JAEA Abstracts

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

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

June 2007

35000875
Crystallization of porcine pancreatic elastase and a preliminary neutron diffraction experiment
Kinoshita, Takayoshi*; Tamada, Taro; Imai, keisuke*; Kurihara, Kazuo; Ohara, Takashi; Kuroki, Ryota
Acta Crystallographica Section F 63(4), p.315-317(2007) ; (JAEA-J 02433)

Porcine pancreatic elastase (PPE) resembles the attractive drug target leukocyte elastase, which has been implicated in a number of inflammatory disorders. In order to investigate the structural characteristics of the covalent inhibitor bound to PPE, including hydrogen and hydration of water, a single crystal of PPE for neutron diffraction study was grown in D₂O containing 0.2 M sodium sulfate (pD=5.0) using the sitting-drop vapor diffusion method. The crystal was grown to a size of 1.6 mm³ by repeated macro-seeding. The neutron diffraction data were collected at room temperature using a BIX-3 diffractometer at the JRR-3 research reactor of the Japan Atomic Energy Agency (JAEA). The data set was integrated and scaled to 2.3Å resolution with space group P212121 and cell dimensions of a=51.2Å , b=57.8Å and c=75.6Å .

35000876
Extraction of uranium from simulated ore by the supercritical carbon dioxide fluid extraction method with nitric acid-TBP complex
Dung, L. T. K.*; Imai, Tomoki*; Tomioka, Osamu; Nakashima, Mikio; Takahashi, Kuniaki; Meguro, Yoshihiro
Analytical Sciences 22(11), p.1425-1430(2006) ; (JAEA-J 02434)

Supercritical fluid extraction (SFE) method using supercritical CO₂ fluid containing a complex of HNO₃-tri-n-butyl phosphate (TBP) as an extractant was applied to extract uranium from a several uranyl phosphate compounds and simulated uranium ores. Extraction method consisting of a static and a dynamic extraction processes was established and experimental condition such as pressure, temperature, and extraction time were optimized. It was found that uranium could be efficiently extracted from both of the uranyl phosphates and simulated ores by the SFE method and then it was demonstrated that SFE was useful as a pretreatment method for uranium analysis in ores.

35000877
The Connection between γ-ray bursts and extremely metal-poor stars; Black hole-forming supernovae with relativistic jets
Tominaga, Nozomu*; Maeda, Keiichi*; Umeda, Hideyuki*; Nomoto, Kenichi*; Tanaka, Masaomi*; Iwamoto, Nobuyuki; Suzuki, Tomoharu*; Mazzali, P. A.*
Astrophysical Journal 657(2, Part2), p.L77-L80(2007) ; (JAEA-J 02435)

Long-duration γ-ray bursts (GRBs) are thought to be connected with luminous and energetic Type Ic supernovae [SNe, called hypernovae (HNe)] resulting from the black-hole (BH) forming collapse of massive stars. For GRBs 060505 and 060614, however, the expected SNe have not been detected. The upper limits to the SN brightness are about 100 times fainter than GRB-associated HNe (GRB-HNe), corresponding to the upper limits to the ejected ⁵⁶Ni masses of M(⁵⁶Ni)˜ 10^-3M_Ο. SNe with a small amount of ⁵⁶Ni ejection are observed as faint Type II SNe. HNe and faint SNe are thought to be responsible for the formaion of extremely metal-poor (EMP) stars. A relativistic jet-induced BH forming explosion of the 40M_Ο star is investigated and hydrodynamic and nucleosynthetic models are presented. These models can explain both GRB-HNe and GRBs without bright SNe in a unified manner. We suggest that GRBs without bright SNe are likely to synthesize M(⁵⁶Ni)˜ 10^-4-10^-3M_Ο or ˜ 10^-6M_Ο.

35000878
Spectroscopic studies of extremely metal-poor stars with the subaru high-dispersion spectrograph, 4; The α-element-enhanced metal-poor star BS 16934-002
Aoki, Wako*; Honda, Satoshi*; Beers, T. C.*; Hidai, Masahide*; Iwamoto, Nobuyuki; Tominaga, Nozomu*; Umeda, Hideyuki*; Nomoto, Kenichi*; Norris, J. E.*; Ryan, S. G.*
Astrophysical Journal 660(1, Part1), p.747-761(2007) ; (JAEA-J 02436)

A detailed elemental abundance analysis has been carried out for the very metal-poor ([Fe/H] = -2.7) star BS 16934-002, which was identified in our previous work as a star exhibiting large overabundances of Mg and Sc. A comparison of the abundance pattern of this star with that of the well-studied metal-poor star HD 122563 indicates excesses of O, Na, Mg, Al, and Sc in BS 16934-002. Of particular interest, no excess of C or N is found in this object, in contrast to CS 22949-037 and CS 29498-043, two previously known carbon-rich, extremely metal-poor stars with excesses of the α elements. No established nucleosynthesis model exists that explains the observed abundancepattern. A supernova model, including mixing and fallback, assuming severe mass loss before explosion, is discussed as a candidate progenitor of BS 16934-002.

35000879
Design, synthesis, and evaluation of [¹⁸⁸Re]Organorhenium-labeled antibody fragments with renal enzyme-cleavable linkage for low renal radioactivity levels
Uehara, Tomoya*; Koike, Miho*; Nakata, Hideo*; Hanaoka, Hiroshi*; Iida, Yasuhiko*; Hashimoto, Kazuyuki; Akizawa, Hiromichi*; Endo, Keigo*; Arano, Yasushi*
Bioconjugate Chemistry 18(1), p.190-198(2007) ; (JAEA-J 02437)

Renal localization of radiolabeled antibody fragments constitutes a problem in targeted imaging and radiotherapy. To estimate the applicability of the molecular design to metallic radionuclides, [¹⁸⁸Re]tricarbonyl(cyclopentadienylcarbonate)rhenium ([¹⁸⁸Re]CpTR-COOH) was conjugated with maleoyl-glycyl-lysine to prepare [¹⁸⁸Re]CpTR-GK. The cleavage of the glycyl-lysine linkage of the compound generates a glycine conjugate of [¹⁸⁸Re]CpTR-Gly. [¹⁸⁸Re]CpTR-GK was conjugated to thiolated Fab fragments to prepare [¹⁸⁸Re]CpTR-GK-Fab. The biodistribution of radioactivity after injection of [¹⁸⁸Re]CpTR-GK-Fab was compared with that of [¹⁸⁸Re]CpTR-Fab. [¹⁸⁸Re]CpTR-GK-Fab exhibited significantly lower renal radioactivity levels than did [¹⁸⁸Re]CpTR-Fab. The analysis of urine samples collected for 6 h postinjection of [¹⁸⁸Re]CpTR-GK-Fab showed that [¹⁸⁸Re]CpTR-Gly was the major radiometabolite. In tumor-bearing mice, [¹⁸⁸Re]CpTR-GK-Fab significantly reduced renal radioactivity levels without impairing the radioactivity levels in tumor. These findings indicate that the molecular design of radioparmaceuticals labeled with metallic radionuclides can be useful by using a radiometal chelate of high inertness and by designing a radiometabolite of high urinary excretion when released from antibody fragments following cleavage of a glycyl-lysine linkage. This study also indicates that a change in chemical structure of a radiolabel attached to a glycyl-lysine linkage significantly affected enzymes involved in the hydrolysis reaction.

35000880
Design, fabrication, and study of wideband multilayer X-ray mirrors
Kozhevnikov, I. V.*; Voronov, A. S.*; Roshchin, B. S.*; Asadchikov, V. E.*; Mednikov, K. N.*; Pirozhkov, A. S.; Ragozin, E. N.*; Wang, Z.*; Zhong, Z.*; Wang, F.*
Crystallography Reports 51(6), p.1075-1081(2006) ; (JAEA-J 02438)

Multilayer depth-graded (aperiodic) W/Si and W/B₄C mirrors with a period changing over depth have been designed, fabricated, and investigated. The mirrors have almost constant reflectance (from 25 to 35% for different mirrors) at a wavelength of 0.154 nm in a wide range of grazing angles (the reflection bandwidth ranges from 0.25° to 0.4°). It is shown that the main reason for the distortions observed on the plateau of the reflection curve is incorrect consideration of the interlayers formed at the interface of neighboring films during fabrication of the structures. The mirrors with sharp interfaces (for example, WSi₂/Si) are preferential for practical purposes.

35000881
PDF analysis on semiconductive CdTe-ZnTe alloy
Yoneda, Yasuhiro; Suzuya, Kentaro; Kohara, Shinji*; Mizuki, Junichiro
Ferroelectrics 339, p.165-174(2006) ; (JAEA-J 02439)

35000882
High power and high efficiency operation of 170GHz gyrotron
Kasugai, Atsushi; Minami, Ryutaro*; Takahashi, Koji; Kobayashi, Noriyuki; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Sakamoto, Keishi
Fusion Science and Technology 51(2T), p.213-216(2007) ; (JAEA-J 02440)

35000883
Dynamics of SOL-divertor plasmas after an ELM crash in tokamak H-mode plasma
Takizuka, Tomonori; Hosokawa, Masanari*
Fusion Science and Technology 51(2T), p.271-273(2007) ; (JAEA-J 02441)

Enhanced particle and heat fluxes to the divertor plates after an ELM crash in H-mode plasmas give the serious load to the plate. We investigate these fluxes with the particle simulation code PARASOL, where an electrostatic PIC method is combined with a Monte-Carlo binary collision model. The electron heat pulse after an ELM crash propagates fast to the plate. Next the ion heat pulse and plasma particle pulse reach the plate slowly with the sound-speed time scale. We study the effect of the ELM-induced-source asymmetry and of the recycling asymmetry on the dynamic behavior of SOL-divertor plasmas. The SOL current plays an important role in the dynamics with the asymmetry.

35000884
Fast measurement of ion temperature using filter charge exchange recombination spectroscopy system towards real-time plasma control in JT-60U
Yoshida, Maiko; Kobayashi, Shinji*; Takenaga, Hidenobu; Sakata, Shinya; Kamada, Yutaka; JT-60 Team
Fusion Science and Technology 51(2T), p.301-303(2007) ; (JAEA-J 02442)

35000885
Relationship between helium isotopes and heat flux from hot springs in a non-volcanic region, Kii Peninsula, Southwest Japan
Umeda, Koji; Sakagawa, Yukihiro*; Ninomiya, Atsushi; Asamori, Koichi
Geophysical Research Letters 34(5), p.L05310_1-L05310_5(2007) ; (JAEA-J 02443)

In order to examine the potential correlation between heat and helium isotope signatures in a non-volcanic region, we estimated the local heat flux using Peclet number analysis of thermal profile from deep boreholes in the Kii Peninsula, Southwest Japan. There is a distinct correlation between the common logarithms of ³He/⁴He ratio and heat flux. Here heat flux values higher than 90 mW/m² are estimated from the deep boreholes and the upward flow of deep fluids predominates over the groundwater recharge of the local hydrology. These results support the recently proposed source model that shows that the high temperature hot springs with significantly higher ³He/⁴He ratio in the Kii Peninsula originate due to the effective transfer of mantle helium and heat from the subcrustal lithosphere by aqueous fluids generated by dehydration of the subducting Philippine Sea slab.

35000886
Structure of beam tracks induced by swift heavy ions in Bi₂Sr₂CaCu₂O₈superconductors
Sasase, Masato*; Okayasu, Satoru; Yamamoto, Hiroyuki; Kurata, Hiroki*; Hojo, Kiichi
Japanese Journal of Applied Physics, Part 1 46(2), p.783-786(2007) ; (JAEA-J 02444)

Columnar defects are produced in semiconductor and insulator materials by swift heavy ion irradiation. It has been considered that the electronic stopping power of irradiating ions is the dominant factor in the formation of defects. However, our recent results suggest that ion-velocity is also an important parameter for use in describing this phenomenon. We investigate the columnar defects produced in Bi₂Sr₂CaCu₂O₈ (Bi-2212) superconductor by heavy ion irradiation (Au^8+,12+, I^8+,29+, Br¹²⁺, and Ni¹¹⁺) in the energy range of 60-600MeV. From tansmission electron microscopy, it is shown that the diameters of columnar defects become smaller and their distribution become narrower with an increase in ion velocity. This is explained as an effect of nuclear collision by calculation of the mean free path for the irradiated ions. The present results imply that nuclear collisions strongly affect the formation of columnar defects, even for swift heavy ion irradiation.

