JAEA Abstracts

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

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

September 2011

39001103
Fabrication of first wall component of ITER test blanket module by HIPping reduced activation ferritic/martensitic steel
Hirose, Takanori; Enoeda, Mikio; Ogiwara, Hiroyuki*; Tanigawa, Hiroyasu
Advances in Technology of Materials And Materials Processing Journal 13(1), p.34-38(2011) ; (JAEA-J 09362)

Reduced activation ferritic martensitic (RAFM) steels are leading candidate structural material for the blanket system of fusion reactors. HIP process is the key technology to fabricate the first wall (FW) with built-in cooling channels for ITER test blanket module. This paper summarizes the current status of our investigation on optimization of HIP condition to obtain the excellent joints and evaluation of FW fabrication process. The pre-HIP treatments, such as pre-heating condition to degas, were optimized to decrease oxidation on the joint surfaces which cause degradation of impact properties. With optimized pre-HIP treatment conditions, toughness of the joint was as well as that of the base metal. As for a component fabrication, a FW full-scale mockup has been developed using a RAFM. The deformation due to HIP process was within allowance level due to bracing. Moreover, fine-grained microstructure was obtained with optimized HIP condition and post HIP heat treatment.

39001104
Low-linear energy transfer radiolysis of liquid water at elevated temperatures up to 350°C; Monte-Carlo simulations
Sanguanmith, S.*; Muroya, Yusa*; Meesungnoen, J.*; Lin, M.; Katsumura, Yosuke*; Mirsaleh Kohan, L.*; Guzonas, D. A.*; Stuart, C. R.*; Jay-Gerin, J.-P.*
Chemical Physics Letters 508(4-6), p.224-230(2011) ; (JAEA-J 09363) [link]

Our Monte-Carlo modeling of the high-temperature radiolysis of water by low-LET radiation was re-examined in an attempt to reconcile our computed g-values of the various radiolytic products with recently re-assessed experimental data up to 350°C. The inclusion in our simulations of the abrupt drop in the rate constant for the self-reaction of hydrated electron above 150°C led us to re-evaluate the temperature dependence of certain parameters intervening in the physicochemical stage of the radiolysis. A very good agreement was found between model and experiment. The importance of the reaction of H atoms with water in the unexplained yield of H₂ above 200°C was also briefly discussed.

39001105
Evaluation of dose rate reduction in a spacecraft compartment due to additional water shield
Sato, Tatsuhiko; Niita, Koji*; Shurshakov, V. A.*; Yarmanova, E. N.*; Nikolaev, I. V.*; Iwase, Hiroshi*; Sihver, L.*; Mancusi, D.*; Endo, Akira; Matsuda, Norihiro; Iwamoto, Yosuke; Nakashima, Hiroshi; Sakamoto, Yukio; Yasuda, Hiroshi*; Takada, Masashi*; Nakamura, Takashi*
Cosmic Research 49(4), p.319-324(2011) ; (JAEA-J 09364) [link]

HZE particle transport codes are the indispensable tool in the shielding design of spacecrafts. We are therefore developing a general-purpose Monte Carlo code PHITS, which can deal with the transports of all kinds of hadrons and heavy ions with energies up to 200 GeV/n in 3-dimensional phase spaces. The applicability of PHITS to space researches has been well verified by comparing the neutron spectra in spacecrafts calculated by the code with the corresponding experimental data. Recently, PHITS was employed in the estimation of radiation fields in the Russian Service Module in ISS. The results of the estimation indicate that PHITS can reproduce experimental data of the dose reduction rates due to water shielding attached on the wall of the Russian crew cabin fairly well. The details of the calculation procedures will be given in the presentation, together with the results of other applications of PHITS to the space exploration.

39001106
Spatial distribution and characteristics of fracture zones near a long-lived active fault; A Field-based study for understanding changes in underground environment caused by long-term fault activities
Niwa, Masakazu; Kurosawa, Hideki; Ishimaru, Tsuneari
Engineering Geology 119(1-2), p.31-50(2011) ; (JAEA-J 09365) [link]

Fracture zone development has a substantial impact on long-term changes in the underground environment because fracture zones are leading candidates as groundwater flowpaths as well as a locus for mechanical disturbance by fracturing. For understanding fracture zone development we surveyed the spatial distribution and characteristics of fracture zones in an area 4 km to the north and 6 km to the south from the western part of the Atotsugawa Fault, a long-lived active fault in central Japan. This study suggests that fracture zones along the Atotsugawa Fault act as a major conduit controlling regional groundwater flow. Based on rock features and deformation fabrics at meso- and microscopic scales, once fracture zones had formed, epigenetic deformation was concentrated in the ancient fracture zones.

39001107
Micropolar fluid behavior on MHD heat transfer flow through a porous medium with induced magnetic field by finite difference method
Sultana, M.*; Haque, M. M.*; Alam, M. M.*; Ferdows, M.; Postelnicu, A.*
European Journal of Scientific Research 53(3), p.477-490(2011) ; (JAEA-J 09366) [link]

A unsteady MHD heat transfer by free convective micropolar fluid flow through an infinite vertical porous medium under the action of strong magnetic field have been studied numerically with induced magnetic field. This investigation is performed for the turbulent boundary layer cooling problem with constant suction velocity. The unconditionally stable implicit finite difference technique is used to solve the non-dimensional momentum, angular momentum, magnetic induction and energy equations. The computed values of fluid velocity, angular velocity, induced magnetic field and temperature distributions as well as the steady-state wall shear stress, wall couple stress, current density and Nusselt number are shown graphically. Finally, the important findings are listed here.

39001108
MHD free convective heat generating unsteady micropolar fluid flow through a porous medium with constant heat and mass fluxes
Haque, M. M.*; Alam, M. M.*; Ferdows, M.; Postelnicu, A.*
European Journal of Scientific Research 53(3), p.491-515(2011) ; (JAEA-J 09367) [link]

Unsteady MHD heat and mass transfer by free convective micropolar fluid flow over an infinite vertical porous medium under the action of transverse magnetic field with thermal diffusion have been studied numerically in the presence of constant heat source. This investigation is performed for both cooling and heating problem with constant suction velocity when the medium is subjected to constant heat and mass fluxes. A finite difference technique with stability and convergence analysis is used to solve the non-dimensional momentum, angular momentum, energy and concentration equations. The computed values of fluid velocity, angular velocity, temperature and concentration distributions, wall shear stress, wall couple stress, Nusselt number and Sherwood number are shown graphically. Finally, a qualitative comparison with previous work is tabulated.

39001109
Mathematical model of domain formation in barium titanate
Yoneda, Yasuhiro
Ferroelectrics 414(1), p.86-89(2011) ; (JAEA-J 09368) [link]

The numerical model of the ferroelectric domain formation has been described with the polarization network, because it has been understood that a long-range network of elastic strain is generated by the inhomogeneity of polarization. Recently, the direct observation of long-range elastic strain has been able to be performed by several methods. We made an attempt to construct a mathematical model of the domain formation in BaTiO₃ using elastic strain as a parameter.

39001110
Physics of plasma control toward steady-state operation of ITER
Kikuchi, Mitsuru; Campbell, D. J.*
Fusion Science and Technology 59(3), p.440-468(2011) ; (JAEA-J 09369) [link]

The ITER is an important step towards fusion energy utilization for human being. Fundamental understanding of physics is quite important as well as understanding of tokamak system and plasma control. In this lecture, I will give an introduction of tokamak research on fusion energy and ITER in light of the main theme of this school plasma control and give some flavors to understand importance of physics by showing some physics elements underlying research towards steady-state operation of reactor relevant tokamak plasmas.

39001111
Influence of a fault system on rock mass response to shaft excavation in soft sedimentary rock, Horonobe area, northern Japan
Tokiwa, Tetsuya; Tsusaka, Kimikazu; Ishii, Eiichi; Sanada, Hiroyuki; Tominaga, Eiji*; Hatsuyama, Yoshihiro*; Funaki, Hironori
International Journal of Rock Mechanics and Mining Sciences 48(5), p.773-781(2011) ; (JAEA-J 09370) [link]

This paper focuses attention on stress field that produced fault system, and presents an example of the relationship between fault system and rock mass response to shaft excavation in soft sedimentary rocks in the Horonobe area, Japan. The directions determined by fault-slip analysis are close to the direction of maximum and minimum diameter reduction in the shaft. The results show that fault system can affects rock mass response to shaft excavation in soft rock and furthermore, and it is considered that the rock mass deformation was controlled by fault system. In addition, it is likely that we can assess and predict rock mass behavior by focusing on palaeo-stress field that produced fault system.

39001112
Properties of a rubidium isotope ion beam extracted from a laser ion source
Tamura, Koji
Japanese Journal of Applied Physics 50(6), p.066301_1-066301_6(2011) ; (JAEA-J 09371) [link]

The atomic beam of rubidium was isotope selectively photoionized by the irradiation of the fundamental output of Ti:sapphire laser. The produced rubidium ions were extracted and collimated with electrodes as a laser ion source. The ion images of ⁸⁵Rb and ⁸⁷Rb were observed at a phosphor screen of MCP. The ion energy corresponded to the potential of the laser irradiated position between the electrodes. The ion source can be one of the isotope selective tools for surface engineering.

39001113
Inhomogeneous dynamic nuclear polarization of protons in a lamella-forming diblock copolymer investigated by a small-angle neutron scattering method
Noda, Yohei; Kumada, Takayuki; Hashimoto, Takeji; Koizumi, Satoshi
Journal of Applied Crystallography 44(3), p.503-513(2011) ; (JAEA-J 09372) [link]

We measured small angle neutron scattering (SANS) for dynamically polarized block copolymer sample, one phase of which were selectively doped with radical. Dynamic nuclear polarization (DNP) caused the neutron scattering length of proton largely, as a result, the SANS intensity. By the analysis of the change of the SANS intensity, we found out the inhomogeneous distribution of the radical induced the inhomogeneous polarization (about 2% for the average polarization being 30%).

39001114
Spin transfer torque in MTJs with synthetic ferrimagnetic layers by the Keldysh approach
Ichimura, Masahiko*; Hamada, Tomoyuki*; Imamura, Hiroshi*; Takahashi, Saburo*; Maekawa, Sadamichi
Journal of Applied Physics 109(7), p.07C906_1-07C906_3(2011) ; (JAEA-J 09373) [link]

Based on the Keldysh Green's function method within the tight-binding model, the spin transfer torque is analyzed in a magnetic tunnel junction with a synthetic ferrimagnetic (SyF) free layer in the ballistic regime. The spin transfer torque exerted on the magnetizations of ferromagnetic bilayers in the SyF free layer tends to rotate the magnetizations in the same direction as a combined motion of the SyF free layer regardless of the bias direction. This rotation causes a reduction of the critical current for the magnetization switching of the SyF free layer which is consistent with experimental observations.

39001115
The Study on abrasive water jet for predicting the cutting performance and monitoring the cutting situation in the water
Nakamura, Yasuyuki; Sano, Kazuya; Morishita, Yoshitsugu; Maruyama, Shinichiro*; Tezuka, Shinichi*; Ogane, Daisuke*; Takashima, Yuji*
Journal of Engineering for Gas Turbines and Power 133(6), p.064501_1-064501_3(2011) ; (JAEA-J 09374) [link]

Abrasive water jet (AWJ), is to shoot the abrasive mixed with high-pressure water to the material for cutting, can cut most materials like metals and concretes in water with long stand-off means the length from the cutting head to the material for cutting. On the other hand, AWJ is required to reduce an amount of the abrasive because it becomes the waste. It is also difficult to monitor the cutting condition by any visual methods like a TV camera in the water becoming cloudy by both used abrasive and cut metal grit. For solving these issues, some cutting tests were conducted and (1) It was possible to predict an optimal supply rate of abrasive by considering the conservation of momentum between the water jet and the abrasive. (2) It was also possible to judge whether the material could be cut successfully or not by detecting the change in the frequency characteristics of vibration or sound caused during the cutting process.

