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CNguyen, B. V. C.*; Murakami, Kenta*; Chena, L.*; Phongsakorn, P. T.*; Chen, X.*; Hashimoto, Takashi; Hwang, T.*; Furusawa, Akinori; Suzuki, Tatsuya*
Nuclear Materials and Energy (Internet), 39, p.101639_1 - 101639_9, 2024/06
Horai, Sawako*; Murakami, Shoichi*; Sakoda, Akihiro; Nakashita, Rumiko*; Kunisue, Tatsuya*; Ishimori, Yuu
Environmental Monitoring and Assessment, 194(6), p.415_1 - 415_25, 2022/06
Times Cited Count：3 Percentile：43.07(Environmental Sciences)This study conducted an investigation of trace element behavior at a former uranium (U) mining site and evaluated environmental impacts to biota. Concentrations of trace elements were determined in sediments, water, and three organism types (insects, frogs, and newts) from three zones in the former U mining site. Concentrations of As and U in the sediments and water samples were the highest at the mill tailings pond site, where post-U extraction remnants have been accumulated. Additionally, among the organisms analyzed the highest levels of these elements/isotopes were found in newts from MP. Considering data analyses of the whole-body element concentrations, bioaccumulation factors, and 
N values for the organisms, it was concluded that newts might be the most vulnerable species in this location. Further monitoring and more accurate evaluation of the ecological impacts are preferred for this former U mining site.
Yoshimura, Kazuo; Doda, Norihiro; Tanaka, Masaaki; Fujisaki, Tatsuya*; Murakami, Satoshi*; Vilim, R. B.*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03
In Japan Atomic Energy Agency, the multilevel simulation system which enables consistent evaluation from the whole plant behavior to the local phenomena is being developed to optimize plant design and enhance the safety of sodium-cooled fast reactors. To validate the coupling method in the MLS system, the 1D-CFD coupling method using Super-COPD for 1D plant dynamics analysis and Fluent for multi-dimensional CFD analysis was applied to the analyses of loss of flow tests in EBR-II. It was confirmed that it could predict multi-dimensional thermal-hydraulic phenomena such as thermal stratification in the upper plenum, Z-shaped pipe, and cold pool, holding the whole plant behavior simultaneously. Moreover, the applicability of the 1D-CFD coupling method to the evaluation of the phenomena in natural circulation conditions was confirmed by comparing the results of the 1D-CFD couple analyses and the measured data.
Shiraki, Fumiya*; Yoshikawa, Taeko*; Oshima, Akihiro*; Oshima, Yuji*; Takasawa, Yuya*; Fukutake, Naoyuki*; Oyama, Tomoko*; Urakawa, Tatsuya*; Fujita, Hajime*; Takahashi, Tomohiro*; et al.
Nuclear Instruments and Methods in Physics Research B, 269(15), p.1777 - 1781, 2011/08
Times Cited Count：8 Percentile：53.37(Instruments & Instrumentation)The graded energy deposition of heavy ion beam irradiation to polymeric materials was utilized to synthesize a novel proton exchange membrane (PEM) with the graded density of sulfonic acid groups toward the thickness direction. Stacked Poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) films were irradiated by Xe
ion beam with the energy of 6 MeV/u under a vacuum condition. Irradiated films were grafted with styrene monomer and then sulfonated. The membrane electrode assembly (MEA) fabricated by the function graded PEM showed improved fuel cell performance in terms of voltage stability. It was expected that the function-graded PEM could control the graded concentration of sulfonic acid groups in PEM.
Gowa, Tomoko*; Shiotsu, Tomoyuki*; Urakawa, Tatsuya*; Oka, Toshitaka; Murakami, Takeshi*; Oshima, Akihiro*; Hama, Yoshimasa*; Washio, Masakazu*
Radiation Physics and Chemistry, 80(2), p.264 - 267, 2011/02
Times Cited Count：8 Percentile：53.37(Chemistry, Physical)High linear energy transfer (LET) heavy ion beams were irradiated to poly(tetrafluoroethylene-co-ethylene) (ETFE) under vacuum and in air. The irradiation effects in ETFE as a function of the depth was precisely evaluated by analyzing each one of the films of the irradiation samples which were made of stacked ETFE films. It was indicated that conjugated double bonds would be generated by heavy ion beam irradiation, and their amounts should show the Bragg-curve-like distributions. Also, it was suggested that higher LET beams would induce radical formation in high density and longer conjugated C=C double bonds could be generated by the second-order reactions. Moreover, for irradiation samples in air, C=O was produced correlating to the yield of oxygen molecules diffusing from the sample surface.
