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Journal Articles

Feasibility study of the one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Journal of Nuclear Engineering and Radiation Science, 7(4), p.042002_1 - 042002_7, 2021/10

For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station (FDNPS) buildings, we propose a novel one-dimensional radiation distribution sensing method using an optical fiber sensor based on wavelength spectrum unfolding. The proposed method estimates the incident position of radiation to the fiber by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of light along the fiber depends on the wavelength. Because this method measures the integrated light intensity, this method can avoid the problem of counting loss and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field. Through basic experiments using the ultraviolet light source and $$^{90}$$Sr/$$^{90}$$Y radioactive point source, basic properties of source position detection were confirmed.

Journal Articles

Development of one-dimensional optical fiber type radiation distribution sensing method based on wavelength spectrum unfolding

Terasaka, Yuta; Watanabe, Kenichi*; Uritani, Akira*; Yamazaki, Atsushi*; Sato, Yuki; Torii, Tatsuo; Wakaida, Ikuo

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

Journal Articles

Comparative study on the thermal behavior of structural concretes of sodium-cooled fast reactor

Kikuchi, Shin; Koga, Nobuyoshi*; Yamazaki, Atsushi*

Journal of Thermal Analysis and Calorimetry, 137(4), p.1211 - 1224, 2019/08

 Times Cited Count:5 Percentile:47.57(Thermodynamics)

In this study, two siliceous concretes with similar specification as structural concretes of SFR were selected for the comparative study of the thermal behavior. The thermal behavior of the structural concretes was investigated in a temperature range from room temperature to 1900 K using TG-differential thermal analysis (DTA) and other supplementary techniques. The softening and melting of the concretes initiated in the thermal decomposition product of the cement portion in the temperature range 1400-1600 K. Because the compositional difference between the cement portion of two different siliceous concretes was characterized by different Ca(OH)$$_{2}$$/CaCO$$_{3}$$ ratios, the melting temperature ranges of those thermal decomposition products are not so significantly different. On the other hand, the melting of the aggregate is directly influenced by the initial composition of SiO$$_{2}$$ compounds.

Journal Articles

Security measures at nuclear fuel facilities, 2; Internal threat countermeasure in cyber-security

Kono, Soma; Yamada, Hiroyuki; Goto, Atsushi*; Yamazaki, Katsuyuki; Nakamura, Hironobu; Kitao, Takahiko

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 2 Pages, 2018/11

no abstracts in English

Journal Articles

Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex, 2; Neutron scattering instruments

Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.

Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12

The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.

Journal Articles

Imaging of root exudates secreted from soybean root to soil by using carbon-11-labeled carbon dioxide and PETIS

Yin, Y.-G.; Suzui, Nobuo; Kawachi, Naoki; Ishii, Satomi; Yamazaki, Haruaki; Koyanagi, Atsushi*; Fujimaki, Shu

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 92, 2013/01

Journal Articles

A New method to analyze individual photosynthetic abilities of young plant seedlings using positron-emitting tracer imaging system (PETIS)

Kawachi, Naoki; Koyanagi, Atsushi*; Suzui, Nobuo; Ishii, Satomi; Yin, Y.-G.; Yamazaki, Haruaki; Iwasaki, Aya*; Ogawa, Kenichi*; Fujimaki, Shu

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 93, 2013/01

Journal Articles

Operator's experience after introduction of random interim inspection at Tokai Reprocessing facilities

Makino, Risa; Ishiyama, Koichi; Kimura, Takashi; Yamazaki, Katsuyuki; Nakamura, Hironobu; Ikeda, Atsushi*; Yamaguchi, Katsuhiro*

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-33-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2012/10

The Integrated Safeguards (IS) applied to JNC-1 site began from August, 2008. At that time, the inspection scheme was replaced from Interim Inventory Verification (IIV) with scheduled day to Random Interim Inspection (RII) with short notice in order to strengthen deterrent against diversion of nuclear materials. To satisfy the requirements for IS in Tokai reprocessing facilities including Tokai Reprocessing Plant and Plutonium Conversion Development Facility, we have cooperated inspectorates to establish remote monitoring systems, and to introduce RII smoothly. Though the new inspection scheme requires additional efforts which contain keeping a certain number of operators every day and declaration of interim inventory lists in a short time, the whole inspection days per year during inter-campaign could be decreased to about 60% by comparing with the conventional IIV. This paper reports the effects after introduction of RII and the future tasks to be discussed regarding RII during campaign from the operator's standpoint.

Journal Articles

Electronic configuration of Mn ions in the $$pi$$-$$d$$ molecular ferromagnetic $$beta$$-Mn phthalocyanine studied by soft X-ray magnetic circular dichroism

Kataoka, Takashi*; Sakamoto, Yuta*; Yamazaki, Yo*; Singh, V. R.*; Fujimori, Atsushi*; Takeda, Yukiharu; Okochi, Takuo*; Fujimori, Shinichi; Okane, Tetsuo; Saito, Yuji; et al.

