JAEA Abstracts

-Research results below have been sorted by order of journals name.

-Sorry, some research results below have no English abstract.

April 2011

39000492
Application of the hierarchical domain decomposition boundary element method to the simplified P₃ equation
Chiba, Go
Annals of Nuclear Energy 38(5), p.1033-1038(2011) ; (JAEA-J 08715)

In the present paper, the hierarchical domain decomposition boundary element method (HDD-BEM), which has been developed to solve the diffusion equation, is applied to the simplified P₃ (SP₃) equation. The solution methodology of the HDD-BEM for the SP₃ equation is provided in the present paper. A computer program ABEMIE based on the HDD-BEM is developed, and a two-dimensional one-group anisotropic scattering benchmark problem is solved with it to verify the present HDD-BEM for the SP₃ equation. Through numerical benchmarking, it is shown that the present method results in good agreement with the solution obtained by using the existing SP_N solver based on the finite element method for both eigenvalue and neutron flux distribution. This benchmark result suggests that the HDD-BEM can be an efficient solver for the SP_N equation.

39000493
Measurement of relative biological effectiveness of protons in human cancer cells using a laser-driven quasimonoenergetic proton beamline
Yogo, Akifumi; Maeda, Takuya; Hori, Toshihiko; Sakaki, Hironao; Ogura, Koichi; Nishiuchi, Mamiko; Sagisaka, Akito; Kiriyama, Hiromitsu; Okada, Hajime; Kanazawa, Shuhei; Shimomura, Takuya; Nakai, Yoshiki*; Tanoue, Manabu*; Sasao, Fumitaka; Bolton, P.; Murakami, Masao*; Nomura, Taisei*; Kawanishi, Shunichi; Kondo, Kiminori
Applied Physics Letters 98(5), p.053701_1-053701_3(2011) ; (JAEA-J 08716)

Human cancer cells are irradiated by laser-driven quasi-monoenergetic protons. Laser pulse intensities at the 5 × 10¹⁹ W/cm² level provide the source and acceleration field for protons that are subsequently transported by four energy-selective dipole magnets. The transport line delivers 2.25 MeV protons with an energy spread of 0.66 MeV and a bunch duration of 20 ns. The survival fraction of in-vitro cells from a human salivary gland tumor is measured with a colony formation assay following proton irradiation at dose levels up to 8 Gy, for which the single bunch does rate is 1 × 10⁷ Gy/s and the effective dose rate is 0.2 Gy/s for 1-Hz repetition of irradiation. Relative biological effectiveness at the 10% survival fraction is measured to be 1.20 ± 0.11 using protons with a linear energy transfer of 17.1 keV/μm.

39000494
Carbon-14 analysis in solidified product of non-metallic solid waste by a combination of alkaline fusion and gaseous CO₂ trapping
Ishimori, Kenichiro; Kameo, Yutaka; Matsue, Hideaki; Oki, Yoshiyuki*; Nakashima, Mikio; Takahashi, Kuniaki
Applied Radiation and Isotopes 69(2), p.506-510(2011) ; (JAEA-J 08717)

In order to establish a simple and rapid analytical method for ¹⁴C in solidified products made from non-metallic low-level radioactive solid wastes by melting treatment, a radiochemical analysis in combination with alkaline fusion as a sample decomposition method was examined. A simulated solidified product containing ¹⁴C, which was prepared by using nuclear reaction ¹⁴N(n, p)¹⁴C with thermal neutron irradiation, was analyzed by the present method to compare with a conventional radiochemical analysis using oxidizing combustion. The reproducible and quantitative recovery of ¹⁴C from the simulated solidified product indicates that the present method is superior and more efficient for ¹⁴C analysis in solidified products than the conventional method using oxidizing combustion.

39000495
Dehydrogenation catalyst for optical organic-hydride detection
Yoshimura, Kimio; Hakoda, Teruyuki; Yamamoto, Shunya; Yoshikawa, Masahito
Applied Surface Science 257(9), p.4428-4431(2011) ; (JAEA-J 08718)

39000496
Photoluminescence via two different excited states in a mononuclear europium(III) complex with tetradentate schiff base ligands
Ebato, Shota*; Watanabe, Masayuki; Nakajima, Kiyohiko*; Tsuchimoto, Masanobu*
Chemistry Letters 39(7), p.706-707(2010) ; (JAEA-J 08719)

A europium(III) complex with tetradentate Schiff base ligands (C₂H₅)₃NH[Eu(3,5Clsalen)₂] was prepared, and its structure was determined by X-ray crystal structure analysis. The complex has an eight-coordinate mononuclear structure with two Schiff base ligands in a meridional form. The complex displays emission bands resulting from ff transitions by excitation at 357 or 234 nm in acetonitrile.

39000497
Nuclear-charge polarization at scission in proton-induced fission of ²³³U
Nishinaka, Ichiro; Tanikawa, Masashi*; Nagame, Yuichiro; Nakahara, Hiromichi*
European Physical Journal A 47(1), p.1-8(2011) ; (JAEA-J 08720)

The most probable charges of secondary fragments in the 11.5 MeV proton-induced fission of ²³³U were determined from the mass yields measured by the double time-of-flight method and the fractional cumulative and independent yields measured radiochemically and reported in literature. The nuclear-charge polarization of primary fragments at scission was obtained by correcting the secondary fragment mass for neutron evaporation. The results show that the nuclear-charge polarization is determined by the minimum potential energy of nuclei at scission and that it is nearly independent not only of mass and excitation energy but also of the neutron-to-proton ratio of the fissioning nucleus.

39000498
Progress of conversion system from CAD data to MCNP geometry data in Japan
Sato, Satoshi; Nashif, H.*; Masuda, Fukuzo*; Morota, Hidetsugu*; Iida, Hiromasa*; Konno, Chikara
Fusion Engineering and Design 85(7-9), p.1546-1550(2010) ; (JAEA-J 08721)

Automatic conversion systems from CAD data to MCNP geometry input data have been developed to convert the CAD data of the fusion reactor with very complicated structure. So far, three conversion systems (GEOMIT-1, ARCNCP and GEOMIT-2) have been developed. The void data can be created in these systems. GEOMIT-1 was developed in 2007, and a lot of manual shape splitting works for the CAD data were required to successfully convert the complicated geometry. ARCNCP was developed in 2008. The algorithm has been drastically improved on automatic creation of ambiguous surface in ARCNCP, and manual shape splitting works can be drastically reduced. The latest system, GEOMIT-2, does not require additional commercial software packages, though the previous systems require them. It has also functions of the CAD data healing and the automatic shape splitting. The geometrical errors of the CAD data can be automatically revised by the healing function, and the complicated geometries can be automatically split into the simple geometries by the shape splitting function. Any manual works are not required in GEOMIT-2. The latest system is very useful for nuclear analyses of fusion reactors.

39000499
Overcurrent analyses in JT-60SA poloidal circuits due to plasma disruption and quench protection intervention
Novello, L.*; Gaio, E.*; Piovan, R.*; Takechi, Manabu; Ide, Shunsuke; Matsukawa, Makoto
Fusion Engineering and Design 86(1), p.33-40(2011) ; (JAEA-J 08722)

The identification of the maximum amplitude of the currents circulating in the circuits is a useful indication for the design both of magnet and power supply components in fusion experiments. This paper evaluates the maximum level of coil overcurrents in the poloidal superconducting magnets of JT-60SA. To derive these information, a complete model capable to take into account all the mutually coupled elements was worked out, including the poloidal superconducting coils, the plasma position control in-vessel coils, the vacuum vessel, the stabilizing plates and the plasma. The model was utilized to analyze plasma disruption and quench protection circuit intervention in a large variety of different conditions to identify the possible overcurrent levels. The paper describes the model and the analyses performed, and presents and discusses the results.

39000500
Feasibility study on cryogenic irradiation facility in JMTR
Inaba, Yoshitomo; Tsuchiya, Kunihiko; Shikama, Tatsuo*; Nishimura, Arata*; Kawamura, Hiroshi
Fusion Engineering and Design 86(2-3), p.134-140(2011) ; (JAEA-J 08723)

The Japan Materials Testing Reactor (JMTR) of the Japan Atomic Energy Agency is a testing reactor with first criticality in March 1968. The reactor has been utilized for various neutron irradiation tests on nuclear fuels and materials, as well as for radioisotope production. The operation of JMTR stopped temporarily in August 2006 for refurbishment and improvement. The renewed JMTR will resume operation in Japanese fiscal year 2011. For the resumption of the new JMTR, the new irradiation facilities, the usability improvements, the target, and the expected roles of the new JMTR have been discussed. As one of the new irradiation facilities, the cryogenic irradiation facility, which is used for the investigation on the low-temperature irradiation behavior of materials such as superconducting magnet materials for fusion reactors, has been desired. In this study, the feasibility of low-temperature irradiation tests with the cryogenic irradiation facility was investigated, and the conceptual design of the facility was carried out. As a result, it was found that irradiation tests at temperatures below 20 K for the development of the superconducting magnet materials can be realized by the installation of an irradiation capsule into an irradiation hole with low γ heating and by the adoption of vacuum jacketed tubes to connect between the capsule and a cooling system.

39000501
Application of X-ray computer tomography for observing the central void formations and the fuel pin deformations of irradiated FBR fuel assemblies
Katsuyama, Kozo; Nagamine, Tsuyoshi; Furuya, Hirotaka
IEEE Transactions on Instrumentation and Measurement 57(5), p.2714-2718(2010) ; (JAEA-J 08724)

In order to observe the structural change in the interior of irradiated fuel assembly, the non-destructive post irradiation examination technique using X-ray computer tomography (X-ray CT) was developed. In this X-ray CT system, the 12 MeV X-ray pulses was used in synchronization with the switch-in of the detector to minimize the effects of the γ ray emissions from the irradiated fuel assembly, and then clear cross section CT image could be successfully obtained.

39000502
Barrier distribution of quasi-elastic backward scattering in very heavy reaction systems
Mitsuoka, Shinichi; Ikezoe, Hiroshi; Nishio, Katsuhisa; Watanabe, Yutaka*; Jeong, S. C.*; Ishiyama, Hironobu*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari
International Journal of Modern Physics E 19(5,6), p.989-996(2010) ; (JAEA-J 08725)

We have measured quasi-elastic scattering cross sections in reactions of ⁴⁸Ti, ⁵⁴Cr, ⁵⁶Fe, ⁶⁴Ni and ⁷⁰Zn + ²⁰⁸Pb, relating to Pb-based cold fusion reactions for super-heavy elements 104, 106, 108, 110 and 112, respectively. A thin target of ²⁰⁸Pb was bombarded by heavy-ion beams supplied from the JAEA tandem-booster accelerator with changing the beam energy in steps of 1.5 MeV. The barrier distributions were derived from the first derivative of the excitation functions measured at backward angles of 172^°, 168^° and 162^°. The centroid of the barrier distributions showed a deviation from several predicted barrier heights toward the low energy side. The shape of the barrier distributions was well reproduced by the results of a coupled-channel calculation taking account of the coupling effects of the collective vibrational excitations in the projectile and target nuclei. We have recently obtained similar results in heavier reactions of ⁷⁶Ge and ⁸⁶Kr + ²⁰⁸Pb.

