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Journal Articles

FEMAXI-7 analysis for modeling benchmark for FeCrAl

Yamaji, Akifumi*; Susuki, Naomichi*; Kaji, Yoshiyuki

IAEA-TECDOC-1921, p.199 - 209, 2020/07

The thermo-physical models and irradiation behavior of FeCrAl as defined by the benchmark organizer have been implemented to FEMAXI-7. Analyses were carried out firstly for the specified normal operation condition. Then, some sensitivity analyses were carried out with different assumptions and model parameters. Under the normal operating condition, the predicted FeCrAl cladded fuel performance was similar to that of Zry cladded fuel with notable, but not major difference regarding late gap closure. Under the simulated LOCA conditions, the burst pressure could be evaluated. The predicted cladding creep strain at burst was mainly attributed to creep strain with negligible plastic strain. Overall, FEMAXI-7 analyses have demonstrated excellent robustness and flexibility in modeling FeCrAl-UO$$_{2}$$ system under normal and LOCA conditions.

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:2 Percentile:58.41(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

Comparison of the extractabilities of tetrachloro- and tetrabromopalladate(II) ions with a thiodiglycolamide compound

Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi

Analytical Sciences, 33(11), p.1305 - 1309, 2017/11

 Times Cited Count:4 Percentile:77.53(Chemistry, Analytical)

Journal Articles

Selective extraction of Pt(IV) over Fe(III) from HCl with an amide-containing tertiary amine compound

Maeda, Motoki*; Narita, Hirokazu*; Tokoro, Chiharu*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi

Separation and Purification Technology, 177, p.176 - 181, 2017/04

 Times Cited Count:9 Percentile:49.88(Engineering, Chemical)

Journal Articles

Process evaluation of use of High Temperature Gas-cooled Reactors to an ironmaking system based on Active Carbon Recycling Energy System

Hayashi, Kentaro*; Kasahara, Seiji; Kurihara, Kohei*; Nakagaki, Takao*; Yan, X.; Inagaki, Yoshiyuki; Ogawa, Masuro

ISIJ International, 55(2), p.348 - 358, 2015/02

 Times Cited Count:3 Percentile:73.31(Metallurgy & Metallurgical Engineering)

Reducing coking coal consumption and CO$$_{2}$$ emissions by application of iACRES (ironmaking system based on active carbon recycling energy system) was investigated using process flow modeling to show effectiveness of HTGRs (high temperature gas-cooled reactors) adoption to iACRES. Two systems were evaluated: a SOEC (solid oxide electrolysis cell) system using CO$$_{2}$$ electrolysis and a RWGS (reverse water-gas shift reaction) system using RWGS reaction with H$$_{2}$$ produced by IS (iodine-sulfur) process. Both the effects on saving of the coking coal and reduction of CO$$_{2}$$ emissions were greater in the RWGS system. It was the reason of the result that excess H$$_{2}$$ which was not consumed in the RWGS reaction was used as reducing agent in the BF as well as CO. Heat balance in the HTGR, SOEC and RWGS modules were evaluated to clarify process components to be improved. Optimization of the SOEC temperature was desired to reduce Joule heat input for high efficiency operation of the SOEC system. Higher H$$_{2}$$ production thermal efficiency in the IS process for the RWGS system is effective for more efficient HTGR heat utilization. The SOEC system was able to utilize HTGR heat to reduce CO$$_{2}$$ emissions more efficiently by comparing CO$$_{2}$$ emissions reduction per unit heat of HTGR.

Journal Articles

Quantitative evaluation of CO$$_{2}$$ emission reduction of active carbon recycling energy system for ironmaking by modeling with Aspen Plus

Suzuki, Katsuki*; Hayashi, Kentaro*; Kurihara, Kohei*; Nakagaki, Takao*; Kasahara, Seiji

ISIJ International, 55(2), p.340 - 347, 2015/02

 Times Cited Count:6 Percentile:55.32(Metallurgy & Metallurgical Engineering)

Use of the Active Carbon Recycling Energy System in ironmaking (iACRES) has been proposed for reducing CO$$_{2}$$ emissions. To evaluate the performance of iACRES quantitatively, a process flow diagram of a blast furnace model with iACRES was developed using Aspen Plus, a chemical process simulator. CO$$_{2}$$ emission reduction and exergy analysis were performed by using mass and energy balance obtained from simulation results. The following CO$$_{2}$$ reduction methods were evaluated as iACRES: solid oxide electrolysis cells (SOEC) with CO$$_{2}$$ capture and separation (CCS), SOEC without CCS, and a reverse water-gas shift reactor powered by a high-temperature gas-cooled reactor. iACRES enabled CO$$_{2}$$ emission reduction by 3-11% by recycling CO and H$$_{2}$$, whereas effective exergy ratio decreased by 1-7%.