39001116
Double loss-of-function mutation in EARLY FLOWERING 3 and CRYPTOCHROME 2 genes delays flowering under continuous light but accelerates it under long days and short days; An Important role for Arabidopsis CRY2 to accelerate flowering time in continuous light
Nefissi, R.*; Natsui, Yu*; Miyata, Kana*; Oda, Atsushi*; Hase, Yoshihiro; Nakagawa, Mayu*; Ghorbel, A.*; Mizoguchi, Tsuyoshi*
Journal of Experimental Botany 62(8), p.2731-2744(2011) ; (JAEA-J 09375) [link]

39001117
Degradation manner of polymer grafts chemically attached on thermally stable polymer films; Swelling-induced detachment of hydrophilic grafts from hydrophobic polymer substrates in aqueous media
Enomoto, Kazuyuki*; Takahashi, Shuichi*; Iwase, Takanori*; Yamashita, Takashi*; Maekawa, Yasunari
Journal of Materials Chemistry 21(25), p.9343-9349(2011) ; (JAEA-J 09376) [link]

The degradation manner of graft-type polymer electrolyte membranes consisting of hydrophilic poly(styrenesulfonic acid) (PSSA) graft polymers (grafts) and thermally and mechanically stable hydrophobic polymer substrates was examined in hot water. Severe weight loss was observed in PSSA-grafted cPTFE and ETFE films but not in a PSSA-grafted PEEK film. The decomposed extracts in water were characterized as PSSA during the whole course of degradation, clearly showing that the PSSA grafts detached from the fluorinated substrates without decomposition or scission of graft polymer chains. This is quite a new degradation manner for graft-type polymer electrolyte membranes; namely, hydrophilic PSSA grafts detach from hydrophobic polymer substrates due to swelling-induced stress at the interfacial boundary in the grafted films.

39001118
Three-dimensional cooling pattern of a granitic pluton, 1; The Study of exsolution sub-solidus reactions in the Toki granite, Central Japan
Yuguchi, Takashi; Tsuruta, Tadahiko; Nishiyama, Tadao*
Journal of Mineralogical and Petrological Sciences 106(2), p.61-78(2011) ; (JAEA-J 09377) [link]

This paper presents results of petrographical studies examining development and variation of sub-solidus reactions recorded in the Toki granite, Central Japan, which show the three-dimensional cooling pattern of this zoned pluton. Samples collected from 19 boreholes in the Toki granite display characteristics indicative of spatial variation in the extent of sub-solidus reactions. Exsolution coarsening has produced microperthite textures with albite - rich lamella in this pluton, whereas deuteric coarsening has resulted in patchperthite with albite - rich patch. The width and spacing of albite - rich lamella in microperthite increase systematically and prominently with elevation in the pluton, indicating that the Toki granite effectively cooled from the roof during the exsolution coarsening stage. The hornblende - plagioclase and ternary feldspar thermometers indicate a temperature range of 780 to 690 °C in which volume diffusion took place, associated with exsolution coarsening.

39001119
Three-dimensional cooling pattern of a granitic pluton, 2; The Study of deuteric sub-solidus reactions in the Toki granite, Central Japan
Yuguchi, Takashi; Tsuruta, Tadahiko; Nishiyama, Tadao*
Journal of Mineralogical and Petrological Sciences 106(3), p.130-141(2011) ; (JAEA-J 09378) [link]

Petrographical studies examining the development and variations of sub-solidus reactions recorded in the Toki granite represent the three-dimensional cooling pattern of this zoned pluton in Central Japan. Samples collected from 19 boreholes in the Toki granite show characteristics indicative of spatial variations in the extent of sub-solidus reactions. Exsolution coarsening has produced microperthite including albite-rich lamellae in this pluton, while deuteric coarsening has resulted in patchperthite, myrmekite, and the reaction rim. The extent of deuteric coarsening reactions can be evaluated by the width and spacing of albite-rich patch in patchperthite, and by the thickness of myrmekite and the reaction rim. The width, spacing and thickness of these textural features increase systematically with elevation and also increase gradually in the horizontal inward in the western part but not in the eastern part of the pluton. The systematic variations in textural development indicate that the Toki granite cooled effectively from the roof and from the western margin during the deuteric coarsening stage. The deuteric coarsening may have occurred at temperatures below 500°C based on ternary feldspar thermometry.

39001120
Oxygen potential of (U_0.88Pu_0.12)O_2±x and (U_0.7Pu_0.3)O_2±x at high temperatures of 1673-1873 K
Kato, Masato; Takeuchi, Kentaro; Uchida, Teppei; Sunaoshi, Takeo*; Konashi, Kenji*
Journal of Nuclear Materials 414(2), p.120-125(2011) ; (JAEA-J 09379) [link]

Many studies on oxygen potentials have been reported, but their data were scattered and the data at high temperatures are limited. In this work, the oxygen potential of (U_0.88Pu_0.12)O_2±x and (U_0.7Pu_0.3)O_2±x was measured at high temperatures of 1673-1873 K using gas equilibrium method using thermo-gravimetry. The influence of Pu addition on the oxygen potential of MOX was discussed. The oxygen potential and the O/M ratio were decided by in-situ analysis. The oxygen partial pressure was adjusted by controlling the ratio of P_H₂/P_H₂O in the flowing gas atmosphere, and the oxygen potential was determined. The oxygen potentials measured by the point defect model. The deviation x varied with the relation of in the near stoichiometric composition region. The oxygen potential increased with increasing Pu content. The values of stoichiometric MOX containing 12% and 30%Pu were determined to be -334 kJ/mol and -296 kJ/mol, respectively, at 1773 K.

39001121
Irradiation effect on mechanical properties in structural materials of fast breeder reactor plant
Nagae, Yuji; Takaya, Shigeru; Wakai, Eiichi; Aoto, Kazumi
Journal of Nuclear Materials 414(2), p.205-210(2011) ; (JAEA-J 09380) [link]

Proper evaluation of neutron irradiation damage on structural materials is important to ensure long life of fast breeder reactor plants (FBR). In this study, the effects of dose, helium content, and the ratio of helium content to dose on tensile and creep properties have been investigated in the assumed irradiation damage range of FBR structural materials. The assumed irradiation damage range is up to about 1 displacement per atom (dpa) and about 30 appm for helium content. Austenitic stainless steel and high-chromium martensitic steel are considered as FBR structural materials. As a result, it is shown that dose is a promising index for evaluating neutron irradiation damage.

39001122
Hydride behavior in zircaloy cladding tube during high-temperature transients
Nagase, Fumihisa
Journal of Nuclear Materials 415(1), p.117-122(2011) ; (JAEA-J 09381) [link]

In order to study the hydride behavior in high burnup fuel cladding in anticipated operational occurrences and accidents, unirradiated hydrided zircaloy-4 cladding tubes were rapidly heated to temperatures ranging from 673 to 1173 K for short periods. Hydrides were localized in the peripheral region of the cladding tubes prior to the annealing, as observed in high burnup fuel cladding. The microstructure did not change due to the annealing at 673 K for the time range below 3600 s. The radial distribution and morphology of hydrides change depending on the temperature and holding time above 873 K. The observed changes are caused by the phase transformation to the α+β or β phase and the subsequent increase in the solid solubility and diffusion of hydrogen in the zircaloy matrix. The micro-hardness in the cross section changes with the hydride redistribution, recrystallization of zircaloy, and phase transformation.

39001123
Impact of revised thermal neutron capture cross section of carbon stored in JENDL-4.0 on HTTR criticality calculation
Goto, Minoru; Shimakawa, Satoshi; Nakao, Yasuyuki*
Journal of Nuclear Science and Technology 48(7), p.965-969(2011) ; (JAEA-J 09382) [link]

In the past, benchmark calculations of criticality approach for the HTTR, which is a Japanese HTGR, were performed by research institutes in several countries, and almost all of the calculations overestimated the excess reactivity. In Japan, the benchmark calculations performed by JAEA also resulted in overestimation. JAEA improved the calculations by revising the geometric model and replacing the nuclear data library with JENDL-3.3, which was the latest JENDL at that time. However, the overestimation remained and this problem has not been resolved until today. We performed calculations of the HTTR criticality approach with several nuclear data libraries, and found that slight difference in the capture cross section of carbon at thermal energy among the libraries causes significant difference in the k_eff values. The cross section value of carbon was not concerned in reactor neutronics calculation because of its small value of the order of 10^-3 burn, and consequently the cross section value was not revised for a long time even in the major nuclear data libraries: JENDL, ENDF/B and JEFF. We thought that the cross section value should be revised based on the latest measurement data in order to improve the accuracy of the neutronics calculations of the HTTR. In April 2010, the latest JENDL;JENDL-4, was released by JAEA, and the capture cross section of carbon was revised. JENDL-4 yielded 0.4%Δk-0.9%Δk smaller k_eff values than JENDL-3.3 in the calculation of the HTTR critical approach, and consequently the problem of the overestimation of the excess reactivity in the HTTR benchmark calculation was resolved.

39001124
Consequence analysis of fluvial erosion scenarios for a HLW repository
Miyahara, Kaname; Kawamura, Makoto*; McKinley, I. G.*; Inagaki, Manabu*; Ebina, Takanori*
Journal of Nuclear Science and Technology 48(7), p.1069-1076(2011) ; (JAEA-J 09383) [link]

In Japan, uplift/erosion scenarios must be analysed even if they occur far in the future, as no assessment cut-off times have yet been defined. For this purpose, the geological record of river terrace formation and their long term evolution has been studied further, with the aim of constructing a more realistic fluvial erosion model compared with the original, rather simple cyclic fluvial erosion model developed in a previous study. The model allows the consequences of erosion of the repository to be assessed, as before using comparisons with natural radionuclide fluxes. This paper describes a conceptual model based on a generalization of field observations in relevant settings and discusses resultant analyses, which again illustrate the effectiveness and robustness of the reference HLW disposal system.

39001125
Benchmark critical experiments of a heterogeneous system of uranium fuel rods and uranium solution poisoned with gadolinium, and application of their results to JACS validation
Tonoike, Kotaro; Miyoshi, Yoshinori; Uchiyama, Gunzo
Journal of Nuclear Science and Technology 48(7), p.1118-1128(2011) ; (JAEA-J 09384) [link]

A series of critical experiments were performed using heterogeneous cores at STACY in JAEA in order to obtain systematic benchmark criticality data concerning the dissolving process in reprocessing plants. Focusing on the use of gadolinium as a soluble poison, critical mass was measured for a combination of uranium dioxide fuel rods and uranyl nitrate solution poisoned with gadolinium (Gd). The Gd concentrations were varied up to 0.1 gGd/L. The other series of experiments were also conducted, as reference cases, varying uranium concentration in the fuel solution without Gd. The results provided benchmark criticality data for validation of neutron multiplication factor calculation on heterogeneous systems such as a dissolver. Validation calculation of JACS based on the newly obtained benchmarks supports the justification of its utilization for the criticality safety analysis.

39001126
Single-shot observation of growing streamers using an ultrafast camera
Takahashi, Eiichi*; Kato, Susumu*; Furutani, Hirohide*; Sasaki, Akira; Kishimoto, Yasuaki*; Takada, Kenji*; Matsumura, Satoshi*; Sasaki, Hiroyasu*
Journal of Physics D; Applied Physics 44(30), p.302001_1-302001_4(2011) ; (JAEA-J 09385) [link]

A recently developed ultrafast camera that can acquire 10⁸ frames per second was used to investigate positive streamer discharge. It enabled single-shot evaluation of streamer evolution without the need to consider shot-to-shot reproducibility. This camera was used to investigate streamers in argon. Growing branches, the transition when a streamer forms a return stroke, and related phenomena were clearly observed.

39001127
Role of residual transition-metal atoms in oxygen reduction reaction in cobalt phthalocyanine-based carbon cathode catalysts for polymer electrolyte fuel cell
Kobayashi, Masaki*; Niwa, Hideharu*; Harada, Yoshihisa*; Horiba, Koji*; Oshima, Masaharu*; Ofuchi, Hironori*; Terakura, Kiyoyuki*; Ikeda, Takashi; Koshigoe, Yuka*; Ozaki, Junichi*; Miyata, Seizo*; Ueda, Shigenori*; Yamashita, Yoshiyuki*; Yoshikawa, Hideki*; Kobayashi, Keisuke*
Journal of Power Sources 196(20), p.8346-8351(2011) ; (JAEA-J 09386) [link]

The electronic structure of Co atoms in CoPc-based carbon catalysts, which were prepared by pyrolyzing a mixture of CoPc and phenol resin polymer up to 1000°C, has been investigated using XAFS analysis and HXPES. The Co K XAFS spectra show that most of the Co atoms are in the metallic state and small quantities of oxidized Co components are present in the samples even after acid washing to remove Co atoms. Based on the difference in probing depth between XAFS and HXPES, it was found that after acid washing, the surface region with the aggregated Co clusters is primarily composed of metallic Co. Since the electrochemical properties remain almost unchanged even after the acid washing process, the residual metallic and oxidized Co atoms themselves will hardly contribute to the ORR activity of the CoPc-based carbon cathode catalysts, implying that the active sites of the CoPc-based catalysts primarily consist of light elements such as C and N.