39000503
Physicochemical properties of dicesium tetravalent plutonium hexanitrate in uranium crystallization process
Nakahara, Masaumi; Nomura, Kazunori; Koizumi, Tsutomu
IOP Conference Series; Materials Science and Engineering 9, p.012065_1-012065_6(2010) ; (JAEA-J 08726)

On U crystallization, there is concern that Cs₂Pu(NO₃)₆ are deposited on the UNH crystal. Physicochemical properties of Cs₂Pu(NO₃)₆ was studied for its condition of formation and decontamination to U in the crystal. The solubility of Cs₂Pu(NO₃)₆ in HNO₃ solution increased with decreasing the HNO₃ concentration at 25 °C. The thermal analysis showed that Cs₂Pu(NO₃)₆ was stable below 245 °C. Since the UNH crystal melts at 60.2 °C, Cs₂Pu(NO₃)₆ was attempt to be separated from the UNH crystal due to their different melting points. Although the decontamination factors of Pu and Cs for U melt was about 1 by using a filter of 5.0 μm, it improved to be about 2 with a filter of 0.45 μm.

39000504
Theoretical optimization of base doping concentration for radiation resistance of InGaP subcells of InGaP/GaAs/Ge based on minority-carrier lifetime
Elfiky, D.*; Yamaguchi, Masafumi*; Sasaki, Takuo*; Takamoto, Tatsuya*; Morioka, Chiharu*; Imaizumi, Mitsuru*; Oshima, Takeshi; Sato, Shinichiro; Elnawawy, M.*; Eldesoky, T.*; Ghitas, A.*
Japanese Journal of Applied Physics 49(12), p.121201_1-121201_7(2010) ; (JAEA-J 08727)

One of the fundamental objectives for research and development of space solar cells is to improve their radiation resistance. InGaP solar cells with low base carrier concentrations under low-energy proton irradiations have shown high radiation resistances. In this study, an analytical model for low-energy proton radiation damage to InGaP subcells based on a fundamental approach for radiative and nonradiative recombinations has been proposed. The radiation resistance of InGaP subcells as a function of base carrier concentration has been analyzed by using the radiative recombination lifetime and damage coefficient K for the minority-carrier lifetime of InGaP. Numerical analysis shows that an InGaP solar cell with a lower base carrier concentration is more radiation-resistant. Satisfactory agreements between analytical and experimental results have been obtained, and these results show the validity of the analytical procedure. The damage coefficients for minority-carrier diffusion length and carrier removal rate with low-energy proton irradiations have been observed to be dependent on carrier concentration through this study. As physical mechanisms behind the difference observed between the radiation-resistant properties of various base doping concentrations, two mechanisms, namely, the effect of a depletion layer as a carrier collection layer and generation of the impurity-related complex defects due to low-energy protons stopping within the active region, have been proposed.

39000505
Effect of base doping concentration on radiation-resistance for GaAs sub-cells in InGaP/GaAs/Ge
Elfiky, D.*; Yamaguchi, Masafumi*; Sasaki, Takuo*; Takamoto, Tatsuya*; Morioka, Chiharu*; Imaizumi, Mitsuru*; Oshima, Takeshi; Sato, Shinichiro; Elnawawy, M.*; Eldesoky, T.*; Ghitas, A.*
Japanese Journal of Applied Physics 49(12), p.121202_1-121202_5(2010) ; (JAEA-J 08728)

GaAs solar cells with the lower base carrier concentration under low energy proton irradiations had shown experimentally the better radiation-resistance. Analytical model based on fundamental approach for radiative and non-radiative recombination has been proposed for radiation damage in GaAs sub-cells. The radiation resistance of GaAs sub-cells as a function of base carrier concentration has been analyzed by using radiative recombination lifetime and damage coefficient for minority carrier lifetime. Numerical analysis shows good agreement with experimental results. The effect of carrier concentration upon the change of damage constant and carrier removal rate have been studied.

39000506
Experimental study on gas entrainment due to nonstationary vortex in a sodium cooled fast reactor; Comparison of onset conditions between sodium and water
Kimura, Nobuyuki; Ezure, Toshiki; Miyakoshi, Hiroyuki; Kamide, Hideki; Fukuda, Takeshi*
Journal of Engineering for Gas Turbines and Power 132(10), p.102908_1-102908_6(2010) ; (JAEA-J 08729)

In sodium-cooled fast reactor, a compact reactor vessel (R/V) with increased sodium flow velocity was designed to reduce the construction cost. One of the thermal hydraulic problems in this design is gas entrainment at the free surface in the R/V. In most of past studies, water experiments were performed to investigate the gas entrainment in the reactor. It is necessary to evaluate an influence of fluid physical property on the gas entrainment phenomena. In this study, sodium experiments were carried out to clarify the onset criteria of the gas entrainment due to a free surface vortex. Water experiments using a test section in which geometry is the same as that in the sodium tests were also performed. The gas entrainment in water slightly tended to take place in comparison with that in sodium under low velocity conditions. Overall onset condition map on lateral and downward flow velocities in the sodium and water experiments were in good agreement.

39000507
Design and construction of IFMIF/EVEDA lithium test loop
Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Ida, Mizuho; Matsushita, Izuru*; Horiike, Hiroshi*; Kanemura, Takuji; Sugiura, Hirokazu*; Yagi, Juro*; Suzuki, Akihiro*; Terai, Takayuki*; Fukada, Satoshi*; Nakamura, Hiroo*
Journal of Engineering for Gas Turbines and Power 133(5), p.052910_1-052910_6(2010) ; (JAEA-J 08730)

As a major Japanese activity for the IFMIF/EVEDA, EVEDA Li Test Loop (ELTL) to simulate hydraulic and impurity conditions of IFMIF is under design and preparation for fabrication. Feasibility of hydraulic stability of the liquid Li target and the purification systems of hot traps are major key issues to be validated. This paper presents the current status of the design and construction of the EVEDA Li Test Loop. Detail designs of the loop components such as the target assembly, tanks, an electro-magnetic pump and flow meter and a cold trap for purification system are described in addition to the flow diagnostics system and the hot traps.

39000508
Pressure fluctuation characteristics of complex turbulent flow in a single elbow with small curvature radius for a sodium-cooled fast reactor
Ebara, Shinji*; Aoya, Yuta*; Sato, Tsukasa*; Hashizume, Hidetoshi*; Yuki, Kazuhisa*; Aizawa, Kosuke; Yamano, Hidemasa
Journal of Fluids Engineering 132(11), p.111102_1-111102_7(2010) ; (JAEA-J 08731)

A multi-elbow piping system is adopted for the Japan Sodium-cooled Fast Reactor (JSFR) cold-legs. Flow Induced Vibration (FIV) is considered to appear due to complex turbulent flow with very high Reynolds number in the piping. In this study, pressure measurement for a single elbow flow is conducted to elucidate pressure fluctuation characteristics originated from turbulent motion in the elbow, which lead potentially to the FIV. Two different scale models, 1/7 and 1/14-scale simulating the JSFR cold-leg piping, are tested experimentally to confirm whether a scale effect in pressure fluctuation characteristics exists. A distinguishing peak can be seen in each power spectrum density (PSD) profile of pressure fluctuation obtained in and downstream of the flow separation region for both scaled models. When nondimensionalized, the PSD profiles show good correspondence regardless of scale model and even of Reynolds number simulated in this study.

39000509
Three-pin cluster CABRI tests simulating the unprotected loss-of-flow accident in sodium-cooled fast reactors
Onoda, Yuichi; Fukano, Yoshitaka; Sato, Ikken; Marquie, C.*; Duc, B.*
Journal of Nuclear Science and Technology 48(2), p.188-204(2011) ; (JAEA-J 08732)

Two three-pin cluster tests simulating the Unprotected Loss-of-Flow (ULOF) accident of Sodium-cooled Fast Reactors (SFRs) were conducted focusing on fuel relocation and freezing behavior. Based on detailed data evaluation and theoretical interpretation for the three-pin cluster tests, it is concluded that axial fuel relocation and freezing are dominated by local fuel enthalpy, and the relation between fuel dispersal and fuel enthalpy observed in these CABRI tests is basically applicable to the pin-bundle condition. It is also clarified that a fuel/steel mixture tends to create tight blockages near the axial ends of the relocating fuel. Part of the fission gas released from the fuel is expected to be trapped within the bottled-up region between the upper and lower blockages and will keep this region pressurized for a relatively long period.

39000510
Validation of a computational simulation method for evaluating thermal stratification in the reactor vessel upper plenum of fast reactors
Ono, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki
Journal of Nuclear Science and Technology 48(2), p.205-214(2011) ; (JAEA-J 08733)

Validation of a numerical simulation method is carried out for thermal stratification phenomena in the reactor vessel upper plenum of advanced sodium-cooled fast reactors. The study mainly focuses on the fundamental applicability of commercial computational fluid dynamics (CFD) codes as well as an in-house code to the evaluation of thermal stratification behavior including the simulation methods such as spatial mesh distribution and RANS-type turbulence models in the analyses.

39000511
Improvement of Tone's method with two-term rational approximation
Yamamoto, Akio*; Endo, Tomohiro*; Chiba, Go
Journal of Nuclear Science and Technology 48(2), p.263-271(2011) ; (JAEA-J 08734)

An improvement of Tone's method, which is a resonance calculation method based on the equivalence theory, is proposed. In order to increase calculation accuracy the two-term rational approximation is incorporated for the representation of neutron flux. Furthermore, some theoretical aspects of Tone's method, i.e., its inherent approximation and choice of adequate multi-group cross section for collision probability estimation, are also discussed. The validity of the improved Tone method is confirmed through a verification calculation in a irregular lattice geometry, which represents part of a LWR fuel assembly. The calculation result clarifies the validity of the present method.

39000512
Sorption behavior of selenium(-II) on rocks under reducing conditions
Iida, Yoshihisa; Tanaka, Tadao; Yamaguchi, Tetsuji; Nakayama, Shinichi
Journal of Nuclear Science and Technology 48(2), p.279-291(2011) ; (JAEA-J 08735)

Batch sorption experiments were carried out to investigate sorption behavior of selenium onto granodiorite, sandy mudstone, tuffaceous sandstone and their major constituent minerals and accessory minerals under reducing conditions. Rocks and groundwater employed in the experiments were sampled with a special care avoiding exposing the rocks and groundwater to the air to minimize their oxidation. The dominant sorbent minerals for selenium were determined to be biotite for granodiorite, and pyrite for sandy mudstone and tuffaceous sandstone at neutral-alkaline pH.