Solid State Communications, 152(9), p.806 - 809, 2012/05

 Times Cited Count:18 Percentile:63.05(Physics, Condensed Matter)

no abstracts in English

Journal Articles

29th report of ITPA topical group meeting

Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06

no abstracts in English

Journal Articles

27th report of ITPA topical group meeting

Osakabe, Masaki*; Shinohara, Koji; Toi, Kazuo*; Todo, Yasushi*; Hamamatsu, Kiyotaka; Murakami, Sadayoshi*; Yamamoto, Satoshi*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 85(12), p.839 - 842, 2009/12

no abstracts in English

JAEA Reports

Horonobe Underground Research Laboratory project research and development plan in Phase 2; H20-21

Iwatsuki, Teruki; Sato, Haruo; Tanai, Kenji; Inagaki, Manabu; Sawada, Atsushi; Niinuma, Hiroaki; Ishii, Eiichi; Maekawa, Keisuke; Tomura, Goji; Sanada, Hiroyuki; et al.

JAEA-Research 2009-002, 156 Pages, 2009/05

JAEA-Research-2009-002.pdf:12.86MB

The research and development plan for geological investigation, engineering technology and safety assessment during the drilling of a shaft down to intermediate depth are summarized according to the Midterm Plan till 2009 Fiscal year of JAEA. This report describes subject, current status and programme in the "Phase 2: Construction phase" (investigations during construction of the underground facilities). Furthermore regarding R&D plan in next Midterm Plan of JAEA, preliminary ideas are summarized.

Journal Articles

Report on ITPA meetings, 24

Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12

no abstracts in English

Journal Articles

Long pulse production of high current D$$^{-}$$ ion beams in the JT-60 negative ion source

Hanada, Masaya; Kamada, Masaki; Akino, Noboru; Ebisawa, Noboru; Honda, Atsushi; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; Komata, Masao; Mogaki, Kazuhiko; et al.

Review of Scientific Instruments, 79(2), p.02A519_1 - 02A519_4, 2008/02

 Times Cited Count:5 Percentile:30.02(Instruments & Instrumentation)

A long pulse production of high-current, high-energy D$$^{-}$$ ion beams was studied in the JT-60U negative ion source that was designed to produce 22 A, 500 keV D$$^{-}$$ ion beams. Prior to the long pulse production, the short pulse beams were produced to examine operational ranges for a stable voltage holding capability and an allowable grid power loading. From a correlation between the voltage holding capability and a light intensity of cathodoluminescence from the insulator made of Fiber Reinforced Plastic insulator, the voltage holding was found to be stable at $$<$$ 340 kV where the light was sufficiently suppressed. The grid power loading for the long pulse operation was also decreased to the allowable level of $$<$$ 1 MW without a significant reduction of the beam power by tuning the extraction voltage (Vext) and the arc power (Parc). These allow the production of 30 A D$$^{-}$$ ion beams at 340 keV from two ion sources at Vacc = 340 kV. The pulse length was extended step by step, and finally reached up to 21 s, where the beam pulse length was limited by the surface temperature of the beam scraper without water cooling. The D$$^{-}$$ ion beams were neutralized to via a gas cell, resulting in a long pulse injection of 3.2 MW D$$^{0}$$ beams for 21 s. This is the first long injection of $$>$$ 20 s in a power range of $$>$$ 3 MW.

Journal Articles

Technical design of NBI system for JT-60SA

Ikeda, Yoshitaka; Akino, Noboru; Ebisawa, Noboru; Hanada, Masaya; Inoue, Takashi; Honda, Atsushi; Kamada, Masaki; Kawai, Mikito; Kazawa, Minoru; Kikuchi, Katsumi; et al.

Fusion Engineering and Design, 82(5-14), p.791 - 797, 2007/10

 Times Cited Count:19 Percentile:79.3(Nuclear Science & Technology)

Modification of JT-60U to a superconducting device (so called JT-60SA) has been planned to contribute to ITER and DEMO. The NBI system is required to inject 34 MW for 100 s. The upgraded NBI system consists of twelve positive ion based NBI (P-NBI) units and one negative ion based NBI (N-NBI) unit. The injection power of the P-NBI units are 2 MW each at 85 keV, and the N-NBI unit will be 10 MW at 500 keV, respectively. On JT-60U, the long pulse operation of 30 s at 2 MW (85 keV) and 20 s at 3.2 MW (320 keV) have been achieved on P-NBI and N-NBI units, respectively. Since the temperature increase of the cooling water in both ion sources is saturated within 20 s, further pulse extension up to 100 s is expected to mainly modify the power supply systems in addition to modification of the N-NBI ion source for high acceleration voltage. The detailed technical design of the NBI system for JT-60SA is presented.