39001128
Coordination characteristics of trivalent lanthanides and actinides in molten hydrate salts of Ca(NO₃)₂ and CaCl₂
Fujii, Toshiyuki*; Okude, Genki*; Uehara, Akihiro*; Sekimoto, Shun*; Hayashi, Hirokazu; Akabori, Mitsuo; Minato, Kazuo; Yamana, Hajimu*
Journal of Radioanalytical and Nuclear Chemistry 288(1), p.181-187(2011) ; (JAEA-J 09387) [link]

Distribution behavior of Ce(III), Am(III), and Cm(III) between tri-n-butyl phosphate solution and molten calcium nitrate hydrate Ca(NO₃)₂·RH₂O or molten calcium chloride hydrate CaCl₂·RH₂O was studied radiochemically. In Ca(NO₃)₂·RH₂O systems, maximum separation factors of Ce and Cm to Am were observed to be 12 (Ce/Am) and 1.7 (Cm/Am). The distribution ratios of these elements increased with the decrease of water activity in the hydrates, and the extractabilities at the water deficient region was less sensitive compared to those at the water abundant region. This trend was similar to the coordination circumstance change observed in electronic absorption spectra of Nd(III) in the hydrates.

39001129
T-dependent nuclear hyperfine coupling at the In site in CeIrIn₅
Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Matsuda, Tatsuma; Haga, Yoshinori; Takeuchi, Tetsuya*; Onuki, Yoshichika*; Walstedt, R. E.*
Journal of the Physical Society of Japan 80(Suppl.A), p.SA009_1-SA009_3(2011) ; (JAEA-J 09388) [link]

We report an ¹¹⁵In NMR study of a single-crystal sample of the heavy fermion superconductor CeIrIn₅. The observed non-linear variation of Knight Shift with static susceptibility in the normal state is consistent with the two-fluid (components) model of Nakatsuji et al, indicating that two individual contributions to static susceptibility exist. However, our results can also be understood in terms of a T-dependent hyperfine coupling, which accounts for the spin-lattice relaxation data naturally on the basis of a one-component dynamical susceptibility. In addition, the observed T-dependence of the hyperfine coupling is scaled to a density of states given by dynamical mean field theory (DMFT). We believe that this contrast between the static and dynamical properties is a crucial dual nature of the heavy fermion crossover, which related with the coherence between localized and itinerant excitations.

39001130
Dilute La-substitutions in CeRhIn₅ studied by means of NMR/NQR techniques
Sakai, Hironori; Kurita, Nobuyuki*; Miclea, C. F.*; Movshovich, R.*; Lee, H.-O.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
Journal of the Physical Society of Japan 80(Suppl.A), p.SA059_1-SA059_3(2011) ; (JAEA-J 09389) [link]

The effect of dilute La substitution in Ce_1-xLa_xRhIn₅ (0≤x≤0.07) has been investigated microscopically by nuclear magnetic/quadrupole resonance (NMR/NQR).By the dilute La substitutions, the 4ν_Q lines for In(1) sites are found to be undisturbed and to have a reasonably narrow width, even in the ordered AF state. These 4ν_Q positions in the La-substituted CeRhIn₅ indicate a decrease of the internal field on In(1) sites, due to the reduction of hyperfine couplings by La substitutions. The spin-lattice relaxation rates (1/T₁) using these 4ν_Q lines at high temperatures can be understood by the reduction of exchange energy and effective moments. On the other hand, 1/T₁ in the AF ordered state can be explained by a gapped Fermi surface and spin fluctuations of uncompensated localized Ce moments near the La ions.

39001131
Possible long-periodic magnetic structure in SmPb₃
Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Amato, A.*; Sugai, Takashi; Haga, Yoshinori; Suzuki, Hiroyuki*
Journal of the Physical Society of Japan 80(Suppl.A), p.SA075_1-SA075_3(2011) ; (JAEA-J 09390) [link]

A series of cubic SmX₃ (X=In, Sn, Pb) compounds has a Γ₈ crystalline-electric-field ground state with various multipolar degrees of freedom. These show phase transitions at low temperatures and a possibility of multipolar ordering has been suggested. However, no microscopic experimental data is available so far and details of the ordered states have not been clarified yet. We performed muon spin relaxation measurements in order to elucidate nature of multipoles in these systems. A breaking of time-reversal symmetry was observed in all the ordered phases in zero applied field, indicating the primary order parameters are magnetic. We also obtained information about the ordered structures from a microscopic point of view.

39001132
First-principles studies for the hydrogen doping effects on iron-based superconductors
Nakamura, Hiroki; Machida, Masahiko
Journal of the Physical Society of Japan 80(7), p.073705_1-073705_4(2011) ; (JAEA-J 09391) [link]

We study hydrogen doping effects in an iron-based superconductor LaFeAsO_1-y by using the first-principles calculation and explore a reason why the superconducting transition temperature is remarkably enhanced by the hydrogen doping. The present calculations reveal that a hydrogen cation stably locating close to an iron atom attracts a negatively-charged FeAs layer and results in structural distortion favorable for further high temperature transition. In fact, the lattice constant a averaged over the employed supercell shrinks and then the averaged As-Fe-As angle α approaches 109.47° with increasing the hydrogen doping amount. Moreover, the calculations clarify electron doping effects of the solute hydrogen and resultant Fermi-level shift. These insights are useful for design of high transition-temperature iron-based superconductors.

39001133
Composite excitation of Josephson phase and spin waves in Josephson junctions with ferromagnetic insulator
Hikino, Shinichi*; Mori, Michiyasu; Takahashi, Saburo; Maekawa, Sadamichi
Journal of the Physical Society of Japan 80(7), p.074707_1-074707_8(2011) ; (JAEA-J 09392) [link]

Coupling of Josephson-phase and spin-waves is theoretically studied in a superconductor/ferromagnetic insulator/superconductor (S/FI/S) junction. Electromagnetic (EM) field inside the junction and the Josephson current coupled with spin-waves in FI are calculated by combining Maxwell and Landau-Lifshitz-Gilbert equations. In the S/FI/S junction, it is found that the current-voltage (I-V) characteristic shows two resonant peaks for each mode of the EM field. Voltages at the resonant peaks are obtained as a function of the normal modes of EM field, which indicates a composite excitation of the EM field and spin-waves in the S/FI/S junction. We also examine another type of junction, in which a nonmagnetic insulator (I) is located at one of interfaces between S and FI. In such an S/I/FFI/S junction, three resonant peaks appear in the I-V curve, since the Josephson-phase couples to the EM field in the I layer.

39001134
Giant enhancement of spin accumulation and long-distance spin precession in metallic lateral spin valves
Fukuma, Yasuhiro*; Le, W.*; Izuchi, Hiroshi*; Takahashi, Saburo; Maekawa, Sadamichi; Otani, Yoshichika*
Nature Materials 10(7), p.527-531(2011) ; (JAEA-J 09393) [link]

The non-local spin injection in lateral spin valves is strongly expected to be an effective method to generate a pure spin current for potential spintronic application. However, the spin-valve voltage, which determines the magnitude of the spin current flowing into an additional ferromagnetic wire, is typically of the order of 1μV. Here we show that lateral spin valves with low-resistivity NiFe/MgO/Ag junctions enable efficient spin injection with high applied current density, which leads to the spin-valve voltage increasing 100-fold. Hanle effect measurements demonstrate a long-distance collective 2π spin precession along a 6-μm-long Ag wire. These results suggest a route to faster and manipulable spin transport for the development of pure spin-current-based memory, logic and sensing devices.

39001135
Effects of complex symmetry-breakings on alpha particle power loads on first wall structures and equilibrium in ITER
Shinohara, Koji; Kurki-Suonio, T.*; Spong, D. A.*; Asunta, O.*; Tani, Keiji*; Strumberger, E.*; Briguglio, S.*; Koskela, T.*; Vlad, G.*; Günter, S.*; Kramer, G.*; Putvinski, S.*; Hamamatsu, Kiyotaka; ITPA Topical Group on Energetic Particles*
Nuclear Fusion 51(6), p.063028_1-063028_12(2011) ; (JAEA-J 09394) [link]

Within the ITPA Topical Group on Energetic Particles, we have investigated the impact of the axisymmetry breaking of the tokamak in ITER. First, the validity of using a 2D equilibrium was investigated: a 3D equilibrium was reconstructed using the VMEC code, and it was verified that no 3D equilibrium reconstruction is needed but it is sufficient to add the vacuum field perturbations onto an 2D equilibrium. Then the alpha particle confinement was studied using ASCOT, and F3D OFMC codes. The distribution of the power load was found to depend on the first wall shape. We also made the first attempt to accommodate the effect of fast ion related MHD on the wall loads in ITER using the HMGC and ASCOT codes. The peak power flux to the wall was found to increase by an order of magnitude. Furthermore, the effect of 3D field which was produced by the ELM mitigation coil on the fast ion confinement was addressed by simulating NBI ions with the F3D OFMC code. The loss power fraction of NBI ions was found to increase from 0.3% to 4-5%.

39001136
Mechanisms of plasma rotation effects on the stability of type-I edge-localized mode in tokamaks
Aiba, Nobuyuki; Furukawa, Masaru*; Hirota, Makoto; Oyama, Naoyuki; Kojima, Atsushi; Tokuda, Shinji*; Yagi, Masatoshi
Nuclear Fusion 51(7), p.073012_1-073012_9(2011) ; (JAEA-J 09395) [link]

We investigate numerically the destabilizing effect of a toroidal rotation on the edge localized MHD mode, which induces the large amplitude edge localized mode (ELM). As the results of this analysis, we reveal that the toroidal rotation with shear can destabilize this MHD mode, and the destabilization is caused by the difference between the plasma rotation frequency and the frequency of the unstable mode. Based on these results, we investigate numerically the stability of JT-60U type-I ELMy H-mode plasmas, and show that the toroidal rotation plays an important role for making the difference of ELM behavior observed in JT-60U plasmas with different plasma rotation profiles.

39001137
Current ramps in tokamaks; From present experiments to ITER scenarios
Imbeaux, F.*; Citrin, J.*; Hobirk, J.*; Hogeweij, G. M. D.*; Köchl, F.*; Leonov, V. M.*; Miyamoto, Seiji; Nakamura, Yukiharu*; Parail, V.*; Pereverzev, G. V.*; Polevoi, A.*; Voitsekhovitch, I.*; Basiuk, V.*; Budny, R.*; Casper, T.*; Fereira, J.*; Fukuyama, Atsushi*; Garcia, J.*; Gribov, Y.*; Hayashi, Nobuhiko; Honda, Mitsuru; Hutchinson, I. H.*; Jackson, G.*; Kavin, A. A.*; Kessel, C. E.*; Khayrutdinov, R. R.*; Labate, L.*; Litaudon, X.*; Lomas, P. J.*; Lönnroth, J.*; Luce, T.*; Lukash, V. E.*; Mattei, M.*; Mikkelsen, D. R.*; Nunes, I.*; Peysson, Y.*; Politzer, P.*; Schneider, M.*; Sips, G.*; Tardini, G.*; Wolfe, S. M.*; Zhogolev, V.*; ASDEX Upgrade Team*; C-Mod Team*; DIII-D Team*; JET-EFDA Contributors*; JT-60U Team; Tore Supra Teams*; Contributors of the EU-ITM ITER Scenario Modelling Group*; ITPA "Integrated Operation Scenarios" Group*; ITPA "Transport and Confinement" Group*
Nuclear Fusion 51(8), p.083026_1-083026_11(2011) ; (JAEA-J 09396) [link]

In order to prepare adequate current ramp-up and ramp-down scenarios for ITER, present experiments from various tokamaks have been analysed by means of integrated modelling in view of determining relevant heat transport models for these operation phases. A set of empirical heat transport models for L-mode has been validated on a multi-machine experimental dataset for predicting the l_i dynamics within ±0.15 accuracy during current ramp-up and ramp-down phases. The most accurate heat transport models are then applied to projections to ITER current ramp-up, focusing on the baseline inductive scenario (main heating plateau current of I_p = 15 MA). These projections include a sensitivity study to various assumptions of the simulation. While the heat transport model is at the heart of such simulations, more comprehensive simulations are required to test all operational aspects of the current ramp-up and ramp-down phases of ITER scenarios. Recent examples of such simulations, involving coupled core transport codes, free-boundary equilibrium solvers and a poloidal field (PF) systems controller are also described, focusing on ITER current ramp-down.