39000513
Removal of liquid and solid impurities from uranyl nitrate hexahydrate crystalline particles in crystal purification process
Nakahara, Masaumi; Nomura, Kazunori; Washiya, Tadahiro; Chikazawa, Takahiro*; Hirasawa, Izumi*
Journal of Nuclear Science and Technology 48(3), p.322-329(2011) ; (JAEA-J 08736)

The purification behavior of uranyl nitrate hexahydrate was investigated to evaluate the decontamination performance of liquid and solid impurities using a dissolver solution of mixed oxide fuel in batch experiments by the sweating and the melt filtration processes. Liquid impurities such as Eu were effectively removed by the sweating method, but solid impurities such as Pu, Cs and Ba were affected a little in the batch experiments. On the other hand, the decontamination factor of Ba increased with 0.45 and 5.0 μm filters in the melt filtration process. Although the decontamination factors of Pu and Cs did not change with 5.0 μm filter, it increased approximately two-fold with 0.45 μm filter. The particle size of Cs₂Pu(NO₃)₆ is a little small and might pass through the 5.0 μm filter in the melt filtration process.

39000514
Electromagnetic pumps for main cooling systems of commercialized sodium-cooled fast reactor
Aizawa, Kosuke; Chikazawa, Yoshitaka; Kotake, Shoji; Ara, Kuniaki; Aizawa, Rie*; Ota, Hiroyuki*
Journal of Nuclear Science and Technology 48(3), p.344-352(2011) ; (JAEA-J 08737)

This study investigates the adequateness of a modular-type EMP system for large-sized (1500 MWe class) sodium-cooled fast reactors. There is concern that such a large EMP will cause flow instability. A modular-type EMP system can solve this issue since smaller EMPs are arranged in parallel and the flow rate of each EMP is reduced. Parallel-module-EMP systems have been investigated as the primary and secondary circulating pumps. The results of the design study and electro-magnetic analysis on the primary main pump confirmed that flow instability does not occur under all operational conditions. The modular-type EMP system is also effective for the secondary system, drastically simplifying the piping arrangement. The results of this study show that the modular-type EMP system is highly compatible with the main circulating pumps of large-sized sodium-cooled fast reactors as well as the advantages gained from adopting this system.

39000515
Thermal conductivities of Zr-based transuranium nitride solid solutions
Nishi, Tsuyoshi; Takano, Masahide; Ichise, Kenichi; Akabori, Mitsuo; Arai, Yasuo
Journal of Nuclear Science and Technology 48(3), p.359-365(2011) ; (JAEA-J 08738)

In this study, we prepared the sintered samples of two kinds of (Zr,Pu,Am)N and (Zr,Np,Pu,Am,Cm)N solid solutions. The thermal diffusivity and heat capacity of Zr-based transuranium nitride solid solutions were measured by a laser flash method and a drop calorimetry, respectively. The thermal conductivities of (Zr,Pu,Am)N and (Zr,Np,Pu,Am,Cm)N were determined from the measured thermal diffusivity, heat capacity and bulk density. It was found that the thermal conductivities of (Zr,Pu,Am)N and (Zr,Np,Pu,Am,Cm)N were higher than that of (Pu,Am)N. It was also found that the thermal conductivities of (Zr,Pu,Am)N and (Zr,Np,Pu,Am,Cm)N obviously increased with temperature in comparison with (Pu,Am)N, although they were smaller than that of ZrN over the temperature range investigated.

39000516
Development of local-scale high-resolution atmospheric dispersion model using Large-Eddy Simulation, 2; Turbulent flow and plume dispersion around a cubical building
Nakayama, Hiromasa; Nagai, Haruyasu
Journal of Nuclear Science and Technology 48(3), p.374-383(2011) ; (JAEA-J 08739)

In this study, we extended the local-scale high-resolution Large-Eddy Simulation (LES) model proposed in Part 1 of this paper and applied it to a simulation of turbulent flow and plume dispersion around a cubical building and investigated the basic performance of the LES model in comparison with the previous experimental data. As a result, the main characteristics of turbulence structures and dispersion behavior agreed well with those of the previous wind tunnel experiment. It is considered that the complex behaviors of turbulent flow and plume dispersion in the near-wake region of a cubic building are successfully simulated using the present LES model.

39000517
Effect of polynomial expansion order of intranode flux treatment in nodal S_N transport calculation code NSHEX for large-size fast power reactor core analysis
Sugino, Kazuteru; Kugo, Teruhiko
Journal of Nuclear Science and Technology 48(3), p.421-428(2011) ; (JAEA-J 08740)

The nodal discrete ordinates (S_N) transport calculation code for three-dimensional hexagonal geometry NSHEX treats intra-node flux distribution by polynomial series and considers angular dependence of flux by the S_N method. For the improvement of calculation accuracy of NSHEX for the practical use to large-size fast reactor plants, the maximum order of polynomial series is extend from two to six. In order to check the effect of the polynomial expansion order, NSHEX is applied to the middle-size fast power reactor core "Monju" and the large-size one "Super Phenix" including various control rod insertion conditions. From the application, it is found that extension of polynomial expansion order is effective especially for the large-size core "Super Phenix" with control rod inserted condition.

39000518
Evaluation of neutron nuclear data on bromine and krypton isotopes for JENDL-4.0
Shibata, Keiichi; Ichihara, Akira; Kunieda, Satoshi
Journal of Nuclear Science and Technology 48(3), p.429-439(2011) ; (JAEA-J 08741)

Neutron nuclear data on ^79,81Br and ^{78,80,82,83,84,85,86}Kr have been evaluated for the evaluated nuclear data library JENDL-4.0 in the energy region from 10^-5 eV to 20 MeV. The resolved resonance parameters were adjusted so as to reproduce the recommended or measured thermal capture cross sections for some isotopes. The statistical model was applied to calculate the cross sections above the resolved resonance region. In the calculations, coupled-channel optical model parameters were used for neutrons. Preequilibrium and direct-reaction processes were taken into account in addition to the compound process. The present evaluation is consistent with available experimental data. The evaluated results were compiled into JENDL-4.0.

39000519
Control of radial size of crosslinked polymer nanowire by ion beam and γ ray irradiation
Tsukuda, Satoshi*; Asano, Atsushi*; Sugimoto, Masaki; Idesaki, Akira; Seki, Shu*; Tanaka, Shunichiro*
Journal of Photopolymer Science and Technology 23(2), p.231-234(2010) ; (JAEA-J 08742)

The nanowires based on polystyrene (PS) and polycarbosilane (PCS) were formed by 450 MeV Xe beam irradiation to their thin films. The nanowires, which formed by crosslinking reaction along the single ion path, can isolated by development procedures. This technique is sometimes called as single particle nanofabrication technique (SPNT). In this paper, tow step irradiation of ion beam and ray was carried out in order to control their radial sizes. The radial sizes of nanowires, based on PS and PCS were increased with the dose of ray. The change of radial sizes, which depended on the dose, was quantitatively measured, and we discussed in terms of radiation induced gel formation.

39000520
Adsorption dynamics on Si(111)-7×7 surface induced by supersonic O₂ beam studied using real-time photoelectron spectroscopy
Yoshigoe, Akitaka; Teraoka, Yuden
Journal of Physical Chemistry C 114(51), p.22539-22545(2010) ; (JAEA-J 08743)

The adsorption mechanisms of O₂ on a Si(111)-7×7 surface were studied using real-time X-ray photoelectron spectroscopy with synchrotron radiation in conjunction with a supersonic molecular-beam technique. It was found that a trapping-mediated adsorption mechanism is dominant at E_n < 0.06 eV. In contrast, an activated adsorption mechanism becomes prominent at E_n > 0.06 eV, along with the trapping-mediated adsorption mechanism which becomes less prevalent with increasing E_n. The saturation coverage at energies over 1.9 eV is approximately 1.6 times larger than that at 0.03 eV. Two different components of the O 1s spectrum and their energy dependence were verified. A marked increase in the tri oxygen component is clearly observed in the O 1s photoelectron spectrum for saturation at E_n > 0.39 eV, which is evidence for the enhancement of dissociative adsorption of O₂ into the subsurface layers. 0.39 eV was taken as the threshold energy for E_n dependence of both initial sticking probability and saturation coverage. The adsorption states induced via the novel reaction channel correlating with E_n were confirmed by the in-situ spectroscopic surface analysis method.

39000521
Influence of size effect on the electronic and elastic properties of diamond films with nanometer thickness
Chernozatonskii, L. A.*; Sorokin, P. B.*; Kuzubov, A. A.*; Sorokin, B. P.*; Kvashnin, A. G.*; Kvashnin, D. G.*; Avramov, P.; Yakobson, B. I.*
Journal of Physical Chemistry C 115(1), p.132-136(2011) ; (JAEA-J 08744)

The atomic structure and physical properties of quasi 2D diamanes (few-layered oriented diamond nanocrystals, covered by hydrogen atoms from both sides) are studied using electronic band structure calculations. It was shown that energy stability linear increases upon increasing of the thickness of proposed structures. All 2D carbon nanoclusters display direct dielectric band gaps with nonlinear quantum confinement response upon the thickness. Elastic properties of diamanes reveal complex dependence upon increasing of the number of <111> layers. All theoretical results were compared with available experimental data.

39000522
Positron microbeam study on vacancy generation caused by stress corrosion crack propagation in austenitic stainless steels
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo
Journal of Physics; Conference Series 262, p.012067_1-012067_4(2011) ; (JAEA-J 08745)

39000523
Development of system based code, 2; Application of reliability target for configuration of ISI requirement
Takaya, Shigeru; Okajima, Satoshi; Kurisaka, Kenichi; Asayama, Tai; Machida, Hideo*; Kamishima, Yoshio*
Journal of Power and Energy Systems (Internet) 5(1), p.60-68(2011) ; (JAEA-J 08746)

System Based Code (SBC) extends the present structural design standard to include the broad areas related to FBR design and operation. Therefore, a quantitative index that can correlate these different areas is required. One such index is the probability of failure. The determination of a target value is also one of the key points. We have proposed a new method to determine reliability targets for structures and components in FBR plants from the viewpoint of safety. In this study, the effectiveness of the probability of failure as an index and the reliability targets produced using the new method are investigated through a trial setting of an in-service inspection (ISI) requirement for a reactor vessel. The results show that the reactor vessel has sufficient reliability even without an ISI. Through this example, we demonstrate that the probability of failure is a promising index and that reliability targets derived using the new method are compatible with SBC.