35000887
Real-time observation of initial thermal oxidation on Si(110)-16×2 surfaces by O 1s photoemission spectroscopy using synchrotron radiation
Suemitsu, Maki*; Kato, Atsushi*; Togashi, Hideaki*; Konno, Atsushi*; Yamamoto, Yoshihisa*; Teraoka, Yuden; Yoshigoe, Akitaka; Narita, Yuzuru*; Enta, Yoshiharu*
Japanese Journal of Applied Physics, Part 1 46(4B), p.1888-1890(2007) ; (JAEA-J 02445)

Initial oxidation of Si(110) surface has been investigated by using real-time X-ray photoemission spectroscopy. The time evolution of the O 1s spectrum shows occurrence of rapid oxidation just after the introduction of the oxygen molecules, which is evidenced by the considerable peak intensity corresponding to oxygen exposure of as low as 1.5L (1L=1.33×10^-4 Pa s). This initial oxide is dominated by a state with a relatively low binding energy, which is gradually replaced by a state with a relatively high binding energy with the increase of the oxygen exposure, resulting in the low-KE shift of the O 1s peak. Comparison with previously reported O 1s spectra from dry-oxidized Si(111) surface suggests oxidation at or around the adatoms of Si(110)-16×2 clean surface as a likely oxidation state for this low-binding-energy peak.

35000888
Observation of initial oxidation on Si(110)-16×2 surface by scanning tunneling microscopy
Togashi, Hideaki*; Takahashi, Yuya*; Kato, Atsushi*; Konno, Atsushi*; Asaoka, Hidehito; Suemitsu, Maki*
Japanese Journal of Applied Physics, Part 1 46(5B), p.3239-3243(2007) ; (JAEA-J 02446)

On Si(110) surface, the hole mobility is enhanced as compared with that on Si(001) surface. This surface is also to be used in the next-generation three-dimensional devices. We conducted scanning-tunneling-microscopy (STM) observation on the initial oxidation of Si(110)-16×2 surface. The present result suggests less occurrence of etching under the oxidation condition. There is a possibility to form an abrupt oxide/Si interface on the Si(110) surface.

35000889
Comparative study on the preparation and properties of radiation-grafted polymer electrolyte membranes based on fluoropolymer films
Chen, J.; Septiani, U.*; Asano, Masaharu; Maekawa, Yasunari; Kubota, Hitoshi*; Yoshida, Masaru
Journal of Applied Polymer Science 103(3), p.1966-1972(2007) ; (JAEA-J 02447)

In this study, ETFE and PVDF films, together with the crosslinked PTFE (cPTFE) films have been compared on the basis of their preparation and properties of radiation-grafted polymer electrolyte membranes (PEM). The proton conductivity and chemical stability of the three types of membranes with the similar ion exchange capacity near 1.0 mmolg^-1 were investigated and discussed in detail. Although the ETFE-based PEM was relatively more stable, its proton conductivity was lower than those of the PVDF- and cPTFE-based membranes. On the other hand, the cPTFE-based membrane showed the significantly higher proton conductivity, but its chemical stability was shorter than that of the ETFE-based membrane. The difference in the preparation and properties of the PEMs was due to the difference in the crystallinity and intrinsic properties of the base films.

35000890
Oriented crystallization of crosslinked cis-1,4-polybutadiene rubber
Saijo, Kenji*; Zhu, Y.*; Hashimoto, Takeji; Wasiak, A.*; Brzostowski, N.*
Journal of Applied Polymer Science 105(1), p.137-157(2007) ; (JAEA-J 02448)

Crosslink cis-1,4-polybutadiene (PB) rubber is known to undergo crystallization during mechanical deformation. This article presents small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and stress-relaxation studies of the structural development in crosslinked PB samples crystallized under various orientation regimes. The studies are concerned with isothermal crystallization at various temperatures (10 to -50°C) and at constant elongation ratios (1-4,5) and hence with the effects of weak -to-intermediate and high orientations on oriented crystalliation versus the behavior of unoriented specimens. Although the crystallization in the weak-to-intermediate orientations is interpreted on the basis of nucleation growth, the crystallization under high orientations is best interpreted on the basis of spinodal crstallization. To the best of our knowledge, this work reports for the first time spinodal-like crystallization on oriented crosslinked polymer melts.

35000891
Parisi function for the ising spin glass in cluster approximations
Yokota, Terufumi
Journal of Magnetism and Magnetic Materials 310(2, Part2), p.e518-e519(2007) ; (JAEA-J 02449)

The Ising spin glass is investigated close to the spin glass transition temperature. Parisi's order parameter function and the de Almeida-Thouless (AT) line are obtained in various cluster approximations. A class of cluster approximations introduced by Baviera, Pasquini, and Serva, the Bethe approximation and cactus approximations are used to study effects of fluctuations on the replica symmetry breaking. Fluctuations seem to cause reduction in the slope of the order parameter function. The locus of the AT line for a cluster approximation changes from that for the Sherrington-Kirkpatrick (SK) model and the change seems to be affected by the existence of a loop in a cluster.

35000892
Influence of pre-irradiation atmosphere on the properties of polymer electrolyte membranes prepared using radiation grafting method
Septiani, U.*; Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru; Kubota, Hitoshi*
Journal of Materials Science 42(4), p.1330-1335(2007) ; (JAEA-J 02450)

The influence of pre-irradiation atmosphere, argon and air, on radiation grafting of styrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and the properties of the ETFE-based radiation-grafted polymer electrolyte membranes were investigated. The preparation and properties of the membranes were found to be strongly influenced by the γ-ray pre-irradiation atmosphere. The proton conductivity was measured in its water-saturated state at 25°C, and the membrane durability was tested in a 3 % H₂O₂ aqueous solution at 60°C. The proton conductivity of the membrane prepared by pre-irradiation under air was higher than that of the membrane prepared under argon with the same ion exchange capacity level. However, the durability of the former was considerably lower than that of the latter. For instance, the membrane with an ion exchange capacity of about 1.0 mmolg-1 prepared under argon was twice as durable as that prepared under air. It was considered that the lower durability of the membrane prepared by pre-irradiation under air was because of the unstable ether bond introduced between the graft chains and the backbone chains. : polymer electrolyte membrane (PEM); radiation grafting; styrene; durability; ETFE

35000893
Polymer electrolyte hybrid membranes prepared by radiation grafting of p-styryltrimethoxysilane into poly(ethylene-co-tetrafluoroethylene) films
Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru
Journal of Membrane Science 296(1-2), p.77-82(2007) ; (JAEA-J 02451)

In order to prepare a polymer electrolyte hybrid membrane with both high proton conductivity and high thermal stability, the p-styryltrimethoxysilane was first grafted into ETFE film by γ-ray preirradiation. The grafted film was then sulfonated to attach sulfonic acid groups onto the aromatic rings of the graft chains, and finally hydrolyzed and condensed to introduce silane-crosslinking between the graft chains. The preparation conditions for grafting and sulfonation, and the properties of the resulting polymer electrolyte membrane, such as ion exchange capacity, proton conductivity, water uptake, and thermal stability, were investigated with respect to its application in fuel cells. It is concluded that the properties of the new polymer electrolyte hybrid membrane are comparable to Nafion, and are superior to a styrene-grafted membrane.

35000894
Repetition rate multiplication capability for a high energy resolution mode of DIANA at J-PARC
Takahashi, Nobuaki; Shibata, Kaoru; Sato, Taku*; Arai, Masatoshi
Journal of Neutron Research 15(1), p.61-67(2007) ; (JAEA-J 02452)

The DIANA spectrometer is an indirect-geometry crystal-analyzer instrument which will be installed at the Materials and Life science experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). The available momentum transfer and energy ranges are from about 0.1 A^-1 to 3.9 A^-1 and from about 2 μeV to 35 meV, respectively. Three analyzer-crystals, PG(002), Ge(311) and Si(111) are planed to put into place. The energy resolutions of each the former two analyzer-crystal setting are sufficiently high, which are about 15 μeV and 40 μeV, respectively. We are especially aiming very high energy resolution of about 2.5 μeV by using the Si(111) analyzer-crystal together with another pulse-shaping mechanism, an optional setting for the DIANA spectrometer. This option can only be attained by using highly sophisticated silicone crystal, i.e. obtaining low mosaicness, and very sharp pulse-shaped incident neutron beam, which is obtained from counter-rotating 2-disk choppers with each rotation frequency of 300 Hz. Although one can attain such a high energy resolution, it is considerably inefficient to chop one very narrow incident neutron energy band from one frame (one pulse from a moderator). If several incident beam having different energy band from each other are available by chopping within one frame several times, the obtainable energy range substantially enlarge. We discuss the advantage and disadvantage of this multiplication, which is named Repetition Rate Multiplication (RRM), of the optional setting for DIANA spectrometer.

35000895
Microstructural evolution of SINQ irradiated austenitic stainless steels
Sawai, Tomotsugu; Kitsunai, Yuji*; Saito, Shigeru; Kikuchi, Kenji
Journal of Nuclear Materials 356(1-3), p.118-121(2006) ; (JAEA-J 02453)

A type 316 stainless steel 316F and Ti-modified type 316 stainless steel JPCA irradiated in SINQ were examined using transmission electron microscopy. Estimated irradiation temperature for two 316F specimens were 250-300°C and that for the JPCA specimen was 255°C. Irradiation damage of these specimens is calculated to be about 10 dpa. Frank loops up to 30 nm and larger perfect loops up to 50 nm were observed in 316F irradiated at 300°C. Frank loops observed in JPCA is somewhat smaller, suggesting lower dislocation bias in JPCA.

35000896
Conceptual design of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) and its recycle characteristics
Uchikawa, Sadao; Okubo, Tsutomu; Kugo, Teruhiko; Akie, Hiroshi; Takeda, Renzo*; Nakano, Yoshihiro; Onuki, Akira; Iwamura, Takamichi
Journal of Nuclear Science and Technology 44(3), p.277-284(2007) ; (JAEA-J 02454)

35000897
Progress on the plant design concept of sodium-cooled fast reactor
Hishida, Masahiko*; Kubo, Shigenobu; Konomura, Mamoru; Toda, Mikio*
Journal of Nuclear Science and Technology 44(3), p.303-308(2007) ; (JAEA-J 02455)

An innovative concept of sodium-cooled fast reactor, named JNC Sodium Cooled FR (JSFR) has been created and modified through the Feasibility Study on Commercialized FR Cycle System, aiming at full satisfaction of the development targets. A modified concept of JSFR applied double-wall straight tube type steam generator (SG) which is excelling in safety for sodium-water reaction has been developed. In addition, decay heat removal system suitable for the straight tube SG has been selected and in-service inspection and repair capabilities have been improved. As the result of this study, the potential to realize this plant concept has been obtained through evaluation concerning safety and economics.

35000898
A Study on precipitation behavior of plutonium and other transuranium elements with N-cyclohexyl-2-pyrrolidone for development of a simple reprocessing process
Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Ikeda, Yasuhisa*; Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*
Journal of Nuclear Science and Technology 44(3), p.354-360(2007) ; (JAEA-J 02456)

Precipitation behavior of Pu and other transuranium elements with N-cyclohexyl-2-pyrrolidone (NCP) has been examined to develop a simple reprocessing based only on precipitation method. From HNO₃ solutions containing only Pu, both Pu(VI) and Pu(IV) were precipitated with NCP, but they required more NCP than in the U(VI) precipitation. Selective U(VI) precipitation from HNO₃ solution containing U(VI) and Pu(IV) was achieved by stirring the solution for sufficient time after addition of NCP with ratio of [NCP]/[U]=1.4. Addition of an enough amount of NCP to U(VI)-Pu(VI) or U(VI)-Pu(IV) solutions gave a quantitative precipitation of both U and Pu. Neither Am(III) nor Np(V) was precipitated in the selective U precipitation and the simultaneous U-Pu precipitation. These results demonstrate the feasibility of the reprocessing by precipitation with NCP.