Journal Articles

Process evaluation of use of HTGRs to an ironmaking system based on active carbon recycling energy system (iACRES)

Hayashi, Kentaro*; Kasahara, Seiji; Kurihara, Kohei*; Nakagaki, Takao*; Yan, X.; Inagaki, Yoshiyuki; Ogawa, Masuro

Tanso Junkan Seitetsu Kenkyukai Saika Hokokusho; Tanso Junkan Seitetsu No Tenkai, p.42 - 62, 2015/02

Reducing coking coal consumption and CO$$_{2}$$ emissions by application of HTGRs (high temperature gas-cooled reactors) to iACRES (ironmaking system based on active carbon recycling energy system) was investigated using process flow modeling. Two systems were evaluated: a SOEC (solid oxide electrolysis cell) system using CO$$_{2}$$ electrolysis and a RWGS (reverse water-gas shift reaction) system using RWGS reaction with H$$_{2}$$ produced by IS (iodine-sulfur) process. Coking coal consumption was reduced from a conventional BF (blast furnace) steelmaking system by 4.3% in the SOEC system and 10.3% in the RWGS system. CO$$_{2}$$ emissions were decreased by 3.4% in the SOEC system and 8.2% in the RWGS system. Remaining H$$_{2}$$ from the RWGS reactor was used as reducing agent in the BF in the RWGS system. This was the reason of the larger reduction of coking coal consumption and CO$$_{2}$$ emissions. Electricity generation for SOEC occupied most of HTGR heat usage in the SOEC system. H$$_{2}$$ production in the IS process used most of the HTGR heat in the RWGS system. Optimization of the SOEC temperature for the SOEC system and higher H$$_{2}$$ production thermal efficiency in the IS process for the RWGS system will be useful for more efficient heat utilization. One typical-sized BF required 0.5 HTGRs and 2 HTGRs for in the SOEC system and RWGS system, respectively. CO$$_{2}$$ emissions reduction per unit heat input was larger in the SOEC system. Recycling H$$_{2}$$ to the RWGS will be useful for smaller emissions per unit heat in the RWGS system.

Journal Articles

Process modeling of iACRES by ASPEN Plus and evaluation of the whole system

Hayashi, Kentaro*; Suzuki, Katsuki*; Kurihara, Kohei*; Nakagaki, Takao*; Kasahara, Seiji

Tanso Junkan Seitetsu Kenkyukai Saika Hokokusho; Tanso Junkan Seitetsu No Tenkai, p.27 - 41, 2015/02

Applying Active Carbon Recycling Energy System to ironmaking (iACRES) process is a promising technology to reduce coal usage and CO$$_{2}$$ emissions. To evaluate performance of iACRES quantitatively, a process flow diagram of the blast furnace model with iACRES was developed using Aspen Plus. CO$$_{2}$$ emission reduction and exergy analysis was predicted by using mass and energy balance obtained from the simulation results. The followings were investigated as iACRES: solid oxide electrolysis cells (SOEC) with CO$$_{2}$$ capture and separation (CCS), SOEC without CCS, and a reverse water-gas shift reactor as the a CO$$_{2}$$ reduction reactor powered by a high-temperature gas-cooled reactor. iACRES could provide CO$$_{2}$$ emission reductions of 3-11% by recycling CO and H$$_{2}$$, whereas the effective exergy ratio decreased by 1-7%.