39001138
Sodium experiments of buoyancy-driven penetration flow into low-power subassemblies in a sodium-cooled fast reactor during natural circulation decay heat removal
Kamide, Hideki; Kobayashi, Jun; Hayashi, Kenji
Nuclear Technology 175(3), p.628-640(2011) ; (JAEA-J 09397) [link]

Natural circulation has a significant role in the decay heat removal function of a sodium cooled reactor. The dipped heat exchanger (DHX) immersed in a reactor upper plenum provides cold sodium in the upper plenum during the decay heat removal operation. This cold sodium covers the top of the core under the natural circulation. Sodium experiments were carried out to find onset condition and penetration depth of such partial reverse flow driven by buoyancy force. A blanket subassembly and the upper plenum were modeled in the test section including an axial upper neutron shielding of the subassembly. The experimental parameters were temperature difference between hot upward flow in the channel and cold fluid in the upper plenum and flow velocity in the channel. The onset conditions of the penetration flow were correlated with Gr and Re numbers as well as basic water experiments. The observed penetration depths were limited in the upper axial neutron shielding of the subassembly.

39001139
Incorporation of the effect of the composite electric fields of molecular ions as a simulation tool for biological damage due to heavy-ion irradiation
Moribayashi, Kengo
Physical Review A 84(1), p.012702_1-012702_7(2011) ; (JAEA-J 09398) [link]

We theoretically study the DNA damage due to the effect of the composite electric field of H₂O⁺ ions produced from the irradiation of a C⁶⁺ ion with the energies of a few MeV/u and a proton with the energy of a few 100 keV/u to 1 MeV/u. We develop a new model for heavy particle irradiation in order to treat this composite electric field. We have found that the number of electrons trapped in the composite electric field depends on the cross sections of heavy particle impact ionization. We have also found that a larger number of electrons is produced due to the existence of the composite electric fields in the case of the irradiation of a C⁶⁺ ion with the energies of a few MeV/u. This may promote the DNA damage, in particular, cluster DNA damage. The models given in this paper are also important in atomic and molecular elementary processes in electric fields and in the production of plasmas due to heavy particle irradiation.

39001140
Search for a 2-quasiparticle high-K isomer in ²⁵⁶Rf
Robinson, A. P.*; Khoo, T. L.*; Seweryniak, D.*; Ahmad, I.*; Asai, Masato; Back, B. B.*; Carpenter, M. P.*; Chowdhury, P.*; Davids, C. N.*; Greene, J.*; Greenlees, P. T.*; Hauschild, K.*; Heinz, A.*; Herzberg, R. -D.*; Janssens, R. V. F.*; Jenkins, D. G.*; Jones, G. D.*; Ketelhut, S.*; Kondev, F. G.*; Lauritsen, T.*; Lister, C. J.*; Lopez-Martens, A.*; Marley, P.*; McCutchan, E.*; Papadakis, P.*; Peterson, D.*; Qian, J.*; Rostron, D.*; Shirwadkar, U.*; Stefanescu, I.*; Tandel, S. K.*; Wang, X.*; Zhu, S.*
Physical Review C 83(6), p.064311_1-064311_7(2011) ; (JAEA-J 09399) [link]

We have identified an isomer with a half-life of 17 μs in ²⁵⁶Rf through a calorimetric conversion electron measurement tagged with implanted ²⁵⁶Rf nuclei using the fragment mass analyzer at Argonne National Laboratory. The low population yield for this isomer suggests that this isomer should not be a 2-quasiparticle high-K isomer which is typically observed in the N = 152 isotones, but should be a 4-quasiparticle one. Possible reasons of the non-observation of a 2-quasiparticle isomer are this isomer decays by fission with a half-life similar to that of the ground state of ²⁵⁶Rf. Another possibility, that there is no 2-quasiparticle isomer at all, would imply an abrupt termination of axially symmetric deformed shape at Z=104.

39001141
Neoclassical transport modeling compatible with a two-fluid transport equation system
Honda, Mitsuru; Fukuyama, Atsushi*; Nakajima, Noriyoshi*
Plasma and Fusion Research (Internet) 6, p.1403008_1-1403008_11(2011) ; (JAEA-J 09400) [link]

A neoclassical transport model compatible with a system of two-fluid equations is proposed. The model is based on the moment approach and is capable of accurately reproducing important neoclassical properties through a simple expression of the neoclassical viscosity tensor, with the aid of the NCLASS module. Applying neoclassical transport theory in a fluid context, we obtain good agreement on first-order flows, poloidal flows, neoclassical resistivity, bootstrap current and particle flux from TASK/TX and NCLASS.

39001142
Gyrokinetic simulations of turbulent transport; Size scaling and chaotic behaviour
Villard, L.*; Bottino, A.*; Brunner, S.*; Casati, A.*; Chowdhury, J.*; Dannert, T.*; Ganesh, R.*; Garbet, X.*; Görler, T.*; Grandgirard, V.*; Hatzky, R.*; Idomura, Yasuhiro; Jenko, F.*; Jolliet, S.; Khosh Aghdam, S.*; Lapillonne, X.*; Latu, G.*; McMillan, B. F.*; Merz, F.*; Sarazin, Y.*; Tran, T. M.*; Vernay, T.*
Plasma Physics and Controlled Fusion 52(12), p.124038_1-124038_18(2010) ; (JAEA-J 09401) [link]

This paper presents some of the main recent advances in gyrokinetic theory and computing of turbulence. A past controversy regarding the finite size (finite ρ^*) effect in ITG turbulence has now been resolved. Now, both Eulerian and Lagrangian global codes are shown to agree and to converge to the flux-tube result in the ρ^* → 0 limit. It is found, however, that an appropriate treatment of geometrical terms is necessary. Turbulent processes are characterized by a chaotic behavior, often accompanied by bursts and avalanches. Performing ensemble averages of statistically independent simulations, starting from different initial conditions, is presented as a way to assess the intrinsic variability of turbulent fluxes and obtain reliable estimates of the standard deviation.

39001143
Development of the PARASOL code and full particle simulation of tokamak plasma with an open-field SOL-divertor region using PARASOL
Takizuka, Tomonori
Plasma Science and Technology 13(3), p.316-325(2011) ; (JAEA-J 09402) [link]

In order to investigate the particle and heat control with divertor system of fusion reactors, numerical simulations have been widely carried out. Fluid codes require further improvement of physics modeling for edge plasmas. The full particle simulation is powerful to study fundamental physics of open-field SOL-divertor plasmas as well as of the whole tokamak plasma including SOL-divertor region. PARASOL code with PIC method and binary collision model has been developed in JAERI and JAEA. Simulations with PARASOL code have been carried out for the above purpose. The one-dimensional (1D) version of PARASOL was applied to investigate the Bohm criterion, the supersonic flow, the SOL heat conduction, and so on. The ELM heat propagation was studied with the 1D-dynamic PARASOL. The two-dimensional version of PARASOL for the whole tokamak plasma with SOL-divertor region was useful to simulate the SOL flow pattern, the electric field formation etc. Based on PARASOL simulation results, physics modeling for the fluid simulation has been developed.

39001144
Thermoresponsive extraction of cadmium(II) ions by poly(TPEN-NIPA) gels; Effect of chain length and branched spacer structure on gel formation and extraction behavior
Inaba, Yusuke*; Tsumagari, Takayuki*; Kida, Tatsuya*; Watanabe, Wataru*; Nakajima, Yasutaka*; Fukuoka, Sachio*; Mori, Atsunori*; Matsumura, Tatsuro; Nakano, Yoshio*; Takeshita, Kenji*
Polymer Journal 43(7), p.630-634(2011) ; (JAEA-J 09403) [link]

N,N,N',N'-(tetrakis-2-pyridylmethyl)ethylenediamine (TPEN) derivatives bearing a polymerizable double bond in the substituent structure of the pyridine ring are synthesized and subjected to copolymerization with N-isopropylacrylamide in the presence of AIBN. The obtained poly(TPEN-NIPA) gels show thermo-responsive swelling/shrinking behaviors and are employed for the extraction of cadmium(II) ion from the aqueous solution to examine the relationship of the gel characteristics and the extraction performance. The polymer gels composed of the TPEN derivative bearing C3, C4, C10 and branched C3 spacer chains are synthesized and temperature-dependent extraction behavior of cadmium ion is compared. These gels extract Cd(II) ion efficiently from the aqueous solution in the swelling state at 5°C, while little extraction is observed at 45°C with shrinking. It is found that poly(TPEN-NIPA) gel of branched C3 spacer (C3b) shows the excellent thermoresponsive extraction performance.

39001145
Retrospective dosimetry using Japanese brick quartz; A Way forward despite an unstable fast decaying OSL signal
Fujita, Hiroki; Jain, M.*; Murray, A. S.*
Radiation Measurements 46(6-7), p.565-572(2011) ; (JAEA-J 09404) [link]

Quartz extracted from burnt bricks has been previously suggested for use in dose estimation in accident dosimetry. In this study the thermoluminescence (TL) and optically stimulated luminescence (OSL) characteristics of quartz extracted from a Japanese commercial red brick produced by Mishima - Renga - Seizoujyo Co. are studied. A comparison of TL and OSL signals allows identification of common source traps. It is observed that OSL from the Japanese brick quartz shows unusual thermal and optical decay characteristics. In particular, the initial OSL signal contains a dominant thermally unstable component, which necessitates a prior heat treatment. Based on these luminescence characteristics, a single - aliquot regenerative - dose (SAR) protocol is developed and tested. Using this OSL SAR protocol a minimum detection limit of ∼ 65 mGy was estimated; this value is similar to that from violet TL dosimetry and similar to that obtained using electron spin resonance dosimetry. Finally, dose - depth profiles after irradiation using ⁶⁰Co and ¹³⁷Cs were measured on two different commercial brick types (Mishima - Renga - Seizoujyo Co. and Hase - Renga Co.). The dose - depth profiles obtained using these sources were distinguishable within experimental errors. It is concluded that OSL from Japanese brick quartz could be used successfully to derive precise estimates of accident dose, and, possibly, distinguish between sources of γ radiation in a nuclear accident.

39001146
LET and dose rate effect on radiation-induced copolymerization of maleimide with styrene in 2-propanol solution
Nakagawa, Seiko*; Taguchi, Mitsumasa; Kimura, Atsushi
Radiation Physics and Chemistry 80(11), p.1199-1202(2011) ; (JAEA-J 09406) [link]

N₂-saturated 2-propanol solutions containing styrene and maleimide were irradiated by electron, proton, He and C-ion beams. The styrene-maleimide copolymer was produced by radical polymerization induced during irradiation. The effects of the radical distribution, which depends on the LET or dose rate, on the molecular weight and the polymer yield were discussed. Both the molecular weight and the polymer yield increased by the decreasing dose rate. These effects increased by irradiation using heavier ions. The polymer yield decreased with the increasing LET value. On the other hand, irradiation at a higher LET value and lower dose rate will produce a polymer with a higher molecular weight. The distribution of radicals in time and space will have an influence on both the molecular weight and the polymer yield.

39001147
Induction of DNA DSB and its rejoining in clamped and non-clamped tumours after exposure to carbon ion beams in comparison to X-rays
Hirayama, Ryoichi*; Uzawa, Akiko*; Matsumoto, Yoshitaka*; Noguchi, Miho; Kase, Yuki*; Takase, Nobuhiro*; Ito, Atsushi*; Koike, Sachiko*; Ando, Koichi*; Okayasu, Ryuichi*; Furusawa, Yoshiya*
Radiation Protection Dosimetry 143(2-4), p.508-512(2011) ; (JAEA-J 09407) [link]

We studied double-strand breaks (DSB) induction and rejoining in clamped and non-clamped transplanted tumours in mice leg after exposure to 80 keV/μm carbon ions and X-rays. The yields of DSB in the tumours were analysed by a static-field gel electrophoresis. The OER of DSB after X-rays was 1.68, and this value was not changed after 1 h rejoining time (1.40). These damages in oxygenated conditions were rejoined 60-70% within 1 h in situ. No difference was found between the exposure to X-rays and carbon ions for the induction and rejoining of DSB. Thus, the values of OER and rejoined fraction after exposure to carbon ions were similar to those after X-rays, and the calculated relative biological effectivenesses of carbon ion were around 1 under both oxygen conditions. The yields of DSB in vivo depend on exposure doses, oxygen conditions and rejoining time, but not on the types of radiation quality.

39001148
Management of cosmic radiation exposure for aircraft crew in Japan
Yasuda, Hiroshi*; Sato, Tatsuhiko; Yonehara, Hidenori*; Kosako, Toshiso*; Fujitaka, Kazunobu*; Sasaki, Yasuhito*
Radiation Protection Dosimetry 146(1-3), p.123-125(2011) ; (JAEA-J 09408) [link]

The National Institute of Radiological Sciences (NIRS) has helped the airlines companies to follow the guideline, particularly for the calculation of aviation route doses. The presentation will show the annual individual doses of aircraft crew calculated for the 2007 fiscal year.