35000899
Separation of actinide elements by solvent extraction using centrifugal contactors in the NEXT process
Nakahara, Masaumi; Sano, Yuichi; Koma, Yoshikazu; Kamiya, Masayoshi; Shibata, Atsuhiro; Koizumi, Tsutomu; Koyama, Tomozo
Journal of Nuclear Science and Technology 44(3), p.373-381(2007) ; (JAEA-J 02457)

Actinides recovery was attempted by the simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery and the SETFICS process for Am and Cm recovery with a view to decreasing the environmental impact. Uranium, Pu and Np co-recovery was conducted under the condition with high nitric acid concentration in the feed solution or scrubbing solution. High nitric acid concentration in the feed solution availed to the Np oxidation not only in the feed solution, but also at the extraction section. This oxidation reaction permitted the Np extraction with U and Pu. In the SETFICS process, a TRUEX solvent of 0.2M CMPO/1.4M TBP was employed to increase the loading of metals. In place of sodium nitrate, HAN was applied to this experimental flow sheet for "salt-free" concept. This experiment was succeeded in Am and Cm product. On high-loading flow sheet, the flow rate of aqueous effluents and spent solvent was expected to decrease in 47% and 54%, respectively.

35000900
Extraction of various metal ions from nitric acid to n-dodecane by Diglycolamide (DGA) compounds
Sasaki, Yuji; Zhu, Z.-X.*; Sugo, Yumi; Kimura, Takaumi
Journal of Nuclear Science and Technology 44(3), p.405-409(2007) ; (JAEA-J 02458)

The extraction of various metals by tetraoctyldiglycolamide (TODGA) from nitric acid to dodecane was investigated. It was obvious that divalent Ca (ionic radius 100pm), trivalent and tetravalent ions with ionic radii of 87-113 and 83-94 pm are highly extractable by TODGA. The limits of metal concentration (LOC) for Ca(II), Nd(III) and Zr(IV) in the extraction solvents, TODGA/dodecane, TODGA+DHOA (dihexyloctamide)/dodecane, TDDGA (tetradecyldiglycolamide) and TDdDGA (tetradodecyldiglycolamide) were determined. It is evident that LOC is influenced strongly and increased with DHOA concentration and the length of alkyl chain attached to N atom of DGA.

35000901
Trial operation of the advanced volume reduction facilities for LLW at JAEA
Nakashio, Nobuyuki; Higuchi, Hidekazu; Momma, Toshiyuki; Kozawa, Kazushige; Tohei, Toshio; Sudo, Tomoyuki; Mitsuda, Motoyuki; Kurosawa, Shigenobu; Hemmi, Ko; Ishikawa, Joji; Kato, Mitsugu; Sato, Motoaki
Journal of Nuclear Science and Technology 44(3), p.441-447(2007) ; (JAEA-J 02459)

The Japan Atomic Energy Agency (JAEA) constructed the Advanced Volume Reduction Facilities (AVRF), in which volume reduction techniques are applied and achieved high volume reduction ratio, homogenization and stabilization by means of melting or super compaction processes for low level solid wastes. It will be able to produce waste packages for final disposal and to reduce the volume of stored wastes by operating the AVRF. The AVRF consist of the Waste Size Reduction and Storage Facilities (WSRSF) and the Waste Volume Reduction Facilities (WVRF); the former have cutting installations for large size wastes and the latter have melting units and a super compactor. Cutting installations in the WSRSF have been operating since July 1999. Radioactive wastes treated so far amount to 750 m³ and the volume reduction ratio is from 1.7 to 3.7. The WVRF have been operating with non-radioactive wastes since February 2003 for the training and the homogeneity investigation in the melting processes. The operation of the pretreatment system in the WVRF with radioactive wastes has partly started in FY2005.

35000902
Research and development program on accelerator driven subcritical system in JAEA
Tsujimoto, Kazufumi; Oigawa, Hiroyuki; Ouchi, Nobuo; Kikuchi, Kenji; Kurata, Yuji; Mizumoto, Motoharu; Sasa, Toshinobu; Saito, Shigeru; Nishihara, Kenji; Umeno, Makoto*; Tazawa, Yujiro*
Journal of Nuclear Science and Technology 44(3), p.483-490(2007) ; (JAEA-J 02460)

For a dedicated transmutation system, Japan Atomic Energy Agency (JAEA) has been proceeding with the research and development (R&D) on an accelerator-driven subcritical system (ADS). JAEA has started a comprehensive R&D program since the fiscal year of 2002 to acquire knowledge and elemental technology for the validation of engineering feasibility of the ADS. In this paper, the outline and the results in the first three-years stage of the program are reported. For R&D on accelerator, a prototype cryomodule was built and its good performance in electric field was examined. For R&D on LBE, various technical data for material corrosion, thermal-hydraulics and radioactive impurity were obtained. For R&D on subcritical core, engineering feasibility for the ADS was discussed using thermal-hydraulic and structural analysis not only in normal operation but also in transient situations. Reactor physics experiments for subcritical monitoring of ADS were performed at critical assemblies.

35000903
Sequential forecasting of the surface and subsurface conditions in the Japan Sea
Hirose, Naoki*; Kawamura, Hideyuki; Lee, H. J.*; Yoon, J.-H.*
Journal of Oceanography 63(3), p.467-481(2007) ; (JAEA-J 02461)

This study estimates and forecasts a realistic change of the Japan Sea by assimilating satellite measurements into an eddy-resolving circulation model. Suboptimal but feasible assimilation schemes of approximate filtering and nudging play essential roles in a system. The sequential updates of error covariance significantly outperforms the asymptotic covariance due to irregular sampling patterns from multiple altimeter satellites. The best estimate shows an average rms difference of 1.2 °C only to the radiometer data, and also explain about half of sea level variances measured by the microwave observation. It is demonstrated that a forecast persistency strongly depends on variable, depth, and location.

35000904
Compilation of wavelengths, energy levels, and transition probabilities for W I and W II
Kramida, A. E.*; Shirai, Toshizo*
Journal of Physical and Chemical Reference Data 35(1), p.423-683(2006) ; (JAEA-J 02462)

Energy levels, wavelengths, and transition probabilities of the first and second spectra of tungsten, W I and W II, have been compiled. Wavelengths of observed transitions and energy levels derived from those wavelengths have been obtained from a critical evaluation of the available literature. Measured transition probabilities for some of the observed transitions have been compiled from the published literature.

35000905
Comparison of the stopping powers calculated by using rate equations with those by the Monte Carlo method
Moribayashi, Kengo
Journal of Physics; Conference Series 58, p.192-194(2007) ; (JAEA-J 02463)

35000906
Study on transient void behavior during reactivity initiated accidents under low pressure condition; Development and application of measurement technique for void fraction in bundle geometry
Satou, Akira; Maruyama, Yu; Asaka, Hideaki; Nakamura, Hideo
Journal of Power and Energy Systems (Internet) 1(2), p.154-165(2007) ; (JAEA-J 02464)

Series of out-of-pile experiments to obtain the knowledge on the transient void behavior during reactivity initiated accidents are in progress at JAEA. In the present series of experiments, the transient void behavior in a test section of 2×2 bundle geometry under atmospheric pressure condition was measured using an impedance technique. The measuring areas and the arrangement of electrodes for the impedance technique were defined on the basis of numerical analyses and scaled model experiments. The comparison was made between the impedance and differential pressure techniques for steady boiling experiments to estimate the accuracy of the impedance technique. The impedance technique showed a good agreement with the void fraction estimated from the differential pressure. The transient void behavior in the bundle geometry was measured using the impedance technique. It was clarified that the transient void behavior depends on both the subcooling of inlet water and the heat generation rate of simulated fuel rod. Local void fraction was influenced by the ratio of flow area to heat transfer area of the simulated fuel rod.

35000907
Development in fission track- thermal ionization mass spectrometry for particle analysis of safeguards environmental samples
Lee, C. G.; Iguchi, Kazunari; Inagawa, Jun; Suzuki, Daisuke; Esaka, Fumitaka; Magara, Masaaki; Sakurai, Satoshi; Watanabe, Kazuo; Usuda, Shigekazu
Journal of Radioanalytical and Nuclear Chemistry 272(2), p.299-302(2007) ; (JAEA-J 02465)

35000908
Recent progress on the development and analysis of the ITPA global H-mode confinement database
McDonald, D. C.*; Cordey, J. G.*; Thomsen, K.*; Kardaun, O. J. W. F.*; Snipes, J. A.*; Greenwald, M.*; Sugiyama, L.*; Ryter, F.*; Kus, A.*; Stober, J.*; DeBoo, J. C.*; Petty, C. C.*; Bracco, G.*; Romanelli, M.*; Cui, Z.*; Liu, Y.*; Miura, Yukitoshi; Shinohara, Koji; Tsuzuki, Kazuhiro*; Kamada, Yutaka; Takizuka, Tomonori; Urano, Hajime; Valovic, M.*; Akers, R.*; Brickley, C.*; Sykes, A.*; Walsh, M. J.*; Kaye, S. M.*; Bush, C.*; Hogewei, D.*; Martin, Y. R.*; Cote, A.*; Pacher, G.*; Ongena, J.*; Imbeaux, F.*; Hoang, G. T.*; Lebedev, S.*; Chudnovskiy, A.*; Leonov, V.*
Nuclear Fusion 47(3), p.147-174(2007) ; (JAEA-J 02467)

This paper describes the updates to and analysis of the International Tokamak Physics Activity (ITPA) Global H-node Confinement Database version 3 (DB3) over the period 1994-2004. Global data, for the energy confinement time and its controlling parameters, have now been collected from 18 machines of different sizes and shapes: ASDEX, ASDEX Upgrade, C-Mod CoMPASS-D, DIII-D, JET, JFT-2M, JT-60U, MAST, NSTX, PBX-M, PDX, START, T-10, TCV, TdeV, TFTR and TUMAN-3M. A wide range of physics studies has been performed on DB3 with particular progress made in the separation of core and edge behavior, dimensionless parameter analyses and the comparison of the database with one-dimensional transport code. A key aim of the database has always been to provide a basis for estimating the energy confinement properties of next step machines such as ITER, and so the impact of the database and its analysis on such machines is also discussed.

35000909
Development of a wide-range paired scintillator with optical fiber neutron monitor for BNCT irradiation field study
Ishikawa, Masayori*; Kumada, Hiroaki; Yamamoto, Kazuyoshi; Kaneko, Junichi*; Bengua, G.*; Unesaki, Hironobu*; Sakurai, Yoshinori*; Tanaka, Kenichi*; Kosako, Toshiso*
Nuclear Instruments and Methods in Physics Research A 551(2-3), p.448-457(2005) ; (JAEA-J 02468)

A wide range thermal neutron detector was developed based on the Scintillator with Optical Fiber (SOF) detectorwhich has been previously used for thermal neutron monitoring during boron neutron capture therapy irradiation. With this new detector system we intended to address the issues of real-time thermal neutron flux measurement and thesimultaneous measurement of a wide range of thermal neutron flux in a BNCT irradiation field which were difficult toimplement with the gold wire activation method. A good agreement between the thermal neutron flux measured by the gold wire activation method and the paired SOF detector system was observed. However, measurements which would normally take a few days to perform with the gold wire activation method were obtained in just about 15 min using the SOF detector system. We also confirmed thedynamic range of linearity for the SOF detector system to be in the order of magnitude of 1e-4.

35000910
Amorphization of carbon materials studied by X-ray photoelectron spectroscopy
Takahiro, Katsumi*; Terai, Atsushi*; Oizumi, Shinnosuke*; Kawatsura, Kiyoshi*; Yamamoto, Shunya; Naramoto, Hiroshi
Nuclear Instruments and Methods in Physics Research B 242(1-2), p.445-447(2006) ; (JAEA-J 02469)

X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy have been applied to investigate amorphization processes by ion irradiation for various carbon materials, including highly oriented pyrolytic graphite (HOPG), isotropic graphite, glassy carbon (GC) and C₆₀ crystalline film. It is found that the asymmetry of the XPS C 1s line increases as the irradiation dose increases. The origin of the asymmetry appeared on the C 1s line is discussed. It is concluded that the asymmetry of the C 1s line is not correlated with the increase in the size of a graphitic layer, but is related with the structural disorders, such as a bond angle disorder.

35000911
Effect of Al and Be ions pre-implantation on formation and growth of helium bubbles in SiC/SiC composites
Taguchi, Tomitsugu; Igawa, Naoki; Wakai, Eiichi; Jitsukawa, Shiro; Snead, L. L.*; Hasegawa, Akira*
Nuclear Instruments and Methods in Physics Research B 256(2), p.669-674(2007) ; (JAEA-J 02470)

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si²⁺, 1.0-MeV He⁺ and 340-keV H⁺) at 1000 °C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by implanting Al or Be ions. These results suggest that Al or Be as transmutation products and impurities may accelerate the growth of He bubbles in SiC/SiC composites under fusion reactor conditions.