Journal Articles

Micro/nanofabrication of poly($$_{L}$$-lactic acid) using focused ion beam direct etching

Oyama, Tomoko; Hinata, Toru*; Nagasawa, Naotsugu; Oshima, Akihiro*; Washio, Masakazu*; Tagawa, Seiichi*; Taguchi, Mitsumasa

Applied Physics Letters, 103(16), p.163105_1 - 163105_4, 2013/10

 Times Cited Count:8 Percentile:58.33(Physics, Applied)

Micro/nanofabrication of biocompatible and biodegradable poly($$_{L}$$-lactic acid) (PLLA) was evaluated using focused Ga ion beam direct etching. The fabrication performance was determined with different ion fluences and fluxes. It was found that the etching speed and fabrication accuracy were affected by irradiation-induced heat because the resistance of PLLA to thermal deformation is decreased when above its glass transition temperature (approximately 60$$^{circ}$$C). By controlling the irradiation conditions, controlled micro/nanostructures of PLLA were fabricated, such as holes ($$phi$$80 nm) and alphabets (width: 100 nm). Moreover, focused ion beam (FIB)-irradiated surfaces were analyzed using micro-area X-ray photoelectron spectroscopy. Owing to reactions such as the physical sputtering of atoms and radiation-induced decomposition, PLLA was gradually carbonized with increasing C=C bonds expected to have good cell attachment properties.

Journal Articles

Micro-/nanofabrication of cross-linked poly($$_{rm L}$$-lactic acid) using electron beam nanoimprint lithography

Okubo, Satoshi*; Nagasawa, Naotsugu; Kobayashi, Akinobu*; Oyama, Tomoko*; Taguchi, Mitsumasa; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*

Applied Physics Express, 5(2), p.027303_1 - 027303_3, 2012/02

 Times Cited Count:3 Percentile:83.71(Physics, Applied)

Electron beam nanoimprint lithography was proposed for fabricating the micro-/nanostructures of cross-linked poly($$_{rm L}$$-lactic acid) (RX-PLLA). PLLA with triallyl isocyanurate (TAIC) solutions were dropped on the Si-molds fabricated by the conventional EB lithography technique. PLLA/TAIC on Si-molds were imprinted and cross-linked with doses from 10 to 500 kGy at room temperature under vacuum. The micro-/nanostructures of RX-PLLA were successfully obtained with high accuracy. Hence, it was found that the imprinted structures of RX-PLLA (100 kGy irradiation) show low line edge roughness and high thermal durability at 120 $$^{circ}$$C.

Journal Articles

Super fast reactor R&D projects in Japan, 4; Numerical estimation of thermal-hydraulic characteristics of supercritical fluids in tight-lattice bundles by three-dimensional two-fluid model analysis code ACE-3D

Nakatsuka, Toru; Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki

Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 5 Pages, 2011/10

To analyze thermal hydraulics in the core of supercritical-water-cooled reactors, JAEA has been improved a three-dimensional two-fluid model analysis code ACE-3D, which has been developed originally for two-phase flow of LWRs. Heat transfer experiments of supercritical fluids flowing in a tube, a vertical annular channel around a heater pin and 7-rod bundles were analyzed with the improved ACE-3D to assess the prediction performance of the code at supercritical region. As a result, it was confirmed that the calculated wall surface temperatures agreed with the measured results. To evaluate thermal hydraulic characteristics of a tight-lattice fuel bundle of Super Fast Reactor, a simplified 19-rod fuel assembly was analyzed. Maximum clad surface temperature was observed at the position facing to the narrowest gap on the center rod near the outlet and the value was 901K. The predicted MCST satisfies thermal design criteria to ensure fuel and cladding integrity.

Journal Articles

Numerical simulation of current distribution in cable-in-conduit conductor for ITER TF coil

Kajitani, Hideki*; Ishiyama, Atsushi*; Koizumi, Norikiyo; Murakami, Haruyuki; Nakajima, Hideo

IEEE Transactions on Applied Superconductivity, 21(3), p.1964 - 1968, 2011/06

 Times Cited Count:3 Percentile:73.24(Engineering, Electrical & Electronic)

The critical current of cable-in-conduit conductor (CICC) for ITER TF coil was measured using SULTAN test facility. However, it was found that a non-uniform current distribution was established due to a non-uniform joint resistance. To more precisely evaluate critical current performance, solder filling joint was applied. To study the effect of solder filled joint on the current distribution, the authors developed a new analysis model. The lumped circuit model and distributed circuit model were used for the conductor and joint, respectively, and they are combined. This allow us to avoid iteration to solve distributed circuit equation, resulting in much reduction of calculation time. The simulation results show that although non-uniform current distribution can be established by ramping current, it is improved at current sharing temperature. Thus, the efficiency of solder filling joint is indicated.