39000524
First observation of quantum oscillations in the ferromagnetic superconductor UCoGe
Aoki, Dai*; Sheikin, I.*; Matsuda, Tatsuma; Taufour, V.*; Knebel, G.*; Flouquet, J.*
Journal of the Physical Society of Japan 80(1), p.013705_1-013705_4(2011) ; (JAEA-J 08747)

We succeeded in growing high quality single crystals of the ferromagnetic superconductor UCoGe and measured the magnetoresistance at fields up to 34 T. The Shubnikov-de Haas signal was observed for the first time in a U-111 system (UTGe, UTSi, T: transition metal). A small pocket Fermi surface (F∼1 kT) with large cyclotron effective mass 25m₀ was detected at high fields above 22 T, implying that UCoGe is a low carrier system accompanied with heavy quasi-particles. The observed frequency decreases with increasing fields, indicating that the volume of detected Fermi surface changes nonlinearly with field. The cyclotron mass also decreases, which is consistent with the decrease of the A coefficient of resistivity.

39000525
Magnetic and superconducting properties of CeRhGe₂ and CePtSi₂
Hirose, Yusuke*; Nishimura, Naoto*; Honda, Fuminori*; Sugiyama, Kiyohiro*; Hagiwara, Masayuki*; Kindo, Koichi*; Takeuchi, Tetsuya*; Yamamoto, Etsuji; Haga, Yoshinori; Matsuura, Masato*; Hirota, Kazuma*; Yasui, Akira; Yamagami, Hiroshi; Settai, Rikio*; Onuki, Yoshichika
Journal of the Physical Society of Japan 80(2), p.024711_1-024711_12(2011) ; (JAEA-J 08748)

Magnetic and superconducting properties of CeRhGe₂ and CePtSI₂ have been investigated by bulk property measurements and neutron scattering experiments. CeRhGe₂ was found to order antiferromagnetically with an ordered moment 1.3 μ_B/Ce along the c-axis of the orthorhombic unit cell. High pressure resistivity measurements revealed a suppression of the antiferromagnetic transition with increasing pressure and the occurrence of superconductivity near the critical pressure where antiferromagnetism vanishes. Quantum-critical characteristics are expected to these compounds.

39000526
Collapse of ferrimagnetism in two-dimensional heisenberg antiferromagnet due to frustration
Nakano, Hiroki*; Simokawa, Tokuro*; Sakai, Toru
Journal of the Physical Society of Japan 80(3), p.033709_1-033709_4(2011) ; (JAEA-J 08749)

We study ferrimagnetism in the ground state of the antiferromagnetic Heisenberg model on the spatially anisotropic kagome lattice, in which the ferrimagnetism of the conventional Lieb-Mattis type appears in the region of weak frustration whereas the ground state is non-magnetic in the isotropic case. Numerical diagonalizations of small finite-size clusters are carried out to examine the spontaneous magnetization. We found that the spontaneous magnetization changes continuously in the intermediate region between the conventional ferrimagnetism and the non-magnetic phase.

39000527
Incommensurate-to-commensurate magnetic phase transition in SmIn₃ observed by muon spin relaxation
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Luetkens, H.*; Sugai, Takashi; Haga, Yoshinori; Suzuki, Hiroyuki*
Journal of the Physical Society of Japan 80(3), p.033710_1-033710_4(2011) ; (JAEA-J 08750)

Magnetic susceptibility χ and muon spin relaxation (μSR) measurements are reported on SmIn₃ with a Γ₈ ground state. Anomalies corresponding to successive phase transitions were observed in χ at T_I∼16.5 K, T_II∼15.1 K, and T_III∼14.7 K. A spontaneous local magnetic field was detected below T_I using the μSR technique on the contrary to a pure quadrupolar ordering scenario proposed in the phase between T_I and T_II. This result clearly indicates that the primary order parameters in all the ordered phases are magnetic. The local field distribution changes at around T_II from a continuous broad one to a sharp one with decreasing temperature, suggesting that an incommensurate to commensurate magnetic phase transition takes place at this temperature. A possible magnetic structure in the ground state and importance of multipolar interactions are discussed.

39000528
First-principles study on the grain boundary embrittlement of metals by solute segregation, 1; Iron(Fe)-Solute(B, C, P, and S) systems
Yamaguchi, Masatake
Metallurgical and Materials Transactions A; Physical Metallurgy and Material 42(2), p.319-329(2011) ; (JAEA-J 08751)

The microscopic mechanism of grain boundary embrittlement in metals by solute segregation has been not well understood for many years. From first-principles calculations, we show here that the calculated cohesive energy (= surface energy - grain boundary energy) of bcc Fe Σ3(111) symmetrical tilt grain boundary is reduced by the segregation of sulfur and phosphorous, while it is increased by the segregation of boron and carbon. The rate of the decrease/increase in the cohesive energy was excellently proportional to the experimental shift in the ductile-to-brittle transition temperature of high-purity iron with increasing segregation. It indicates that the change in the cohesive energy of grain boundary plays a key role in the grain boundary embrittlement.

39000529
First-principles study on the grain boundary embrittlement of metals by solute segregation, 2; Metal(Fe, Al, Cu)-Hydrogen (H) systems
Yamaguchi, Masatake; Ebihara, Kenichi; Itakura, Mitsuhiro; Kadoyoshi, Tomoko*; Suzudo, Tomoaki; Kaburaki, Hideo
Metallurgical and Materials Transactions A; Physical Metallurgy and Material 42(2), p.330-339(2011) ; (JAEA-J 08752)

The microscopic mechanism of grain boundary embrittlement in metals by hydrogen trapping (segregation) has been not well understood for many years. From first-principles calculations, we show here that the calculated cohesive energy of bcc Fe Σ3(111) and fcc Al(Cu) Σ5(012) symmetrical tilt grain boundaries with varying the trapping density of hydrogen can be significantly reduced by hydrogen trapping; it indicates that the reduction of the cohesive energy of the grain boundary may cause the hydrogen-induced grain-boundary embrittlement in Fe, Al, and Cu, although the possibility of hydrogen trapping at grain boundary is very different among those metals. Considering the "mobile" effect of hydrogen during fracture, more hydrogen atoms coming from solid solution state can be trapped on the gradually formed two fracture surfaces in addition to the already trapped "immobile" hydrogen atoms at the grain boundary before fracture.

39000530
Remote glovebox size reduction in glovebox dismantling facility
Kitamura, Akihiro; Watahiki, Masatoshi; Kashiro, Kashio
Nuclear Engineering and Design 241(3), p.999-1005(2011) ; (JAEA-J 08753)

Glovebox dismantling facility is a facility to dismantle gloveboxes and recover any residual nuclear fuel material from the gloveboxes. The facility possesses one robotic arm and six master slave manipulator arms to remotely size reduce contaminated gloveboxes. In this paper the facility is described and the size reduction activity procedures are introduced. Data obtained from one of the glovebox size reduction activities, which was done by both remote and manual size reduction methods, was analyzed and a comparison of these two methods is discussed.

39000531
Neutron imaging of micron-size structures by color center formation in LiF crystals
Matsubayashi, Masahito; Faenov, A. Y.*; Pikuz, T.*; Fukuda, Yuji; Kato, Yoshiaki*
Nuclear Instruments and Methods in Physics Research A 622(3), p.637-641(2010) ; (JAEA-J 08754)

Demonstration of neutron imaging by color center formation in LiF crystals is reported. Neutron radiography images of various objects, including thin Au wires, Cd plates, Gd plates and thin liquid tubes, have been recorded. The data show that neutron imaging with LiF have many excellent properties; high spatial resolution of 5.4 μm, little granular noises, good linearity and large dynamic range. The high resolution neutron imaging with LiF will be useful for various applications such as quantitative characterizations of neutron sources and electric devices composed of low-Z elements such as Li-ion batteries and fuel cells.

39000532
Stress and temperature dependence of the structure of the martensite and X-phase in Ni₂MnGa
Fukuda, Takashi*; Terai, Tomoyuki*; Kushida, Hiroaki*; Kakeshita, Tomoyuki*; Osakabe, Toyotaka; Kakurai, Kazuhisa
Philosophical Magazine 90(14), p.1925-1935(2010) ; (JAEA-J 08755)

The stress and temperature dependence of the structure of the X-phase in Ni₂MnGa has been investigated by neutron diffraction measurements under compressive stress to clarify the structural relationship among the P-, I-, M- and X-phases. The structure of the X-phase in Ni₂MnGa depends strongly on stress and temperature compared to the M- or I-phase. In association with the X → M transformation, both the position and intensity of the satellite reflection changes drastically, regardless of stress and temperature, while with X → P transformation, the intensity of the satellite reflection fades gradually. For the I → X transformation, the position and intensity of the satellite changes drastically when transformation occur under compressive stress, while the changes are continuous under zero stress. These results strongly suggest the existence of a multicritical point in Ni₂MnGa.

39000533
Temperature dependence of the electronic structure of Sr₁₄Cu₂₄O₄₁ studied by resonant inelastic X-ray scattering
Yoshida, Masahiro; Ishii, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Murakami, Yoichi*; Mizuki, Junichiro; Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; Endo, Yasuo*
Physica C 470(Suppl.1), p.S145-S146(2010) ; (JAEA-J 08756)

Sr_14-xCa_xCu₂₄O₄₁ (SCCO), which is composed of two-leg ladders and edge-sharing chains, is the first superconducting cuprate without CuO₂ planes. By substituting Ca for Sr, holes are transferred from the chains to the ladders. It was recently shown that charge ordering (CO) along the leg direction in the ladder occurs at x=0 and the periodicity is five times the unit length along the c axis. In order to investigate the electronic excitations associated with the CO, we carried out resonant inelastic X-ray scattering (RIXS) experiments for SCCO (x=0,6). Cu-K RIXS can directly probe the momentum-dependent electronic excitations related to the Cu site, which are resonantly enhanced by tuning the incident photon energy to the Cu K-edge. We measured the q dependence of the intraband excitations, which is associated with the dynamics of doped holes in the Zhang-Rice singlet band. The intensity is enhanced at the momentum q=(q_rung,q_leg)=(0,2π/5) corresponding to the periodicity of the CO in x=0, while the temperature dependence of the enhancement is different for x=0 and x=6. We discuss the relationship between our experimental results and the occurrence of the CO.