39001149
Study on migration behaviour of ²³⁷Np and ²⁴¹Am in near-surface environments
Tanaka, Tadao; Ya-Anant, N.*
Radiation Protection Dosimetry 146(1-3), p.303-306(2011) ; (JAEA-J 09409) [link]

Laboratory scale experiments were performed to investigate migration behavior of ²³⁷Np and ²⁴¹Am, which were deposited onto the ground surface from spent fuel reprocessing facilities, in near-surface environment. Column migration experiments were conducted by varying the volume of eluting solution, for a sandy soil and a reddish soil. There seemed to be two chemical species of ²³⁷Np in the sandy soil column; one is cationic and the other is particulate form. The particulates moved without significant interaction with the sandy soil. The sorption of cationic ²³⁷Np was controlled by both a reversible ion-exchange reaction and irreversible reactions. Most of ²⁴¹Am formed rather large particulates and trapped in the sandy soil column. The ²³⁷Np and ²⁴¹Am loaded into the reddish soil column moved deeper with increasing eluting volume. The sorption was mainly controlled by ion-exchange reaction. The migration behavior could be significantly evaluated by the distribution coefficient.

39001150
Production and properties of transuranium elements
Nagame, Yuichiro; Hirata, Masaru
Radiochimica Acta 99(7-8), p.377-393(2011) ; (JAEA-J 09411) [link]

We summarize historical perspective of the transuranium elements, neptunium (Np) through lawrencium (Lr), and recent progress on production, and nuclear and chemical properties of these elements. Exotic decay properties of heavy nuclei are also introduced. Chemical properties of transuranium elements in aqueous and solid states are summarized based on the actinide concept.

39001151
Factors controlling mobility of ¹²⁷I and ¹²⁹I species in an acidic groundwater plume at the Savannah River Site
Otosaka, Shigeyoshi; Schwehr, K.*; Kaplan, D.*; Roberts, K.*; Zhang, S.*; Xu, C.*; Li, H.-P.*; Ho, Y.-F.*; Brinkmeyer, R.*; Yeager, C.*; Santschi, P.*
Science of the Total Environment 409(19), p.3857-3865(2011) ; (JAEA-J 09412) [link]

Spatial distributions of concentrations and speciation of radioiodine (¹²⁹I) and stable iodine (¹²⁷I) in groundwater in the vicinity of the F-area seepage basin at the U.S. Department Energy of Savannah River Site were investigated. ¹²⁹I concentration in groundwater was 8.6 Bq/L immediately downstream of the seepage basin (well FSB-95DR), and decreased with distance from the infiltration basin. ¹²⁷I concentration decreased similarly to that of ¹²⁹I. Although there was no potential ¹²⁷I source in wastes in the basin, ¹²⁷I also showed a similar gradient to that of ¹²⁹I. High concentrations of ¹²⁷I or ¹²⁷I were not detected in groundwater collected from wells located outside of the mixed waste plume of this area. The high iodide concentrations in groundwater near the basin were presumed to be caused by dissolution of iodide from soil due to gradually increasing of pH values in the last decade.

39001152
Material attractiveness analysis of protected plutonium production for fast breeder reactors
Permana, S.; Suzuki, Mitsutoshi; Saito, Masaki*
Transactions of the American Nuclear Society 104(1), p.714-715(2011) ; (JAEA-J 09413)

Material attractiveness concepts for evaluating the level of proliferation resistance of nuclear fuel have been evolving and can be useful for determining general rules to assess the potential use of nuclear material for explosive devices. The two approaches examined here for evaluating material attractiveness are the attractiveness (ATTR) and figure of merit (FOM) concepts. Similar trend of material attractiveness level with ATTR and FOM is obtained by introducing MA doping in the blanket region and these loading MA is effective to reduce the material attractiveness level to practically unusable level of ATTR and low attractiveness level of FOM2.

39001153
A Study of shallow groundwater flow based on groundwater level and geological structures in the Horonobe area, Hokkaido (in Japanese)
Yokota, Hideharu; Yamamoto, Yoichi; Maekawa, Keisuke
Chikasui Gakkai-Shi 53(2), p.193-206(2011) ; (JAEA-J 09415) [link]

It is important for assessing the safety of geological disposal of high-level radioactive waste to understand shallow to deep groundwater flow as the driving force of mass transport. JAEA has been carrying out the surface hydrological investigation in the Horonobe area, Hokkaido. Results of groundwater-level observations, and relationship between distributions of groundwater-level and geological structures suggest that constructions of underground facilities have no effect on shallow groundwater-level fluctuations, and that water infiltrate from ground surface into shallow underground in the snow covered season, and that water infiltrate into deeper underground along faults. In the future, it is necessary to quantitatively assess the water infiltration and recharge based on directly and/or indirectly observed data of evapotranspiration and soil moisture content by weighing lysimeter and ADR method soil moisture meter, and tensiometer.

39001154
Long-term impact on the marine environment; Simulation of the marine dispersion of released radionuclides from Fukushima-Daiichi Nuclear Power Plant and estimation of internal dose from marine products (in Japanese)
Nakano, Masanao
Nippon Genshiryoku Gakkai-Shi 53(8), p.559-563(2011) ; (JAEA-J 09416) [link]

Significant radioactive release was happened from the Fukushima-Daiichi Nuclear Power Plant after the attack of big tsunami at 11th March, 2011. The calculation code LAMER, developed by JAEA, performed the long-term and worldwide diffusion of radioactive materials in seawater, then estimated the radioactive concentration in seawater and internal dose by consumption of marine products. Assuming 8.45 PBq release, the seawater concentration in April 2012 was calculated to be 23 Bq/m³ for ¹³⁷Cs at most, which is 14 times higher than the present background level. The internal dose by ¹³¹I, ¹³⁴Cs, ¹³⁷Cs in marine products was calculated to be 1.8μSv/a at most, which are comparable with the past dose induced by the past atmospheric nuclear tests.

39001155
Effect of the Fukushima accident to Europe and the United States; The United States and France firmly keep nuclear power generation and Germany decided to gradually exit; International organizations promote sharing of information and lessons from Fukushima (in Japanese)
Kitamura, Takafumi; Hanai, Tasuku; Sato, Ikken
Nippon Genshiryoku Gakkai-Shi 53(8), p.569-575(2011) ; (JAEA-J 09417) [link]

Japan is a country far away from Europe and the US. The news of the accident occurred in this country was immediately reached to countries throughout the world and the image of the explosion was repeated on TV screens. This accident aroused various discussions on nuclear policy. The responses of countries divided with the US and France maintaining the stance of promoting nuclear power and Germany and Italy clarifying its policy to withdraw from nuclear energy. This report provides information on the responses to the accident taken by the US and other states.

39001156
Review of the recent development and release of the PHITS code (in Japanese)
Sato, Tatsuhiko
RIST News (51), p.13-19(2011) ; (JAEA-J 09420) [link]

We review the recent development and release of the PHITS code.

39001157
Development of thermal-hydraulic nuclear safety analysis code in Japan and overseas countries (in Japanese)
Nakamura, Hideo
RIST News (51), p.30-42(2011) ; (JAEA-J 09421) [link]

Long-term core cooling against any possible accident situations should be firmly secured and confirmed by the safety analyses using computer codes during the design phase of nuclear power plant. The accident at Fukushima Daiichi made us duly aware of incompleteness in the assumptions made for the safety analyses as well as the importance of the computer codes that accurately analyze such accidents. This paper tries to remind kinds, methods of utilization and development status of the computer codes for safety analysis, and to briefly review recent development efforts of such computer codes in Korea and China, both to re-consider how our code development should be in Japan.

39001158
Characterization of initial oxidation process on high-index silicon surfaces by real-time photoemission spectroscopy (in Japanese)
Ono, Shinya*; Inoue, Kei*; Morimoto, Masahiro*; Arae, Sadanori*; Toyoshima, Hiroaki*; Yoshigoe, Akitaka; Teraoka, Yuden; Ogata, Shoichi*; Yasuda, Tetsuji*; Tanaka, Masatoshi*
Shingaku Giho 111(114), p.23-27(2011) ; (JAEA-J 09422) [link]

The initial oxidation on high-index silicon surfaces with (113) and (120) orientations at 820 K has been investigated by real-time X-ray photoemission spectroscopy (Si 2p and O 1s) using 687 eV photons. The time evolutions of the Siⁿ⁺ (n=1-4) components in the Si 2p spectrum indicate that the Si²⁺ state is suppressed on high-index surfaces compared with Si(001). The O 1s state consists of two components, a low-binding-energy component (LBC) and a high-binding-energy component (HBC). It is suggested that the O atom in strained Si-O-Si contributes to the LBC component. The reaction rates are slower on high-index surfaces compared with that on Si(001).

39001159
Prediction of creep-fatigue life based on fracture energy in modified 9Cr-1Mo steel (in Japanese)
Nagae, Yuji
Tainetsu Kinzoku Zairyo Dai-123-Iinkai Kenkyu Hokoku 52(2), p.125-134(2011) ; (JAEA-J 09423)

39001160
Manufacturability and strength assessment of modified 9Cr-1Mo steel products for Japan sodium cooled fast reactor components, 1; Forging with large thickness (in Japanese)
Nagae, Yuji; Enuma, Yasuhiro*; Oshikiri, Masato*; Date, Shingo*; Toyoshi, Akira*; Aizawa, Taiki*; Koyama, Yoichi*; Yanagisawa, Yusuke*
Tainetsu Kinzoku Zairyo Dai-123-Iinkai Kenkyu Hokoku 52(2), p.161-169(2011) ; (JAEA-J 09424)

39001161
Manufacturability and strength assessment of modified 9Cr-1Mo steel products for Japan sodium cooled fast reactor components, 2; Long thin-walled tubes with small diameter (in Japanese)
Wakai, Takashi; Onizawa, Takashi; Obara, Satoshi; Nakashima, Takashi*; Yokoyama, Tetsuo*; Iseda, Atsuro*; Ogumo, Shinya*; Futagami, Satoshi*
Tainetsu Kinzoku Zairyo Dai-123-Iinkai Kenkyu Hokoku 52(2), p.171-181(2011) ; (JAEA-J 09425)

To enhance the economic competitiveness, high-Cr ferritic steels are adopted as the structural materials for JSFR, because the steels have both excellent high temperature strength and thermal properties. Among the high-Cr ferritic steels, modified 9Cr-1Mo steel (compatible to ASTM A213 T91) is a candidate of the structural material for the demonstration facility of JSFR, because the steel has superior microstructure stability at elevated temperature for long time. As for the steam generator tubes, to enhance the safety, straight double-walled tubes will be employed. In this study, the following technical issues were investigated; (1) Industrial manufacturability of thin-walled small bore tubes made of modified 9Cr-1Mo steel, (2) performance demonstration of the thin-walled small bore tubes, (3) industrial manufacturability of double-walled tubes using the thin-walled small bore tubes and (4) extraction of technical problems to manufacture the double-walled tubes for the JSFR steam generator. As a result, thin-walled small bore tubes made of modified 9Cr-1Mo steel were successfully manufactured by using the existing industrial facilities, up to 17m in length. The mechanical properties of the tubes satisfy the requirements from plant designing, as well as those from the material strength standards. Further, double walled tubes were also manufactured, up to 15m in length. The surface conditions of the tubes and the contact pressure between inner and outer tubes should be optimized.

39001162
Features of the J-PARC linac
Kobayashi, Tetsuya
AIP Conference Proceedings 1336 , p.29-32(2011) ; (JAEA-J 09426) [link]

Japan Proton Accelerator Research Complex (J-PARC) will be one of the highest intensity proton accelerators in the world aiming to realize 1 MW class of the beam power. The accelerator consists of a 400-MeV linac, a 3-GeV rapid-cycling synchrotron (RCS) and a main ring synchrotron (MR), and the accelerated beam is applied to several experimental facilities. The acceleration field error in all of them should be within ±1% in amplitude and ±1 degree in phase because the momentum spread of the RCS injection beam is required to be within ±0.1%. For the cavity field stabilization, a high-stable optical signal distribution system is used as the RF reference, and sophisticated digital feedback and feed-forward system is working well in the low level RF control system. Consequently the providing beam to the RCS is very stable, and the beam commissioning and the experiments of the application facilities have been progressed steadily.