Journal Articles

Micro-fabrication of biodegradable polymers using focused ion beam

Okubo, Satoshi*; Takahashi, Tomohiro*; Takasawa, Yuya*; Gowa, Tomoko*; Sasaki, Takashi*; Nagasawa, Naotsugu; Tamada, Masao; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*

Journal of Photopolymer Science and Technology, 23(3), p.393 - 397, 2010/11

 Times Cited Count:4 Percentile:83.81(Polymer Science)

Microfabrication of biodegradable polymers such as poly(butylene succinate-${it co}$-adipate) (PBSA) and poly($$varepsilon$$-caprolactone) (PCL) were demonstrated using focused ion beam (FIB) with maskless direct etching. As the result, the micro structures of PBSA and PCL were obtained. The etching depth of both PBSA and PCL were increased with increasing FIB fluence, and the etching rates were estimated to be about 1.3 $$times$$ 10$$^{-18}$$ $$mu$$m/(ions cm$$^{-2}$$) and 1.2 $$times$$ 10$$^{-18}$$ $$mu$$m/(ions cm$$^{-2}$$), respectively. Moreover, very thin films of PBSA and PCL were made by spin-coating method. The thicknesses of the spin-coated samples were about 200 nm, and the surface roughness was less than 10 nm (RMS). The fine structures such as micro-gear of PBSA and PCL were obtained without solid debris. The line width of the fabricated structure was about 250 nm.

Journal Articles

Numerical simulation of critical current performance in Nb$$_{3}$$Sn strand subjected to periodic bending deformation

Murakami, Haruyuki*; Ueda, Hiroshi*; Ishiyama, Atsushi*; Koizumi, Norikiyo; Okuno, Kiyoshi

Denki Gakkai Rombunshi, B, 128(6), p.853 - 859, 2008/06

In the ITER Engineering Design Activity (EDA), it was revealed the critical current of the Nb$$_{3}$$Sn model coil conductor degraded by periodic strand bending caused by enormous electromagnetic force. We developed a simulation code based on the distributed circuit to investigate dependency of the critical current performance on bending strain. The results of the numerical simulations were in good agreement with the experiments. The dependence of the critical current on periodic transverse load, temperature, pitch of periodic load, thickness of Ta barrier which prevents Cu stabilizer to be contaminated by Sn, twist pitch of the strand and RRR of the bronze matrix is investigated using developed code. The results show the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that shorter twist pitch of the cable and larger bending stiffness prevent the critical current degradation.

Journal Articles

Numerical simulation of critical current degradation of Nb$$_{3}$$Sn strand in CIC conductor

Murakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 18(2), p.1051 - 1054, 2008/06

 Times Cited Count:2 Percentile:78.46(Engineering, Electrical & Electronic)

Critical current was degraded by periodic transverse load in a CICC. A simulation code was developed to study mechanism of this degradation in details. The simulation results were compared with results of experiment in which single strand was periodically bent. Since the test results could not be simulated well in the previous work, the authors carried out improvements of the model, such as use of electro-plastic model and detail evaluation of conductance among filaments. By these improvements the agreement between the simulation and experiment can be modified. This results in verifying validity of our code. Using our code, the general dependence of the critical current degradation on strand configuration, such as barrier thickness, RRR of bronze and twist pitch of filament, are evaluated. The results show barrier thickness affects critical current performance because of its large bending rigidity. On the other hand, RRR of bronze and twist pitch of filament hardly affects critical current performance.

Journal Articles

Numerical simulation of critical current and n-value in Nb$$_{3}$$Sn strand subjected to bending strain

Murakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 17(2), p.1394 - 1397, 2007/06

 Times Cited Count:18 Percentile:32.21(Engineering, Electrical & Electronic)

Critical current of ITER mode coil degraded as increase of electromagnetic force. It was shown that the periodic bending of the strand caused this degradation from analysis based on results of experiments in which periodic transverse load is artificially applied to single strand. However, since the experiments were carried out under a certain condition, general relation between transverse load and critical current was not obtained. The authors therefore developed a numerical simulation code. The simulation results are in good agreement with test results. The general dependence of the critical current on temperature and pitch of periodic load is studied using our code. The simulation results reveal that the reduced critical current depends on the temperature and is a function of the bending strain independent of the pitch of the periodic load.

