Present status of J-PARC MUSE

Shimomura, Koichiro*; Koda, Akihiro*; Pant, A. D.*; Natori, Hiroaki*; Fujimori, Hiroshi*; Umegaki, Izumi*; Nakamura, Jumpei*; Tampo, Motonobu*; Kawamura, Naritoshi*; Teshima, Natsuki*; et al.

Journal of Physics; Conference Series, 2462, p.012033_1 - 012033_5, 2023/03

https://doi.org/10.1088/1742-6596/2462/1/012033

Three-dimensional cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities (Effects of unburned-gas temperature and heat loss)

Kadowaki, Satoshi; Nogami, Masato*; Thwe Thwe, A.; Katsumi, Toshiyuki*; Yamazaki, Wataru*; Kobayashi, Hideaki*

Nihon Kikai Gakkai Rombunshu (Internet), 85(879), p.19-00274_1 - 19-00274_13, 2019/11

https://doi.org/10.1299/transjsme.19-00274

We dealt with three-dimensional cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities to elucidate the effects of unburned-gas temperature and heat loss by adopting the three-dimensional compressible Navier-Stokes equation. As the unburned-gas temperature became lower and the heat loss became larger, the growth rate decreased and the unstable range narrowed. With a decrease of unburned-gas temperature, the normalized growth rate increased and the normalized unstable range widened, which was because the temperature ratio of burned and unburned gases became larger. The obtained hexagonal cellular fronts were qualitatively consistent with the experimental results. As the heat loss became larger, the burning velocity of a cellular flame normalized by that of a planar flame increased. This was because diffusive-thermal effects became stronger owing to the increase of apparent Zeldovich number caused by the decrease of flame temperature.

Tuning of ultra-slow muon transport system

Adachi, Taihei*; Ikedo, Yutaka*; Nishiyama, Kusuo*; Yabuuchi, Atsushi*; Nagatomo, Takashi*; Strasser, P.*; Ito, Takashi; Higemoto, Wataru; Kojima, Kenji*; Makimura, Shunsuke*; et al.

JPS Conference Proceedings (Internet), 8, p.036017_1 - 036017_4, 2015/09

https://doi.org/10.7566/JPSCP.8.036017

Development of microbeam formation and single-ion hit technologies at the TIARA cyclotron

Yokota, Wataru; Sato, Takahiro; Kamiya, Tomihiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Funayama, Tomoo; Sakashita, Tetsuya; et al.

JAEA-Technology 2014-018, 103 Pages, 2014/09

JAEA-Technology-2014-018.pdf:123.66MB

The world's first microbeam focusing technology for heavy ions of hundreds MeV accelerated by a cyclotron has been developed at the TIARA facility in the Takasaki Advanced Radiation Research Institute of the Japan Atomic Energy Agency. The technology enables us to form a microbeam of less than 1 m in diameter and to shoot a specified point on a target by one ion (single-ion hit) with spatial accuracy of microbeam size. In the course of the development, a cyclotron technology to accelerate a small energy-spread beam of hundres MeV, which is necessary for focusing to 1 m, has been developed as well as a beam focusing apparatus, beam size measurement and so forth based on the several-MeV microbeam/single-ion hit system of the TIARA electrostatic accelerators. Applicability of the technologies was examined by actual use in irradiation experiment and the result were fed back to them. This paper reports the process and the results of the development over ten years.

The EPICS-based remote control system for muon beam line devices J-PARC MUSE

Ito, Takashi; Nakahara, Kazutaka*; Kawase, Masato; Fujimori, Hiroshi*; Kobayashi, Yasuo*; Higemoto, Wataru; Miyake, Yasuhiro*

Journal of Physics; Conference Series, 225, p.012022_1 - 012022_5, 2010/06

https://doi.org/10.1088/1742-6596/225/1/012022

The Experimental Physics and Industrial Control System (EPICS) provides software infrastructure and framework for building distributed control systems (DCS) to operate beam line devices. The DCS based on EPICS has been adopted by many accelerator facilities in the world, where reliability, maintainability, and scalability of the system have been demonstrated. This system is also used to operate the high energy proton accelerator in the Japan Proton Accelerator Research Complex (J-PARC). We here report on the EPICS-based remote control system developed for operating the decay muon beam line in J-PARC. Major functions of beam line devices, three bending magnets, eighteen quadrupole magnets, and four slits, are accessible via Ethernet from a graphical user interface composed of the Motif Editor and Display Manager (MEDM).