39001163
Refreshable decrease in peak height of ion beam induced transient current from silicon carbide metal-oxide-semiconductor capacitors
Oshima, Takeshi; Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Deki, Manato; Nozaki, Shinji*
AIP Conference Proceedings 1336 , p.660-664(2011) ; (JAEA-J 09427) [link]

Metal-Oxide-Semiconductor (MOS) capacitors were fabricated on n-type 4H- and 6H-SiC epitaxial layers, and transient currents induced in SiC MOS capacitors by ion incidence were investigated. Transient Ion Beam Induced Current (TIBIC) measurements were performed using 15 MeV oxygen ions. As a result, the TIBIC peak height decreased with increasing number of incident ions. For example, the TIBIC signal peak for a 4H-SiC MOS capacitor at a reverse bias of 15 V was 0.18 mA at the beginning. The peak decreased to be 0.10 mA after 1800 ion irradiation. After that, the forward bias of 1 V was applied to the MOS capacitor and the TIBIC measurements were carried out under the same conditions. As a result, the peak height was recovered to be 0.18 mA. In general, the response of charge de-trapping by deep levels in wide bandgap semiconductors is very slow and they act as fixed charge. Since dense electron-hole pairs are generated by ion incident and holes move to the SiO₂/SiC interface by the electric field (applied reverse bias). Therefore, the decrease in TIBIC signal peak can be interpreted in terms of the recombination of negatively charged acceptor type deep levels with ion induced holes.

39001164
Neutron diffraction study of hydrogen-ordered ice XI; Annealing effect and memory effect
Arakawa, Masashi*; Kagi, Hiroyuki; Fernandez-Baca, J. A.*; Chakoumakos, B. C.*; Fukazawa, Hiroshi
Physics and Chemistry of Ice 2010 , p.329-338(2011) ; (JAEA-J 09428)

We measured neutron diffraction profiles of KOD, NaOD, LiOD, Ca(OD)₂, and ND₃-doped ices. Ice XI, which is a hydrogen-ordered phase of normal ice (ice Ih), was observed in the KOD and NaOD-doped ices although Ca(OD)₂ and ND₃-doped ice did not transformed to ice XI. The mass fraction of ice XI to that of the doped ice (f) was estimated using Rietveld analysis for each doped ice. The f value of the doped ice, which had once experienced being ice XI, was larger than that of the doped ice, which had never experienced being ice XI. The large f value of the doped ice indicates that small hydrogen-ordered domains remained above the transition temperature between ice XI and Ih. Our results suggest that large amounts of ice on icy bodies in our solar system can transform to ice XI. In this paper, we discussed the existence of the small hydrogen-ordered domains in space and the evolution of icy grain.

39001165
Circulation improvement of articles in journals written in non-english languages; A Special journal titles translation list of journals written in Japanese for the international bibliographical database
Gonda, Mayuki; Kunii, Katsuhiko; Nakajima, Hidemitsu; Ikeda, Kiyoshi; Itabashi, Keizo; Koike, Akemi*; Igarashi, Ayumi*
Proceedings of 12th International Conference on Grey Literature (GL-12) , p.113-117(2011) ; (JAEA-J 09429)

Circulation of scientific information improves internationally today, and English which is "universal language" takes the leading part for scientific communication. On the other hand, non-English articles are still "gray literatures" due to language barriers though physical circulation improves as well as English articles. In the International Nuclear Information System (INIS) database operated by the International Atomic Energy Agency (IAEA), bibliographic information such as title and abstract etc. is written in English. This feature of the INIS database contributes to international circulation of scientific information of the nuclear field. However, titles of journals written by non-English language were described by transliterated Roman alphabet, non-native users cannot understand natures and subjects of journals written by non-English language. Non-native users cannot understand the nature of the journal with this journal title description, and then they fail to get the useful article. This language barrier should be broken through as soon as possible for circulation improvement of journals written by non-English language. So we develop a special journal titles translation list of journals written in Japanese for the INIS database, as attempt to improve circulation of articles in journals written by non-English language. We will release this list on the INIS database for circulation improvement of journals written by non-English language, and we will implement the list into the database for user's convenience in the future.

39001166
Graft-type polymer electrolyte membranes consisting of poly(ether ether ketone) prepared by radiation technique
Maekawa, Yasunari; Hasegawa, Shin; Koshikawa, Hiroshi; Chen, J.
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.104-105(2011) ; (JAEA-J 09430)

We applied the radiation-induced grafting to poly(ether ether ketone) film, which was mechanically and thermally stable aromatic hydrocarbon polymers, so-called "super engineering plastics". The developed PEEK-based polymer electrolyte membrane (PEM) with 96 μm thickness exhibited 1.5 times higher conductivity and 2.3 times higher mechanical strength, compared with conventional fluorinated PEM. The single fuel cell device maintained stable operation over 1000 hours under the operation at 95°C. According to the high mechanical strength of PEEK substrates, we could reduce the film thickness of PEEK-based PEM down to 10 μm. The PEEK-based PEM with film thickness of 10 and 19 μm showed higher cell voltages than that of Nafion at the current density in the range from 0.2 to 1.0 A/cm².

39001167
Radiation-induced grafting of acrylonitrile monomer onto cellulose nonwoven fabric
Saiki, Seiichi; Puspitasari, T.*; Seko, Noriaki
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.124-125(2011) ; (JAEA-J 09431)

Cellulose has been studied as trunk polymer of radiation-induced grafting as well as synthetic polymers. However, cellulose is easy to be degraded and be brittle by irradiation. In this topic, to lower the dose for radiation-induced grafting on cellulose, radiation-induced grafting with o/w emulsion which has ever succeeded to achieve high degree of grafting on synthetic polymer with lower dose was studied using acrylonitrile monomer as a model of typical vinyl monomer. As a result, degree of grafting in the case of emulsion system increased remarkably compared to organic solvent system. And, from 10% to 20% of acrylonitrile monomer concentration, micelle size and degree of grafting increased with increment of acrylonitrile monomer concentration respectively. It is assumed that larger micelles accelerate grafting reaction. As a whole, the effectiveness of radiation emulsion grafting were elucidated even in the case of cellulose as well as trunk polymer.

39001168
Preparation of amine-type adsorbents with emulsion graft polymerization of 4-hydroxybutyl acrylate glycidylether
Ma, H.; Hoshina, Hiroyuki; Seko, Noriaki
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.132-135(2011) ; (JAEA-J 09432)

In this study, a pre-irradiation method was used for emulsion graft polymerization of 4-hydroxybutyl acrylate glycidylether (4-HB) onto polyethylene/polypropylene (PE/PP) nonwoven fabric. After 30 kGy irradiation, with 4-HB concentration of 5%, surfactant span 20 of 0.5% at 40 °C for 2 h, the trunk polymer was made grafted at a Dg of 135%. 4-HB-grafted PE/PP nonwoven fabric was modified by ethylenediamine (EDA). With a Dg of 135%, the amine group density of the adsorbent is 2.8 mol/g. The adsorption test was carried out by batch experiment in several metal ion solutions, and the removal ratio from the EDA modified adsorbent of the metal ions is in the order of Cu²⁺ > Pb²⁺ > Zn²⁺ > Ni²⁺ > Li⁺. Compared with glycidyl methacrylate (GMA) which is a typical functional monomer for graft polymerization, 4-HB-grafted adsorbent exhibited not only better mechanical property but also higher adsorption capacity of Cu²⁺ and Pb²⁺.

39001169
Recovery of precious metals using biomass
Hirota, Koichi; Parajuli, D.; Seko, Noriaki
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.136-137(2011) ; (JAEA-J 09433)

Conventional methods for the recovery of precious metals are solvent extraction, chemical precipitation, and use of ion exchange resins. However these methods are facing to significant disadvantages like high capital costs, large chemical and energy requirements, and generation of toxic sludge or other waste products creating additional burden. Development of biomass based sorbents is a better, probably the best, option with lower capital cost and higher efficiency. Although the biomass-sorbents are better than the existing methods, the methods of preparing sorbents from them usually use several kinds of chemicals. In the present work, biomass has been modified with functional groups after electron beam irradiation and its performance for the recovery of precious metals has been studied. The obtained results are compared with that of chemically modified derivative.

39001170
Development of a new grafting system for making metal adsorbent
Seko, Noriaki; Ueki, Yuji; Thi Yen Ninh, N.*; Bang, L. T.*; Tamada, Masao
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.140-141(2011) ; (JAEA-J 09434)

To make a practical synthesis process for metal adsorbents, we have developed a new emulsion grafting system instead of general organic solvent system. A glycidyl methacrylate (GMA) was used for precursor monomer which can be introduced many functional unit after grafting. The emulsion state of GMA in water with surfactants was stable during grafting time. Although irradiation dose was necessary 200 kGy to make adsorbents in organic system, in general, we found that a pre-irradiation dose could be reduced until 10 kGy. This result implies that water can be considered as an effective grafting solvent, and the new emulsion grafting system is high effective for grafting rate.

39001171
Synthesis of fibrous metal adsorbent by radiation-induced emulsion grafting of ethyl styrenesulfonate
Ueki, Yuji; Seko, Noriaki; Tamada, Masao
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.144-145(2011) ; (JAEA-J 09435)

A fibrous metal adsorbent was synthesized by radiation-induced emulsion grafting of ethyl styrenesulfonate (ETSS) onto a polyethylene nonwoven fabric, followed by hydrolysis of the ETSS grafted chains to form styrenesulfonate grafted chains. The degree of grafting (Dg) could be controlled up to 810% (4.2 mmol-ETSS/g-adsorbent) by changing the pre-irradiation dose, ETSS concentration, grafting temperature and grafting time. The sulfonic acid (SO₃H) group density and conversion ratio of ETSS reached 3.7 mmol-SO₃H/g-adsorbent and 88%, respectively. The performance of the fibrous metal adsorbent was evaluated by batchwise adsorption test of Cu(II). The adsorption rates of the fibrous adsorbents were 11 to 205 times higher than that of commercial granular resin, depending on the Dg of adsorbents. The adsorption equilibrium times of adsorbents having Dg of 50%, 100%, 200%, 400% and 700% were 7, 20, 60, 90 and 130 min, respectively (granular resin: > 24 h).

39001172
Development of grafted type poly(ether ether ketone) electrolyte membranes; Morphology of PEEK substrate and radiation-induced graft polymerization.
Hasegawa, Shin; Chen, J.; Koshikawa, Hiroshi; Iwase, Hiroki*; Koizumi, Satoshi; Onuma, Masato*; Maekawa, Yasunari; Iwase, Hiroki*
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.238-239(2011) ; (JAEA-J 09436)

Radiation-induced graft polymerization of sulfo-containing styrene derivatives into crystalline poly(ether ether ketone) (PEEK) substrates was carried out to prepare thermally and mechanically stable polymer electrolyte membranes based on an aromatic hydrocarbon polymer, so-called "super-engineering plastics". Graft polymerization of the sulfo-containing styrene, ethyl 4-styrenesulfonate (E4S) into PEEK substrates with degrees of crystallinity (DC) of 11 - 26% gradually progressed, achieving a grafting degree of more than 50% after 72 hours, whereas graft polymerization of the substrates with DC above 26% did not proceed. When morphological change in these films were measured by SAXS, PEEK films with DC larger than 26% showed a new peak at d=14 nm, corresponding to lamella structure. Thus, the suppression of graft polymerization of PEEK films with DC above 26% was due to obstruct of monomer diffusion by the formation of the oriented lamella structure.

39001173
Preparation of anion-exchange membranes for fuel cell applications by γ-ray pre-irradiation grafting
Koshikawa, Hiroshi; Yamaki, Tetsuya; Asano, Masaharu; Maekawa, Yasunari; Yamaguchi, Susumu*; Yamamoto, Kazuya*; Asazawa, Koichiro*; Yamada, Koji*; Tanaka, Hirohisa*
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.240-241(2011) ; (JAEA-J 09437)

The anion-exchange membranes (AEM) for fuel cells were prepared by the radiation-induced graft polymerization of chloromethylstyrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and subsequent quaternization of the grafts with trimethylamine. When the AEM were treated in 1M-KOH and washed with N₂-saturated water, the membranes with chloride form can be converted quantitatively to hydroxide form. However, the hydroxide form was easily converted to the bicarbonate form by the treatment in non-bubbled (CO₂ dissolved) water. When we introduced the crosslinkers in polymer grafts, which is proved to be very effective in the proton conducting PEM having a poly(styrenesulfonic acid) grafts, the grafted AEM with both chloride and hydroxide forms showed only slight decrease of water uptake. It should be noted that AEM with hydroxide form showed very high tendency to absorb water.

39001174
Radiation degradation of graft-type polymer electrolyte membranes
Sawada, Shinichi; Iwai, Yasunori; Yamanishi, Toshihiko; Maekawa, Yasunari
Proceedings of 12th International Conference on Radiation Curing in Asia (RadTech Asia 2011) (Internet) , p.242-243(2011) ; (JAEA-J 09438)

In the polymer-electrolyte-membrane (PEM) water electrolysis system in the international thermonuclear experimental reactor (ITER), the PEM material with high radiation resistivity is required. In this study, we investigated the radiation degradation behavior of the PEMs synthesized by radiation grafting method based on poly(ethylene-co-tetrafluoroethylene) (ETFE) and poly(etheretherketone) (PEEK) films. The PEMs were irradiated by 500-kGy γ-ray at 300 K, and then characterized in terms of their remaining weight, ion exchange capacity (IEC), proton conductivity, and breaking tensile strength (BTS). The ETFE-based PEM was significantly degraded in all the properties. Contrary to the ETFE PEMs, the PEEK PEM after irradiation did not lose their properties, probably because its aromatic hydrocarbon backbones were very resistant against irradiation. This result makes us expect that the PEEK PEM can be employed in the practical electrolyzer in ITER.

