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Ishihara, Keisuke; Kanazawa, Shingo; Kozawa, Masachiyo; Mori, Masakazu; Kawahara, Takahiro
JAEA-Technology 2017-002, 27 Pages, 2017/03
JAEA-Technology-2017-002.pdf:21.88MB
At radioactive waste management facilities in the Nuclear Science Research Institute, solid radioactive wastes are stored by using containers such as 200L drums and pallets to tier containers in 2 to 4 stacks in the height direction in waste storage facilities (Waste Storage Facility No.1, Waste Storage Facility No.2 and Waste Size Reduction and Storage Facility). On March 11, 2011, the Great East Japan Earthquake was happened, and some waste packages dropped from their pallets and large number of waste packages moved from their original position and inclined due to the influence of the earthquake in the waste storage facilities. There was no experience of rearrangement works to set those dropped and unbalanced waste packages in their original position and it was necessary to prepare detailed work procedures and progress for this task to prevent the occurrence of industrial accidents. Therefore, we prepared detailed work manual and repeatedly carried out mock-up test. And then, we started rearrangement work from April 2011 after confirmation of workers skill and adequacy of the work manual. Finally, all rearrangement works for stored waste packages took about four and half years and were completed in September 2015 without any accident and shutdown of storage function. This report summarizes the countermeasures to reduce exposure doses of workers and to prevent the occurrence of industrial accidents during the rearrangement works.
Takei, Satoshi*; Oshima, Akihiro*; Oyama, Tomoko; Ito, Kenta*; Sugahara, Kigen*; Kashiwakura, Miki*; Kozawa, Takahiro*; Tagawa, Seiichi*; Hanabata, Makoto*
Japanese Journal of Applied Physics, 53(11), p.116505_1 - 116505_7, 2014/11
Times Cited Count：10 Percentile：41.38(Physics, Applied)The application of natural linear polysaccharide to green resists was demonstrated for electron beam (EB) and extreme-ultraviolet (EUV) lithography. Because of the water solubility of natural polysaccharides, the water spin-coating and water-developable processes realize an environmentally friendly manufacturing process for next-generation electronic devices. The developed green resist with a weight-average molecular weight of 83,000 and 70 mol % hydroxyl groups was found to have acceptable properties such as spin-coat ability on 200 mm wafers, pillar patterns of 100-400 nm with a high EB sensitivity of 10 
C/cm
, etch selectivity with a silicon-based middle layer in CF
plasma treatment, and high prediction sensitivity to EUV region.
Takei, Satoshi*; Oshima, Akihiro*; Ichikawa, Takumi*; Sekiguchi, Atsushi*; Kashiwakura, Miki*; Kozawa, Takahiro*; Tagawa, Seiichi*; Oyama, Tomoko; Ito, Shoji*; Miyasaka, Hiroshi*
Microelectronic Engineering, 122, p.70 - 76, 2014/06
Times Cited Count：24 Percentile：76.82(Engineering, Electrical & Electronic)Biomass-derived branched sugar resist material was developed for environmentally-friendly electron beam lithography (EBL). The developed resist enables organic solvent-free water-developable process. The resist performance was evaluated using 75 keV EBL system. Lines of 50-200 nm were fabricated with high sensitivity of 7 C/cm. The resist is developable in pure water at 23 
C for 60 s, and it has acceptable CF etch selectivity.
Uesaka, Takahiro; Kozawa, Masachiyo; Matsumoto, Junko; Endo, Masayuki; Kinoshita, Junichi; Suzuki, Takeshi; Suzuki, Hisao; Morishita, Satoru; Sakamoto, Yu
JAEA-Technology 2012-015, 29 Pages, 2012/06
JAEA-Technology-2012-015.pdf:3.22MB
In Japan Atomic Energy Agency Nuclear Science Research Institute waste treatment building No.2 treat intermediate-level solid waste. Solid wastes are reduced in volume by compaction. They are then canned in stainless can, which are subsequently put in 200-liter concrete-lined drums or 1-m
concrete containers, filled with concrete. To prepare for disposal in future, be able to make fit with the technical standard of waste package, we were asked to change the lid type shielded container. Therefore due to the change of lid type shielded container, we confirmed integrity of it with evaluation of close volt by drop analysis, evaluation of shielding, and drop test with a prototype model.
Oishi, Kazuki*; Ito, Takashi; Higemoto, Wataru; Yamazaki, Takahiro*; Uehara, Akira*; Kozawa, Katsuya*; Kimishima, Yoshihide*; Uehara, Masatomo*
Physica C, 470(Suppl.1), p.S705 - S706, 2010/12
Times Cited Count：2 Percentile：12.12(Physics, Applied)Tomimoto, Hiroshi; Kato, Yasushi; Owada, Hiroyuki; Sato, Nao; Shimazaki, Yosuke; Kozawa, Takayuki; Shinohara, Masanori; Hamamoto, Shimpei; Tochio, Daisuke; Nojiri, Naoki; et al.