Journal Articles

Ratio of transverse diffusion coefficient to mobility of electrons in high-pressure xenon and xenon doped with hydrogen

Kobayashi, Shingo*; Hasebe, Nobuyuki*; Hosojima, Takehiro*; Ishizaki, Takeshi*; Iwamatsu, Kazuhiro*; Mimura, Mitsuteru*; Miyachi, Takashi*; Miyajima, Mitsuhiro*; Pushkin, K.*; Tezuka, Chikara*; et al.

Japanese Journal of Applied Physics, Part 1, 45(10A), p.7894 - 7900, 2006/10

 Times Cited Count:11 Percentile:57.39(Physics, Applied)

We have obtained the ratio of transverse diffusion coeffcient to mobility of electrons multiplied by the elementary charge, in Xe and Xe+H$$_{2}$$ under electric fields at a higher pressure of 1 MPa in comparison with preceding experiments. The result shows that the density effect (non-linear effect) of the ratio in both of pure Xe and Xe+H$$_{2}$$ is $$<$$15% below 1 MPa over the reduced electric field range from 0.08 to 0.6$$times$$10$$^{-17}$$V$$cdot$$cm$$^{2}$$. We also found that the diffusion of an electron swarm is suppressed by adding trace of hydrogen to high-pressure xenon gas. Discussion is made of Xe+H$$_{2}$$ gas to a new $$gamma$$-ray camera. Trace of hydrogen to high-pressure xenon gas. Discussion is made of Xe+H$$_{2}$$ gas to a new $$gamma$$-ray camera.

Journal Articles

Numerical simulation of the critical current and n-value in Nb$$_{3}$$Sn strand subjected to bending strain

Hirohashi, Masayuki*; Murakami, Haruyuki*; Ishiyama, Atsushi*; Ueda, Hiroshi*; Koizumi, Norikiyo; Okuno, Kiyoshi

IEEE Transactions on Applied Superconductivity, 16(2), p.1721 - 1724, 2006/06

 Times Cited Count:9 Percentile:51.01(Engineering, Electrical & Electronic)

To demonstrate the applicability of Nb$$_{3}$$Sn CICCs to ITER, four Nb$$_{3}$$Sn model coils have been constructed and tested. The experimental results showed that the measured critical current (Ic) degraded. In addition, the larger is the applied electromagnetic force, the larger the magnitude of the degradation is. The degradation in n-value was also observed. One of the explanations of this degradation is a local strand bending. This consideration has been supported by the test results. However, general dependence of Ic on periodic bending strain has not been clarified in this test since the experiments were carried out at a certain magnetic field, temperature and strain. Therefore, a numerical simulation code was developed to study the general dependence of the Ic and n-value of the Nb$$_{3}$$Sn strand on periodic bending strain. A distributed constant circuit model is applied to simulate current transfer among the filaments in the strand. The simulation results show relatively good agreement with the experiment results but some modification in modeling is required for more accurate simulation.

Journal Articles

Evaluation of three dimensional microstructures on silica glass fabricated by ion microbeam

Nishikawa, Hiroyuki*; Souno, T.*; Hattori, M.*; Oki, Y.*; Watanabe, E.*; Oikawa, Masakazu*; Arakawa, Kazuo; Kamiya, Tomihiro

JAERI-Review 2003-033, TIARA Annual Report 2002, p.254 - 256, 2003/11

no abstracts in English

Journal Articles

Radiation effects and surface deformation of silica by ion microbeam

Nishikawa, Hiroyuki*; Souno, T.*; Hattori, M.*; Nishihara, Y.*; Oki, Y.*; Watanabe, E.*; Oikawa, Masakazu*; Kamiya, Tomihiro; Arakawa, Kazuo

Nuclear Instruments and Methods in Physics Research B, 191(1-4), p.342 - 345, 2002/05

 Times Cited Count:3 Percentile:74.2(Instruments & Instrumentation)

no abstracts in English

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