39001175
Preparation of reference materials on radiochemical analysis for low-level radioactive waste generated from Japan Atomic Energy Agency
Ishimori, Kenichiro; Kameo, Yutaka; Nakashima, Mikio*; Takahashi, Kuniaki
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM) , 7p.(2010) ; (JAEA-J 09439)

In order to prepare simulated reference materials of solidified products using a laboratory-scale electric furnace instead of a plasma heating device, melting tests of miscellaneous simulated solid wastes were conducted. Under the optimum melting conditions, reference materials containing α-ray emitting nuclides (²³⁷Np, ²⁴¹Am and ²⁴⁴Cm) or γ-ray emitting nuclides (⁶⁰Co, ¹³⁷Cs and ¹⁵²Eu) were prepared. For reference materials containing β-ray emitting nuclides such as ¹⁴C and ³⁶Cl, a preparation method with nuclear reaction ¹⁴N(n, p)¹⁴C or ³⁵Cl(n, γ)³⁶Cl by thermal neutron irradiation was attempted. The radioactivity concentrations of the reference materials were evaluated from radiochemical analysis. It was confirmed that the reference materials could be successfully prepared on the present preparation methods.

39001176
Study on evaluation models of management data for decommissioning of FUGEN
Shibahara, Yuji; Izumi, Masanori; Nanko, Takashi; Tachibana, Mitsuo; Ishigami, Tsutomu
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM) , 7p.(2010) ; (JAEA-J 09440)

In the Fugen nuclear power plant (FUGEN), the dismantling of equipments in the turbine building has started in 2008, and the dismantling of equipments around the reactor is scheduled around in 2015. To evaluate the management data on this dismantling of equipments around reactor appropriately, it is very important to study whether the conventional evaluation models have the applicability for FUGEN or not. The study on the evaluation models of management data for the dismantling of equipments in FUGEN is reported in this paper.

39001177
Development of an accurate methodology for measuring the pore fluid pH of low-pH cementitious materials
Alonso, M. C.*; García Calvo, J. L.*; Pettersson, S.*; Cuñado, M.*; Vuorio, M.*; Weber, H.*; Ueda, Hiroyoshi*; Naito, Morimasa; Walker, C.
Proceedings of 13th International Congress on the Chemistry of Cement (13th ICCC) (CD-ROM) , 7p.(2011) ; (JAEA-J 09441)

Low pH cementitious (LopHC) materials are expected to be used in the construction of an underground repository for the geological disposal of high level radioactive waste (HLW). A fundamental aspect of the development of LopHC is the accurate and reliable measurement of the pore fluid pH in order to qualify and help quantify mix designs to achieve specific pH targets. The main objective of the current research is the development of an agreed protocol for measuring the pH value of LopHC. There are four different methods described in the literature for characterizing the pore solution of cementitious materials: (1) Pore fluid expression; (2) Leaching methods, including both in-situ and ex-situ techniques); (3) Percolation methods; and (4) Embedded pH sensors. In a first step, different parameters that may affect the measured pH values were evaluated, including the solid/liquid ratio, fineness, carbonation, time, and the results obtained from a pH meter in comparison with an OH titration. Based on the results obtained from the first step, selected protocols were proposed and tested for reproducibility and repeatability in 8 laboratories of 7 countries using the same LopHC sample. The proposed methodologies showed very promising results with low deviation and high reproducibility and have allowed the development of an agreed set of simple protocols for the determination of pH in LopHC.

39001178
High temperature oxidation of FBR structural materials in carbon dioxide and in air
Furukawa, Tomohiro; Kato, Shoichi; Inagaki, Yoshiyuki; Aritomi, Masanori*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 5p.(2011) ; (JAEA-J 09442)

A key problem in the application of a supercritical carbon dioxide (CO₂) turbine cycle to a fast breeder reactor is the corrosion of structural materials brought about by supercritical CO₂ at high temperatures. In this study, high-temperature oxidation tests on the structural materials were performed in carbon dioxide pressurized at 0.2 and 1 MPa, and in air, and the oxidation behavior were compared. Results of investigating the effect of CO₂ pressure including the previous reports tested at 10 MPa and at 20 MPa, the effect was hardly observed for all steels. In air environment, weight gain caused by high temperature oxidation was much lower than that in CO₂.

39001179
Cerebral methodology based computing to estimate real phenomena from large-scale nuclear simulation
Suzuki, Yoshio
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 8p.(2011) ; (JAEA-J 09443)

In nuclear field, it is indispensable to estimate real phenomena from simulations in order to improve the safety and security of nuclear power plants. Here, the analysis of uncertainty included in simulations is needed to reveal sensitivity of uncertainty due to randomness, to reduce the uncertainty due to lack of knowledge and to lead a degree of certainty by verification and validation (V&V) and uncertainty quantification (UQ) processes. To realize this, we propose "Cerebral Methodology based Computing (CMC)" as computing processes with deductive and inductive approaches by referring human reasoning processes. We have established its prototype system and applied it to a thermal displacement analysis of a nuclear power plant. The result shows that our idea is effective to reduce the uncertainty and to get the degree of certainty.

39001180
Management of radioactive materials for the disassembly of JT-60U fusion tokamak device
Sukegawa, Atsuhiko; Miya, Naoyuki; Oikawa, Akira
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 8p.(2011) ; (JAEA-J 09444)

The radioactivities on the materials of JT-60U fusion device, which decommissioning is underway toward the upgraded superconducting tokamak machine, have been evaluated by calculation and measurements on the specimens of the structure materials and the components. In the induced activities on those materials, the highest activation on the material was stainless steel. The essential nuclide was ⁶⁰Co in the stainless steels. The stainless steel 316 of about 35 tons constitutes the base of interiorities as a first wall on the vacuum vessel in JT-60U. For the management of radioactive materials, the evaluation for the steels with the activated nuclides is important. The activated structure materials are kept in the controlled area in the JT-60 facilities, according to the criteria for handling activated materials by the defined domestic government.

39001181
Analysis of a loss of forced cooling test using the High Temperature Engineering Test Reactor (HTTR)
Takamatsu, Kuniyoshi; Ueta, Shohei; Sawa, Kazuhiro
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 10p.(2011) ; (JAEA-J 09445)

The three gas circulators trip test and the vessel cooling system stop test as the safety demonstration test by using the High Temperature engineering Test Reactor (HTTR) are under planning to demonstrate inherent safety features of High Temperature Gas-cooled Reactor (HTGR). All three gas circulators to circulate the helium gas as the coolant are stopped to simulate the loss of forced cooling in the three gas circulators trip test. The stop of the vessel cooling system located outside the Reactor Pressure Vessel (RPV) to remove the residual heat of the reactor core follows the stop of all three gas circulators in the vessel cooling system stop test. The analysis of the reactor transient for such tests and abnormal events postulated during the test is performed. From the result of analysis, it is confirmed that the three gas circulators trip test and the vessel cooling system stop test can be performed within the region of the normal operation in the HTTR.

39001182
Preliminary evaluation of JSFR achievement level to risk targets
Kurisaka, Kenichi; Okamura, Shigeki*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 10p.(2011) ; (JAEA-J 09446)

Japan Atomic Energy Agency (JAEA) has been developing the Japan Sodium-cooled Fast Reactor (JSFR) in the Fast Reactor Cycle Technology Development (FaCT) Project. Risk targets were set out as part of the safety-related design requirement: i.e., the quantitative safety design requirements on the core damage frequency (CDF) and the containment failure frequency (CFF). This paper describes a preliminary evaluation of achievement level of JSFR to the risk targets at the FaCT project phase-I: JFY2006 to JFY2010. A Level-1 PSA has been implemented preliminarily to evaluate the CDF related to internal initiators in power operation. The calculated CDF became lower than the both requirements on CDF and CFF. For seismic events, the seismic fragility of principal structures and components was evaluated in terms of core damage prevention. This evaluation was based on the seismic response analysis, which considered the seismic isolation effect and the hardening effect of the laminated rubber bearing in the isolation devices. As a result, we confirmed that the principal structures and components of JSFR have sufficient seismic margin. Based on this, we judged the risk target could be achieved against the seismic event.

39001183
Numerical investigation on large-scale eddy structure in unsteady pipe elbow flow at high Reynolds number conditions with large eddy simulation approach
Tanaka, Masaaki; Ohshima, Hiroyuki
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM) , 12p.(2011) ; (JAEA-J 09447)

A study on flow induced vibration of the primary cooling system of JSFR consisting of a large diameter pipe and a pipe elbow with short curvature radius corresponding to its diameter has been conducted. In this paper, numerical simulations for several pipe elbows with different pipe diameters and curvature radii were conducted at high Reynolds number conditions. Numerical results in each condition were compared with the experimental results in literature. Unsteady flow characteristics and pressure fluctuation generation mechanism in the short-elbow were clarified in relation to the large-scale eddy motion.

39001184
Development of LBB assessment method for Japan Sodium Cooled Fast Reactor (JSFR) pipes, 5; Crack growth assessment method for pipes made of Mod.9Cr-1Mo steel
Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Tokiyoshi, Takumi*; Kikuchi, Koichi*; Xu, Y.*; Tsukimori, Kazuyuki
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 8p.(2011) ; (JAEA-J 09448)

This paper studies the master curve to estimate the crack length when a postulated initial crack unexpectedly grows and penetrates the pipe thickness. In order to obtain the fatigue crack and creep crack growth characteristics of modified 9Cr-1Mo steel pipes, fatigue crack and creep crack growth tests were conducted using compact tension (CT) specimens and crack growth rates for both fatigue and creep at elevated temperature were obtained. Based on the obtained material characteristics and the results of a series of crack growth calculations, a relationship between the penetrated crack length and the ratio of membrane to total stress, so called as master curve, was proposed. In this study, master curves were proposed for pipes made of modified 9Cr-1Mo steel as a function of pipe geometry, i.e. the ratio of radius to thickness.

39001185
An Evaluation method for plastic buckling of cantilever type pipes controlled by displacement loads, 2; Verification of proposal method by buckling test
Ando, Masanori; Tezuka, Taiji*; Nakamura, Toshio*; Okawa, Tomohiro*; Enuma, Yasuhiro*; Kawasaki, Nobuchika; Tsukimori, Kazuyuki
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 8p.(2011) ; (JAEA-J 09449)

Displacement controlled buckling tests are carried out with cantilever type pipes made of Mod.9Cr-1Mo steel fixed at lower end. The top of pipe is pulled by servo pulser machine. To confirm the effect of configuration, pipe thickness and length, four kinds of pipes are supplied for buckling test in the room temperature. In addition these tests, high temperature test is carried out at 550°C. Comparison of test results and FEA results proved that examinations are adequately predictable by FEA. The relationship between reaction force and displacement at pipe top is predicted accurately. Therefore proposed estimation method of buckling criterion, which is constructed by series of FEAs, is good corresponding to the test results.

39001186
The Creep-fatigue evaluation method for intermediate hold conditions; Proposal and validation
Okajima, Satoshi; Kawasaki, Nobuchika*; Kato, Shoichi; Kasahara, Naoto
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 8p.(2011) ; (JAEA-J 09450)

In this paper, for the application to the Japan Sodium-cooled Fast Reactor (JSFR), the creep-fatigue damage evaluation method is improved to consider the intermediate holding condition. The improved method is validated through both of the uni-axial and the structure model creep-fatigue tests. In these validations, the target material is 316FR steel, which is planned to use for the reactor vessel. In the conventional method, in order to evaluate the creep damage conservatively, the maximum tensile value in the thermal stress transient cycle is used as the initial stress. The improved method evaluates the creep damage using the lower initial stress than the conventional method, while it has the rational margin.

39001187
Benchmark analysis on the failure probability assessment of piping with stress corrosion cracks
Arakawa, Manabu*; Narumi, Kentaro; Machida, Hideo*; Onizawa, Kunio
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 8p.(2011) ; (JAEA-J 09451)

This paper describes the benchmark analysis results performed between two PFM analysis codes for structural reliability evaluation of primary loop recirculation system (PLR) piping of a boiling water reactor. The two codes PASCAL-SP and PEPPER-M used for this benchmark analysis have been independently developed by Japan Atomic Energy Agency and TEPCO Systems Corporation, respectively. After the validity of the deterministic analytical procedures in these codes was checked, the failure probability assessment of PLR piping containing cracks due to stress corrosion cracking was carried out according to some regulatory requirements and the rules on fitness-for-service in Japan. The analytical results from both codes were well in agreement. From comparison of the results, influences of some items and parameters on failure probabilities were identified.

