yoshinori; Sugie, Tatsuo

Nuclear Fusion, 52(1), p.013012_1 - 013012_21, 2012/01

https://doi.org/10.1088/0029-5515/52/1/013012

3D effect of ferromagnetic materials on alpha particle power loads on first wall structures and equilibrium on ITER

Shinohara, Koji; Kurki-Suonio, T.*; Spong, D.*; Asunta, O.*; Tani, Keiji*; Strumberger, E.*; Briguglio, S.*; Gnter, S.*; Koskela, T.*; Kramer, G.*; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/node77.htm#19143

A Dinuclear Ni(-H)Ru complex derived from H

Ogo, Seiji*; Kabe, Ryota*; Uehara, Keiji*; Kure, Bunsho*; Nishimura, Takashi*; Menon, S. C.*; Harada, Ryosuke*; Fukuzumi, Shunichi*; Higuchi, Yoshiki*; Ohara, Takashi; et al.

Science, 316(5824), p.585 - 587, 2007/04

https://doi.org/10.1126/science.1138751

A novel dinuclear nickel-ruthenium complex with a bridging hydrido ligand, a Ni(-H)Ru complex, was obtained from the reaction of a dinuclear NiRu aqua complex with dihydrogen (H) in water under ambient conditions. The structure of the Ni(-H)Ru complex was unequivocally determined by neutron analysis. This is the first crystal structure of (six-coordinated Ni)(-H)M (M=transition metal atoms) that is similar to the core structure of the proposed active form of the [NiFe]hydrogenase.