39000534
Resonant inelastic X-ray scattering of La₂Cu_0.95Ni_0.05O₄
Ishii, Kenji; Ikeuchi, Kazuhiko*; Jarrige, I.; Mizuki, Junichiro; Hiraka, Haruhiro*; Yamada, Kazuyoshi*; Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi*; Endo, Yasuo*; Ishii, Hirofumi*; Cai, Y. Q.*
Physica C 470(Suppl.1), p.S155-S157(2010) ; (JAEA-J 08757)

Substitution of a specific element for a component is often used to elucidate its role in the superconductors. For a complete understanding of the substitution effect not only on the superconductivity but also on the electronic states, element-selective experiments are required. In this respect, resonant inelastic X-ray scattering (RIXS) has proven to be a powerful experimental technique enabling element-selective diagnosis of charge excitations. By tuning the incident photon energy to a given absorption edge of the element, the excitations involving the element are resonantly enhanced. In addition, RIXS has the advantage that momentum dependence can be measured. Using RIXS, we have measured the electronic excitations at the substituting sites in La₂Cu_0.95Ni_0.05O₄ and La₂Ni_0.95Cu_0.05O₄. Near the absorption edge of the substituting element, namely the Ni K-edge for La₂Cu_0.95Ni_0.05O₄ and the Cu K-edge for La₂Ni_0.95Cu_0.05O₄, charge transfer excitations from the 2p level of neighboring oxygen to the upper Hubbard band of the substituted Ni/Cu are observed. Experimental spectra are qualitatively reproduced by a theoretical calculation based on a d-p model.

39000535
High-pressure suppression of long-range magnetic order in the triangular-lattice antiferromagnet CuFeO₂
Terada, Noriki*; Osakabe, Toyotaka; Kitazawa, Hideaki*
Physical Review B 83(2), p.020403_1-020403_4(2011) ; (JAEA-J 08758)

We succeeded in observing pressure-suppressed magnetic long-range ordering (LRO) in the triangular-lattice antiferromagnet CuFeO₂, using neutron-diffraction experiments under an isotropic pressure. The magnetic LRO of the four-sublattice ground state under ambient pressure in CuFeO₂ almost disappears at the high pressure of 7.9 GPa, and is replaced by an incommensurate order with temperature-independent wave number of (0.192 0.192 1.5). The incommensurate wave number observed at 7.9 GPa corresponds to that observed just above the temperature at which lattice distortion and magnetic LRO simultaneously occur under ambient pressure. Therefore, the long-range magnetic ordering disappears because the high pressure suppressed the lattice distortion that otherwise relieves spin frustration and leads the spin system to LRO.

39000536
Electronic structure of lithium amide
Kamakura, Nozomu; Takeda, Yukiharu; Saito, Yuji; Yamagami, Hiroshi; Tsubota, Masami*; Paik, B.*; Ichikawa, Takayuki*; Kojima, Yoshitsugu*; Muro, Takayuki*; Kato, Yukako*; Kinoshita, Toyohiko*
Physical Review B 83(3), p.033103_1-033103_4(2011) ; (JAEA-J 08759)

The electronic structure of lithium amide, which is lightweight complex hydride expected as a high-capacity hydrogen storage material, is investigated by N 1s soft X-ray emission spectroscopy (XES) and absorption spectroscopy (XAS). The overall feature of the electronic structure of lithium amide by the XES and XAS is consistent with the band calculation, while the strongly hybridized state with H 1s is located at higher binding energy than the band calculation.

39000537
Momentum-resolved electronic excitations in the Mott insulator Sr₂IrO₄ studied by resonant inelastic X-ray scattering
Ishii, Kenji; Jarrige, I.; Yoshida, Masahiro; Ikeuchi, Kazuhiko*; Mizuki, Junichiro; Ohashi, Kei*; Takayama, Tomohiro*; Matsuno, Jobu*; Takagi, Hidenori*
Physical Review B 83(11), p.115121_1-115121_5(2011) ; (JAEA-J 08760)

We report an Ir L₃-edge resonant inelastic X-ray scattering (RIXS) measurement of the low-lying electronic excitations in Sr₂IrO₄ over the complete Brillouin zone of the IrO₂ plane. A remarkably strong inelastic signal which exceeds the elastic scattering in intensity is observed. Peaks observed at 0.5, 3.2, and 6.0 eV are respectively ascribed to an interband transition across the Mott gap and charge-transfer excitations from the O 2p band to the Ir 5d bands. The dispersion of the Mott gap excitation is found to be particularly weak. This is interpreted as a signature of the narrow 5d bands of the novel Mott insulating state of Sr₂IrO₄ induced by the strong spin-orbit interaction.

39000538
New estimate for the time-dependent thermal nucleosynthesis of ¹⁸⁰Ta^m
Hayakawa, Takehito; Kajino, Toshitaka*; Chiba, Satoshi; Mathews, G.*
Physical Review C 81(5), p.052801_1-052801_4(2010) ; (JAEA-J 08761)

The nucleosynthesis of ¹⁸⁰Ta has remained an unsolved problem. The supernova neutrino process has been proposed as the origin of ¹⁸⁰Ta but its model calculation overproduces the ¹⁸⁰Ta solar abundance. This may originate from the unique feature that the naturally occurring abundance of ¹⁸⁰Ta is actually a meta-stable isomer, while the ground state is beta-unstable. We have made a new time-dependent calculation of the supernova production ratio of the long-livedisomer in ¹⁸⁰Ta. Such a time-dependent solution is crucial for understanding the production and survival of this isotope. We find that the explicit time evolution of the synthesis of ¹⁸⁰Ta using the available nuclear data shows ¹⁸⁰Ta can be produced by neutrino process and neutrino temperature of 4 MeV.

39000539
γ-ray strength function method and its application to ¹⁰⁷Pd
Utsunomiya, Hiroaki*; Goriely, S.*; Akimune, Hidetoshi*; Harada, Hideo; Kitatani, Fumito; Goko, Shinji*; Toyokawa, Hiroyuki*; Yamada, Kawakatsu*; Kondo, Takeo*; Ito, Osamu*; Kamata, Masaki*; Yamagata, Tamio*; Lui, Y.-W.*; Daoutidis, I.*; Arteaga, D. P.*; Hilaire, S.*; Koning, A.*
Physical Review C 82(6), p.064610_1-064610_5(2010) ; (JAEA-J 08762)

The γ-ray strength function method (γSF method) is devised to indirectly determine radiative neutron capture cross sections for radioactive nuclei. This method is applied here to the ¹⁰⁷Pd case. Photoneutron cross sections were measured for ^105,106,108Pd near neutron threshold with quasi-monochromatic laser-Compton-scattering γ-ray beams. These photoneutron cross sections as well as the reverse radiative neutron capture cross sections for ^104,105Pd are used to provide constraints on the ¹⁰⁷Pd(n,γ) ¹⁰⁸Pd cross section.

39000540
Neutron one-quasiparticle states in ²⁵¹Fm₁₅₁ populated via the α decay of ²⁵⁵No
Asai, Masato; Tsukada, Kazuaki; Haba, Hiromitsu*; Ishii, Yasuo; Ichikawa, Takatoshi*; Toyoshima, Atsushi; Ishii, Tetsuro; Nagame, Yuichiro; Nishinaka, Ichiro; Kojima, Yasuaki*; Sueki, Keisuke*
Physical Review C 83(1), p.014315_1-014315_12(2011) ; (JAEA-J 08763)

Excited states in ²⁵¹Fm populated via the α decay of ²⁵⁵No are studied in detail through α-γ coincidence and α fine structure measurements. Spin-parities and neutron configurations of the excited states in ²⁵¹Fm as well as the ground state of ²⁵⁵No are definitely identified on the basis of deduced internal conversion coefficients, lifetimes of γ transitions, rotational-band energies built on one-quasiparticle states, and hindrance factors of α transitions. It is found that the excitation energy of the 1/2⁺[620] state in N=151 isotones increases with the atomic number, especially at Z≥100, while that of the 1/2⁺[631] state decreases at Z=100. Energy systematics of the one-quasiparticle states in the N=151 isotones are discussed in terms of the evolution of nuclear deformation involving the hexadecapole and hexacontatetrapole deformations.

39000541
Impact of plasma poloidal rotation on resistive wall mode instability in toroidally rotating plasmas
Aiba, Nobuyuki; Shiraishi, Junya; Tokuda, Shinji*
Physics of Plasmas 18(2), p.022503_1-022503_5(2011) ; (JAEA-J 08764)

Rotation effect on the stability of the resistive wall mode (RWM) is investigated in a cylindrical plasma and a toroidal plasma with not only a toroidal rotation but also a poloidal rotation. In the case that a poloidal rotation frequency is not so large, the effect of a poloidal rotation can be treated with the modified toroidal rotation frequency, which is determined by subtracting a toroidal component of the rotation parallel to the magnetic field from the toroidal rotation frequency. This effect of a poloidal rotation on the RWM stability depends on its rotational direction, and when this modified toroidal rotation frequency is larger than the original toroidal rotation frequency, a poloidal rotation enhances the stabilizing effect of a rotation on RWM stability. This result indicates that a poloidal rotation produces a dependence of the critical toroidal rotation frequency for stabilizing RWM on the rotational direction of a toroidal rotation in the same magnetic configuration.

39000542
Surface analysis of single-crystalline β-FeSi₂
Yamada, Yoichi*; Mao, W.*; Asaoka, Hidehito; Yamamoto, Hiroyuki; Esaka, Fumitaka; Udono, Haruhiko*; Tsuru, Tomohito
Physics Procedia 11, p.67-70(2011) ; (JAEA-J 08765)

Clean surfaces of the single crystalline β-FeSi₂ have been prepared and investigated. From XPS (X-ray Photoelectron Spectroscopy) measurements of the surface oxide, it is found that the surface Si is mainly oxidized while Fe isn't. After removing the surface oxide, clean surface can be obtained showing reasonable structure in LEED (Low-Energy Electron Diffraction) and STM (Scanning Tunneling Microscope). No drastic surface reconstruction is found reflecting strong Fe-Si bond. DFT (Density Functional Theory) calculation suggests the spin polarized surface DOS (Density Of State) when Fe comes at the surface.

39000543
Surface characterization of homoepitaxial β-FeSi₂ film on β-FeSi₂(111) substrate by X-ray photoelectron and absorption spectroscopy
Esaka, Fumitaka; Yamamoto, Hiroyuki; Udono, Haruhiko*; Matsubayashi, Nobuyuki*; Yamaguchi, Kenji; Shamoto, Shinichi; Magara, Masaaki; Kimura, Takaumi
Physics Procedia 11, p.150-153(2011) ; (JAEA-J 08766)

Surface characterization of homoepitaxial β-FeSi₂ film on β-FeSi₂(111) substrate has been performed by X-ray photoelectron and X-ray absorption spectroscopy.