35000912
Sputter etching effect of the substrate on the microstructure of β-FeSi₂ thin film prepared by ion beam sputter deposition method
Sasase, Masato*; Shimura, Kenichiro*; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Shamoto, Shinichi; Hojo, Kiichi
Nuclear Instruments and Methods in Physics Research B 257(1-2), p.186-189(2007) ; (JAEA-J 02471)

Beta iron disilicide (β-FeSi₂) is one of the candidate materials for a compound semiconductor. We have employed ion beam sputter deposition method to grow highly oriented β-FeSi₂ film on a single crystal Si(100) substrate. In the present study, sputter etching effect of the substrate is investigated by the cross-sectional transmission electron microscope (TEM) observation in order to observe nanostructural changes as a function of Ne⁺ energy. The observed TEM images show that the 1 keV sputtering provides uniform films with few defects and smooth interface. The number of the produced defects rapidly increases with the energy. The obtained β-FeSi₂ tends to form small grains at the higher energy. Quite rough surface is also observed in this condition. Higher energies produce excessive amount of damages for the substrate to form epitaxially grown film. These results imply that a certain fluence is required for better quality of the deposited film.

35000913
Assessment of ¹⁸⁶Re chelate-conjugated bisphosphonate for the development of new radiopharmaceuticals for bones
Uehara, Tomoya*; *; Ogawa, Kazuma*; Akizawa, Hiromichi*; Hashimoto, Kazuyuki; Nakayama, Morio*; Arano, Yasushi*
Nuclear Medicine and Biology 34(1), p.79-87(2007) ; (JAEA-J 02472)

In this study, a key factor affecting the pharmacokinetics of a chelate-conjugated BP was investigated to estimate the validity and the applicability of molecular design. Chemically inert and well-characterized [¹⁸⁶Re]CpTR-Gly was conjugated with 3-amino-1-hydroxypropylidene-1,1-bisphosphonate and purified by HPLC to prepare [¹⁸⁶Re]CpTR-Gly-APD. Plasma stability, plasma protein binding, hydroxyapatite (HA) binding and the pharmacokinetics of [¹⁸⁶Re]CpTR-Gly-APD were compared with those of ¹⁸⁶Re 1-hydroxyethylidene-1,1-diphosphonate (HEDP). The HPLC-purified [¹⁸⁶Re]CpTR-Gly-APD showed higher plasma stability, higher HA binding, higher bone accumulation and lower plasma protein binding than did ¹⁸⁶Re -HEDP. Although ¹⁸⁶Re -HEDP possessed HA binding and bone accumulation similar to those of [¹⁸⁶Re]CpTR-Gly-APD, the specific activity of ¹⁸⁶Re -labeled BPs was found to play a crucial role in bone accumulation and blood clearance. Thus, the molecular design of chelate-conjugated BP would be useful for the development of bone-seeking radiopharmaceuticals with a variety of radionuclides by selecting chelating molecules that provide high specific activities.

35000914
Spiral spin structure in the Heisenberg pyrochlore magnet CdCr₂O₄
Matsuda, Masaaki; Takeda, Masayasu; Nakamura, Mitsutaka; Kakurai, Kazuhisa; Osawa, Akira*; Leli`evre-Berna, E.*; Chung, J.-H.*; Ueda, Hiroaki*; Takagi, Hidenori*; Lee, S.-H.*
Physical Review B 75(10), p.104415_1-104415_6(2007) ; (JAEA-J 02473)

A frustrated spinel CdCr₂O₄ undergoes a three-dimensional spin-Peierls transition at T_N = 7.8 K from a cubic paramagnetic to a tetragonal Néel state. The Néel state has a spiral magnetic structure with a characteristic wave vector of (0,δ,1) when the c axis elongated. Here we report our spherical neutron polarimetry experiments to investigate the spiral spin structure in detail. Our results indicate that the spins lie in the ac plane perpendicular to the direction of the spiral modulation. We also found that the spiral structure in the ac plane is elliptical with the c-component larger by ˜24% than the a-component, suggesting a strong coupling between the magnetic structure and structural distortion. Unpolarized neutron diffraction under an external magnetic field has also been performed. The magnetic field dependence suggests existence of magnetic anisotropy in the Néel state, which is consistent with our previous inelastic studies.

35000915
Identification of a low plasma-rotation threshold for stabilization of the resistive-wall mode
Takechi, Manabu; Matsunaga, Go; Aiba, Nobuyuki; Fujita, Takaaki; Ozeki, Takahisa; Koide, Yoshihiko; Sakamoto, Yoshiteru; Kurita, Genichi; Isayama, Akihiko; Kamada, Yutaka; JT-60 Team
Physical Review Letters 98(5), p.055002_1-055002_4(2007) ; (JAEA-J 02474)

The plasma rotation necessary for stabilization of resistive wall modes (RWMs) is investigated by controlling the toroidal plasma rotation with external momentum input by injection of tangential neutral beams. The observed threshold is 0.3 % of the Alfvén velocity and much smaller than the previous experimental results obtained with magnetic braking. This low critical rotation has a very weak β dependence as the ideal wall limit is approached. These results indicate that for large plasmas such as in future fusion reactors with low rotation, the requirement of the additional feedback control system for stabilizing RWM is much reduced.

35000916
ELM frequency dependence on toroidal rotation in the grassy ELM regime in JT-60U
Oyama, Naoyuki; Kamada, Yutaka; Isayama, Akihiko; Urano, Hajime; Koide, Yoshihiko; Sakamoto, Yoshiteru; Takechi, Manabu; Asakura, Nobuyuki; JT-60 Team
Plasma Physics and Controlled Fusion 49(3), p.249-259(2007) ; (JAEA-J 02475)

35000917
Optimisation of a laser-plasma soft X-ray source excited in a pulsed xenon jet
Levashov, V. E.*; Mednikov, K. N.*; Pirozhkov, A. S.; Ragozin, E. N.*
Quantum Electronics 36(6), p.549-552(2006) ; (JAEA-J 02476)

A "clean" (debris-free) pulsed soft X-ray (12.5 - 25 nm) source excited by nanosecond neodymium laser pulses in a pulsed xenon jet was optimised. The source efficiency in the λ < 15 nm range is improved due to the weakening of photoabsorption in the peripheral regions of the gas jet in going over to the supersonic regime of xenon gas flow into vacuum, as well as due to the laser beam focusing onto the plateau edge in the radial gas density profile nearest to the observer. The source efficiency at 13.5 nm is 0.22% into a solid angle of 2π sr into a 0.5 nm band.

35000918
Coherent X-ray diffraction for domain observation
Owada, Kenji; Namikawa, Kazumichi; Mizuki, Junichiro; Shimomura, Susumu*; Nakao, Hironori*; Ito, Kazuki*; Matsushita, Mitsuyoshi*; Yoneda, Yasuhiro; Murakami, Yoichi*; Hirota, Kazuma*
Transactions of the Materials Research Society of Japan 32(1), p.7-10(2007) ; (JAEA-J 02477)

An X-ray speckle pattern well reflects a particle or domain alignment on the inside of materials. Detecting the alignment is important for understanding a function of the materials such as ferroelectric, piezoelectric materials, photonic crystals and so on. We have thus constructed the apparatus for coherent X-ray diffraction at BL22XU@SPring-8, high quality slits for obtaining the full coherent X-ray beam, high resolution X-ray CCD camera for obtaining the well-resolved speckle pattern, and so on. By using the devices, we have successfully observed the speckle pattern from Cu₃Au, the ferroelectric material PZN-9%PT (91%Pb(Zn_1/3Nb_2/3)O₃-9%PbTiO₃) and Sr-doped BaTiO₃. The 2DFFT image gives us a spatial autocorrelation function which includes the information of the arrangement of the domains in the crystal within micrometers scale.

35000919
Direct observation of non-strain-free style domain in BaTiO₃ crystal by synchrotron X-ray topography
Yoneda, Yasuhiro; Komura, Yoshiki*; Suzuki, Yoshio*; Morimura, Ryota*; Kojima, Akira*; Mizuki, Junichiro
Transactions of the Materials Research Society of Japan 32(1), p.31-34(2007) ; (JAEA-J 02478)

We performed X-ray diffraction topography on a BaTiO₃ single crystal by high-coherent synchrotron X-rays. Since the domain configuration of the BaTiO₃ crystal was unstable and fluctuated as temperature fluctuated, an excellent temperature control system is needed for the domain observation. We used a milli-Kelvin (mK) cell, which can control a BaTiO₃ crystal within ± 1mK. By combining the coherent X-ray and the mK-cell, one can detect the lattice strain very sensitively around the domain boundary. The lattice strain reduced as temperature increased, and disappeared at 100°C, which is much lower than the phase transition temperature of the BaTiO₃, and the BaTiO₃ crystal still remained in the ferroelectric tetragonal phase. This behavior can be interpreted by the existence of the so-called "non-strain-free style domain", which is reported firstly by Takashige et al.

35000920
Magnetic and dielectric behavior of the ruthenium double perovskite oxides R₂MRuO₆ (R=La, Pr and Nd, M=Mg, Co, Ni and Zn)
Yoshii, Kenji; Ikeda, Naoshi*; Mori, Shigeo*; Yoneda, Yasuhiro; Mizumaki, Masaichiro*; Tanida, Hajime*; Kawamura, Naomi*
Transactions of the Materials Research Society of Japan 32(1), p.51-54(2007) ; (JAEA-J 02479)

Magnetic and dielectric properties of the ruthenium double perovskites R₂MRuO₆ were studied (M=Co, Ni, Zn, Mg). The materials with the magnetic M²⁺ ions (M=Co and Ni) showed magnetic ordering and large dielectric constants (about 5000). On the other hand, for the non-magnetic M²⁺ ions (M=Mg and Zn), magnetic ordering was not observed. In addition, their dielectric constants were found to be small (about 100-200). Together with the result of the dielectric response, the large dielectric constants for M=Co and Ni may be related to a smooth response of polar regions. Investigations of the properties of R₂MRuO₆ with R=Pr and Nd are also being carried out, and their results are briefly discussed.

35000921
Gasochromic coloration of non-stoichiometric WO_3-x films
Inoue, Aichi; Yamamoto, Shunya; Nagata, Shinji*; Takano, Katsuyoshi; Yoshikawa, Masahito; Shikama, Tatsuo*
Transactions of the Materials Research Society of Japan 32(1), p.107-110(2007) ; (JAEA-J 02480)

We investigated the gasochromic coloration of amorphous tungsten oxide films having compositions between WO_0.25 and WO_3.0. The films were deposited on SiO₂ or glassy carbon substrates by the reactive radio frequency (r. f.) magnetron sputtering with varying oxygen partial pressure. The oxygen and hydrogen concentration of the tungsten oxide films were determined using the Rutherford Backscattering Spectrometry (RBS) and the Elastic Recoil Detection Analysis (ERDA), respectively. The optical transmission was examined for the films coated with palladium catalysis during the exposure of diluted hydrogen gas. Superior gasochromic properties were obtained for the films consisting of tungsten trioxide WO₃. For the films with lower oxygen concentration than WO₃, the optical transmission hardly changed during the hydrogen exposure. A large concentration of hydrogen about 0.7 per a tungsten atom was found in the WO₃ films. The hydrogen retention drastically decreased with a decrease of the oxygen concentration.

35000922
Effect of tungsten valences on gasochromic coloration in tungsten oxide thin films
Takano, Katsuyoshi; Inoue, Aichi; Yamamoto, Shunya; Miyashita, Atsumi; Yoshikawa, Masahito
Transactions of the Materials Research Society of Japan 32(1), p.159-162(2007) ; (JAEA-J 02481)

Ion irradiations with ⁴He⁺ at 350 keV were performed for the tungsten tri-oxide (WO₃) films. Gasochromic coloration of the irradiated films was observed by a measurement of optical transmittance with the expose of 1 % hydrogen. The extent of coloration level of the irradiated film with the fluence of 1 × 10¹⁷ ions/sm² is 7.5 times lager than that of non-irradiated film. W 4f photoemission spectra for the films were measured by X-ray photoelectron spectroscopy. From the fitting analysis for the spectra, the non-irradiated film has only W⁶⁺. In the irradiated film with the fluence of 1 × 10¹⁷ ions/sm², it is estimated that 17 % and 4 % of the amount of W⁶⁺ change into W⁵⁺ and W⁴⁺, respectively. The improvement of the gasochromic coloration of the irradiated WO₃ films relates to the increment of oxygen deficient tungstens induced by the irradiation.

