Satou, Yukihiko; Sueki, Keisuke*; Sasa, Kimikazu*; Yoshikawa, Hideki; Nakama, Shigeo; Minowa, Haruka*; Abe, Yoshinari*; Nakai, Izumi*; Ono, Takahiro*; Adachi, Koji*; et al.
Geochemical Journal, 52(2), p.137 - 143, 2018/00
Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*
Bunseki Kagaku, 66(4), p.251 - 261, 2017/04
no abstracts in English
Kawatsuma, Shinji; Nakai, Koji; Suzuki, Yoshiharu; Kase, Takeshi
QST-M-2; QST Takasaki Annual Report 2015, P. 81, 2016/12
Radiation Tolerance of semiconductor components on the shelf, utilized on the robots for emergency response or decommissioning in nuclear facilities, should be estimated. Just after the Fukushima Daiichi NPPs accidents occurred, a guideline, of irradiation tolerance estimation and management method of semiconductor components on the shelf, was tried to be made based on the old database developed in the course of Bilateral Servo Manipulator under the high radiation and high contamination environments. The estimation was conservative, because the data in the database were old and mainly based on the test results of silicon semiconductors. Ga-As Semiconductors are coming major recently, and expected to be higher radiation tolerance. For those reason, present semiconductor devices have irradiated and the irradiation tolerance have estimated.
Shimojo, Kojiro; Nakai, Ayaka*; Okamura, Hiroyuki; Saito, Takumi*; Ohashi, Akira*; Naganawa, Hirochika
Analytical Sciences, 30(4), p.513 - 517, 2014/04
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Sagisaka, Akito; Pirozhkov, A. S.; Pikuz, T.; Faenov, A.*; Ogura, Koichi; Fukami, Tomoyo; Matsukawa, Kenya*; et al.
Review of Scientific Instruments, 85(2), p.02A705_1 - 02A705_4, 2014/02
High intensity laser-plasma interaction has attracted considerable interest for a number of years. The laser-plasma interaction is accompanied by generation of various charged particle beams. Results of simultaneous novel measurements of electron-induced photonuclear neutrons (photoneutron), which are a diagnostic of the laser-plasma interaction, are proposed to use for optimization of the laser-plasma ion generation. The proposed method is demonstrated by the laser irradiation with the intensity os 110 W/cm on the metal foil target. The photoneutrons are measured by using NE213 liquid scintillation detectors. Heavy-ion signal is registered with the CR39 track detector simultaneously. The measured signals of the electron-induced photoneutrons are well reproduced by using the Particle and Heavy Ion Transport code System (PHITS). The results obtained provide useful approach for analyzing the various laser based ion beams.
Shimojo, Kojiro; Nakai, Ayaka; Okamura, Hiroyuki; Ohashi, Akira*; Naganawa, Hirochika
Analytical Sciences, 29(1), p.147 - 150, 2013/01
Suzuki, Toru; Nakai, Ryodai; Kamiyama, Kenji; Seino, Hiroshi; Koyama, Kazuya*; Morita, Koji*
NEA/CSNI/R(2012)2, p.381 - 391, 2012/07
For the probabilistic safety assessment (PSA) of sodium-cooled fast reactors (SFRs), JAEA consolidated the analytical methodologies and technical basis for all phases/sequences to be evaluated in the Level 2 PSA. In addition to the existing computational codes such as SAS4A, SIMMER-III, DEBNET, ARGO and APPLOHS, JAEA newly developed MUTRAN and SIMMER-LT in order to evaluate the long term behaviors of the material-relocation in the degraded core. These tools enabled the systematic assessment for the in-vessel accident sequences. For the ex-vessel accident sequences, JAEA also improved CONTAIN/LMR taking into account the feature of SFRs and verified the analytical models utilizing the new experiments such as sodium-concrete reaction test. In addition, the technical basis for constructing event trees was compiled, in which the dominant factors having significant effects on the event progression were corresponded to the related experiments and analytical results.
Watahiki, Masatoshi; Akai, Masanori; Nakai, Koji; Iemura, Keisuke; Yoshino, Masanori*; Hirano, Hiroshi*; Kitamura, Akihiro; Suzuki, Kazunori
Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.101 - 109, 2012/02
Gloveboxes used for plutonium fuel development and fabrication are eventually dismantled for replacement or decommissioning. Since equipment interior and the inner surface of gloveboxes are contaminated in radioactive materials, glovebox dismantling work is performed by workers wearing an air fed suit with mechanical tools in a plastic enclosure system to control the spread of contamination. Various improvements of enclosure system are implemented including modification of the rooms to decontaminate and undress the air fed suit and introduction of inflammable filter and safety film near the size reduction workspace against fire. We describe the countermeasures deployed in the enclosure system against potential hazards and how these devices work in the real dismantling activities.
Kitamura, Akihiro; Nakai, Koji; Namekawa, Takashi; Watahiki, Masatoshi
Nuclear Engineering and Design, 241(7), p.2614 - 2623, 2011/07
We developed a remote control system to display recreated three dimensional information of workspace from measured data obtained by laser rangefinder and to operate manipulator arm remotely. In order to evaluate the effectiveness and usefulness of developed system, we implemented remote handling experiments using mock up equipment and compared the performances of remote operation conducted by the present control system with that by the usual camera based control system. Impressions of operator on the performance of each system are collected and NASA TLX tests are conducted. It was observed that the present system reduced workload stresses and reinforced visual information during remote operation.