39000544
Surface structures on β-FeSi₂ formed by heat-treatment in ultra-high vacuum and their influence for homoepitaxial growth
Matsumura, Seidai*; Ochiai, Kunihito*; Udono, Haruhiko*; Esaka, Fumitaka; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Hojo, Kiichi
Physics Procedia 11, p.174-176(2011) ; (JAEA-J 08767)

The surface structures on the surface of β-FeSi₂ substrate after heat treatment in ultra high vacuum and their influence on homoepitaxial growth were investigated. It was found that the dip structures appeared on the surface of β-FeSi₂ (100) substrate after heat treatment above 1023 K, where the evaporation of surface oxide layer (SiO_x) occurred. The composition of the dip structure was Fe-rich as compared to nominal β-FeSi₂ composition (Si/Fe=2). This result indicates that the decomposition from β-FeSi₂ to ε-FeSi would occur on the surface. The surface morphology observed after heat treatment depended on the orientation of the substrate. In addition, homoepitaxial films with smooth surface on β-FeSi₂ (111) substrate at the growth temperature of 973 and 1073 K were obtained.

39000545
Isolation and characterization of suppressors of the early flowering 3 in Arabidopsis thaliana
Natsui, Yu*; Nefissi, R.*; Miyata, Kana*; Oda, Atsushi*; Hase, Yoshihiro; Nakagawa, Mayu*; Mizoguchi, Tsuyoshi*
Plant Biotechnology 27(5), p.463-468(2010) ; (JAEA-J 08768)

EARLY FLOWERING 3 (ELF3) is a circadian clock protein with a major role in maintaining circadian rhythms in plants. In this work, elf3-101 was mutagenized by EMS in plants of the Lansberg erecta background to isolate suppressors of elf3 and to understand the molecular mechanisms of flowering time controlled by ELF3. Two suppressors, sel106 obtained from this screen and sel5 from a precious study, were chosen for further analysis. Genetic mapping, gene expression analysis, and sequencing identified sel106 and sel5 as new alleles of gi and fca, respectively. Genetic interactions between elf3 and gi and between elf3 and fca in the control of the floral activator FLOWERING LOCUS T were also investigated. Six suppressor of elf3 were classified at least into four subgroups based on the expression of such floral regulators as GI, CO, FT, SVP, and FLC, and on their flowering times under LL, LD, and SD. This classification scheme is useful for the characterization of unidentified suppressor mutations.

39000546
Synthesized intensity of emission lines of hydrogen isotopes and impurities in the ITER divertor plasma
Iwamae, Atsushi; Sugie, Tatsuo; Ogawa, Hiroaki; Kusama, Yoshinori
Plasma Physics and Controlled Fusion 53(4), p.045005_1-045005_17(2011) ; (JAEA-J 08769)

Intensity of emission lines in the ITER divertor plasma is synthesized using a model of the edge and scrape-off layer plasmas. The intensity of hydrogen isotopes and impurities observed with the divertor optical system of the Impurity Influx Monitor (Divertor) is estimated. In both the inner and outer divertor plasmas, ionizing and recombining plasma components are observed for C_I-III and recombining plasma component is dominant for C_IV-V. Line-of-sight integrated spectra are synthesized in the wavelength range of 200 nm to 1000 nm using photon emission coefficients. In order to evaluate the carbon impurity influx, Γ_C, identifying the plasma component, i.e. ionizing or recombining plasma component, is important.

39000547
Radiation-induced graft polymerization of functional monomer into poly(ether ether ketone) film and structure-property analysis of the grafted membrane
Hasegawa, Shin; Takahashi, Shuichi*; Iwase, Hiroki*; Koizumi, Satoshi; Morishita, Norio; Sato, Ken*; Narita, Tadashi*; Onuma, Masato*; Maekawa, Yasunari
Polymer 52(1), p.98-106(2011) ; (JAEA-J 08770)

Radiation-induced graft polymerization of sulfo-containing styrene derivatives into poly(ether ether ketone) (PEEK) substrates was carried out to prepare thermally and mechanically stable polymer electrolyte membranes based on an aromatic hydrocarbon polymer. Graft polymerization of ethyl 4-styrenesulfonate into a 32% crystallinity degree PEEK substrate hardly progressed, whereas graft polymerization into 11% PEEK substrate gradually progressed, achieving a grafting degree of more than 50% after 72 h. From Electron Spin Resonance analysis of irradiated PEEK films, it apparent the graft polymerization initiate from the phenoxy radicals. Small-angle X-ray scattering and small-angle neutron scattering observations clearly showed that the graft-type PEEK membranes possessed ion channel domains with the average distance of 13 nm, being larger than that of Nafion. Furthermore, there was a micro-structure in the ion channels with the average distance of 1.8 nm.

39000548
Quark-hadron mixed phase with hyperons in protoneutron stars
Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*
Proceedings of Science (Internet) , 5p.(2011) ; (JAEA-J 08771)

We study the quark-hadron mixed phase in proto-neutron stars with the finite-size effects. In the calculations of pasta structures appeared in the mixed phase, the Gibbs conditions require the pressure balance and chemical equilibrium between two phases besides the thermal equilibrium. We find that the region of the mixed phase is limited due to thermal instability. Moreover, we study the effects of neutrinos to the pasta structures. As a result, we find that the existence of neutrinos make the pasta structures unstable, too. These characteristic features of the hadron-quark mixed phase should be important for the middle stage of the evolutions of proto-neutron stars.

39000549
Reconstruction of Holocene environmental changes in the Kiso-Ibi-Nagara compound river delta, Nobi Plain, central Japan, by diatom analyses of drilling cores
Saegusa, Yoshie*; Sugai, Toshihiko*; Ogami, Takashi*; Kashima, Kaoru*; Sasao, Eiji
Quaternary International 230(1-2), p.67-77(2011) ; (JAEA-J 08772)

We reconstructed Holocene environmental changes by analyzing diatom assemblages of four drilling cores from the Nobi Plain, central Japan. We identified five diatom assemblage zones: (1) freshwater species dominant; (2) increase of marine and brackish-marine species, indicating transgression; (3) marine species dominant; (4) increase of freshwater species, indicating marine regression as a result of delta progradation; and (5) freshwater species dominant, in ascending order. It became clear that the shoreline migrated landward (transgression) faster than it migrated seaward (regression) by the comparison the diatom assemblages and lithological units. The transgressive diatom assemblage changes (decrease in marine-brackish water species) took up to 1000 years, whereas regressive changes required only a few hundred years. Diatom analysis is useful for reconstructing not only Holocene sea-level changes and sedimentary environments but also local geographic effects.

39000550
Use of electrical conductivity to analyze depositional environments; Example of a Holocene delta sequence on the Nobi Plain, central Japan
Niwa, Yuichi*; Sugai, Toshihiko*; Saegusa, Yoshie*; Ogami, Takashi*; Sasao, Eiji
Quaternary International 230(1-2), p.78-86(2011) ; (JAEA-J 08773)

We assessed the usefulness of electrical conductivity (EC) of stirred Holocene deltaic sediments from three cores from the Nobi Plain, Japan, as a proxy for marine transgression and regression. Marine deposits showed high EC, terrestrial deposits low EC, and brackish deposits intermediate. Because it was positively correlated with the percentage of marine diatom species, EC in inner bay deposits primarily reflected salinity. In the YM core (the youngest of the three cores), EC of the inner bay deposits was weakly positively correlated with clay content. EC of inner bay clayey deposits was generally higher in YM than in KZN, suggesting that the lower EC in older clayey sediments results from compaction. These findings suggest that the EC values of fine sediments initially record salinity but may decrease gradually over time under the influence of compaction. Thus, to reconstruct the original salinity, the effects of compaction and of grain size distribution should be evaluated.

39000551
Synthesis of palladium nanoparticles in a ceramic matrix using radiation grafting method
Yoshimura, Kimio; Hakoda, Teruyuki; Sugimoto, Masaki; Yamamoto, Shunya; Yoshikawa, Masahito
Radiation Physics and Chemistry 80(4), p.587-590(2011) ; (JAEA-J 08774)

39000552
ESR detection procedure of irradiated papaya containing high water content
Kikuchi, Masahiro; Shimoyama, Yuhei; Ukai, Mitsuko*; Kobayashi, Yasuhiko
Radiation Physics and Chemistry 80(5), p.664-667(2011) ; (JAEA-J 08775)

ESR signals were recorded from irradiated papaya at liquid nitrogen temperature (77 K), and freeze-dried irradiated papaya at room temperature (295 K). Two side peaks from the flesh at the liquid nitrogen temperature indicated a linear dose response for 3-14 days after the γ-irradiation. The line shapes recorded from the freeze-dry specimens were sharper than those at liquid nitrogen temperature.

39000553
Monochromatic X-ray emission from laser produced plasma with a clean ultra-short laser pulse
Zhang, Z.*; Nishikino, Masaharu; Nishimura, Hiroaki*; Kawachi, Tetsuya; Sagisaka, Akito; Orimo, Satoshi; Ogura, Koichi; Pirozhkov, A. S.; Yogo, Akifumi; Okano, Yasuaki*; Oshima, Shinsuke*; Fujioka, Shinsuke*; Kiriyama, Hiromitsu; Kondo, Kiminori; J-KAREN Laser Operation Group
Reza Kenkyu 38(9), p.698-701(2010) ; (JAEA-J 08776)

Monochromatic X-ray generation from Cu plates was experimentally studied by using a high contrast femtosecond laser pulse. Absolute yield of Ka line at 8 keV was measured as a function of laser pulse contrast ration and irradiation intensity. The conversion efficiency of 8 × 10^-5 /sr, the highest value ever obtained, has been demonstrated at 5.5 × 10¹⁶ W/cm² with a contrast ratio of 10^-11.

39000554
Conceptual design of the collection optics for the edge Thomson scattering system in ITER
Yatsuka, Eiichi; Hatae, Takaki; Suito, Satoshi*; Aida, Yoshiyuki*; Kusama, Yoshinori
Review of Scientific Instruments 81(10), p.10D541_1-10D541_4(2010) ; (JAEA-J 08777)

The difficulty in the edge Thomson scattering (TS) diagnostic in ITER is caused by the neutron and γ-ray irradiation. The vacuum window shall not directly face to a plasma. The TS light is relayed through the relaying optics with labyrinth, and collected to the optical fiber bundles. The total transmissivity of the TS light from a plasma to the optical fiber is approximately 30%. An electron density of 2×10¹⁹ m^-3 is enough to measure electron temperature and electron density within a 10% and 5% margin of error, respectively, with 5 mm of the spatial resolution. The super-Gaussian beam is the ideal laser profile for the laser injection optics to avoid the break-down of filling gas at the calibration of the spectral transmissivity.

