Decommissioning of uranium handling facility for development of nuclear fuel manufacturing equipment

Kageyama, Tomio; Denuma, Akio; Koizumi, Jin*; Odakura, Manabu*; Haginoya, Masahiro*; Isaka, Shinichi*; Kadowaki, Hiroyuki*; Kobayashi, Shingo*; Morimoto, Taisei*; Kato, Yoshiaki*; et al.

JAEA-Technology 2022-033, 130 Pages, 2023/03

JAEA-Technology-2022-033.pdf:9.87MB

Uranium handling facility for development of nuclear fuel manufacturing equipment (Mockup room) was constructed in 1972. The Mockup room has a weak seismic resistance and is deteriorating with age. Also, the original purpose with this facility have been achieved and there are no new development plans using this facility. Therefore, interior equipment installed in this facility had been dismantled and removed since March 2019. After that, the Mockup room was inspected for contamination, and then controlled area in the Mockup room was cancelled on March 29th 2022. A total of 6,549 workers (not including security witnesses) were required for this work. The amount of non-radioactive waste generated by this work was 31,300 kg. The amount of radioactive waste generated by this work was 3,734 kg of combustible waste (103 drums), 4,393 kg of flame resistance waste (61 drums), 37,790 kg of non-combustible waste (124 drums, 19 containers). This report describes about the dismantling and removing the interior equipment in the Mockup room, the amount of waste generated by this work, and procedure for cancellation the controlled area in the facility.

Radiochemical research for the advancement of Mo/Tc generator by (n,) method, 2

Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kato, Yoshiaki; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.

KURNS Progress Report 2019, P. 157, 2020/08

https://www.rri.kyoto-u.ac.jp/PUB/report/PR/ProgRep2019/ProgressReport2019_online.pdf#page=173

no abstracts in English

An Application of three-dimensional geological information system to underground construction

Kato, Nobuyoshi*; Tsusaka, Kimikazu; Nago, Makito*; Yamagami, Masahito*; Matsubara, Makoto*; Shigehiro, Michiko*; Aizawa, Takao*; Kamemura, Katsumi*

Chishitsu To Chosa, (139), p.17 - 22, 2014/04

no abstracts in English

An Investigation for long-term storage of a spent zeolite adsorption vessel; Estimation of washing out salt component in a spent zeolite adsorption vessel, 1

Sato, Hiroyuki; Terada, Atsuhiko; Hayashida, Hitoshi; Kamiji, Yu; Kobayashi, Jun; Yamagishi, Isao; Morita, Keisuke; Kato, Chiaki

JAEA-Research 2013-042, 25 Pages, 2014/03

JAEA-Research-2013-042.pdf:5.13MB

Spent zeolite adsorption vessels in the Fukushima No.1 nuclear power plant are kept for long-term with washing out with fresh water for prevention of corrosion remaining salt component in vessel. However, corrosion result is concerned by residual concentration of salt component, washing out experiment is carried out using actual and unspent adsorption vessel (KURION). KURION adsorption vessel is filled with 1,650 ppm of sodium chloride (1,000 ppm of chloride ion) and washed out with pure water for estimating washing effect in this experiment. Pure water is streamed with volume flow rate 4.5 m/h, chloride concentration in vessel is measured with drainage sample water. 1,000 ppm of chloride concentration is decreased till 0.5 ppm and below by washing out with about double pure water volume of adsorbing material filling volume in vessel, washing out is more effective in KURION adsorption vessel.

Development of a high current H ion source for cyclotrons

Eto, Haruhiko*; Aoki, Yasushi*; Mitsubori, Hitoshi*; Arakawa, Y.*; Mitsumoto, Toshinori*; Yajima, S.*; Sakuraba, Junji*; Kato, Takanori*; Okumura, Yoshikazu

Review of Scientific Instruments, 85(2), p.02B107_1 - 02B107_3, 2014/02

https://doi.org/10.1063/1.4827577

High current hydrogen negative ion source is required to increase the accelerated beam current of the cyclotrons for many medical applications such as cancer therapy and medical radioisotope production. A new negative ion source has been designed and fabricated. The ion source is a multi-cusp type. Optimization of the ion source is in progress, such as the optimization of the magnetic filter which prevents high temperature electrons from entering into the negative ion production region, improvement of the extraction electrode's shape and configuration of dipole magnets etc. A small quantity of Cs has been introduced into the ion source to enhance the negative ion beam current. The ion source produced 16mA of DC hydrogen negative ion beam with the Cs-seeded operation at a low arc discharge power of 2.8 kW.

