Plant system study of France-Japan common concept on Sodium-cooled Fast Reactor

Kato, Atsushi; Yamamoto, Tomohiko; Ando, Masato; Chikazawa, Yoshitaka; Murakami, Hisatomo*; Oyama, Kazuhiro*; Kaneko, Fumiaki*; Higurashi, Koichi*; Chanteclair, F.*; Chenaud, M.-S.*; et al.

EPJ Nuclear Sciences & Technologies (Internet), 8, p.11_1 - 11_10, 2022/06

https://doi.org/10.1051/epjn/2022006

This paper provides an overview of plant system studies to establish a common technical view for Sodium-cooled Fast Reactor concept between France and Japan based on ASTRID600 and the new concept with downsized output called ASTRID150. One of important issues on a reactor structure design is to enhance seismic resistance to be tolerable against strong earthquake such that postulated in Japan. A concept of High Frequency Design is shared, and the design options related to HFD have been examined and design recommendations are established. In addition, this paper include results of studies for a steam generator, a decay heat removal system, a fuel handling system and a containment vessel.

Safety enhancement approach against external hazard on JSFR reactor building

Yamamoto, Tomohiko; Kato, Atsushi; Chikazawa, Yoshitaka; Hara, Hiroyuki*

Nuclear Technology, 206(12), p.1875 - 1890, 2020/12

https://doi.org/10.1080/00295450.2020.1726155

This paper gives a detailed evaluation of the countermeasures for the external hazards and severe accidents that could impact the 2010 JSFR design building by lessons learned from the Fukushima Daiichi Nuclear Power Plant (Fukushima I NPP) accident.

New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

https://doi.org/10.1007/s10751-016-1381-7

Secondary sodium fire measures in JSFR

Chikazawa, Yoshitaka; Kato, Atsushi*; Yamamoto, Tomohiko; Kubo, Shigenobu; Ohno, Shuji; Iwasaki, Mikinori*; Hara, Hiroyuki*; Shimakawa, Yoshio*; Sakaba, Hiroshi*

Nuclear Technology, 196(1), p.61 - 73, 2016/10

https://doi.org/10.13182/NT15-131

JSFR adopts double boundary for all sodium components. However, design measures are investigated for the secondary sodium fire inside the reactor building, which might be assumed as design extension conditions (DECs). Candidates of sodium fire measures in the secondary sodium systems such as sodium drain, nitrogen injection, pressure release valve, catch pan and leak sodium drain system have been compared from the view point of safety. Wide range of sodium fires in the steam generator room and air cooler have been analyzed evaluating performances of the candidate sodium fire measures.

Epitaxial transformation of hcp-fcc Ti sublattices during nitriding processes of evaporated-Ti thin films due to nitrogen-implantation

Chen, Y.*; Feng, X.*; Kasukabe, Yoshitaka*; Yamamoto, Shunya; Yoshikawa, Masahito; Fujino, Yutaka*

Journal of Alloys and Compounds, 577(Suppl.1), p.S18 - S24, 2013/11

https://doi.org/10.1016/j.jallcom.2011.10.113

Epitaxial transformation processes of titanium films due to Nitrogen-implantation have been clarified through in-situ observations by using transmission electron microscope(TEM)and electron energy loss spectroscope, along with molecular orbital calculations. The N ions with 62 keV are implanted into as-deposited Ti films which consist of hcp-Ti and TiH with preferred orientations, in the 400 kV analytic high resolution TEM combined with ion accelerators at JAEA Takasaki. Thus, titanium nitride (TiN) films with preferred orientations are epitaxially formed by the inheritance of partial atomic arrangement of hcp-Ti or TiH in as-deposited Ti films and by the occupation of octahedral sites by N atoms, which elucidates that epitaxial transformation of hcp-fcc Ti sublattices occurs.

Evaluation of external hazard on JSFR reactor building

Yamamoto, Tomohiko; Kato, Atsushi; Chikazawa, Yoshitaka; Ito, Kei; Iwasaki, Mikinori*; Akiyama, Yo*; Oya, Takeaki*

Proceedings of 2013 International Congress on Advances in Nuclear Power Plants (ICAPP 2013) (USB Flash Drive), 9 Pages, 2013/04

The Japan sodium-cooled fast reactor (JSFR) is planning to adopt a steel-plate reinforced concrete (SC) structure reactor building and an advanced seismic isolation system for reactor building. In the response of Fukushima Dai-ichi Nuclear Power Plant (Fukushima I NPP) accident, the evaluation and countermeasure study of earthquake, and other external hazards on JSFR has been analyzed based on 2010 JSFR design. This paper describes the detail of evaluation and countermeasure of earthquake, tsunami and other external hazards to JSFR reactor building.