39000555
In-situ spectral calibration method for the impurity influx monitor (divertor) for ITER using angled physical contact fibers
Iwamae, Atsushi; Ogawa, Hiroaki; Sugie, Tatsuo; Kusama, Yoshinori
Review of Scientific Instruments 82(3), p.033502_1-033502_4(2011) ; (JAEA-J 08778)

The in-situ calibration method for the impurity influx monitor (divertor) is experimentally examined. The total reflectance of the optical path from the focal point of the Cassegrain telescope to the first mirror is derived using a micro retro-reflector array. An optical fiber with angled physical contact (APC) connectors reduces the return edge reflection. APC fibers and a multimode coupler increase the signal-to-noise ratio by about one order compared to that of triple-branched fibers and enable measurement of the wavelength dependence of the total reflectance of the optical system even after potential deterioration of mirror surfaces reduces reflectance.

39000556
Rotational symmetry breaking in the hidden-order phase of URu₂Si₂
Okazaki, Ryuji*; Shibauchi, Takasada*; Shi, H. J.*; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Onuki, Yoshichika; Ikeda, Hiroaki*; Matsuda, Yuji*
Science 331(6016), p.439-442(2011) ; (JAEA-J 08779)

The nature of the broken symmetry in the so-called "hidden order" phase transition in the heavyfermion compound URu₂Si₂ has posed a long-standing mystery. We report the emergence of an in-plane anisotropy of the magnetic susceptibility below the transition temperature, which breaks the four-fold rotational symmetry of the tetragonal URu₂Si₂. Our findings suggest that the hidden order phase is an electronic "nematic" phase, a translationally invariant metallic phase with spontaneous breaking of rotational symmetry.

39000557
Site dependent hardening of the lanthanum metal lattice by hydrogen absorption
Machida, Akihiko; Watanuki, Tetsu; Omura, Ayako*; Ikeda, Tomohiro*; Aoki, Katsutoshi; Nakano, Satoshi*; Takemura, Kenichi*
Solid State Communications 151(5), p.341-345(2011) ; (JAEA-J 08780)

The compressibility of lanthanum (La) metal and its hydrides were measured at room temperature by high pressure synchrotron X-ray diffraction. La metal pressurized in a hydrogen medium forms a hydride with an fcc metal lattice, which likely contains hydrogen at a concentration close to 3.0. Equations of state have been determined by helium compression experiments for LaH₂ with tetrahedral interstitial sites fully occupied with hydrogen atoms and for LaH_2.46 with octahedral interstitial sites partially occupied with hydrogen atoms and tetrahedral sites fully occupied. Both hydrides possess fcc metal lattices. These values are three times larger than that of La metal and are very close to each other despite the difference in hydrogen occupation states. The hardening of the metal lattice by hydrogenation is attributed predominantly to hydrogen--metal interactions at the tetrahedral sites and is most pronounced for La, which has the largest ionic radius among rare-earth metals.

39000558
Middle Pleistocene tephras erupted from the Iizuna Volcano in the Kabura-gawa river basin in the northern Kanto district, Japan (in Japanese)
Tajikara, Masayoshi; Takada, Keita*; Furusawa, Akira*; Sugai, Toshihiko
Dai Yonki Kenkyu 50(1), p.21-34(2011) ; (JAEA-J 08781)

Three major fluvial terraces are developed well along the Kabura-gawa river, tributary of the Tone-gawa river. We detected cryptotephras in overbank and aeolian deposits covering the middle terrace gravels, and examined petrologic character. We also investigated petrologic character of the Iizuna-Kamitaru tephra (In-Kt) and the Iizuna-Nishiyama (In-Ny) tephra extracted from the outcrops near the Iizuna volcano. Based on these data, we identified possibly In-Kt and In-Ny tephra at the bottom of overbank deposits on the middle terrace of the Kabura-gawa river. This indicates that the middle terrace was formed through aggradation at glacial age of marine oxygen isotope stage 6. The Kabura-gawa river basin is located out of the previously reported distribution area of In-Kt. This fact implies that In-Kt is distributed more widely in the northern Kanto and southern Tohoku regions, and that In-Kt is useful as marker tephra of the middle Pleistocene in these regions.

39000559
Neutron radiography (in Japanese)
Matsubayashi, Masahito
Hamon 21(1), p.35-36(2011) ; (JAEA-J 08782)

39000560
An Introduction to neutron imaging (in Japanese)
Matsubayashi, Masahito
Hamon 21(1), p.55-58(2011) ; (JAEA-J 08783)

39000561
Application of stress measurement techniques using neutron diffraction (in Japanese)
Suzuki, Hiroshi
Hihakai Kensa 60(2), p.79-85(2011) ; (JAEA-J 08784)

39000562
Industrial use of neutrons (Trial use program); Neutron radiography (in Japanese)
Matsubayashi, Masahito; Iikura, Hiroshi
Isotope News (682), p.11-14(2011) ; (JAEA-J 08785)

39000563
Improvement of probabilistic fracture mechanics analysis code PASCAL2 for reactor pressure vessel focusing on weld-overlay cladding (in Japanese)
Nishikawa, Hiroyuki*; Onizawa, Kunio
Nippon Genshiryoku Gakkai Wabun Rombunshi 10(1), p.12-23(2011) ; (JAEA-J 08787)

Probabilistic fracture mechanics analysis code PASCAL2 has been developed in JAEA to support the validation of the codes and standards which provide the structural integrity assessment method of reactor pressure vessels during pressurized thermal shock. In this study, the evaluation methods of flaw initiation and growth considering weld-overlay cladding in PASCAL2 and non-destructive inspection models have been improved. Using the improved PASCAL2 code, effects of the initiation and growth models of a cladding flaw and the non-destructive inspection model on the failure probability have been analyzed. The analysis results, indicating the application of the improved initiation model decreases the conditional probability of failure, suggested the most feasible models. The results also showed that only maximum detection probability affected the failure probability among the parameter of the improved non-destructive inspection model.

39000564
Design and trial manufacturing of JT-60SA vacuum vessel (in Japanese)
Masaki, Kei; Shibama, Yusuke; Sakurai, Shinji; Shibanuma, Kiyoshi; Sakasai, Akira
Nippon Genshiryoku Gakkai Wabun Rombunshi 10(1), p.55-62(2011) ; (JAEA-J 08788)

JT-60 is planned to be upgraded to JT-60SA superconducting tokamak machine. This project is the JA-EU satellite tokamak program under both Broader Approach program and Japanese domestic program. The JT-60SA tokamak is composed of the following main components; vacuum vessel (VV), thermal shield, superconducting coils (toroidal field coil, equilibrium field coil, center solenoid), cryostat, heating facilities. The VV has a D-shape poloidal cross section and a double wall structure to ensure high rigidity and high toroidal one-turn resistance simultaneously. The material of the VV is 316L stainless steel with low cobalt content of < 0.05wt%. Before start of the VV manufacturing, fundamental welding R&D was performed to study the manufacturing procedures. The manufacturing procedures were successfully established with a trial manufacturing of 20 ^° upper half of the VV. Based on the results, the actual VV manufacturing has started in November 2009.

39000565
Phenix to Monju; FBR development and Japan role, 1; Incident in development of FBR and its effect on the development (in Japanese)
Konomura, Mamoru
Nippon Genshiryoku Gakkai-Shi 53(3), p.211-214(2011) ; (JAEA-J 08789)

It is not too much to say that R&D people have common sense to manage incidents in development of FBR with a method of risk analysis. In order to avoid an accident from some incidents, a reactor plant is designed with a way of defense in depth and a concept of multiple function and diversity in the design phase and is constructed and operated with enhancement of its reliability. Actually it is impossible to avoid any mechanical incidents. But the reliability can be enhanced by these incidents with appropriate risk management. In this sense, incidents are valuable for development of FBR. We should pay attention to developer's attitude how he understand incidents and how he improve his system on condition that he keeps transparency of information to public.

39000566
Operation and control of fusion reactor (in Japanese)
Sakamoto, Yoshiteru
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.55-61(2011) ; (JAEA-J 08791)

This report summarizes the characteristics and control method of burning plasma based on plasma physics. The burning plasma is characterized by self-regulating system with wide space and time scales. It is important viewpoints for controlling the burning plasma that the control matrix includes information of time and space scales.

39000567
Fundamental approach and design requirement for ensuring safety (in Japanese)
Hayashi, Takumi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.75-81(2011) ; (JAEA-J 08792)

There are general safety advantages of fusion reactor, such as no reactivity initiated accident, in comparison with fission reactor. However, it has been difficult to discuss detail of the safety approach itself and the safety design considered with the safety aspect of fusion reactor, because of the lack of design information of fusion reactor. There is only one case that the safety approach of ITER had been discussed and summarized through the invitation preparation activity of ITER in Japan. At that time, Nuclear Safety Commission of Japan (NSC) published two important decision papers of ITER safety. Ministry of Education, Culture, Sport, Science and Technology summarized the documents of the approach for ensuring ITER safety, based on the decision papers of NSC. In this section, differences of safety aspect between fusion reactor and ITER are summarized, and the safety approach of fusion reactor in Japan is discussed in comparison with those of ITER.

39000568
Plant design (in Japanese)
Matsukawa, Makoto; Matsuda, Shinzaburo
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.82-85(2011) ; (JAEA-J 08793)

This is the article of plant design for Tokamak type nuclear fusion reactor. The feature and their required capacity of power supply system, tritium handling system and cooling system are described. Especially, the power supply system to be used for pulsed power load was explained in detail using examples of ITER and next generation Tokamak from a view point of necessary energy, power perturbation of grid and new energy storage system.

39000569
Performance of plasma confinement (in Japanese)
Sakamoto, Yoshiteru
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.86-91(2011) ; (JAEA-J 08794)

This report describes the database of fusion plasma such as (1) scalings of energy confinement time for L-mode and H-mode plasmas, (2) scalings of power threshold, (3) edge pedestal characteristics, (4) internal transport barrier physics, (5) particle transport and (6) toroidal rotation.

39000570
Operation limit (in Japanese)
Sakamoto, Yoshiteru; Tobita, Kenji
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.92-97(2011) ; (JAEA-J 08795)

The operation region of fusion reactor should be set below the operation limit with appropriate margins. This report describes the operation limit in fusion reactor, especially (1) beta limit, (2) density limit, (3) disruption and incidental events, (4) control of disruption.

39000571
Control of plasma current sustainment (in Japanese)
Sakamoto, Yoshiteru
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.112-116(2011) ; (JAEA-J 08796)

Non-inductive current drive is essential for steady-state operation of tokamak. This report describes characteristics and issues of various current drive method from the viewpoint of DEMO design, such as (1) neutral beam injection, (2) electron cyclotron wave, (3) ion cyclotron wave, (4) lower hybrid wave and (5) the other method.