JAEA Reports

Development of a neutron reflectometer SUIREN at JRR-3

Yamazaki, Dai; Moriai, Atsushi; Tamura, Itaru; Maruyama, Ryuji; Ebisawa, Toru*; Takeda, Masayasu; Soyama, Kazuhiko

JAEA-Technology 2007-030, 21 Pages, 2007/03

JAEA-Technology-2007-030.pdf:4.13MB

A new neutron reflectometer "SUIREN" has been developed and started its operation at the research reactor JRR-3 of JAEA in 2006. SUIREN (Apparatus for Surface and Interface investigations with Reflection of Neutrons) provides monochromatic neutron beam with wavelength of 3.8 $$AA$$ and vertical sample geometry, which is suitable for studies on interfaces involving solid layers of soft materials, magnetic materials, neutron mirrors and many other things. Collimated neutron intensity is about 2.1$$times$$10$$^4$$$$sim$$2.6$$times$$10$$^4$$ n/s/cm$$^{2}$$ with =0.08 deg at the sample position. Background is as low as 4.5$$times$$10$$^{-3}$$ n/s when a local beam shutter is closed. A demonstration experiment showed that specular reflectivity of a silicon substrate of 3 inches in diameter can be measured down to 10$$^{-6}$$ over 0 $$<$$ Qz $$<$$ 0.22 $$AA$$$$^{-1}$$ in 27 hours. This paper describes the beam-line and components of the SUIREN reflectometer, some results of test measurements and future plans.

Journal Articles

Ultrarelativistic electron generation during the intense, ultrashort laser pulse interaction with clusters

Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Hayashi, Yukio; Homma, Takayuki; Inoue, Norihiro*; Kando, Masaki; Kanazawa, Shuhei; Kiriyama, Hiromitsu; Kondo, Shuji; et al.

Physics Letters A, 363(2-3), p.130 - 135, 2007/02

Collimated relativistic electrons up to 58 MeV with an electron charge of 2.1 nC were generated by the interaction of intense laser pulses with the Ar cluster target at the laser intensity of 3.5$$times$$10$$^{19}$$W/cm$$^{2}$$. The resulting spectrum does not fit a Maxwellian distribution, but is well described by a two-temperature Maxwellian, which indicates two mechanisms of the electron acceleration. Two dimensional particle-in-cell simulations demonstrate an important role of clusters. The higher energy electrons are injected when they are expelled from the clusters by the laser pulse field. They then gain their energy during the direct acceleration by the laser pulse, whose phase velocity in the underdense plasma is larger than speed of light in vacuum. The lower energy electrons, which are injected during the plasma wave breaking, are accelerated by the wakefield.

Journal Articles

Estimation of photon dose generated by a short pulse high power laser

Hayashi, Yukio; Fukumi, Atsushi*; Matsukado, Koji*; Mori, Michiaki; Kotaki, Hideyuki; Kando, Masaki; Chen, L.-M.; Daito, Izuru; Kondo, Shuji; Kanazawa, Shuhei; et al.

Radiation Protection Dosimetry, 121(2), p.99 - 107, 2006/12

 Times Cited Count:15 Percentile:73.49(Environmental Sciences)

The authors obtain a new equation to estimate the forward component of a photon dose which is generated through the interaction between a target and a short pulse high power laser. As the equation is quite simple, it is useful for calculating the photon dose. The equation shows that the photon dose is proportional to the electron temperature for the range of its temperature $$>$$ 3 MeV, and proportional to square of the electron temperature for the range of its temperature $$<$$ 3 MeV. The dose estimated with this method is roughly consistent with the result of Monte Carlo simulation. On someassumptions and corrections, it can reproduce experimental results obtained and the dose result calculated at other laboratories.

JAEA Reports

Evaluation of heat exchange performance for the auxiliary component cooling water system cooling tower in HTTR

Tochio, Daisuke; Kameyama, Yasuhiko; Shimizu, Atsushi; Inoi, Hiroyuki; Yamazaki, Kazunori; Shimizu, Yasunori; Aragaki, Etsushi; Ota, Yukimaru; Fujimoto, Nozomu

JAEA-Technology 2006-045, 43 Pages, 2006/09

JAEA-Technology-2006-045.pdf:5.97MB

The auxiliary component cooling water system (ACCWS) is one of the cooling system in High Temperature Engineering Test Reactor (HTTR) The ACCWS has the features not only many facilities cooling but also heat sink of the vessel cooling system which is one of the engineering safety features. Therefore, the ACCWS is required to satisfy the design criteria of heat removal performance. In this report, heat exchange performance data of the rise-to-power-up test and the in-service operation for the ACCWS cooling tower was evaluated. Moreover, the evaluated values were compared with the design values, and it is confirmed that ACCWS cooling tower has the required heat exchange performance in the design.

Journal Articles

A New neutron reflectometer SUIREN at JRR-3

Yamazaki, Dai; Soyama, Kazuhiko; Moriai, Atsushi; Tamura, Itaru; Nakamura, Kiyoshi

Hamon, 16(3), p.174 - 176, 2006/07

no abstracts in English

56 (Records 1-20 displayed on this page)