Sato, Shoichi*; Ichimura, Makoto*; Yamaguchi, Yusuke*; Katano, Makoto*; Imai, Yasutaka*; Murakami, Tatsuya*; Miyake, Yuichiro*; Yokoyama, Takuro*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.
Plasma and Fusion Research (Internet), 5, p.S2067_1 - S2067_4, 2010/12
Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are studied. ICE due to H-ions is identified from the difference of the toroidal wave number of 2nd ICE(D). The parameter dependence for the appearance of ICE(H) is investigated from the experimental conditions and also is studied by using "Escape Particle Orbit analysis Code (EPOC)".
Izawa, Yasukazu*; Nishihara, Katsunobu*; Tanuma, Hajime*; Sasaki, Akira; Murakami, Masakatsu*; Sunahara, Atsushi*; Nishimura, Hiroaki*; Fujioka, Shinsuke*; Aota, Tatsuya*; Shimada, Yoshinori*; et al.
Journal of Physics; Conference Series, 112, p.042047_1 - 042047_4, 2008/00
Times Cited Count：8 Percentile：93.57(Physics, Fluids & Plasmas)In the development of a high power EUV source used in the EUV lithography system, we have been constructed EUV database of laser-produced tin plasma by the theoretical and experimental studies. On the basis of our understanding, the optimum conditions of lasers and plasmas were clarified, and we proposed the guidelines of laser plasma to obtain clean, efficient and high power EUV source for the practical EUV lithography system. In parallel to such studies, novel targets and high power laser system to generate the optimized EUV source plasma have been developed.
Saito, Kimiaki; Saito, Hidetoshi*; Kunieda, Etsuo*; Narita, Yuichiro*; Myojoyama, Atsushi*; Fujisaki, Tatsuya*; Kawase, Takatsugu*; Kaneko, Katsutaro*; Ozaki, Masahiro*; Deloar, H. M.*; et al.
Joho Shori, 48(10), p.1081 - 1088, 2007/10
no abstracts in English
Kanno, Ikuo*; Hishiki, Shigeomi*; Murakami, Haruko*; Sugiura, Osamu*; Murase, Yasuhiro*; Nakamura, Tatsuya; Katagiri, Masaki
Nuclear Instruments and Methods in Physics Research A, 520(1-3), p.93 - 95, 2004/03
Times Cited Count：2 Percentile：18.14(Instruments & Instrumentation)no abstracts in English
Hasegawa, Masatoshi*; Sakurai, Hideyuki*; Shin, Masako*; Okamoto, Masahiko*; Ishiuchi, Shogo*; Asakawa, Isao*; Tamamoto, Tetsuo*; Ono, Tatsuya*; Oikawa, Masakazu*; Kamiya, Tomihiro; et al.
no journal, ,
no abstracts in English
Ichimura, Makoto*; Yamaguchi, Yusuke*; Sato, Shoichi*; Katano, Makoto*; Ouchi, Toshiaki*; Muro, Taishi*; Sekihara, Yusuke*; Murakami, Tatsuya*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.
no journal, ,
Fluctuations in the ion cyclotron range of frequency are investigated both on GAMMA 10 and JT-60U. Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are described. ICE due to H-ions is newly identified. ICE(T) with lower frequency has larger wave numbers than ICE (
He) in the same discharge. The excitation of slow Alfv
n waves is elucidated for the first time as the mechanism for ICE due to T-ions. The anisotropy of T-ions at the outer plasma edge is evaluated by using Escape Particle Orbit analysis Code (EPOC).
Sato, Shoichi*; Ichimura, Makoto*; Yamaguchi, Yusuke*; Katano, Makoto*; Imai, Yasutaka*; Murakami, Tatsuya*; Miyake, Yuichiro*; Yokoyama, Takuro*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.
no journal, ,
Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are studied. ICE due to H-ions is identified from the difference of the toroidal wave number of 2nd ICE(D). The parameter dependence for the appearance of ICE(H) is investigated from the experimental conditions and also is studied by using "Escape Particle Orbit analysis Code (EPOC)".