35000923
Polarized neutron reflectometry as a nondestructive tool for studies on the buried interfaces in magnetic thin films
Takeda, Masayasu
Transactions of the Materials Research Society of Japan 32(1), p.199-202(2007) ; (JAEA-J 02482)

35000924
In-situ X-ray diffraction study of InAs/GaAs(001) quantum dot growth
Takahashi, Masamitsu; Kaizu, Toshiyuki; Mizuki, Junichiro
Transactions of the Materials Research Society of Japan 32(1), p.209-214(2007) ; (JAEA-J 02483)

Molecular beam epitaxial (MBE) growth of InAs/GaAs(001) quantum dots was investigated by grazing-incidence X-ray diffraction using a diffractometer integrated with an MBE apparatus, which was installed on beamline 11XU at SPring-8. Use of synchrotron radiation and a two-dimensional X-ray detector enabled X-ray diffraction intensity mapping in the reciprocal lattice space at a rate of less than 10 s per frame. A series of X-ray diffraction images revealed the evolution of the strain, composition and height of InAs quantum dots during the growth process including InAs nanoisland formation, growth interruption and encapsulation with GaAs. Because the propagation of X-rays is not hindered even in gaseous atmosphere, this technique can be applied to vapor-phase epitaxy as well and thus is suitable for industrial applications.

35000925
Nuclear development in Asia focusing on India; The Dawn of a new nucelar age (The Second half) (in Japanese)
Fujiie, Yoichi*; Sato, Koji
Enerugi Rebyu 27(4), p.38-42(2007) ; (JAEA-J 02484)

35000926
Repercussion effect of radiological education observed in MEXT promoted Science Partnership Project (SPP) (in Japanese)
Yanagisawa, Kazuaki; Sasagawa, Sumiko*; Nakano, Koji*
Hoshasen Kyoiku 10(1), p.23-48(2006) ; (JAEA-J 02486)

35000927
International Workshop on Crystallography at High Pressures (in Japanese)
Hattori, Takanori
Koatsuryoku No Kagaku To Gijutsu 17(1), p.75-76(2007) ; (JAEA-J 02487)

The international workshop "crystallography at high pressures-2006", which was held at Dubna in Russia from Sept. 28th to Oct 1st., is introduced. The workshop was organized by the Commission on High Pressure of the International Union of Crystallography and the Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research (JINR). About 80 participants attended the workshop and 31 oral presentations and 36 poster presentation have done. The workshop consisted of the following sessions: Simple elements, Molecular Solids, Physical Properties of Magnetic Structures, Material Sciences and high-pressure Synthesis, Mineral Physics and Geophysics, Technical developments, Organics, Liquid and amorphous Materials, Carbon and nano materials. In the conference, many noticeable studies which are unfamiliar to high-pressure scientists, such as neutron scattering or γ-ray angular correlation, were presented by the scientists in JINR. The pulse neutron source IBR-2 and the experiments which have done in that facility are also introduced.

35000928
Experimental results of sulfuric-acid flow boiling (in Japanese)
Noguchi, Hiroki; Ota, Hiroyuki; Kubo, Shinji; Onuki, Kaoru; Hino, Ryutaro
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(1), p.1-4(2007) ; (JAEA-J 02488)

35000929
Investigation of a model to evaluate the pyrolysis properties of zinc stearate (in Japanese)
Abe, Hitoshi; Tashiro, Shinsuke; Miyoshi, Yoshinori
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(1), p.10-21(2007) ; (JAEA-J 02489)

In MOX fuel fabrication facility, zinc stearate will be added into the MOX powder as addition material. If the material is added in large excess by miss operation, criticality characteristics of the MOX fuel would be influenced because it has neutron moderation effect. If criticality condition should be induced by the excess addition, physical variations, such as melting and pyrolysis of the material, must be caused by the fission energy and dynamic characteristics of the MOX fuel must be affected. To contribute quantitative evaluation of the dynamic characteristics, thermal properties data such as exo/endothermic calorific values, reaction rates, etc. with the respective physical variations and release behavior of pyrolysis gas were measured. It was found the exo/endothermic behavior with rinsing temperature of the material could be divided into six regions and rapid pressure rise caused by the pyrolysis reaction over about 400 °C. Furthermore, on the basis of the results, evaluation model for the thermal properties under the criticality condition was also investigated.

35000930
Fundamental philosophy on the safety design of the HTTR-IS hydrogen production system (in Japanese)
Ohashi, Kazutaka; Nishihara, Tetsuo; Kunitomi, Kazuhiko
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(1), p.46-57(2007) ; (JAEA-J 02490)

Japan Atomic Energy Agency (JAEA) has been conducting an R&D work on the VHTR reactor system and IS hydrogen production system to realize hydrogen production using nuclear heat. As a part of this activity, JAEA is planning to connect an IS test system to the High Temperature Engineering Test Reactor (HTTR) to demonstrate its technical feasibility. This paper proposes a fundamental philosophy on the safety design of the HTTR-IS hydrogen production system including the methodology to select postulated abnormal events and its event sequences and to define safety functions of the IS system to ensure the reactor safety. Also the measure to clarify the IS system as non-reactor system is proposed.

35000931
Hydrochemical changes associated with construction of a large underground facility (in Japanese)
Iwatsuki, Teruki; Amano, Yuki; Ioka, Seiichiro; Saegusa, Hiromitsu; Takeuchi, Ryuji
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(1), p.73-84(2007) ; (JAEA-J 02491)

Hydrochemical changes of the groundwater in sedimentary rocks were observed during construction of the Mizunami Underground Laboratory. The observation of hydraulic head and groundwater chemistry indicates that rock formations with low hydraulic conductivity act as barriers to hydraulic disturbances, while higher conductivity zones provide a preferential flow path. Groundwater flow to the drifts creates chemical changes by mixing among chemically different groundwaters. It is therefore meaningful to monitor the water pressure and chemistry at highly conductive rock formations during construction and operation of underground facilities. Pre-construction investigations to determine the geology, hydraulic conductivity and baseline hydrochemistry are essential for understanding the disturbance around the underground facility caused by construction. An approximate four month interruption in pumping allowed the underground workings to temporarily fill with groundwater.

35000932
Research activities of Japan Nuclear Data Committee in fiscal years of 2003 and 2004 (in Japanese)
Igashira, Masayuki*; Watanabe, Yukinobu*; Fukahori, Tokio; Okumura, Keisuke; Katakura, Junichi; Chiba, Satoshi; Shibata, Keiichi; Yamano, Naoki*; Nakagawa, Tsuneo; Odano, Naoteru*; Ando, Yoshihira*; Okajima, Shigeaki
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(1), p.85-96(2007) ; (JAEA-J 02492)

This technical note summarizes research activities on nuclear data carried out by Japanese Nuclear Data Committee (JNDC) during the fiscal years of 2003 and 2004. During this period, the nuclear data files for special purposes (JENDL-HE-2004 and JENDL-PD-2004) were released. Other activities are described: analysis of post nuclear fuel irradiation experiments, nuclear chart and nuclear data evaluation for astrophysics.

35000933
JAEA's response to GNEP (in Japanese)
Sagayama, Yutaka
Nippon Genshiryoku Gakkai-Shi 49(3), p.172-178(2007) ; (JAEA-J 02493)

35000934
Development of beryllides as advanced neutron multipliers for fusion blankets (in Japanese)
Tsuchiya, Kunihiko; Kawamura, Hiroshi; Mishima, Yoshinao*; Yoshida, Naoaki*; Tanaka, Satoru*; Uchida, Munenori*; Ishida, Kiyohito*; Shibayama, Tamaki*; Munakata, Kenzo*; Sato, Yoshiyuki*; Iwakiri, Hirotomo*; Onuma, Ikuo*
Purazuma, Kaku Yugo Gakkai-Shi 83(3), p.207-214(2007) ; (JAEA-J 02495)

35000935
Determination of ¹²⁹I in seawater by accelerator mass spectrometry with solvent extraction method (in Japanese)
Gasa, Shinichi*; Sawafuji, Natsuko*; Kabuto, Shoji; Kinoshita, Naoki; Amano, Hikaru; Kawamura, Hisao*
Radioisotopes 56(4), p.155-162(2007) ; (JAEA-J 02496)

35000936
Verification technologies for nuclear test (in Japanese)
Naoi, Yosuke; Shinohara, Nobuo
Tekunokarento (440), p.1-12(2007) ; (JAEA-J 02497)

35000937
A Trial observation of the EM-ACROSS signal for the long-distance transmission (in Japanese)
Nakajima, Takahiro; Nagao, Hiromichi*; Sayanagi, Keizo*; Noda, Yoichi*; Nagao, Toshiyasu*; Kumazawa, Mineo; Hasada, Yoko*
Tokai Daigaku Kaiyo Kenkyujo Kenkyu Hokoku (28), p.21-28(2007) ; (JAEA-J 02498)

Observation test was successfully made on the faint EM-ACROSS signals transmitted through the Earth's crust over the distance of 30 km. We transmitted a set of three sine waves around 1Hz from the grounded wire source with the dipole moment 4A × 150m. The signal level observed at the distance of 30 km was in the order of 0.01pT, which is 10^-3 lower than the average level of environmental electromagnetic noise at the observation sites. The signal-to-noise ratio (S/N) of the observations becomes up to 5 by means of the optimized stacking of the raw observation data for the 40 days. signal-to-noise ratio (S/N) becomes larger. The result of this trial observation becomes a substantial experience for the monitoring of the area of earthquake generation or volcanoes in the future.

35000938
Statistics of meteorites (in Japanese)
Osawa, Takahito
Tokei Joho 56(4), p.46-50(2007) ; (JAEA-J 02499)

35000939
Measurement of residual stress distribution in laser-shock peened Ti-alloy using hard synchrotron X-rays (in Japanese)
Suzuki, Kenji*; Shobu, Takahisa; Tanaka, Keisuke*
Zairyo 56(3), p.217-222(2007) ; (JAEA-J 02500)

A plate of a Ti alloy, Ti₆Al₄V, with a thickness of 9 mm was laser-shock peened. The distribution of the residual stress throughout the plate thickness was nondestructively measured with the transmission and reflection conditions of the strain scanning method using hard synchrotron X-rays of 70 keV energy. The distributions of the in-plane and out-of-plane strains were measured by using the 004 and 112 diffractions of alpha-Ti phase. The out-of plane strain measured for the 112 diffraction agreed with the value calculated from out-of-plane strains based on isotropic elasticity, while that for the 004 diffraction was higher than the prediction. The discrepancy for the case of the 004 diffraction was caused by the intergranular strain due to plastic anisotropy. The use of the 112 diffraction was recommended for the stress measurement. The residual stress on the surface was compression of about -500 MPa and the compression zone extended about 1.8 mm below the surface.

35000940
Wave propagation behavior of a multi-connected structure
Nishida, Akemi
Proceedings of 13th International Congress on Sound and Vibration (ICSV-13) (CD-ROM) , 7p.(2006) ; (JAEA-J 02501)

It is crucial to continuously maintain safety and functionality in a nuclear plant. In particular, in response to the recent piping damage accident, the necessity for detailed analysis has increased. The author has continuously researched stress wave propagation in frame structures in order to clarify the wave propagation behavior of non-periodic and complicated assembled structures. A spectrum element method (SEM) has been adopted as one of the effective methods, and its application to a real-sized structure is desired. When carrying out simulation of the wave propagation phenomenon of piping systems, it was found that the frame element in SEM was required to be adopted by considering the shear and torsional deformations. By using this method, a multi-connected frame model with infinite boundaries is analyzed and compared with the experimental results in this paper. As the results, the applicability of the presented element is shown.

35000941
Study on chemical reactivity control of liquid sodium; Research program
Saito, Junichi; Ara, Kuniaki; Sugiyama, Kenichiro*; Kitagawa, Hiroshi*; Oka, Nobuki*; Yoshioka, Naoki*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 5p.(2007) ; (JAEA-J 02502)

Liquid sodium is used as the coolant of the fast breeder reactor (FBR), because of its high thermal conductivity and wide temperature range of liquid. However the chemical reactivity with water and oxygen of sodium is very high. So an innovative technology to control the reactivity is desired.The purpose of this study is to reduce the chemical reactivity of liquid sodium by dispersing the nanometer-size metallic particles into liquid sodium. Sub-themes of this study are nanoparticles production, evaluation of reaction control of liquid sodium, and feasibility study to FBR. In this paper, we describe the research program of them.

