Upgrade of the 3-MeV linac for testing of accelerator components at J-PARC

Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.

Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012077

We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.

Comparison of solid-water partitions of radiocesium in river waters in Fukushima and Chernobyl Areas

Takahashi, Yoshio*; Fan, Q.*; Suga, Hiroki*; Tanaka, Kazuya; Sakaguchi, Aya*; Takeichi, Yasuo*; Ono, Kanta*; Mase, Kazuhiko*; Kato, Kenji*; Kanivets, V. V.*

Scientific Reports (Internet), 7(1), p.12407_1 - 12407_11, 2017/09

https://doi.org/10.1038/s41598-017-12391-7

We focused on factors controlling partition of radiocesium on particulate matters and sediments in rivers of Fukushima and Chernobyl. Radiocesium is more soluble in the Pripyat River (Chernobyl) due to weaker interaction of radiocesium with clay minerals caused by the inhibition effect of the adsorbed humic substances. In contrast, particulate matters and sediments in the Kuchibuto River (Fukushima) display high adsorption affinity with lesser inhibition effect of adsorbed humic substances. This difference is possibly governed by the geology and soil type of provenances surrounding both catchments.

Clay-based modeling approach to diffusion and sorption in the argillaceous rock from the Horonobe URL; Application to Ni(II), Am(III), and Se(IV)

Tachi, Yukio; Suyama, Tadahiro; Yotsuji, Kenji; Ishii, Yasuo; Takahashi, Hiroaki*

CMS Workshop Lectures, Vol.21, p.241 - 250, 2016/00

https://www.clays.org/other-cms-publications-wrksh21/

Sorption and diffusion of radionuclides in argillaceous rocks are key processes in the safe geological disposal. The diffusion and sorption behavior of Ni(II), Am(III) and Se(IV) in mudstone from the Horonobe URL were investigated by experimental and modeling approaches. Effective diffusivities obtained by the through-diffusion experiments were in the sequence of Cs, Ni, HTO, I, Se(SeO), Am(Am(CO)) by comparison with the previous study. The distribution coefficient values were consistent with those obtained by batch sorption tests. These results were interpreted by the clay-based modeling approach coupling the thermodynamic sorption model assuming key contributions of clays (smectite and illite) and the diffusion model assuming the electrical double layer theory and the simplified pore model with size distribution. This clay-based model could provide reasonable account of observed trends and could be basically applicable for various radionuclides.

Study on heat transfer surface temperature variation during pool nucleate boiling by measuring instantaneous surface temperature distribution with infrared radiation camera

Koizumi, Yasuo; Takahashi, Kazuki*; Uesawa, Shinichiro; Yoshida, Hiroyuki; Takase, Kazuyuki

Proceedings of 9th International Conference on Boiling and Condensation Heat Transfer (Boiling & Condensation 2015) (DVD-ROM), 10 Pages, 2015/04

Pool nucleate boiling heat transfer experiments were performed for water at 0.101 MPa to examine the elementary process of the nucleate boiling. The copper printed circuit board of a 1.57 mm thick Bakelite plate coated with a 0.035 mm thick copper membrane was used for a heat transfer surface. The size of the heat transfer surface was 10 mm 10 mm. Direct current was supplied to it to heat it up. The Bakelite plate of the backside of the copper layer was taken by 7 mm 10 mm. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. The time and the space resolution of the infrared cameras used in experiments were 120 Hz and 0.315 mm 0.315 mm, respectively. Surface temperatures just before the burn-out measured with 120 Hz suggest that the surface temperature was steadily low at a large part of the heat transfer surface. A small hot-dry area came out at the critical heat flux condition. Then, this small hot-dry area iterated to expand and shrink and gradually grew. Other area was still wetted and kept at low temperature. Eventually the small hot-dry area started to grow continuously and a whole part of the heat transfer surface became hot-dry to reach the physical burn-out. The heat transfer surface was divided into two large areas; the hot-dry area and the low-temperature-wetted area until the physical burn-out. The local surface heat flux variation derived from measured surface temperature variation clearly illustrated that the boundary between the dried area and the wetted area moved back and forth and the dried arear gradually grew to reach physical bourn-out at the critical heat flux condition.

