Applicability evaluation of Type A transport container for off-site transportation of small-amount of fuel debris

Sakamoto, Masahiro; Okumura, Keisuke; Kanno, Ikuo; Matsumura, Taichi; Terashima, Kenichi; Riyana, E. S.; Mizokami, Masato*; Mizokami, Shinya*

JAEA-Research 2024-017, 14 Pages, 2025/03

JAEA-Research-2024-017.pdf:1.34MB

In the TEPCO's Fukushima Daiichi Nuclear Power Station (1F), a trial retrieval of fuel debris with small-amount from Unit 2 is planned. The retrieved fuel debris will be transported out of 1F to Institutes in Ibaraki prefecture for analysis. The analyzed results will be utilized for the improvement of the processes (retrieval, transportation and storage) in the fuel debris management as feedback, and also for the development of technologies necessary in the future. The weight of fuel debris in the trial retrieval is planned to be a few grams. After the trial, the scale of retrieval will be expanded step by step. In the trial retrieval, a rational transportation container should be considered beforehand, according to the laws and regulations associated with the off-site transportation. The transportation container has a classification and the classification is decided according to the radioactivity of the material in the container. In this report, we evaluated the applicability of the Type A transport container to contribute to the safety assessment of retrieved fuel debris.

Development of a theoretical scaling factor method for the inventory estimation of difficult-to-measure nuclide Cs-135 in fuel debris and radioactive wastes

Sakamoto, Masahiro; Okumura, Keisuke; Kanno, Ikuo; Matsumura, Taichi; Terashima, Kenichi; Riyana, E. S.; Kaneko, Junichi*; Mizokami, Masato*; Mizokami, Shinya*

Journal of Nuclear Science and Technology, 10 Pages, 2025/00

https://doi.org/10.1080/00223131.2025.2478926

Origin of magnetically dead layers in spinel ferrites FeO grown on AlO; Effects of postdeposition annealing studied by XMCD

Nonaka, Yosuke*; Wakabayashi, Yuki*; Shibata, Goro; Sakamoto, Shoya*; Ikeda, Keisuke*; Chi, Z.*; Wan, Y.*; Suzuki, Masahiro*; Tanaka, Arata*; Tanaka, Masaaki*; et al.

Physical Review Materials (Internet), 7(4), p.044413_1 - 044413_10, 2023/04

https://doi.org/10.1103/PhysRevMaterials.7.044413

Depletion calculation of subcritical system with consideration of spontaneous fission reaction

Riyana, E. S.; Okumura, Keisuke; Sakamoto, Masahiro; Matsumura, Taichi; Terashima, Kenichi

Journal of Nuclear Science and Technology, 59(4), p.424 - 430, 2022/04

https://doi.org/10.1080/00223131.2021.1974970

Gamma detector response simulation inside the pedestal of Fukushima Daiichi Nuclear Power Station

Riyana, E. S.; Okumura, Keisuke; Terashima, Kenichi; Matsumura, Taichi; Sakamoto, Masahiro

Mechanical Engineering Journal (Internet), 7(3), p.19-00543_1 - 19-00543_8, 2020/06

https://doi.org/10.1299/mej.19-00543

Analysis of radicals induced in irradiated foods

Kishida, Keigo*; Kaimori, Yoshihiko*; Kawamura, Shoei*; Sakamoto, Yuki*; Nakamura, Hideo*; Kikuchi, Masahiro; Shimoyama, Yuhei; Kobayashi, Yasuhiko; Ukai, Mitsuko*

Shokuhin Shosha, 47(1), p.1 - 5, 2012/09

https://doi.org/10.5986/jrafi.47.1

no abstracts in English

Progress of high-power and long-pulse ECRF system development in JT-60

Kobayashi, Takayuki; Isayama, Akihiko; Yokokura, Kenji; Shimono, Mitsugu; Hasegawa, Koichi; Sawahata, Masayuki; Suzuki, Sadaaki; Terakado, Masayuki; Hiranai, Shinichi; Sato, Fumiaki; et al.

Nuclear Fusion, 51(10), p.103037_1 - 103037_10, 2011/10

https://doi.org/10.1088/0029-5515/51/10/103037

A new gyrotron operation technique to increase oscillation efficiency was developed on the JT 60 ECRF system. The electron pitch factor was optimized by controlling anode voltage within 0.1 s after the start of the operation. By applying this technique, the gyrotron output power of 1.5 MW for 4 s was recorded, for the first time. The reduced collector heat load at 1.5 MW operations was reduced by 20% and it will be acceptable for longer pulse operation. A new gyrotron with an improved mode converter was developed in order to demonstrate reduction of the stray radiation which had limited the pulse length. The stray radiation was reduced to 1/3 of that of the original gyrotron. A conditioning operation of the improved gyrotron is proceeding up to 31 s at 1 MW. These progresses significantly contribute to enhancing the high power and long pulse capability of the ECRF system toward JT 60SA.

Research and development of nuclear fusion

Ushigusa, Kenkichi; Seki, Masahiro; Ninomiya, Hiromasa; Norimatsu, Takayoshi*; Kamada, Yutaka; Mori, Masahiro; Okuno, Kiyoshi; Shibanuma, Kiyoshi; Inoue, Takashi; Sakamoto, Keishi; et al.

Genshiryoku Handobukku, p.906 - 1029, 2007/11

no abstracts in English

Development of completely Solenoidless tokamak operation in JT-60U

Ushigome, Masahiro*; Ide, Shunsuke; Ito, Satoshi*; Jotaki, Eriko*; Mitarai, Osamu*; Shiraiwa, Shunichi*; Suzuki, Takahiro; Takase, Yuichi*; Tanaka, Shigetoshi*; Fujita, Takaaki; et al.

Nuclear Fusion, 46(2), p.207 - 213, 2006/02

https://doi.org/10.1088/0029-5515/46/2/003

This papaer studies on tokamak plasma start-up completely without central solenoid (CS). On the JT-60 tokamak it is demonstrated that a completely CS-less Ip start-up to 100 kA was achieved even without any null-point by Electron cyclotron range of frequencies (ECRF) and outer PF coil current swing only. Necessary conditions (the EC power, the toroidal field etc.) were clarified. Moreover, it was succeded to maintain Ip = 260kA for 1 sec without CS by NB only. In addition Ip ramp-up by EC and NB only (without LHCD) from 215 to 310kA was achieved. In a high confinement reversed shear discharge, a result suggesting bootstrap over drive was obtained.

Objectives and design of the JT-60 superconducting tokamak

Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.

Nuclear Fusion, 43(7), p.606 - 613, 2003/07

https://doi.org/10.1088/0029-5515/43/7/314

no abstracts in English