JAEA-Technology 2009-025, 29 Pages, 2009/06
JAEA-Technology-2009-025.pdf:21.78MB
The first driver fuel of the HTTR (High Temperature Engineering test Reactor) was loaded in 1998 and the HTTR reached first criticality state in the same year. The HTTR has been operated using the first driver fuel for a decade. In Fuel elements assembling, 4770 of fuel rods which consist of 12 kinds of enrichment uranium are loaded into 150 fuel graphite blocks for HTTR second driver fuel elements. Measures of prevention of fuel rod miss loading, are employed in fuel design. Additionally, precaution of fuel handling on assembling are considered. Reception of fuel rods, assembling of fuel elements and storage of second driver fuels in the fresh fuel storage rack in the HTTR were started since June, 2008. Assembling, storage and pre-service inspection were divided into three parts. The second driver fuel assembling was completed in September, 2008. This report describes concerns of fuel handling on assembling and storage work for the HTTR fuel elements.
Ichimura, Makoto*; Higaki, Hiroyuki*; Kakimoto, Shingo*; Yamaguchi, Yusuke*; Nemoto, Kenju*; Katano, Makoto*; Kozawa, Isao*; Muro, Taishi*; Ishikawa, Masao; Moriyama, Shinichi; et al.
Fusion Science and Technology, 51(2T), p.150 - 153, 2007/02
Times Cited Count：1 Percentile：11.32(Nuclear Science & Technology)In magnetically confined plasmas, fluctuations in the ion cyclotron range of frequency (ICRF) will be driven by the presence of non-thermal ion energy distribution. In strong ICRF heating experiments on the GAMMA 10 tandem mirror, plasmas with a strong temperature anisotropy have been formed. Alfven-ion-cyclotron (AIC) modes are spontaneously excited due to strong temperature anisotropy. High-energy ions are trapped in the local mirror and will form the velocity distribution with the strong anisotropy. To study the relation among the AIC modes, ICEs and beam-driven electrostatic instabilities with non-thermal energy distribution is the main purpose of this work. When the NBs are injected, the magnetic fluctuations due to injected beams and FP ions are detected by ICRF antennas used as pickup loops on JT-60U. The wave excitation near ion cyclotron and its higer harmonic frequencies are studied experimentally and theoretically in plasmas with non-thermal ion energy distribution.
Yoshida, Yoichi*; Yang, J.*; Kondo, Takafumi*; Seki, Shuhei*; Kozawa, Takahiro*; Tagawa, Seiichi*; Shibata, Hiromi*; Taguchi, Mitsumasa; Kojima, Takuji; Namba, Hideki
JAEA-Review 2005-001, TIARA Annual Report 2004, p.183 - 185, 2006/01
A heavy-ion-pulse radiolysis technology was developed using a single-photon-counting system. In the system, the ion beam was injected a thin scintillator before irradiating the sample. The light emitted from the scintillator by the ion irradiation was used as analyzing source to detect the absorption of primary species in water. Measurement of time-dependent absorption of hydrated electrons in water was achieved using the system, which demonstrates the usefulness of this technique.
Nagaishi, Ryuji; Kimura, Takaumi; Yoshida, Yoichi*; Kozawa, Takahiro*; Tagawa, Seiichi*
Journal of Physical Chemistry A, 106(39), p.9036 - 9041, 2002/10
Times Cited Count：3 Percentile：8.65(Chemistry, Physical)no abstracts in English
Ichimura, Makoto*; Higaki, Hiroyuki*; Yamaguchi, Yusuke*; Nemoto, Tatsuki*; Katano, Makoto*; Motegi, Yukimi*; Kozawa, Isao*; Muro, Taishi*; Ishikawa, Masao; Moriyama, Shinichi; et al.
no journal, ,
The wave excitation in the ion cyclotron range of frequency (ICRF) is strongly affected by the boundary conditions. The formation of eigenmodes depends on the plasma parameters, their spatial profiles, the magnetic field profile and so on. The main subject of this presentation is the establishment of plasma diagnostics with ICRF waves. In GAMMA 10, the injection of low power ICRF waves into the plasma as active diagnostics has been tested. The preliminary results are reported. In JT-60U, the ion cyclotron emissions (ICEs) due to high energy ions from the neutral beam injections and the fusion reactions have been clearly observed. The frequency spectra of ICEs also depend on the plasma parameters. ICEs for passive diagnostic tools are discussed.