35000942
Test results of volatile radionuclide evaporation from liquid lead-bismuth and their comparison with test from sodium pool
Ono, Shuji; Miyahara, Shinya; Kurata, Yuji
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 6p.(2007) ; (JAEA-J 02503)

Evaporation tests were conducted to investigate fundamental liquid-to-gas transfer behavior of volatile radionuclides ²¹⁰Po, Cs, and Te in a lead-bismuth eutectic (LBE) using the "transpiration" method, which has already contributed in a Na-cooled FBR study. Since both LBE test and Na test focus on the evaporation of the same nuclides, it is possible to compare the nuclides' volatility between in LBE and in Na. This paper describes first the reviewed evaporation characteristics of fission products in Na, next the evaporation test results of fission or activation products in LBE. The importance of investigating ²¹⁰Po evaporation is demonstrated through the estimation of vapor amount in a cover gas region of an LBE-cooled system. Furthermore, comparison is made for the volatility of Cs and Te in two kinds of coolant Na and LBE based on the test results. The accumulated data can serve as significant database utilized in liquid-metal-cooled reactor accident analysis tools.

35000943
Thermal-hydraulic design of high conversion type core of FLWR
Kobayashi, Noboru; Onuki, Akira; Okubo, Tsutomu; Uchikawa, Sadao
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 6p.(2007) ; (JAEA-J 02504)

A thermal-hydraulic design of the high-conversion (HC) type core of the innovative water reactor for flexible fuel cycle (FLWR) was constructed. HC-FLWR is required to proceed to the breeder type of FLWR with no change of any reactor systems. Although tightness of the fuel pin arrangement is significantly different between the two types of cores, the natural circulation cooling is adopted in both cores. TRAC analyses were performed under the condition that chimney length for natural circulation and the setting of the inlet orifice were common to the both types of cores. Form loss coefficients of lower tie-plate were differently set to control the natural circulation flow rate and feed water temperature were adjusted to realize preferable value of average void fraction of HC-FLWR core. The analyses showed that both types of the FLWR could be cooled by the same reactor system.

35000944
Validation of neutronics calculation codes for VHTR nuclear design using HTTR experimental data
Goto, Minoru; Nakagawa, Shigeaki; Takamatsu, Kuniyoshi; Takeda, Tetsuaki
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 6p.(2007) ; (JAEA-J 02505)

In order to validate applicability of neutronics calculation codes for a nuclear design of the VHTR, analysis of the core characteristics were performed for the HTTR. Additionally, effects of difference of nuclear data libraries on the core calculations for the HTTR were studied for JENDL(Japan), ENDF/B(U.S.A.) and JEFF(Europe). The calculation result of the HTTR excess reactivity at room temperature condition by the MVP was in good agreement with the experimental data within 0.4%Δk/k and that by the SRAC, meanwhile, overestimated the experimental data about 1.5%Δk/k.In consequence of the comparison between the HTTR core calculation results performed by the MVP and the experimental data, JENDL-3.3, ENDF/B-VI.8 and JEFF-3.1 yielded the excess reactivity agreement with the experiments within 0.4%Δk/k, 0.7%Δk/k and 0.7%Δk/k, respectively.

35000945
Countermeasures planned for reducing water inflow into deep shafts at the Mizunami Underground Research Laboratory
Kuji, Masayoshi; Sato, Toshinori; Mikake, Shinichiro; Hara, Masato; Minamide, Masashi; Sugihara, Kozo
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02506)

The Mizunami Underground Research Laboratory (MIU) is being constructed. The MIU consists of two 1,000 m-deep shafts with several research galleries. The diameter of the shafts are 6.5 m and 4.5 m, respectively. Horizontal tunnels to connect the shafts are excavated at 100 m depth intervals. The Middle stage, at about 500 m depth, and the Main stage at about 1,000 m depth will be the main locations for scientific investigations. Current depths of shafts are 180 m and 191 m respectively, in November, 2006. During the construction, the quantity of water inflow into the shafts is increasing and disturbing the project progress. In order to reduce the quantity of water inflow, post-excavation grouting and pre-excavation grouting are planned. A test of post-excavation grouting was undertaken in the Ventilation shaft and the applicability of several techniques were evaluated.

35000946
Development of design technology on thermal-hydraulic performance in tight-lattice rod bundles, 1; Approach and verification
Onuki, Akira; Kureta, Masatoshi; Yoshida, Hiroyuki; Tamai, Hidesada; Liu, W.; Misawa, Takeharu; Takase, Kazuyuki; Akimoto, Hajime
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02507)

R&D project to investigate thermal-hydraulic performance in tight-lattice rod bundles for Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been progressed at Japan Atomic Energy Agency in collaboration with power utilities, reactor vendors and universities since 2002. In this series-study, we will summarize the R&D achievements using large-scale test facility (37-rod bundle with full-height and full-pressure), model experiments and advanced numerical simulation technology. This first paper described the master plan for the development of design technology and showed an executive summary for this project up to FY2005. The thermal-hydraulic characteristics in the tight-lattice configuration were investigated and the feasibility was confirmed based on the experiments. We have developed the design technology including 3-D numerical simulation one to evaluate the effects of geometry/scale on the thermal-hydraulic behaviors.

35000947
Data analysis on glovebox size reduction activity in glovebox dismantling facility
Kitamura, Akihiro; Nakamichi, Shinya; Okada, Takashi
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02508)

Data on glovebox dismantling activities in the Glovebox Dismantling Facility (GDF) were analyzed to identify the work structure and the time consumed for each activity. As a result, we were able to categorize dismantling activities regarding time estimation point of view. The activities those of which variations are around 30% or less, were defined as "predictable activities", and activities those of which total time is small compare to the whole dismantling work were defined as "suppressible activities", and other as "unpredictable activities". In terms of these definition the time interval for unit activity were evaluated and found that almost all of the work can be predicted within 30% uncertainly.

35000948
Study of rock-like oxide fuels under irradiation
Shirasu, Noriko; Kuramoto, Kenichi; Nakano, Yoshihiro; Yamashita, Toshiyuki; Ogawa, Toru
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02509)

To evaluate the irradiation behavior of the rock-like oxide fuel, irradiation experiments were carried out. Three fuels were prepared; a single phase fuel of yttria-stabilized zirconia containing UO₂ (U-YSZ) and two particle-dispersed fuels of U-YSZ particles in spinel or corundum matrix. These fuels were irradiated in JRR-3 for about 280 days. The burnups were about 11% FIMA. The fission gas release rate (FGR) was determined by puncture test and gas analysis. Corundum-based fuel showed extremely high FGR (88%). On the other hand, the U-YSZ single-phase fuel showed very low FGR (5%). Microstructure analyses for irradiated fuel pellets were carried out by ceramography and EPMA. The restructuring of fuel pellet was not observed in the spinel-based fuel irradiated below 1400 K. Significant appearance changes were not also observed for corundum-based fuel.

35000949
Conceptual design of Innovative Water Reactor for Flexible Fuel Cycle (FLWR)
Okubo, Tsutomu; Uchikawa, Sadao; Nakano, Yoshihiro; Akie, Hiroshi; Kobayashi, Noboru; Fukaya, Yuji
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02510)

For the future sustainable energy supply based on the matured LWR technologies, a concept of FLWR has been studied in JAEA. The concept utilizes the tight-lattice core loaded with the MOX fuel, and consists of two steps. The first step realizes a high conversion type one (HC-FLWR) to keep the smooth technical continuity from the LWR technologies. The second is the RMWR concept, which realizes a high conversion ratio over 1.0 for Pu multiple recycling. The key point is that the two core concepts utilize the same size fuel assemblies, and hence, the former can proceed to the latter in the same reactor system based flexibly on the future fuel cycle circumstances. In the present paper, investigation results on the FLWR conceptual design are presented. The design of the HC-FLWR core has been recently improved, and detailed core properties have been evaluated by the neutronics and thermal-hydraulics coupled calculations. The core can achieve the average burn-up around 55GWd/t.

35000950
Experimental and modeling studies on sorption and migration of americium in porous sedimentary materials
Tanaka, Tadao; Nakayama, Shinichi
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02511)

35000951
Thermodynamic understanding on swelling pressure of bentonite buffer
Sato, Haruo
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 7p.(2007) ; (JAEA-J 02512)

35000952
Establishing priorities for HLW R&D in the 21^st century
Umeki, Hiroyuki; Naito, Morimasa; Makino, Hitoshi; Osawa, Hideaki; Nakano, Katsushi; Miyamoto, Yoichi; McKinley, I. G.*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02513)

35000953
SIMMER-III; A Coupled neutronics-thermohydraulics computer code for safety analysis
Yamano, Hidemasa; Tobita, Yoshiharu; Fujita, Satoshi; Suzuki, Toru; Kamiyama, Kenji; Morita, Koji*; Maschek, W.*; Pigny, S.*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02514)

To simulate complex phenomena during core disruptive accidents in sodium-cooled fast reactors, JAEA has been developing the SIMMER-III code,which is two-dimensional, multi-velocity-field, multi-phase, multi-component, Eulerian, fluid-dynamics code coupled with a fuel-pin model and a space- and energy-dependent neutron kinetics model. Recently, the three-dimensional code SIMMER-IV is also developed with the same physical model as SIMMER-III. In the present paper, the models and methods of SIMMER-III/IV are briefly reviewed with highlighting the recent improvements. The major achievements of the code assessment program are then described, followed by presentation of practical applications. A three-dimensional calculation with SIMMER-IV are also shown to indicate more realistic accident scenario. In addition, this calculation result show the disrupted core state for investigating the post-accident material relocation and heat removal phase.

35000954
Two-dimensional stress corrosion cracking model for reactor structural materials
Igarashi, Takahiro; Miwa, Yukio; Kaji, Yoshiyuki; Tsukada, Takashi
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02515)

The two-dimensional intergranular stress corrosion cracking (IGSCC) growth model has been developed to simulate branching cracks of IGSCC. In the model, the IGSCC is grown using the "grain-scaled" factors such as the length and strength of grain boundary and so on. Especially, the corrosion of grain boundary and the influence of shear stress acting on the grain boundary are introduced in the model. Using the model, computer simulation of crack growth was carried out under several load conditions with changing the ratio of axial to shear stress against the grain boundary. As a result of the simulations, we found out that the cause of crack branching was the influence of shear stress against the grain boundary, and that the synergistic effect of shear stress and corrosion of grain boundary leads to the oblique crack growth.

35000955
Present state of crack growth and crack initiation studies performed in the Halden reactor
Nakano, Junichi; Karlsen, T. M.*; Hogberg, N. W.*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02516)

To evaluate factors affecting irradiation assisted stress corrosion cracking (IASCC) behavior, the OECD Halden Reactor Project (HRP) is performing in-core crack growth and crack initiation studies in the Halden boiling water reactor (HBWR). In the crack growth studies, compact tension (CT) specimens are prepared from irradiated stainless steels (SSs), types 316NG, 347, 304L and 304 with neutron fluences in the range of 9.0×10²⁰ - 1.2×10²² n/cm² (E > 1 MeV). The crack growth measurements are conducted in simulated boiling water reactor (BWR) and pressurized water reactor (PWR) environments. In a crack initiation study, miniature tensile specimens are machined from a type 304L SS irradiated to 8.0×10²¹ n/cm² (E > 1 MeV). Constant load is applied to the 30 specimens which are exposed to a simulated BWR environment. 5 signal changes indicating specimen failure have been detected since May 2002, when the test began.

35000956
Study on thermal stratification in a compact reactor vessel; Effects of Richardson number and upper plenum geometries
Nakayama, Okatsu; Ogawa, Hiroshi*; Kimura, Nobuyuki; Hayashi, Kenji; Tobita, Akira; Kamide, Hideki
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02517)

Water experiment using an 1/10th scaled upper plenum model was carried out to investigate thermal stratification after a scram in a compact reactor, which has high velocity local flow in the upper plenum. The experiments showed that the rising speed of the stratification interface was dependent on Richardson number and the temperature gradient of the stratification interface was also influenced by the temperature difference and fluctuation. Furthermore, the temperature gradient could be reduced greatly by changing position of structure in the upper plenum.