Development of multi-purpose MW gyrotrons for fusion devices

Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.

Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06

https://doi.org/10.1088/0029-5515/53/6/063003

Hydrogen concentration behavior in the IHTS of Monju

Ito, Kazuhiro; Tanabe, Hiromi; Kaneko, Yoshihisa; Kagota, Eiichi; Takahashi, Yasuo

Proceedings of 2013 International Congress on Advances in Nuclear Power Plants (ICAPP 2013) (USB Flash Drive), 10 Pages, 2013/04

The Monju is equipped with two types of hydrogen-meters to detect water leakage in steam generators. Since they are so highly-sensitive as to detect minor water leak from a steam generator tube, they sometimes detect hydrogen concentration increases at plant operational condition changes such as start-up without any water leak. No water leak was experienced during one year operation of the Startup Test up to 40% in 1995, although hydrogen concentration sometimes increased at plant operational condition changes. The H behavior of Monju IHTS during the previous Startup Test was examined and the following knowledge was obtained: The in-sodium H behaves in parallel with the IHTS sodium temperature. In-cover-gas H behavior is more complicated and sensitive to plant operational condition changes such as plant load changes than the in-sodium one. Both types of H-meters underwent a certain degree of zero level drift during one year operation.

In-beam -ray spectroscopy of Cf by neutron-transfer reactions using a Cf target

Takahashi, Ryuta; Ishii, Tetsuro; Asai, Masato; Nagae, Daisuke*; Makii, Hiroyuki; Tsukada, Kazuaki; Toyoshima, Atsushi; Ishii, Yasuo; Matsuda, Makoto; Makishima, Akiyasu*; et al.

Physical Review C, 81(5), p.057303_1 - 057303_4, 2010/05

https://doi.org/10.1103/PhysRevC.81.057303

The ground-state bands of Cf have been established up to 10, 12, and 10 states, respectively, by in-beam -ray spectroscopy using neutron-transfer reactions with a O beam and a highly radioactive Cf target. The deexcitation rays in Cf were identified by taking coincidences with outgoing particles of O measured with Si - detectors, and by selecting their kinetic energies. This is the first in-beam -ray spectroscopy for Cf isotopes.

Radioactive waste management in O-arai Research and Development Center

Maeda, Atsushi; Kowata, Koichi; Yamazaki, Yasuo; Takahashi, Kozo; Okubo, Toshiyuki; Miyazaki, Hitoshi

Dekomisshoningu Giho, (33), p.58 - 66, 2006/03

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_33.pdf

By the Japan Atomic Energy Agency (JAEA), designed decommissioning of nuclear facility and the treatment and disposal of radioactive waste will be carried out systematically and efficiently as responsibility as the installer of the nuclear power facility and generator of radioactive waste. This paper shows the present status of radioactive waste management in O-arai Research and Development Center, one of the research and development bases of JAEA. The management of low-level radioactive waste, including those accepted from outside operator of O-arai district, is carried out by the major premise of ensuring safety at O-arai Waste Management Facility. Treatment related to volume reduction and stabilization by means such as incineration and compression of solid waste, and solidification of liquid, as well as waste storage management is steadfastly promoted, so that these substances may be adequately stored and managed until they are disposed of.

ITER engineering design

Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01

http://ci.nii.ac.jp/naid/40004988703

no abstracts in English

The XAFS beamline BL01B1 at SPring-8

Uruga, Tomoya*; Tanida, Hajime*; Yoneda, Yasuhiro; Takeshita, Kunikazu*; Emura, Shuichi*; Takahashi, Masao*; Harada, Makoto*; Nishihata, Yasuo; Kubozono, Yoshihiro*; Tanaka, Tsunehiro*; et al.

Journal of Synchrotron Radiation, 6(Part3), p.143 - 145, 1999/05

An x-ray absorption fine-structure (XAFS) spectroscopy beamline, BL01B1, was installed at a bending magnet source at SPring-8 and has been open to users since October 1997. It was designed for XAFS experiments covering a wide energy range. Position tables and automatical control programs were established to adjust the x-ray optics and achieve the designed performance of the beamline under each experimental condition. This has enabled conventional XAFS measurements to be made with a good data quality from 4.5 to 110 keV.