Sodium-cooled Fast Reactors

Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.

Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07

https://shop.elsevier.com/books/sodium-cooled-fast-reactors/morishita/978-0-12-824076-2

This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.

Progress of divertor simulation research toward the realization of detached plasma using a large tandem mirror device

Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.

Journal of Nuclear Materials, 463, p.537 - 540, 2015/08

https://doi.org/10.1016/j.jnucmat.2014.12.063

Roles of argon seeding in energy confinement and pedestal structure in JT-60U

Urano, Hajime; Nakata, Motoki; Aiba, Nobuyuki; Kubo, Hirotaka; Honda, Mitsuru; Hayashi, Nobuhiko; Yoshida, Maiko; Kamada, Yutaka; JT-60 Team

Nuclear Fusion, 55(3), p.033010_1 - 033010_9, 2015/03

https://doi.org/10.1088/0029-5515/55/3/033010

Physics picture of improving energy confinement with argon seeding at high density has been investigated in JT-60U. Better confinement is sustained at high density by argon seeding accompanied by higher core and pedestal temperatures. Peaked density profiles are kept with argon seeding. Density peaking and dilution effects lower the pedestal density at a given averaged density. The pedestal density in the argon seeded plasmas which is relatively lower than that in a single deuterium puff enables the pedestal temperature to be higher. The density peaking is a key factor of sustaining better confinement in argon seeded H-mode plasmas.

Dismantlement of large fusion experimental device JT-60U

Ikeda, Yoshitaka; Okano, Fuminori; Sakasai, Akira; Hanada, Masaya; Akino, Noboru; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; Kubo, Hirotaka; Kobayashi, Kazuhiro; et al.

Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(4), p.167 - 178, 2014/12

https://doi.org/10.3327/taesj.J14.007

The JT-60U torus was disassembled so as to newly install the superconducting tokamak JT-60SA torus. The JT-60U used the deuterium for 18 years, so the disassembly project of the JT-60U was the first disassembly experience of a fusion device with radioactivation in Japan. All disassembly components were stored with recording the data such as dose rate, weight and kind of material, so as to apply the clearance level regulation in future. The lessons learned from the disassembly project indicated that the cutting technologies and storage management of disassembly components were the key factors to conduct the disassembly project in an efficient way. After completing the disassembly project, efforts have been made to analyze the data for characterizing disassembly activities, so as to contribute the estimation of manpower needs and the radioactivation of the disassembly components on other fusion devices.

Development of divertor simulation research in the GAMMA 10/PDX tandem mirror

Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.

Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10

Magnification of a polarization angle with a Littrow layout brazed grating

Sasao, Hajime; Arakawa, Hiroyuki*; Kubo, Hirotaka; Kawano, Yasunori; Itami, Kiyoshi

Review of Scientific Instruments, 85(8), p.086106_1 - 086106_3, 2014/08

https://doi.org/10.1063/1.4892478

The Emission rates of CH, CD and C spectral bands and a re-evaluation of the chemical sputtering yield of the JT-60U carbon divertor plates

Nakano, Tomohide; Higashijima, Satoru; Kubo, Hirotaka; Asakura, Nobuyuki; Fukumoto, Masakatsu

Nuclear Fusion, 54(4), p.043004_1 - 043004_10, 2014/03

https://doi.org/10.1088/0029-5515/54/4/043004

We have determined the CH photon emission rate defined as the number of photons over dissociation and/or ionization event of , from the ratio of the measured emission intensity of CH spectral band to the injection rate into the divertor plasma of JT-60U. Similar photon emission rates of CD for , CH and for and have also been determined. Interestingly, during the and the injection, the spectral band intensity increases, suggesting that injected reacts with the carbon divertor plates to form heavier hydrocarbons. From the determined emission rates, previously published chemical sputtering yields, have been reevaluated. The reevaluated total chemical sputtering yield becomes lower () compared to the original () and the dependence on the incident ion flux and energy becomes weaker.

Contribution of Ne ions to radiation enhancement in JT-60U divertor plasmas

Nakano, Tomohide; Asakura, Nobuyuki; Kubo, Hirotaka; JT-60 Team

Journal of Nuclear Materials, 438, p.S291 - S296, 2013/07

https://doi.org/10.1016/j.jnucmat.2013.01.049

It is already concluded that neon injection is more effective than argon injection in order to enhance the radiative power from the divertor plasmas in JT-60U. In this study, we have investigated radiation processes of neon ions in low-temperature and high-density divertor plasmas with spectroscopic technique. It was observed that the emission intensities of Ne VII spectral lines became high during plasma detachment. A collisional-radiative model analysis with the intensity ratio of Ne VII emission lines gave an electron temperature of 100 eV and a radiative power of only 5% of total radiative power, measured with a bolometer. Because C IV emission intensity was low, it is probable that the radiative power of C IV was also low. Therefore, it is possible that neon and carbon ions at other charge states contribute much to the total radiative power from the divertor plasma.

Highly charged tungsten spectra observed from JT-60U plasmas at 8 and 14 keV

Yanagibayashi, Jun*; Nakano, Tomohide; Iwamae, Atsushi; Kubo, Hirotaka; Hasuo, Masahiro*; Itami, Kiyoshi

Journal of Physics B; Atomic, Molecular and Optical Physics, 43(14), p.144013_1 - 144013_6, 2010/07

https://doi.org/10.1088/0953-4075/43/14/144013

We observe the vacuum ultraviolet spectra of highly charged tungsten ions in plasmas at electron temperatures of 8 keV and 14 keV. The observed emission lines in a wavelength range of 2.6 3.2 nm for the plasma at 8 keV are identified to be the transitions of . The observed emission lines at 2.0 nm and 2.3 nm at 14 keV are identified to be the transitions of and transitions of , respectively.

Zeeman polarimetry measurement for edge current density determination using Li-beam probe on JT-60U

Kamiya, Kensaku; Fujita, Takaaki; Kojima, Atsushi; Kubo, Hirotaka

Review of Scientific Instruments, 81(3), p.033502_1 - 033502_8, 2010/03

https://doi.org/10.1063/1.3309793

Zeeman polarimetry system has been developed for the edge current density measurement in the JT-60U tokamak. The diagnostic has 20-ch viewing chords covering the plasma peripheral region with a spatial resolution of 1cm. Li-beam injection with beam current of up to 5mA has been achieved. The edge current density profile with the local peak at / 0.9 has been identified in the H-mode plasma, which is correlated with large pressure gradient in the pedestal region.