J-PARC decay muon channel construction status

Strasser, P.*; Shimomura, Koichiro*; Koda, Akihiro*; Kawamura, Naritoshi*; Fujimori, Hiroshi*; Makimura, Shunsuke*; Kobayashi, Yasuo*; Nakahara, Kazutaka*; Kato, Mineo*; Takeshita, Soshi*; et al.

Journal of Physics; Conference Series, 225, p.012050_1 - 012050_8, 2010/06

https://doi.org/10.1088/1742-6596/225/1/012050

Recent results of R&D activities on tritium technologies for ITER and fusion reactors at TPL of JAEA

Yamanishi, Toshihiko; Hayashi, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Arita, Tadaaki; Hoshi, Shuichi; et al.

Fusion Engineering and Design, 83(10-12), p.1359 - 1363, 2008/12

https://doi.org/10.1016/j.fusengdes.2008.08.010

At TPL (Tritium Process Laboratory) of JAEA, ITER relevant tritium technologies have been studied. The design studies of Air Detritiation System have been carried out in JAEA as a contribution of Japan to ITER. For the tritium processing technologies, our efforts have been focused on the research of the tritium recovery system of ITER test blanket system. A ceramic proton conductor has been studied as an advanced blanket system. A series of fundamental studies on tritium safety technologies not only for ITER but also for fusion DEMO plants has also been carried out at TPL of JAEA. The main research activities in this field are the tritium behavior in a confinement and its barrier materials; monitoring; accountancy; detritiation and decontamination etc. In this paper, the results of above recent activities at TPL of JAEA are summarized from viewpoint of ITER relevant and future fusion DEMO reactors.

Operational results of the safety systems of the tritium process laboratory of the Japan Atomic Energy Agency

Yamanishi, Toshihiko; Yamada, Masayuki; Suzuki, Takumi; Shu, Wataru; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Hoshi, Shuichi; et al.

Fusion Science and Technology, 54(1), p.315 - 318, 2008/07

https://doi.org/10.13182/FST08-A1821

The construction of the building and safety systems of the TPL was completed until 1985. The operations of the safety systems with tritium have been started from March 1988. The amount of tritium held at the TPL was 13 PBq at March 2007. The average tritium concentration in a stream from a stack of the TPL to environment was 6.010 Bq/cm; and is 1/100 smaller than that of the regulation value for the concentration of HTO in the air in Japan. The safety operation results with tritium have thus been obtained. A set of failure data of several main components of the TPL was also obtained as the valuable data for fusion tritium facilities.

Establishment of a rearing system of the extremotolerant tardigrade ; A New model animal for astrobiology

Horikawa, Daiki*; Kunieda, Takekazu*; Abe, Wataru*; Watanabe, Masahiko*; Nakahara, Yuichi*; Yukuhiro, Fumiko*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; et al.

Astrobiology, 8(3), p.549 - 556, 2008/06

https://doi.org/10.1089/ast.2007.0139

We report the successful rearing of the herbivorous tardigrade, , by supplying the green alga as food. The life span was 35 d, deposited eggs required 5.7 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90C and -196C and exposure to 99.8% acetonitrile or irradiation with 4000 Gy He ions. Based on their life history traits and tolerance to extreme stresses, might be a suitable model for astrobiological studies of multicellular organisms.

Studies on the behavior of tritium in components and structure materials of tritium confinement and detritiation systems of ITER

Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; et al.

Nuclear Fusion, 47(12), p.1645 - 1651, 2007/12

https://doi.org/10.1088/0029-5515/47/12/001

The confinement and removal of tritium are the key subjects for safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell building, tritium is often released, as vapor and is in contact with the inner walls. Also those of an ITER tritium plant building will be exposed to tritium in an accident. However, the data are scarce, especially on the penetration of tritium into the concrete of the wall materials. The tritium released in the buildings is removed by the Atmosphere Detritiation Systems (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF is used in ITER, and is expected to be released in an accident such as fire. Although the SF gas has the potential as a catalyst poison, the performance of ADS with the existence of SF has not been confirmed yet. Tritiated water is produced in the regeneration process of ADS, and is subsequently processed by the ITER Water Detritiation System (WDS). One of the key components of WDS is an electrolysis cell. The electrolysis cell is made of organic compounds, and there is no data on the durability of the cell exposed to tritium. To overcome these issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behavior in concrete; (2) effect of SF on performance of ADS; and (3) tritium durability of electrolysis cell of ITER-WDS.