Electron-beam-induced color imaging of acid-chromic polymer films

Maekawa, Yasunari; Yuasa, Kanako*; Enomoto, Kazuyuki; Matsushita, Harumi*; Kato, Jun*; Yamashita, Takashi*; Ito, Kazuo*; Yoshida, Masaru

Chemistry of Materials, 20(16), p.5320 - 5324, 2008/08

https://doi.org/10.1021/cm800650q

Polymer films with acid-responsive chromic dyes and acid generators have been designed for an electron beam (EB)-induced color imaging system. Arylsulfonic acid esters and triphenylsulfonium salts were used as an EB-sensitive acid generator; the acid (H) allows a chromic reaction with rhodamine B base (RB) and 4,4'-bis(dimethylamino)benzhydrol (BH) to be triggered. Upon EB irradiation, poly(methyl methacrylate) (PMMA) films consisting of RB or BH and acid generators exhibited a characteristic absorption band with max at 560 and at 612 nm, respectively, and an isosbestic point. These spectral changes clearly indicate that colorless chromic dyes in PMMA are transformed selectively to the colored form. The color imaging of these films was performed by electron beam direct writing (EBDW) with a 50 nm diameter beam to form 100 - 1000 nm line and space patterns and was evaluated by optical and confocal laser microscopy. EBDW on the acid chromic polymer films, especially for BH, yielded clear color imaging of 100 - 200 nm line and space patterns with a dose of only 10 C/cm. The confocal laser microscopy gave thinner lines than the laser wavelength (632.8 nm), probably because of the large change in refractive index of the patterned film induced by EB irradiation even with a low energy dose.

Regioselectivity control of radiation-induced reaction; Electron beam-induced Fries rearrangement of sulfonamide within -cyclodextrin inclusion complex

Kato, Jun*; Kakehata, Hiroyuki*; Maekawa, Yasunari; Yamashita, Takashi*

Chemical Communications, (43), p.4498 - 4500, 2006/11

https://doi.org/10.1039/B606689E

EB (electron beam) irradiation of sulfonamide within -cyclodextrin (-CD) inclusion complex in the solid state induced the solvent-free Fries rearrangement, which proceeded at a shorter reaction time with reversed regioselectivity by inclusion into -CD, compared with that of sulfonamide crystals; the -CD as a restricted nanospace had much effect on the reactivity and regioselectivity of the solvent-free EB-Fries rearrangement.

Electron beam-induced fries rearrangement of sulfonamide and sulfonate crystals

Kato, Jun*; Maekawa, Yasunari; Yoshida, Masaru

Chemistry Letters, 34(2), p.266 - 267, 2005/02

https://doi.org/10.1246/cl.2005.266

We have investigated the useful EB induced reactions of sulfonamide and sulfonate derivatives in the crystalline state. In this letter, we found that the EB sensitivity of sulfonic acid derivatives in the crystalline tate was much higher than that of the corresponding carboxylic acid derivatives, which was distinct from the results using other energy sources, to give Fries rearrangement products. It is notable that these reactions are solvent-free and are accompanied by the transformation of amide and ester linkages to hydrophilic aniline and phenol groups; especially, an acidic sulfonamide can be converted to the corresponding basic aniline derivatives. These new EB induced transformations can significantly contribute to designing new materials for EB lithography as well as nanoscopic architectures.

J-PARC timing system

Tamura, Fumihiko; Yoshikawa, Hiroshi; Yoshii, Masahito*; Chiba, Junsei*; Kato, Tadahiko*; Takagi, Akira*

Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.677 - 679, 2004/08

We describe the overvier of the J-PARC timing system. J-PARC accelerators consists of the linac, the RCS and the MR, which have different repetition rates. The beam destinations of the linac and RCS are different in each pulse. We present the precise timing system which governs the accelerator timing.

Radiation-induced reactions the lowest excited states in cinnamic acid crystals

Maekawa, Yasunari; Inaba, Tomonori; Hobo, Hiroki; Narita, Tadashi*; Koshikawa, Hiroshi; Moon, S.; Kato, Jun; Yoshida, Masaru

Chemical Communications, (18), p.2088 - 2089, 2002/09

Radiation-induced reactions of cinnamic acid derivatives have been examined and compared them with photoreactions in the crystalline states; all the reaction products were exactly the same as those of the photoreactions, indicating that the reactions proceed only via the lowest excited state to give [2+2]cycloadducts, E/Z isomerization products, or starting molecules.