39000572
Integrated performance (in Japanese)
Sakamoto, Yoshiteru
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.117-121(2011) ; (JAEA-J 08797)

This paper reports the present status of the integrated performance achieved in tokamak experiments and critical issues towards DEMO reactor. The achieved integrated performance towards DEMO reactor is visualized using by introducing the radar-screen diagram with the normalized performance. The normalized plasma parameters foreseen in DEMO have been developed experimentally in world-wide, but the highly integrated performance and long sustainment have not yet been achieved. The main differences of physics requirements between ITER and DEMO provides the critical issues such as the capability for non-inductive current drive, power handling in edge and divertor, ELM mitigation and the controllability of self-organized system. Such critical issues towards DEMO should be addressed with attention to trade-off relationships.

39000573
Blanket and energy conversion system (in Japanese)
Tanigawa, Hisashi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.128-143(2011) ; (JAEA-J 08798)

This article is a part of text book for a tokamak fusion reactor focusing on design methodology, related plasma physics and engineering technology. The article shows roles and specification of a blanket and energy conversion systems. Some of major candidates of the blanket concepts are summarized and their status and issues are discussed. A water-cooled ceramic breeder concept developed by JAEA is explained in detail, and present issues for the concept are summarized. The design method including nuclear, structural and thermal analysis is explained. It is shown that different candidates can be considered for cooling conditions and selection of breeder materials. Technologies for tritium and material developments were discussed focusing on relation with the blanket design and their issues are summarized.

39000574
Structural components with high temperature environment (in Japanese)
Araki, Masanori; Suzuki, Satoshi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.155-161(2011) ; (JAEA-J 08799)

For the nuclear fusion reactor, issues of heat removal technologies, its thermal stresses and fatigues of the divertor component as a part of report in the core plasma physics and the engineering technologies for DEMO reactor are described in this session.

39000575
Fuel supply, evacuation, and processing systems (in Japanese)
Hayashi, Takumi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.170-175(2011) ; (JAEA-J 08800)

In ITER, once through burn up of DT fuel, which is injected in the vacuum reactor vessel, will be less than one %. Even in the fusion reactor, that will be a few or several % level. Therefore, almost all DT fuel will be exhausted from the vacuum vessel as the plasma exhaust. How to recover and purify the DT fuel in the plasma exhaust effectively is one of the most important design issues for fusion reactor. In this section, current R&D situations of each sub systems for fusion fuel cycle are summarized, such as fuel injection, evacuation, purification & recovery, isotope separation, storage and accountancy. Optimization of each sub systems and further issues are also discussed for an effective fusion fuel processing system.

39000576
Operation and maintenance (in Japanese)
Kakudate, Satoshi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.194-200(2011) ; (JAEA-J 08801)

39000577
Occupational, environmental and public safety (in Japanese)
Hayashi, Takumi
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.200-205(2011) ; (JAEA-J 08802)

Based on the discussions of ITER design, this section summarizes the issues toward DEMO fusion reactor, focused on the shielding systems for radiation protection, the controlling systems for radioactive isotopes concentration in a room air and in the stack exhaust during normal and incident/accident conditions, and also various waste (gaseous, liquid, and solid types) processing systems. From the general safety design point of view, (1) dose rate at the site boundary in the normal operation should be controlled as low as reasonably achievable (= less than 0.1 micro Sv/h), (2) dose at the site boundary in a hypothetical accident should be controlled less than 5 mSv, and (3) dose rate in the radiological controlled area should be also controlled less than 10 micro Sv/h for exposure protection of radiation workers.

39000578
Appendix 2; High temperature thermal engineering (in Japanese)
Inagaki, Yoshiyuki; Ogawa, Masuro
Purazuma, Kaku Yugo Gakkai-Shi 87(Suppl.), p.219-229(2011) ; (JAEA-J 08803)

39000579
Adaptive visualization for analyzing large-scale network datasets (in Japanese)
Miyamura, Hiroko; Ozahata, Satoshi*; Nakao, Akihiro*; Kawashima, Konosuke*
Shingaku Giho 110(190), p.103-108(2010) ; (JAEA-J 08804)

In this paper, we propose a visualization technique for handling large-scale experiment datasets in distributed file system. Traditional network visualization techniques have problem that not all data can be displayed at the same time because the file-sharing network data is too large-scale. Therefore, we propose a concept of adaptive network graph display, in which the graph style can be changed according to the details of user's observation. We construct a visualization system based on this concept. When observing data globally, the proposed system selectively displays information based on the clustering result, and when observing data locally, the system displays detailed information. This technique is a basic technology for computational science to achieve large-scale datasets handling which is a problem in atomic energy related fields.

39000580
Heat generation and cooling optimization of the superconducting coils for JT-60SA (in Japanese)
Kamiya, Koji; Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Yoshida, Kiyoshi
Teion Kogaku 46(1), p.10-17(2011) ; (JAEA-J 08805)

JT-60SA project replaces the JT-60U tokamak with a full superconducting tokamak. The helium refrigerator cools the superconducting coils by circulating 4.4 K, 0.6 MPa supercritical helium in the circulation loop at certain mass flow rate. Since the cooling power of the helium refrigerator is determined by the heat load of the superconducting coils, estimation of the heat generation and required mass flow rate to acquire sufficient temperature margin is of crucial importance. In this paper, optimizing the mass flow rate in the superconducting coils was attempted to satisfy 1 K temperature margin. Then, it is shown that the consequent maximum pressure drop in the circulation loop is 81 kPa to result in minimizing the heat load of the supercritical helium circulation pump.

39000581
Evaluation of extrapolation for creep-fatigue life by hysteresis energy (in Japanese)
Nagae, Yuji; Takaya, Shigeru
Zairyo 60(2), p.108-115(2011) ; (JAEA-J 08806)

The creep-fatigue life has been evaluated by the hysteresis energy in 316FR stainless steel with low carbon and medium nitrogen, which is a candidate for structural material in Fast Breeder Reactor (FBR) plant with the design life of 60 years. The creep-fatigue is a main damage mode to prevent. The hysteresis energy rate is considered as the parameter to predict the life time. It is clear that the relationship between this parameter and the time to failure can be approximately expressed by the power-law function. The function depends on the ratio of plastic strain to total strain. Total fracture energy for creep-fatigue loading intends to be independent of the ratio of plastic strain to total strain in long-term test condition. The value is related to grain boundary strength for creep-fatigue loading because fracture mode in long-term test condition is intergranular fracture. The life could be predicted by the function in the case of no significant change of fracture energy. Coarse precipitation, for example sigma phase, might be considered as a factor to be change the fracture energy. It is important to predict the precipitation formation. The result of life prediction by the hysteresis energy rate is compared with that of the time fraction rule based on "Demonstration Reactor Design Standard (Draft)". Predicted life intends to be comparable in both methods.

39000582
Electrochemical measurements in boiling nitric acid solutions containing radioactive elements by using small cell with a portion for spectral analysis function (in Japanese)
Kato, Chiaki; Ueno, Fumiyoshi; Yamamoto, Masahiro; Hakamatsuka, Yasuyuki; Ban, Yasutoshi; Morita, Yasuji; Uchiyama, Gunzo; Nojima, Yasuo*; Fujine, Sachio*
Zairyo To Kankyo 60(2), p.69-71(2011) ; (JAEA-J 08807)

It was reported that the metric ions such as Pu and Np contained in reprocessing solutions would accelerate corrosion of stainless steals due to those ions changing higher oxidizer. It's difficult that those ions was used in laboratory test because of radioactive elements. However it's important to understand oxide stats of those ions and electrochemical behavior on stainless steals in order to estimate corrosion rate of materials in reprocessing plats. Furthermore laboratory test with very a little solution volume is demanded for handling radioactive elements. This paper shows that developed a small electrochemical cell with a spectral analysis function and those results of polarization curves on stainless steals and oxide stats of Np(IV)/Np(V) and Pu(IV)/Pu(VI) in boiling nitric acid solutions.

39000583
Influence of operational conditions on retardation parameters measured by diffusion experiment in compacted bentonite
Ishii, Yasuo; Seida, Yoshimi; Tachi, Yukio; Yoshikawa, Hideki
Materials Research Society Symposium Proceedings, Vol.1265 , p.233-238(2010) ; (JAEA-J 08808)

Influence of stagnation of the test tracer solution and diffusion resistance in the filters on data acquisition were measured by Cs⁺ and I^- diffusion experiments and the range of uncertainties of these effects was estimated by calculation of the simulated experimental component. From the ID experiment and the model analysis, it was found that the simultaneous data acquisition of RD and ID methods decreased the residue of retardation parameters effectively.

39000584
Update on lithium safety handling work
Furukawa, Tomohiro; Hirakawa, Yasushi; Kato, Shoichi; Kondo, Hiroo; Nakamura, Kazuyuki
Proceedings of 3rd IFMIF/EVEDA Workshop (Internet) , 4p.(2010) ; (JAEA-J 08810)

The object of this task, Development of Li safety handing technology in EVEDA LF-5, is to dedicate data needed for design relating safety and Li treatment and impurity monitoring. This task consists of (a) experiments of lithium fire, (b) chemical analysis of impurity in lithium and (c) experiments of lithium chemical reaction. The validation test on the lithium fire and the preliminary tests on lithium impurity and lithium chemical reaction were started in 2009. This paper describes the current status of the lithium safety handling task.

39000585
Radiation processing of polymers and its applications (in Japanese)
Tamada, Masao
Genshiryoku Kyokasho "Hoshasen Riyo" , p.58-73(2011) ; (JAEA-J 08814)

Polymer materials are available for many kinds of commodity and industrial products. Graft polymerization is a sophisticate technique to impart desired functions into trunk polymers. A nonwoven material can be converted to fibrous adsorbent for metal ions by the graft polymerization. The obtained fibrous adsorbents have been applied to removal of cadmium from waster of scallop processing and recovery of uranium from seawater. Properties of biopolymers have been modified by crosslinking. Crosslinked poly(lactic acid) is applicable for heat shrinkable tubes. Biodegradable and water adsorption hydrogels prepared by crosslinked polysaccharides can be used as fermentation treatment of livestock excrement. Degraded chitosan is effective for plant activator.

39000586
Diagnosis of plant using radiation; Plant research using Positron-imaging technique (in Japanese)
Matsuhashi, Shimpei
Genshiryoku Kyokasho "Hoshasen Riyo" , p.210-238(2011) ; (JAEA-J 08815)

39000587
Medical application of radiation (in Japanese)
Matsuhashi, Shimpei; Ishioka, Noriko
Genshiryoku Kyokasho "Hoshasen Riyo" , p.240-273(2011) ; (JAEA-J 08816)

39000588
Spent nuclear fuels and actinides (in Japanese)
Kimura, Takaumi
Reametaru Binran, 3 , p.243-261(2010) ; (JAEA-J 08817)

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JAEA > JAEA Library > JOPSS > Papers Published in Journals [Back Issues] > April 2011