35000957
Development of fast reactor structural integrity monitoring technology using optical fiber sensors
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka; Aoyama, Takafumi
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02518)

Significant thermal stresses are loaded on the structures of sodium-cooled fast reactor (SFR) due to high temperature and large temperature gradients associated with employing sodium coolant. Therefore, it is important to monitor the temperature variation and related stress on the cooling system piping in order to assure structural integrity. Structural integrity monitoring can be enhanced by an optical fiber sensor, which is capable of continuous or dispersed distribution measurements of various physical properties such as radiation dose, temperature, strain, displacement and acceleration. In the experimental fast reactor Joyo, displacement and vibration measurements of the primary cooling system have been carried out using Fiber Bragg Grating (FBG) sensors to evaluate the durability and measurement accuracy of FBG sensors in a high γ ray environment. The data were successfully obtained with no significant signal loss up to an accumulated γ ray dose of approximately 4×10⁴Gy corresponding to 120EFPDs operation. Measured displacement of the piping support was nearly equal to the calculated thermal displacement. Measured vibration power spectra of the piping support were similar to those measured with a reference acceleration sensor. The measured results indicate that the FBG sensor is applicable for monitoring the displacement and vibration of fast reactor cooling system integrity in a high γ ray environment.

35000958
Grouting methodology in crystalline rock
Nobuto, Jun*; Kobayashi, Shinji*; Nishigaki, Makoto*; Mikake, Shinichiro; Sato, Toshinori
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02519)

Authors are conducting research on construction technologies such as water sealing measures as a scientific and technological basis for geological disposal. In this paper, the application patterns of grouting technology to excavation work in deep underground are selected first, and potential grouting material for each pattern is summarized. Next, the method to achieve high level water tightness in crystalline rock with suspension grout like cement and bentonite slurry is studied. Finally, focusing on pre-excavation grouting for horizontal tunnels, the effective injection method is studied.

35000959
Application of bias factor method with use of virtual experimental value to prediction uncertainty reduction in void reactivity worth of breeding light water reactor
Kugo, Teruhiko; Mori, Takamasa; Kojima, Kensuke; Takeda, Toshikazu*
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM) , 8p.(2007) ; (JAEA-J 02520)

Utilizing the critical experiments for MOX fueled tight lattice LWR cores at FCA XXII-1 cores, we have evaluated prediction uncertainty reduction in coolant void reactivity worth of a breeding LWR core based on the bias factor method. In the present study, to extend the applicability of the bias factor method, we have introduced an exponentiated experimental value as a virtual experimental value and formulated the prediction uncertainty reduction with the bias factor method extended by the concept. From the numerical evaluation, it has been shown that the prediction uncertainty due to cross section errors has been reduced by the use of the concept of the virtual experimental value. It is concluded that the introduction of virtual experimental value can effectively utilize experimental data and extend applicability of the bias factor method.

35000960
ITB-events and their triggers in T-10 and JT-60U
Neudatchin, S. V.*; Takizuka, Tomonori; Sakamoto, Yoshiteru; Hayashi, Nobuhiko; Isayama, Akihiko; Kislov, A. Ya.*; Krylov, S. V.*; Pavlov, Yu. D.*; Shirai, Hiroshi; Borshegovskii, A. A.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02521)

Non-local transport bifurcations inside and around ITB were found in various JT-60U reverse shear (RS) and normal shear (NrS) plasmas and called ITB-events. The abrupt reduction of transport in the central part of the plasma column often interrupts a slow diffusive inward cold pulse propagation (CPP) in T-10. CPP is created by a cut-off of the off-axis ECRH. This phenomenon may referred to ITB-events as well. In many cases these events occur, when the central safety factor q decreases below unity. In JT-60U low-power heated RS plasmas, ITB-events are observed at the crossing of minimum of q equal to 3.5, 3, 2.5 values. Internal MHD n=1 activity has been reported earlier as ITB-events trigger in JT-60U. The present paper shows that an ITB-event is triggered by a series of small internal disruptions probably associated with q=2.5 surface in RS plasmas. In a high-poloidal-beta NrS shot, an ITB-event occurs in correlation with the start of ELMs series. The total heat flux reduces abruptly in the zone 0.3<r/a<0.7. This new finding of this ITB event suggests the possibility to control the ITB formation by inducing the ELM-like MHD activity.

35000961
Studies on behavior of tritium in components and structure materials of tritium confinement and detritiation systems of ITER
Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; Uzawa, Masayuki*; Nishikawa, Masabumi*; Yamanishi, Toshihiko
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02522)

35000962
Prevention of the 2/1 neoclassical tearing mode in DIII-D
Prater, R.*; La Haye, R. J.*; Luce, T. C.*; Petty, C. C.*; Strait, E. J.*; Ferron, J. R.*; Humphreys, D. A.*; Isayama, Akihiko; Lohr, J.*; Nagasaki, Kazunobu*; Politzer, P. A.*; Wade, M. R.*; Welander, A. S.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02523)

Onset of the m/n=2/1 neoclassical tearing mode (NTM) has been prevented in high-performance DIII-D discharges using localized electron cyclotron current drive (ECCD). Active tracking of the q=2 surface location, using real-time equilibrium reconstructions with motional Stark effect data, allows the current drive to be maintained at the rational surface even in the absence of a detectable mode. With the application of this technique in DIII-D hybrid discharges, the 2/1 mode is avoided and good energy confinement is maintained for more than 1 second with β at the estimated n=1 no-wall stability limit for ideal kink modes (β_T approximately equals 3.9 % and normalized beta β_N approximately equals 3.2). The results can be understood through modeling using the modified Rutherford equation.

35000963
Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport
Hayashi, Nobuhiko; Takizuka, Tomonori; Ozeki, Takahisa; Aiba, Nobuyuki; Oyama, Naoyuki
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02524)

An integrated transport simulation code TOPICS-IB with a stability code for the peeling-ballooning modes and a scrape-off-layer (SOL) model has been developed to clarify self-consistent effects of edge localized modes (ELMs) and SOL on the plasma performance. Experimentally observed collisionality dependence of the ELM energy loss is found to be caused by both the edge bootstrap current and the SOL transport. The bootstrap current decreases with increasing the collisionality and intensifies the magnetic shear at the pedestal region. The increase of the magnetic shear reduces the width of eigenfunctions of unstable modes, which results in the reduction of the area and the edge value near the separatrix of the ELM enhanced transport. On the other hand, when an ELM crash occurs, the energy flows into the SOL and the SOL temperature rapidly increases. The increase of the SOL temperature lowers the ELM energy loss due to the flattening of the radial edge gradient. The parallel electron heat conduction determines how the SOL temperature increases. For higher collisionality, the conduction becomes lower and the SOL electron temperature increases more. By the above two mechanisms, the ELM energy loss decreases with increasing the collisionality. The bootstrap current and the SOL transport have the major effect on the collisionality dependence.

35000964
Evaluating electron cyclotron current drive stabilization of neoclassical tearing modes in ITER; Implications of experiments in ASDEX upgrade, DIII-D, JET, and JT-60U
La Haye, R. J.*; Prater, R.*; Buttery, R. J.*; Hayashi, Nobuhiko; Isayama, Akihiko; Maraschek, M. E.*; Urso, L.*; Zohm, H.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02525)

Resistive neoclassical tearing mode (NTM) islands will be the principal limit on stability and performance in ITER as beta is well below the ideal kink limit. NTM island control in ITER is predicted to be challenging both because of the relatively narrower marginal island widths and the relatively broader electron cyclotron current drive (ECCD). Measurements from ASDEX Upgrade, DIII-D, and JET in beta rampdown experiments are used to determine the marginal island size for m/n=3/2 NTM removal. This is compared to data from ASDEX Upgrade, DIII-D and JT-60U with elimination of the m/n=3/2 island by continuous ECCD at near constant beta. The empirical marginal island size is consistent in both sets of removal experiments and found to be about twice the ion banana width. A common methodology is developed for fitting the saturated m/n=3/2 island before (or without) ECCD in all four experimental devices. To this is added (and model tested to experiments) the effect of unmodulated co-ECCD on island stabilization including both replacing the missing bootstrap current and making the classical tearing stability index more negative. The experimentally benchmarked model is then used to evaluate ITER. The ITER ECCD upper launcher with up to 20 MW of injected power is appraised with or without modulation for both the m/n=3/2 mode and the m/n=2/1 NTM (which can lock to the resistive wall and induce disruption). An m/n=2/1 rotating island model with drag from eddy current induced in the resistive wall is used to predict the necessary ECCD to keep the island from locking as a function of the rotation in ITER. The planned relatively wide ECCD should be capable of regulating the island width to avoid mode locking with the anticipated rotation in ITER but there is little margin available for inevitable misalignment. Narrower ECCD of more power and/or more rotation in ITER would increase confidence in island control and successful operation.

35000965
Development of advanced tritium breeders and neutron multipliers for DEMO solid breeder blankets
Tsuchiya, Kunihiko; Hoshino, Tsuyoshi; Kawamura, Hiroshi; Mishima, Yoshinao*; Yoshida, Naoaki*; Terai, Takayuki*; Tanaka, Satoru*; Munakata, Kenzo*; Kato, Shigeru*; Uchida, Munenori*; Nakamichi, Masaru; Yamada, Hirokazu; Yamaki, Daiju; Hayashi, Kimio
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02526)

35000966
Interplay between zonal flows/GAMs and ITG turbulence in tokamak plasmas
Miyato, Naoaki; Kishimoto, Yasuaki; Li, J. Q.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02527)

Zonal flow behaviour and its effect on turbulent transport in tokamak plasmas are investigated by global fluid simulations of electrostatic ion temperature gradient (ITG) driven turbulence. It is found that oscillatory zonal flows called geodesic acoustic modes (GAMs) appearing in a high q (safety factor) region have the same frequency in a certain radial region whose width is almost proportional to √ρ_ia in positive shear tokamaks, and the radial wavelength of the GAMs is proportional to ρ_i, where ρ_i is an ion Larmor radius and a is a minor radius of a plasma. The turbulent transport is affected by the nonlocal behaviour of the GAMs. It seems that the radial width of the region connecting a low tranport region where the stationary zonal flows are dominant with a high transport region where the GAMs are dominant is related with the nonlocal width of the GAMs. In reversed shear tokamaks with high q, turbulent transport is high even in a minimum q region because the GAMs are dominant. The turbulent transport is reduced in the minimum q region when q is enough low to damp the GAMs. The difference of zonal flow behaviour causes the difference of the turbulent transport and may trigger formation of ion internal transport barriers in both positive and reversed shear tokamaks.

35000967
Radiation processes of impurities and hydrogen in detached divertor plasmas of JT-60U
Nakano, Tomohide; Kubo, Hirotaka; Asakura, Nobuyuki; Shimizu, Katsuhiro; Konoshima, Shigeru; Fujimoto, Kayoko; Kawashima, Hisato; Higashijima, Satoru
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02528)

Volume recombination of C⁴⁺ and e^- into C³⁺ is observed for the first time in detached plasmas with MARFE. It is found that the recombination flux of C⁴⁺ to C³⁺ is comparable to the ionization flux of C³⁺ to C⁴⁺, and that the recombination zone is above an X-point and beneath the ionization zone. This result suggests that this volume recombination predominantly produces C³⁺ ions, which contribute 60-80 % to the total radiation power in the divertor plasma.

35000968
Turbulent transport associated with GAM dynamics near critical gradient regime; GAM intermittency
Kishimoto, Yasuaki; Miki, Kazuhiro*; Miyato, Naoaki; Li, J. Q.*; Anderson, J.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02529)

We found a new type of intermittent dynamics of transport near critical gradient associated with the emission and propagation of geodesic acoustic mode (GAM) coupled with zonal flow based on our global gyro-fluid ITG turbulence simulations. We may refer the prominent dynamics to GAM intermittency. The intermittent bursts are triggered by the onset of spatially propagating GAM when the turbulent energy exceeds a critical value. The GAMs suffer a collisionless damping during the propagation and nonlocally transfer local turbulence energy to wide radial region as that of zonal flow. The stationary component of zonal flows gradually increases over many periods of quasi-periodic intermittent bursts and eventually quenches the turbulence, leading to a nonlinear up-shift of the linear critical gradient, i.e., the Dimits shift. The gradual increase of zonal flow results from the accumulation of non-damped residual part during the propagation of GAMs in each cycle of bursts. The period of burst becomes shorter as the temperature gradient increases. An extended minimum model including dynamical GAM damping which qualitatively describes the intermittent dynamics obtained in our simulation is presented.

