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Owada, Mitsuhiro; Nakanishi, Yoshiki; Murokawa, Toshihiro; Togashi, Kota; Saito, Katsunori; Nonaka, Kazuharu; Sasaki, Yu; Omori, Koji; Chinone, Makoto; Yasu, Hideto; et al.
JAEA-Technology 2024-013, 221 Pages, 2025/02
The uranium enrichment facilities at the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency (JAEA) were constructed sequentially to develop uranium enrichment technology with centrifugal separation method. The developed technologies were transferred to Japan Nuclear Fuel Limited until 2001. And the original purpose has been achieved. Wastewater Treatment Facility, one of the uranium enrichment facilities, was constructed in 1976 to treat radioactive liquid waste generated at the facilities, and it finished the role in 2008. In accordance with the Medium/Long-Term Management Plan of JAEA Facilities, interior equipment installed in this facility had been dismantled and removed since November 2021 to August 2023. This report summarizes the findings obtained through the work related to dismantling and removal of interior equipment for decommissioning of Wastewater Treatment Facility.
Ishii, Yumiko*; Miura, Hikaru*; Jo, J.*; Tsuji, Hideki*; Saito, Rie; Koarai, Kazuma; Hagiwara, Hiroki; Urushidate, Tadayuki*; Nishikiori, Tatsuhiro*; Wada, Toshihiro*; et al.
PLOS ONE (Internet), 17(5), p.e0268629_1 - e0268629_17, 2022/05
Times Cited Count:6 Percentile:47.65(Multidisciplinary Sciences)We investigated the variability in Cs activity concentration in individual aquatic insects in detritivorous caddisfly (
) and carnivorous dobsonfly (
) larvae from the Ota River, Fukushima. Caddisfly larvae showed sporadically higher radioactivity, whereas no such outliers were observed in dobsonfly larvae. Autoradiography and scanning electron microscopy analyses confirmed that these caddisfly larvae samples contained radiocesium-bearing microparticles (CsMPs), which are insoluble Cs-bearing silicate glass particles. CsMPs were also found in potential food sources of caddisfly larvae, such as periphyton and drifting particulate organic matter, indicating that larvae may ingest CsMPs along with food particles of similar size. Although CsMPs distribution and uptake by organisms in freshwater ecosystems is relatively unknown, our study demonstrates that CsMPs can be taken up by aquatic insects.
Nishimura, Shoichiro*; Torii, Hiroyuki*; Fukao, Yoshinori*; Ito, Takashi; Iwasaki, Masahiko*; Kanda, Sotaro*; Kawagoe, Kiyotomo*; Kawall, D.*; Kawamura, Naritoshi*; Kurosawa, Noriyuki*; et al.
Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08
Times Cited Count:16 Percentile:82.28(Optics)Miyajima, Yusuke*; Saito, Ayaka*; Kagi, Hiroyuki*; Yokoyama, Tatsunori; Takahashi, Yoshio*; Hirata, Takafumi*
Geostandards and Geoanalytical Research, 45(1), p.189 - 205, 2021/03
Times Cited Count:6 Percentile:34.03(Geochemistry & Geophysics)Uncertainty for elemental and isotopic analyses of calcite by LA-ICP-MS is largely controlled by the homogeneity of the reference materials (RMs) used for normalization and validation. In order to produce calcite RMs with homogeneous elemental and isotopic compositions, we incorporated elements including U, Pb, and rare earth elements into calcite through heat- and pressure-induced crystallization from amorphous calcium carbonate that was precipitated from element-doped reagent solution. X-ray absorption spectra showed that U was present as U(VI) in the synthesized calcite, probably with a different local structure from that of aqueous uranyl ions. The uptake rate of U by our calcite was higher in comparison to synthetic calcite of previous studies. Variations of element mass fractions in the calcite were better than 12% 2RSD, mostly within 7%. The Pb/
Pb ratio in the calcite showed
1% variations, while the
U/
Pb ratio showed 3-24% variations depending on element mass fractions. Using the synthetic calcite as primary RMs, we could date a natural calcite RM, WC-1, with analytical uncertainty as low as
3%. The method presented can be useful to produce calcite with controlled and homogeneous element mass fractions, and is a promising alternative to natural calcite RMs for U-Pb geochronology.