Iemura, Keisuke; Nakai, Koji; Watahiki, Masatoshi; Kitamura, Akihiro; Suzuki, Kazunori; Aoki, Yoshikazu
Dekomisshoningu Giho, (43), p.2 - 9, 2011/03
Plutonium fuel fabrication facility is constructed in 1972 and it is almost 40 years of age and equipment and components comprises the facility start degrading. Therefore we need to start dismantling gloveboxes from old ones first and at the same time to maintain the facility components and structures and gloveboxes as necessary. Also, since waste storage space is limited in the site, we effectively use open spaces generated after removing gloveboxes and equipment as temporal waste storage space. After shipping these wastes from the facility, final characterization of the facility will be conducted and demolition of the facility will be take place.
Nakai, Ryodai; Suzuki, Toru; Kamiyama, Kenji; Seino, Hiroshi; Koyama, Kazuya*; Morita, Koji*
Proceedings of 8th International Topical Meeting on Nuclear Thermal-Hydraulics, Operation and Safety (NUTHOS-8) (CD-ROM), 12 Pages, 2010/10
The evaluation technology of Level-2 PSA for Sodium-Cooled Fast Reactors (SFRs) was established in order to systematically assess the core damage sequences. In addition to the existing computational tools for Level-2 PSA, the computational tools, MUTRAN and SIMMER-LT were developed for core material relocation phase. Also the analytical models, CORCON and VANESA, were improved based on newly performed experiments for the ex-vessel phase taking into account the feature of SFRs. The technical information was compiled as technical database used in the construction and quantification of level-2 PSA event trees for SFRs. The technical basis was established for the Level-2 PSA for SFRs.
Furuya, Takaaki*; Hara, Kazufumi*; Hosoyama, Kenji*; Kojima, Yuji*; Nakai, Hirotaka*; Nakanishi, Kota*; Sakai, Hiroshi*; Umemori, Kensei*; Sawamura, Masaru; Shinoe, Kenji*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2923 - 2925, 2010/05
A prototype module including a couple of 1.3 GHz superconducting 9-cell cavities has been designed as the main linac of cERL which is the test facility to establish the basic ERL technology at KEK. The shape of 9-cell Nb structure is optimized to accelerate a CW beam of 100 mA with sufficiently damped higher order modes (HOM) which is achieved by adopting an eccentric fluted beam pipe and a cylindrical beam pipe of a large diameter of 120 mm. Extracted HOMs are absorbed by the ferrite cylinders bonded on the copper beam pipes by HIP process. A power coupler with double disk-ceramics has been developed to transfer an RF of 20 kW CW to the cavity in full reflection. The test results of fabrication, cooling and RF performance for these components are integrated as the prototype module of the main linac for cERL facility.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Ishiyama, Hironobu*; Hashimoto, Takashi; Ishikawa, Tomoko*; Watanabe, Yutaka*; Das, S. K.*; Miyatake, Hiroari; Mizoi, Yutaka*; Fukuda, Tomokazu*; Tanaka, Masahiko*; Fuchi, Yoshihide*; et al.
Physics Letters B, 640(3), p.82 - 85, 2006/09
The excitation function of the Li(,n)B reaction was measured while identifying the final state event by event in the region of E = 0.7 - 2.6 MeV using a highly efficient detector system and a low-energy Li beam. The results are much improved both in statistics and precisions, and show smaller cross sections than those of previous measurements by a factor of more than 2 in the low-energy region of E 1.5 MeV. A resonance-like structure is found at around E = 0.85 MeV.
Das, S. K.*; Fukuda, Tomokazu*; Mizoi, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Tanaka, Masahiko*; Yoshikawa, Nobuharu*; Jeong, S.-C.*; et al.
AIP Conference Proceedings 847, p.374 - 376, 2006/07
no abstracts in English
Hashimoto, Takashi; Ishiyama, Hironobu*; Ishikawa, Tomoko*; Kawamura, Takashi*; Nakai, Koji*; Watanabe, Yutaka*; Miyatake, Hiroari; Tanaka, Masahiko*; Fuchi, Yoshihide*; Yoshikawa, Nobuharu*; et al.
Nuclear Instruments and Methods in Physics Research A, 556(1), p.339 - 349, 2006/01
A new type of three dimensional tracking and proportional gas counter has been developed. Adopting a gating-grid system, performance of the detector becomes stable under the injection rate of charged particles less than 410 pps. It is a useful detection system for astrophysical experiments using radioactive nuclear beams, since the efficiency is so high as 100 %.
Kusakabe, Toshio*; Miyamoto, Yoshiharu*; Ishida, Rikiya*; Ito, Kojiro*; Kuroyanagi, Nobuhiro*; Nakai, Yota*; Shirai, Toshizo
Nuclear Instruments and Methods in Physics Research B, 205, p.600 - 604, 2003/05
no abstracts in English
Nose, Tadao*; Matsumura, Akira*; Yamamoto, Tetsuya*; Shibata, Yasushi*; Yoshida, Fumiyo*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Matsushita, Akira*; Nakai, Kei*; Yamada, Takashi*; et al.
UTRCN-G-29, p.114 - 123, 2001/00
no abstracts in English
Matsumura, Akira*; Yamamoto, Tetsuya*; Shibata, Yasushi*; Akutsu, Hiroyoshi*; Yasuda, Susumu*; Matsushita, Akira*; Nakai, K.*; Yamada, Takashi*; Takano, Shingo*; Mizutani, Taro*; et al.
Proceedings of 9th International Symposium on Neutron Capture Therapy for Cancer, p.29 - 30, 2000/10
no abstracts in English
Hashimoto, Takashi; Mitsuoka, Shinichi; Ichikawa, Shinichi; Ikezoe, Hiroshi; Miyatake, Hiroari; Ishiyama, Hironobu*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Tanaka, Masahiko*; et al.
no journal, ,
no abstracts in English