Design evaluation method of steel-plate reinforced concrete structure containment vessel for sodium-cooled fast reactor

Yamamoto, Tomohiko; Kato, Atsushi; Chikazawa, Yoshitaka; Negishi, Kazuo

Journal of Disaster Research, 7(5), p.645 - 655, 2012/10

http://www.fujipress.jp/finder/xslt.php?mode=present&inputfile=DSSTR000700050016.xml

Japan Sodium-cooled Fast Reactor (JSFR) adopts a new concept of a containment vessel called steel plate reinforced concrete containment vessel (SCCV). The SCCV is considered to be effective to shorten construction period thanks for elimination of rebar work at a site compared with applying a reinforced concrete CV. An SFR CV is lower pressure environment than the LWR CV, although environmental temperature of the SFR is much higher than that of LWR in the accident of coolant leakage. Therefore it is important to investigate its characteristics under high temperature to adopt the SC structure to the JSFR CV because the CV shall keep their containment function in the accidents to be assumed in design. This paper describes the construction of design evaluation method from design, experimental and analytical point of view.

In-situ observation of nitriding processes of evaporated-Ti thin films due to ion implantation in an analytical transmission electron microscope

Kasukabe, Yoshitaka*; Chen, Y.*; Yamamoto, Shunya; Yoshikawa, Masahito; Fujino, Yutaka*

e-Journal of Surface Science and Nanotechnology (Internet), 9, p.191 - 198, 2011/04

https://doi.org/10.1380/ejssnt.2011.191

The purpose of this work is to study changes of the crystallographic and electronic structures of Ti films by heating and by nitriding during N-implantation into Ti films, using in-situ transmission electron microscope equipped with the instrument for electron energy loss spectroscopy, and then to clarify the atomistic nitriding processes of Ti thin films due to the N-implantation with the aid of self-consistent charge discrete variational X molecular orbital calculations. It is clarified that the maximum concentration of N in Ti films during the N-implantation and the change of electronic structures near the fermi level, respectively, depend on the implantation temperature and the ratio of N/Ti in Ti films. Furthermore, taking into account the bonding interaction of Ti sublattices with ligand N atoms, the transformation mechanisms between hcp-Ti and fcc-Ti sublattices due to the implantation of N atoms are discussed.

Development of a plasma generator for a high power NBI ion source

Dairaku, Masayuki; Watanabe, Kazuhiro; Tobari, Hiroyuki; Kashiwagi, Mieko; Inoue, Takashi; Sakamoto, Keishi; Hanada, Masaya; Akino, Noboru; Ikeda, Yoshitaka; Yamamoto, Takumi*

JAEA-Technology 2008-091, 23 Pages, 2009/03

JAEA-Technology-2008-091.pdf:5.82MB

A plasma generator whose inner dimensions are 25 cm in width, 59 cm in length, and 31 cm in depth for a high power and long pulse ion source in neutral beam injector has been designed and fabricated. The plasma generator has a beam extraction area of 12 cm in width and 46 cm in length. A target of the output beam using the plasma generator is to produce deuterium positive ion beams up to 120 keV, 65 A for longer than 200 s pulses. Arrangement of the permanent magnets and filaments has been designed by using an electron trajectory simulation code to produce uniform and high density plasma with high proton yield. Cooling channels have been also designed to operate the long pulse plasma generation with a 100 kW arc discharge power.

Atomistic nitriding processes of titanium thin films due to nitrogen-implantation

Kasukabe, Yoshitaka*; Nishida, Shinsaku*; Yamamoto, Shunya; Yoshikawa, Masahito; Fujino, Yutaka*

Applied Surface Science, 254(23), p.7942 - 7946, 2008/09

https://doi.org/10.1016/j.apsusc.2008.03.191

In order to clarify atomistic growth processes of TiN films due to ion implantation, in-situ observations by using transmission electron microscope and electron energy loss spectroscope at JAEA-Takasaki have been carried out, along with composition analysis and with the characterization of the electronic structure by molecular orbital calculation. The characterization of electronic structure of Ti films before and after implantation indicates that octahedral sites of hcp-Ti with larger space have higher electron density, which leads to the invasion of implanted ions into octahedral sites, and that the hcp-fcc transformation is induced by the shear in 010 direction on (001) plane, promoted by the forming of -type covalent bonds mainly consisted of hybridized orbitals due to combination of Ti3d and N2p, and by the weakening of Ti-Ti bonds.