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count:13 Percentile:98.52(Quantum Science & Technology)Ichikawa, Kenta*; Kanda, Hironori; Yoshioka, Naoki*; Ara, Kuniaki; Saito, Junichi; Nagai, Keiichi
Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07
Studies on the suppression of the reactivity of sodium itself have been performed on the basis of the concept of suspended nanoparticles in liquid sodium (sodium nanofluid). According to the experimental and theoretical results of studies for sodium nanofluid, velocity and heat of sodium nanofluid-water reaction are lower than those of the pure sodium-water reaction. The analytical model for the peak temperature of a sodium nanofluid-water reaction jet has been developed in consideration of these suppression effects by the authors. In this paper, the prediction method for mitigation effects for a damage of adjacent tubes in a steam generator tube rupture (SGTR) accidents is arranged by applying this analytical model for the peak temperature of the reaction jet. On the assumption that the sodium nanofluid is used for the secondary coolant of sodium-cooled fast reactor (SFR), mitigation effects under the design-base accident (DBA) condition and the design-extension condition (DEC) of SGTR are estimated by using this method. As a result, there is a possibility to reduce the number of damaged tubes and to suppress the pressure generated by SGTR accidents by using sodium nanofluid in the secondary coolant.
Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.
Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00
no abstracts in English
Ninomiya, Kazuhiko*; Kubo, Kenya*; Nagatomo, Takashi*; Higemoto, Wataru; Ito, Takashi; Kawamura, Naritoshi*; Strasser, P.*; Shimomura, Koichiro*; Miyake, Yasuhiro*; Suzuki, Takao*; et al.
Analytical Chemistry, 87(9), p.4597 - 4600, 2015/05
Times Cited Count:28 Percentile:70.15(Chemistry, Analytical)Nagao, Seiya*; Niibori, Yuichi*; Tanaka, Tadao; Sasaki, Takayuki*; Saito, Takumi*; Kirishima, Akira*; Yoshikawa, Hideki; Iijima, Kazuki; Hama, Katsuhiro; Iwatsuki, Teruki; et al.
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 20(1), p.3 - 14, 2013/06
This paper shows a current status of groundwater colloids studies on the performance assessment of geological disposal of radioactive wastes in Japan, and summaries realistic approach of the colloids studies at a substantial research network for Japanese universities and institutes.
Kokubu, Yoko; Nishizawa, Akimitsu*; Suzuki, Mototaka*; Owaki, Yoshio*; Nishio, Tomohiro*; Matsubara, Akihiro; Saito, Tatsuo; Ishimaru, Tsuneari; Umeda, Koji; Hanaki, Tatsumi
Nuclear Instruments and Methods in Physics Research B, 294, p.43 - 45, 2013/01
Times Cited Count:4 Percentile:31.99(Instruments & Instrumentation)The Tono Geoscience center of JAEA installed the JAEA-AMS-TONO system at 1997. Since 1998, the system has routinely used for C-AMS. Recently, about 800 samples/y have been measured mainly for studies of neotectonics and hydrogeology in relation to research of geosphere stability for long-term Isolation of high-level radioactive waste. Under the common-use facility program, the system has also been used by researchers of universities and other institutes. In addition,
Be-AMS has been developed for geochronological study. A gas ionisation detector was exchanged. As the detector has a gas absorber cell which has larger volume than the previous one, it is possible to remove
B efficiently. Test measurement by using several standard samples supplied from University of California, Berkeley was performed. Ratios of
Be/
Be were comparable to the certified values, indicating that our system has sufficient ability to be useful to
Be-AMS.
Tsuchiya, Kunihiko; Ito, Masayasu; Kitagishi, Shigeru; Endo, Yasuichi; Saito, Takashi; Hanawa, Yoshio; Dorn, C. K.*
JAEA-Conf 2012-002, p.111 - 114, 2012/12
no abstracts in English
Ueda, Yoshio*; Oya, Kaoru*; Ashikawa, Naoko*; Ito, Atsushi*; Ono, Tadayoshi*; Kato, Daiji*; Kawashima, Hisato; Kawamura, Gakushi*; Kenmotsu, Takahiro*; Saito, Seiki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(9), p.484 - 502, 2012/09
no abstracts in English
Miyamura, Hiroko; Kureta, Masatoshi; Segawa, Mariko; Kubo, Jun*; Saito, Takafumi*; Suzuki, Yoshio; Takemiya, Hiroshi
Visualization of Mechanical Processes (Internet), 1(3), 8 Pages, 2011/10
The use of high frame rate neutron radiography has been proposed as a method for recording images of oil in a running car engine. However, it is difficult to capture the behavior of oil from such images, because the images are dark and blurry. Therefore, we attempt to overcome this problem using a multi-scale image processing technique, in which the oil regions are classified based on scale. This method can be used to focus attention on objects with a particular scale. In addition, we propose a technique by which to capture the time-dependent behavior of oil using spatio-temporal image analysis. Using these techniques, the region of interest can be determined and observed carefully.
