Actively convected liquid metal divertor

Shimada, Michiya; Hirooka, Yoshihiko*

Nuclear Fusion, 54(12), p.122002_1 - 122002_7, 2014/12

https://doi.org/10.1088/0029-5515/54/12/122002

Tungsten is considered to be the most promising material for divertor in a fusion reactor. Tungsten divertor can withstand the heat loads of ITER, but the heat loads of DEMO divertor is a challenge. Pulsive heat loads as those associated with disruption could melt tungsten targets. The surface would not be flat after subsequent resolidification, which would significantly deteriorate its heat handling capability. Furthermore, DBTT of tungsten is rather high: 400C, which would become even higher after neutron irradiation, possibly resulting in cracks in tungsten. Our proposal is to use liquid metal for the divertor target material and actively circulate it with force. A simplified analysis of mhd equation in a cylindrical geometry suggests that the engineering requirement is modest. This analysis suggests that this new divertor concept merits further investigation.

Evaluation of contact strength of LiTiO pebbles with different diameters

Tsuchiya, Kunihiko; Kawamura, Hiroshi; Tanaka, Satoru*

Fusion Engineering and Design, 81(8-14), p.1065 - 1069, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.07.031

no abstracts in English

Confinement of alpha particles in a low-aspect-ratio tokamak reactor

Tani, Keiji; Tobita, Kenji; Iio, Shunji*; Tsutsui, Hiroaki*; Nishio, Satoshi; Aoki, Takayuki*

Denki Gakkai Rombunshi, A, 125(11), p.938 - 942, 2005/11

https://doi.org/10.1541/ieejfms.125.938

Studies on the loss of fusion produced alpha particles enhanced by toroidal field (TF) ripple in a low-aspect-ratio tokamak reactor (VECTOR) have been made by using an orbit-following Monte-Carlo code. The ripple loss is strongly reduced as the aspect ratio becomes low. Consequently, alpha particles are well confined in VECTOR. Thanks to the good confinement of alphas in a low-aspect-ratio system, the number of TF coils can be reduced to about 6, one half of the original VECTOR, by installing cooling systems near the outer edge of plasma and making allowances for about 30% increase in the bore diameter of TF coils.

Behavior on LiTiO under varied surface condition

Olivares, R.*; Oda, Takuji*; Oya, Yasuhisa*; Tanaka, Satoru*; Tsuchiya, Kunihiko

Fusion Engineering and Design, 75-79, p.765 - 768, 2005/11

https://doi.org/10.1016/j.fusengdes.2005.06.041

no abstracts in English

Control of particle size and density of LiTiO pebbles fabricated by indirect wet processes

Tsuchiya, Kunihiko; Kawamura, Hiroshi; Takayama, Tomoo*; Kato, Shigeru*

Journal of Nuclear Materials, 345(2-3), p.239 - 244, 2005/10

https://doi.org/10.1016/j.jnucmat.2005.06.005

no abstracts in English

Intelligible seminar on fusion reactors, 7; Optimum materials for the realization of fusion reactor

Hasegawa, Akira*; Tsuchiya, Kunihiko; Ishitsuka, Etsuo

Nihon Genshiryoku Gakkai-Shi, 47(8), p.536 - 544, 2005/08

http://ci.nii.ac.jp/naid/10015604920

no abstracts in English

Local bonding states of ion-irradiated graphite characterized by photon-stimulated desorption (PSD) spectroscopy

Sekiguchi, Tetsuhiro; Baba, Yuji; Shimoyama, Iwao; Nath, K. G.

Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.437 - 441, 2005/06

https://doi.org/10.1016/j.elspec.2005.01.156

no abstracts in English

Low temperature tritium release experiment from lithium titanete breeder material

Tsuchiya, Kunihiko; Kawamura, Hiroshi; Nakamichi, Masaru*; Sagawa, Hisashi

JAERI-Tech 2005-013, 56 Pages, 2005/03

JAERI-Tech-2005-013.pdf:6.4MB

no abstracts in English

Optimization study on the normal conducting center post for the low aspect ratio tokamak reactor

Song, Y.*; Nishio, Satoshi

Fusion Engineering and Design, 72(4), p.345 - 362, 2005/01

https://doi.org/10.1016/j.fusengdes.2004.08.002

This paper presents detailed optimization results and design windows for the engineering design of normal conducting (NC) center post based on the analysis of thermal-hydraulic, static stress and critical buckling. At the same time a method to reduce the stress in the center post have been proposed, which can be applied to enhance the possibility of normal conducting center post in the future power plants. When the method of improvement for reducing the stress is applied in the system of the center post, the maximum magnet field can be improved from 8.6T to 15T.

Extra radiation hardening and microstructural evolution in F82H by high-dose dual ion irradiation

Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Matsukawa, Shingo; Naito, Akira*; Jitsukawa, Shiro; Oka, Keiichiro*; Tanaka, Teruyuki*; Onuki, Somei*

JAERI-Review 2004-025, TIARA Annual Report 2003, p.159 - 161, 2004/11

https://jopss.jaea.go.jp/pdfdata/JAERI-Review-2004-025-p0117-p0247.pdf

The objectives of this study are to evaluate radiation hardening on ion-irradiated F82H up to 100 dpa and to examine the extra component of radiation hardening due to implanted helium atoms (up to 3000 appmHe) in F82H under ratio of 0, 10, 100 appmHe/dpa.The ion-beam irradiation experiment was carried out at the TIARA facility of JAERI. Specimens were irradiated at 633 K by 10.5 MeV Fe ions with/without 1.05 MeV He ions. Micro-indentation tests were performed at loads to penetrate about 0.40 mm in the irradiated specimens using an UMIS-2000. The results are summarized as follows:1) As a result of the single irradiated F82H, the micro-hardness tended to increase about 30 dpa. 2) The extra radiation hardening was obviously caused by co-implanted helium atoms more than 1000 appm in F82H irradiated at 633 K. 3) In the dual-beam (100 appmHe/dpa) irradiated microstructure, nano-voids and fine defects were observed. It is suggested that the formation of nano-voids causes the extra radiation hardening by helium co-implantation.