Gowa, Tomoko*; Shiotsu, Tomoyuki*; Urakawa, Tatsuya*; Oka, Toshitaka; Murakami, Takeshi*; Oshima, Akihiro*; Hama, Yoshimasa*; Washio, Masakazu*
no journal, ,
Takasawa, Yuya*; Fukutake, Naoyuki*; Takahashi, Tomohiro*; Urakawa, Tatsuya*; Oshima, Yuji*; Gowa, Tomoko*; Shiraki, Fumiya*; Fujita, Hajime*; Oka, Toshitaka; Murakami, Takeshi*; et al.
no journal, ,
Tanaka, Masaaki; Murakami, Satoshi*; Fujisaki, Tatsuya*; Oki, Hiroshi*; Ohno, Shuji; Kamide, Hideki
no journal, ,
Numerical estimation method to analyze unsteady flow phenomena in the upper plenum and the hot-leg piping system in sodium cooled fast reactor has been developed. As for the high cycle thermal fatigue, outline of development status of a numerical simulation code MUGTHES and numerical estimation method including V&V process are explained. As for the flow-induced vibration phenomena, construction of a numerical model of the hot-leg piping integrated into a symmetric half domain of the upper plenum is explained and numerical results relating to applicable numerical schemes and turbulence model (RSM) are briefly mentioned.
Tanaka, Masaaki; Kikuchi, Norihiro; Hamase, Erina; Murakami, Satoshi*; Fujisaki, Tatsuya*; Imai, Yasutomo*
no journal, ,
For safety enhancement of sodium-cooled fast reactor, decay heat removal system (DHRS) by using the natural circulation without depending on the pump as the mechanical equipment is recognized as one of the most effective method. The numerical estimation method which can predict thermal hydraulic phenomena in the reactor vessel during DHRS operation is necessarily required. In this study, appropriate modeling to predict the inter wrapper flow which is caused in the gap between fuel subassemblies is preliminary investigated. The validation of the numerical results is carried out in comparison with the measured temperature data in the scaled sodium test facility named PLANDTL-1. Through the simulation, potential applicability of the gap model using the correlation equations to simulate the thermal hydraulics behavior of the inter-wrapper flow in the core is indicated.
Yoshimura, Kazuo; Doda, Norihiro; Fujisaki, Tatsuya*; Murakami, Satoshi*; Tanaka, Masaaki
no journal, ,
The multi-level simulation system with 1D-CFD coupling method which enables to evaluate various phenomena from the whole plant dynamics to the local thermal hydraulics has been developed. The numerical simulation of the ULOF test in the experimental fast reactor EBR-II in the U.S. is performed for validation study of the 1D-CFD coupling method, which combines a one-dimensional plant dynamics analysis (1D) code with a computational fluid dynamics (CFD) code. Through the numerical simulation, it was shown that the whole plant response and the multi-dimensional thermal hydraulics in the core upper plenum could be simulated. And the applicability of the 1D-CFD coupling method to plant scale analysis was confirmed in comparison with the experimental results.
Tsuchimochi, Ryota; Kato, Masato; Nakajima, Tatsuya; Hirooka, Shun; Watanabe, Masashi; Nakamichi, Shinya; Murakami, Tatsutoshi; Ishii, Katsunori
no journal, ,
Uranium and Plutonium mixed oxide (MOX) pellets used as fast reactor fuels have been produced from several raw materials by mechanical blending method. It is essential to control the pellet density which is one of the important fuel specifications, but it is difficult to understand relationships among many parameters in the production. Database for MOX production was prepared from production results of JOYO and MONJU. The input data of eighteen types were chosen from production process and made a data set. A machine learning model for predicting the sintered density of MOX pellets was derived by gradient boosting regressor.
Nakajima, Tatsuya; Kato, Masato; Tsuchimochi, Ryota; Hirooka, Shun; Watanabe, Masashi; Nakamichi, Shinya; Murakami, Tatsutoshi; Ishii, Katsunori
no journal, ,
no abstracts in English