Miyamura, Hiroko; Kureta, Masatoshi; Segawa, Mariko; Kubo, Jun*; Saito, Takafumi*; Suzuki, Yoshio; Takemiya, Hiroshi
Proceedings of 11th Asian Symposium on Visualization (ASV-11) (CD-ROM), 4 Pages, 2011/06
In this paper, we report that our image analysis technique, which has be proposed for analyzing large-scale and complex simulation and measurement experiment results in nuclear field was applied to the industrial problems. The Japan Atomic Energy Agency and Nissan Motor Co., Ltd. proposed a high-speed camera using neutron radiography, and developed the technology to capture the flow of oil in a car engine. However the recorded images are blurred, it is difficult to visualize and analyze the behavior of oil in detail. Therefore, we try to overcome this by using multi-scale analysis, which is an image processing technique on image emphasis. In addition, we present a spatio-temporal image analysis for capturing the behavior of oil that is not yet understood in detail. In this presentation, we discuss the effectiveness of our image analysis technique.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.521 - 523, 2010/09
The fabrication of a new RFQ has been started as a backup machine for the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those are brazed together. A one-step vacuum brazing of a unit tank was adopted to unite these four vanes together with the flanges and ports. At the first tank brazing, the vacuum leak has been occurred due to the non-uniform temperature rise during the heating. Repair of this leakage and the results of the improved brazing of the second tank are reported.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Kawamata, Hiroshi*; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.518 - 520, 2010/09
The fabrication of a new RFQ has been started in the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those will be brazed together. To reduce the costs and periods to develop the special formed bite for the modulation machining, a numerical controlled machining using a conventional ball-end-mill was adopted for the vane modulation cutting instead of the wheel shape cutter. The dimension accuracy was confirmed by cutting test pieces. Moreover, the obtained surface seems smooth enough for the operation. Results of the ball-end-mill machining for the vanes are described.
Yamamoto, Masahiro*; Uchiyama, Takashi*; Miyajima, Tsukasa*; Honda, Yosuke*; Sato, Kotaro*; Matsuba, Shunya*; Saito, Yoshio*; Kobayashi, Masanori*; Kurisu, Hiriki*; Hajima, Ryoichi; et al.
Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.717 - 720, 2010/08
A 500-kV photocathode DC electron gun which can supply the beam of a low emittance and a high average current has been developed in collaboration with KEK, JAEA, Hiroshima Univ., Nagoya Univ. and Yamaguchi Univ. The vacuum of the gun chamber has to be lower Extreme High Vacuum for maintain cathode-life time. A titanium chamber and new material of ceramic were employed to reduce outgassing rate. The result of outgassing rate of the gun chamber is described in this report.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.783 - 785, 2010/05
The J-PARC RFQ (length 3.1 m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05 MeV to 3 MeV toward the following DTL. The stability of the operating RFQ decreased for a few months at the end of 2008, then, we started a preparation of a new RFQ as a backup machine in the case of RFQ problem. The beam dynamics design of the new RFQ is the same as the current cavity for a quick resumption of operation, however, the engineering and RF designs are changed to improve stability. The processes of the vane machining and the surface treatments have been carefully considered to reduce the discharge problem. The vacuum brazing technique has been chosen for vane jointing. The design of the new RFQ and the fabrication progress is descried in this proceeding.
Yoshimoto, Masahiro; Takeda, Osamu; Kawase, Masato; Yamazaki, Yoshio; Kinsho, Michikazu; Saito, Yoshio*; Kabeya, Zenzaburo*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3930 - 3932, 2010/05
At the 3 GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex), the scheme of H charge exchange injection using stripping foils is adopted. The charge exchange system is composed of three stripping foil devices. The first stripping foil device, which converts the H
beam from the 181 MeV LINAC into the H
beam, can replace the broken foil with new one in vacuum remotely and automatically. In September 2007, mechanical trouble with the first stripping foil device had occurred just before the RCS beam commissioning was started. The magnetic coupling of the transfer rod had been decoupled and the transfer rod had been broken which was caught in the vacuum gate valve. We studied the trouble cause, re-examined the structural design and the selection for the material, and then verified the specification from endurance tests with sample pieces. Then the improved device was installed in the ring in September 2008.
Miyamura, Hiroko; Kureta, Masatoshi; Segawa, Mariko; Kubo, Jun*; Saito, Takafumi*; Suzuki, Yoshio; Takemiya, Hiroshi
Denki Gakkai Kenkyukai Shiryo, Sangyo Keisoku Seigyo Kenkyukai (IIC-10-73), p.7 - 12, 2010/03
An experiment is conducted to measure the water and oil in a metallic object by neutron radiography. In this approach, visualization of the oil in a rotating car engine at high speed is achieved by using the proposed high-speed camera. However, because the oil is mist and liquid, it is difficult to identify these conditions and to analyze them. Therefore, we try to identify the oil condition in the engine by employing a multi-scale analysis, which is an image processing technique.