35000969
Inter-machine comparison of intrinsic toroidal rotation
Rice, J. E.*; Ince-Cushman, A.*; de Grassie, J. S.*; Eriksson, L.-G.*; Sakamoto, Yoshiteru; Scarabosio, A.*; Bortolon, A.*; Burrell, K. H.*; Fenzi-Bonizec, C.*; Greenwald, M. J.*; Groebner, R. J.*; Hoang, G. T.*; Koide, Yoshihiko; Marmar, E. S.*; Pochelon, A.*; Podpaly, Y.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02530)

Parametric scalings of the intrinsic (spontaneous, with no external momentum input) toroidal rotation observed on a large number of tokamaks have been combined with an eye toward revealing the underlying mechanism(s) and extrapolation to future devices. The intrinsic rotation velocity has been found to increase with plasma stored energy or pressure in JET, Alcator C-Mod, Tore Supra, DIII- D, JT-60U and TCV, and to decrease with increasing plasma current in some of these cases. Use of dimensionless parameters has led to a roughly unified scaling with Mach number in proportion to normalized beta, although a variety of Mach numbers works fairly well; scalings of the intrinsic rotation velocity with normalized gyro-radius or collisionality show no correlation. Whether this suggests the predominant role of MHD phenomena such as ballooning transport over turbulent processes in driving the rotation remains an open question. For an ITER discharge with β_N=2.6, an intrinsic rotation Alfv'en Mach number of M_A ˜0.02 may be expected from the above deduced scaling, possibly high enough to stabilize resistive wall modes without external momentum input.

35000970
Active control of neoclassical tearing modes toward stationary high-beta plasmas in JT-60U
Isayama, Akihiko; Oyama, Naoyuki; Urano, Hajime; Suzuki, Takahiro; Takechi, Manabu; Hayashi, Nobuhiko; Nagasaki, Kazunobu*; Kamada, Yutaka; Ide, Shunsuke; Ozeki, Takahisa; JT-60 Team
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02531)

35000971
Simulations on the nonlinear mode coupling in multiple-scale drift-type turbulence with coherent flow structures
Li, J.*; Uzawa, Ken*; Lin, Z.*; Kishimoto, Yasuaki; Miyato, Naoaki; Matsumoto, Taro; Dong, J. Q.*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 8p.(2007) ; (JAEA-J 02532)

The dynamics of secondary, anisotropic coherent structures behaving as a stationary wave, including zonal/mean flows, streamers and low-frequency long wavelength fluctuations, in multiple-scale turbulence in tokamak plasmas is investigated by performing 3D simulations as well as 2D modeling analyses. The role of nonlinear mode coupling is specifically discussed as a ubiquitous principal interaction mechanism in the dual processes of the generation and back-action of secondary structures on ITG and ETG turbulence. Here two new results are evidently presented on the importance of the mode coupling interaction: (1) While secondary zonal flows and long wavelength modes are generated through nonlinear mode coupling, the same back-action process can deform the spectral distribution in inertia range from the power-law scaling into an exponential-law dependence. The turbulence may be reduced due to the local and/or nonlocal free energy transfer to stable region. (2) Streamer-like long wavelength fluctuations driven by the most unstable ETG modes, can saturate slab ETG turbulence through producing a k_y -mode coupling that corresponds to the toroidal mode coupling in tokamak plasma, suggesting a low ETG fluctuation level and electron transport. Furthermore, the effect of ITG generated zonal flows regarded as a wave-type mean flow on the generation of zonal flows in ETG turbulence is also discussed with an emphasis on the role of nonlinear mode coupling.

35000972
Extended steady-state and high-beta regimes of net-current free heliotron plasmas in the large helical device
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; Nagayama, Yoshio*; Shimozuma, Takashi*; Watanabe, Kiyomasa*; Masuzaki, Suguru*; Miyazawa, Junichi*; Morisaki, Tomohiro*; Morita, Shigeru*; Odachi, Satoshi*; Ono, Noriyasu*; Saito, Kenji*; Sakakibara, Satoru*; Takeiri, Yasuhiko*; Tamura, Naoki*; Toi, Kazuo*; Tokitani, Masayuki*; Yokoyama, Masayuki*; Yoshinuma, Mikiro*; Ikeda, Katsunori*; Isayama, Akihiko; Ishii, Kameo*; Kubo, Shin*; Murakami, Sadayoshi*; Nagasaki, Kazunobu*; Seki, Tetsuo*; Takahata, Kazuya*; Takenaga, Hidenobu; LHD Experimental Group*
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM) , 12p.(2007) ; (JAEA-J 02533)

The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 5×10²⁰m^-3, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high β and long pulse.

35000973
Numerical analysis of unsteady gas entrainment phenomena using dynamic SGS model
Sakai, Masayuki*; Tanaka, Nobuatsu*; Oshima, Hiroyuki
Proceedings of 5th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-5) , p.301-304(2006) ; (JAEA-J 02534)

The flowing gas or liquid in the industrial machines, it is important that improving in quality. We analyzed about systems of unsteady gas entrainment with the analysis code for turbulence eddy flow, which based on local inter-scale equilibrium assumption (LISEA). And we speculated about adequacy of LES application and affect of mesh division on unsteady gas entrainment phenomenon. In the result, we obtain the following knowledge about unsteady eddy problems as object. (1) LES affected by mesh division more than DNS. So appropriate result needs to give consideration to mesh division. (2) DNS affected lightly by mesh mutation in the purview of this analysis. (3) In the case of using LES, it needs to set proper parameters carefully.

35000974
Direct numerical simulation of gas entrainment from free-surface
Kunugi, Tomoaki*; Kawara, Zensaku*; Ose, Yasuo*; Ito, Kei; Sakai, Takaaki
Proceedings of 5th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-5) , p.385-390(2006) ; (JAEA-J 02535)

In order to design the compact FBR with higher coolant velocity compared to the conventional reactor designs, it is necessary to clarify a criterion of a cover gas entrainment (GE) from the free-surface of the coolant pool in the reactor vessel to the heat exchanger through the hot leg. Three flow regimes are considered as the GE phenomena: a vortex dimple, a waterfall and a surface disturbance. In this study, to evaluate the GE vortex phenomena: especially for the vortex dimple, the DNS based on the MARS (Multi-interfaces Advection and Reconstruction Solver (Kunugi, 2001)) were performed for simulating the unsteady vortex-shedding experiment accompanied with the GE phenomena (Okamoto et al., 2004). The applicability of the present DNS to predict the onset of the GE vortex phenomena is discussed.

35000975
Application of supercritical fluid extraction to metal separation in the field of nuclear technology
Meguro, Yoshihiro; Tomioka, Osamu; Takahashi, Kuniaki; Wada, Ryutaro*; Yamamoto, Seiichi*; Fukuzato, Ryuichi*
Proceedings of 8th International Symposium on Supercritical Fluids (ISSF 2006) (CD-ROM) , 6p.(2006) ; (JAEA-J 02536)

A large-scale apparatus having a reaction vessel of ca. 4000 cm³ was developed for supercritical CO₂ leaching. An ultrasonic wave oscillator, stirring device, and piston compressor were equipped to the apparatus to enhance mass transfer rate of substances in supercritical CO₂. A sea sand sample, an incinerated ash sample, and a porous alumina brick sample, in which uranium oxide was adsorbed, were prepared as simulated samples of radioactive wastes and uranium was tried to remove from these samples to supercritical CO₂ including nitric acid - tri-n-butyl phosphate complex as a reactant using the apparatus. By several times of the uranium separation, more than 99% of uranium was removed from the sea sand sample and the ash sample. When the mass transfer enhanced system was operated, it was confirmed that separation efficiency of uranium was improved and then 99% of uranium could be removed form the ash sample.

35000976
Knowledge retention at JAERI and 8 resembled foreign research institutes
Yanagisawa, Kazuaki
Proceedings of American Nuclear Society Conference on Nuclear Training and Education (CONTE 2007) (CD-ROM) , p.93-94(2007) ; (JAEA-J 02537)

A valuable and retainable knowledge born by a result of research activity in a nuclear institute should be stocked explicitly in the form of research paper. This time, by using research papers stocked by JAERI and 8 resembled foreign research institutes, an institutional comparison was performed by a bibliometric method. It is revealed from the present bibliometric study that a nuclear knowledge in JAERI and 8 resembled foreign research institutes is retained successfully not only in INIS but also in ECD over 50 years. The retained knowledge is revealed to be useful for executing an institutional comparison. Within the present scope one concludes that the champion between JAERI and 8 resembled foreign research institutes is ORNL during the period 1978-2002. JAERI is in the 2nd position in INIS but is in the 7th position in ECD.

35000977
Status of reduced enrichment program for research reactors in Japan
Kinase, Masami; Sagawa, Hisashi; Nakagome, Yoshihiro*; Unesaki, Hironobu*
Proceedings of International Meeting on Reduced Enrichment for Research and Test Reactors 2006 (RERTR 2006) (Internet) , 10p.(2006) ; (JAEA-J 02538)

The reduced enrichment programs for the JRR-3M, JRR-4 and JMTR of Japan Atomic Energy Research Institute (JAERI) has been completed until 1999. The KUR of Kyoto University Research Reactor Institute (KURRI) has been partially completed and is still in progress under the Joint Study Program with Argonne National Laboratory (ANL). The JRR-3M using LEU silicide fuel elements has done a functional test by the Japanese Government in 2000, and the property of the reactor core was satisfied. JAERI established a "U-Mo fuel ad hoc committee" for feasibility study concerning future LEU fuel instead of the silicide fuel in 2001, and an installation of the U-Mo fuel was estimated from 2012, even the irradiation tests are carried out successfully. The U.S. Policy of Foreign Research Reactor Spent Nuclear Fuels is strongly expected to expand the policy until U-Mo fuel installed. The Japanese Government approved a cancellation of the KUHFR Project in February 1991, and in April 1994 the U.S. Government gave an approval to utilize HEU fuel in the KUR instead of the KUHFR. Therefore, the KUR will be operated with HEU fuel until March 2006, then the full core conversion with LEU fuel will be done. All KUR spent fuel elements will be sent to the U.S. by March 2008.

35000978
A Three-dimensional meso-scale modeling for helium bubble growth in metals
Suzudo, Tomoaki; Kaburaki, Hideo; Wakai, Eiichi
Proceedings of Joint International Topical Meeting on Mathematics & Computations and Supercomputing in Nuclear Applications (M&C+SNA 2007) (CD-ROM) , 10p.(2007) ; (JAEA-J 02539)

A three-dimensional meso-scale computer model using a Monte-Carlo simulation method has been proposed to simulate the helium bubble growth in metals. The primary merit of this model is that it enables the visual comparison between the microstructure observed by the TEM imaging and those by calculations. The modeling is so simple that one can control easily the calculation by tuning parameters. The simulation results are confirmed by the ideal gas law and the capillary relation.

35000979
A Challenge for computing in the 21st century; Radwaste knowledge management
Umeki, Hiroyuki
Proceedings of Joint International Topical Meeting on Mathematics & Computations and Supercomputing in Nuclear Applications (M&C+SNA 2007) (CD-ROM) , 11p.(2007) ; (JAEA-J 02540)

35000980
Present status and the future of special libraries; The Case of the library of a scientific and technical research institute (in Japanese)
Nakamoto, Hideshiro*; Itabashi, Keizo; Ishikawa, Masashi; Yonezawa, Minoru; Habara, Tadashi
Kagaku Gijutsu Toshokan No Genzai To Mirai; Nippon Genshiryoku Kenkyujo Toshokan No Genba Kara , 185p.(2007) ; (JAEA-J 02542)

35000981
Pressure-induced structural changes in liquid III-V compounds
Hattori, Takanori; Taga, Naohito*; Takasugi, Yukinobu*; Kinoshita, Tomohiro*; Narushima, Takashi*; Tsuji, Kazuhiko*; Kikegawa, Takumi*
Photon Factory Activity Report 2005, Part A , p.42-43(2006) ; (JAEA-J 02547)

35000982
Maintenance management corresponding to plant life in JOYO (in Japanese)
Suto, Masayoshi; Ichige, Satoshi; Isozaki, Kazunori
UTNL-R-0459 , p.5_1-5_9(2007) ; (JAEA-J 02548)

35000983
Treatment of fuel assembly washing water from JOYO (in Japanese)
Nakano, Tomoyuki
UTNL-R-0459 , p.7_1-7_10(2007) ; (JAEA-J 02549)

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