39001188
An Evaluation method for plastic buckling of cantilever type pipes controlled by displacement loads, 1; Proposal of the estimation method and the criterion
Ando, Masanori; Tezuka, Taiji*; Nakamura, Toshio*; Okawa, Tomohiro*; Enuma, Yasuhiro*; Kawasaki, Nobuchika; Tsukimori, Kazuyuki
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 9p.(2011) ; (JAEA-J 09452)

Estimation method of the buckling criterion of cantilever type pipes subjected to lateral displacements is proposed. We define the criterion of the deformation controlled buckling based on bending strain at buckling portion. Then finite element method is used to estimate the displacement and bending strain at local buckling portion on the displacement controlled buckling. All of the finite element analysis are carried out by using the material properties of Mod.9Cr-1Mo and 316FR. As the result, an equation which represents the limitation for displacement controlled buckling of cantilever type pipes is proposed.

39001189
Manufacturing status of JT-60SA vacuum vessel and the related technology of welding
Shibama, Yusuke; Masaki, Kei; Sakurai, Shinji; Shibanuma, Kiyoshi; Sakasai, Akira
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 10p.(2011) ; (JAEA-J 09453)

This paper focuses on the JT-60SA vacuum vessel (VV, 150 tons) and presents manufacturing status of the VV with the design concept and the related technology of welding. The VV is a torus type vessel to ensure the sufficient ultrahigh vacuum space for core plasma and consists of 18 sectors with 73 port penetrations. The dimensions are the maximum major radius of 5.0 m and height of 6.6 m with a double wall structure to secure the stiffness against operational loads. The type 316L stainless steel is selected as a structural material and various welding technologies are developed. The weldment is mostly manipulated to achieve uniform welding quality and the welding conditions are evaluated to explore the distortion reduction, and to increase deposition rate. These resultants are applied to the 20 degree upper half mock-up and the manufacturing procedures, the correction of the welding distortion, and the optimization of constraint jigs are obtained.

39001190
Development of LBB assessment method for Japan Sodium Cooled Fast Reactor (JSFR) pipes, 4; Verification of crack opening displacement assessment method for thin wall pipes made of Mod.9Cr-1Mo steel
Wakai, Takashi; Machida, Hideo*; Yoshida, Shinji*; Kawashima, Fumiko*; Kikuchi, Koichi*; Xu, Y.*; Tsukimori, Kazuyuki
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 10p.(2011) ; (JAEA-J 09454)

This paper describes the improved COD assessment method and verifies the validity of the method based on the results of a series of four-point bending tests at elevated temperature using thin wall modified 9Cr-1Mo steel pipe containing a circumferential through wall crack. As a result, COD values calculated by the proposed method were in a good agreement with the experimental results for the uniform pipe without weld. In the case that the crack was machined at weld metal or heat affected zone (HAZ), proposed method predicted relatively larger COD than the experimental results. The causes of such discrepancies were discussed comparing with the results of finite element analyses. Based on these examinations, the rational leak rate evaluation method in LBB assessment was proposed.

39001191
Comparison of creep-fatigue evaluation methods with notched specimens made of Mod.9Cr-1Mo steel
Ando, Masanori; Hirose, Yuichi*; Karato, Takanori*; Watanabe, Sota*; Inoue, Osamu*; Kawasaki, Nobuchika; Enuma, Yasuhiro*
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 11p.(2011) ; (JAEA-J 09455)

To compare and evaluate these estimation methods, a series of creep-fatigue test was carried out with notched specimens. All the specimens were made of Mod.9Cr-1Mo steel. Deformation controlled creep-fatigue tests and temperature controlled creep-fatigue tests were performed and creep-fatigue lives, crack initiation and propagation processes were observed by digital micro-scope and replica method. A series of elastic Finite Element Analysis were carried out and number of cycles to failure was predicted by several creep-fatigue damage evaluation methods. Then these results were compared with test results. Four types of evaluation methods which are stress reduction locus method, simple elastic-follow up method, the method using conventional Neuber's rule and the methods described in JSME FBR design code were applied. In addition that, experimental based estimation were also compared.

39001192
Effects of graphite surface roughness on bypass flow computations for an HTGR
Tung, Y.-H.*; Johnson, R. W.*; Sato, Hiroyuki
Proceedings of 2011 ASME Pressure Vessels and Piping Conference (PVP 2011) (CD-ROM) , 12p.(2011) ; (JAEA-J 09456)

The present study examines the effects of graphite surface roughness on the bypass flow for different relative roughness factors on three gap widths. Wall shear stress and heat transfer results for several turbulence models and their associated wall treatments are first compared for flow in a single tube in the prismatic HTGR core. The results are compared to published correlations for wall shear stress and Nusselt number in turbulent pipe flow. Calculations are also compared to ones made previously using a different CFD code. Results indicate that increasing surface roughness increases the maximum fuel and helium temperatures as do increases in gap width. However, maximum coolant temperature variation due to increased gap width is not changed by surface roughness.

39001193
Assessment system of marine environment in the Japan Sea
Kawamura, Hideyuki; Kobayashi, Takuya; Togawa, Orihiko; Onitsuka, Go*
Proceedings of 7th International Conference on Natural Computation/8th International Conference on Fuzzy Systems and Knowledge Discovery , p.1742-1746(2011) ; (JAEA-J 09457)

An assessment system of marine environment in the Japan Sea is developed in Japan Atomic Energy Agency to calculate a movement of pollutants such as radionuclides and their effect on Japanese people. The assessment system consists of three models, ocean general circulation model, particle random-walk model, and dose assessment model. The assessment system was applied so far to a numerical experiment of an oil spill accident and a numerical experiment for reproduction of concentration of anthropogenic radionuclides in the Japan Sea. In addition, the lower trophic level ecosystem model is being developed to estimate a suspended solid in the Japan Sea.

39001194
Development and future challenge for Advanced Solution Measurement and Monitoring System (ASMS)
Nakamura, Hironobu; Mukai, Yasunobu; Yoshimoto, Katsunobu; Tamura, Takayuki*; Iwamoto, Tomonori*
Proceedings of INMM 52nd Annual Meeting (Internet) , 9p.(2011) ; (JAEA-J 09458)

JNFL and JAEA are collaboratively developing an Advanced Solution Measurement and monitoring System (ASMS) that is direct Pu measurement NDA system in the large scale solution tank containing purified plutonium nitrate for the improvement of current safeguards subjects to be solved, and for next generation safeguards instrument (NGSI). In this report, we summarize the first step results of ASMS development regarding quantitative measurement methodology. In order to establish quantitative measurement, accurate MCNPX modeling and calculations are very important and necessary. After calibration exercise implementation, we successfully obtained calibration constants (slope), and the total measurement uncertainty was about 3% for ²⁴⁰Pu effective mass for 2 hours measurement except for the low level region. In addition, the image of safeguards by design and collaboration of SMMS are also presented.

39001195
The Impact of advanced technologies on the efficiencies of safeguards and facility operations
Hoffheins, B.; Miyaji, Noriko; Asano, Takashi; Nagatani, Taketeru; Ishiyama, Koichi; Kimura, Takashi; Kodani, Yoshiki
Proceedings of INMM 52nd Annual Meeting (Internet) , 10p.(2011) ; (JAEA-J 09459)

Following Japan's conclusion of the Additional Protocol and the IAEA's broader conclusion regarding the peaceful nature of Japan's nuclear activities, the Japan government and facility operators have worked with the IAEA to apply integrated safeguards to increase inspection efficiency and to ensure verification correctness and completeness. These safeguards approaches rely heavily on the implementation of advanced technologies such as unattended surveillance and non-destructive assay measurement, automated nuclear material accounting, solution monitoring and remote monitoring. These technologies have enabled random interim inspections; they have also reduced the level of effort required for nuclear material accounting and inspection activities. A more comprehensive understanding of the impact of advanced technologies on operation and inspection processes would be useful for developing methodologies to support better system design and evaluation of existing systems.

39001196
Design and trial manufacturing of the thermal shield for JT-60SA
Kamiya, Koji; Ichige, Toshikatsu; Honda, Atsushi; Yoshida, Kiyoshi
Proceedings of International Cryogenic Engineering Conference 23 (ICEC-23) and International Cryogenic Materials Conference 2010 (ICMC 2010) , p.797-802(2011) ; (JAEA-J 09460)

The JT-60 is planned to be upgraded to a full-superconducting tokamak referred as the JT-60 Super Advance (JT-60SA) as one of the JA-EU Broader Approach projects. In the JT-60SA, the superconducting magnets are to be surrounded with the thermal shield to reduce the radiation heat from the plasma vacuum vessel and from the ambient temperature. This study describes the design concept and current status of the JT-60SA thermal shield followed by thermal analysis focusing on the vacuum vessel side thermal shield (VVTS). Subsequently, the structural analysis in the plasma operation mode and at assembly was conducted. Finally, the trial model of the 10 degree VVTS and its manufacturing tolerance are presented.

39001197
Development of Level 2 PSA methodology for sodium-cooled fast reactors; Overview of evaluation technology development
Suzuki, Toru; Nakai, Ryodai; Kamiyama, Kenji; Seino, Hiroshi; Koyama, Kazuya*; Morita, Koji*
Proceedings of OECD/NEA Workshop on PSA for New and Advanced Reactors (CD-ROM) , 10p.(2011) ; (JAEA-J 09461)

For the probabilistic safety assessment (PSA) of sodium-cooled fast reactors (SFRs), JAEA consolidated the analytical methodologies and technical basis for all phases/sequences to be evaluated in the Level 2 PSA. In addition to the existing computational codes such as SAS4A, SIMMER-III, DEBNET, ARGO and APPLOHS, JAEA newly developed MUTRAN and SIMMER-LT in order to evaluate the long term behaviors of the material-relocation in the degraded core. These tools enabled the systematic assessment for the in-vessel accident sequences. For the ex-vessel accident sequences, JAEA also improved CONTAIN/LMR taking into account the feature of SFRs and verified the analytical models utilizing the new experiments such as sodium-concrete reaction test. In addition, the technical basis for constructing event trees was compiled, in which the dominant factors having significant effects on the event progression were corresponded to the related experiments and analytical results.

39001198
Fission dynamics in heavy ion collisions on ²³⁸U
Nishio, Katsuhisa
Proceedings of Scientific Workshop on Nuclear Fission Dynamics and the Emission of Prompt Neutrons and γ rays , p.77-84(2011) ; (JAEA-J 09462) [link]

Fragment mass distributions for fission after full momentum transfer (FMT) were measured for the ³⁰Si, ³¹P, ^34,36S, ⁴⁰Ar + ²³⁸U reactions at bombarding energies around the Coulomb barrier. The experiment was carried out at the JAEA tandem accelerator facility. We observed strong variation of the mass distribution on beam energy and projectile nuclei. In the reaction of ³⁶S + ²³⁸U we observed a transition from symmetry to asymmetry mass distributions when the beam energies were decreased from the above-barrier to sub-barrier values. The mass asymmetry was A_L/A_H = 74 /200, which corresponds to the fission valley leading to the doubly closed-shell nuclei ⁷⁸Ni/²⁰⁸Pb. The fission channel is populated by quasifission, which is the disintegration without forming the compound nucleus. The incident-energy dependence is strongly correlated with the prolate deformation of ²³⁸U and the orientation at the initial impact. The results indicate that the reaction starting at the polar collisions on ²³⁸U has larger quasifission probability. We observed the mass asymmetry in the quasifission channel depends on the projectiles. The parameter indicates the approaching distance of a system to the compound nucleus states before disintegrating as quasifission.

39001199
Quality management report of radioactive waste for geological disposal; Function and requirement of vitrified high radioactive waste necessary for final disposal (in Japanese)
Yoshinuma, Akihiko; Shiotsuki, Masao; Nakayama, Jiro
Chiso Shobun Taisho Hoshasei Haikibutsu No Hinshitsu Manejimento, Chiso Shobun-nioite Hitsuyo To Kangaerareru Koreberu Hoshasei Haikibutsu "Garasu Kokatai" No Kino To Yoken Hokokusho (Internet) , 54p.(2011) ; (JAEA-J 09463) [link]

39001200
Development of ion beam applications for JAEA-Tokai tandem accelerator (in Japanese)
Matsuda, Makoto; Asozu, Takuhiro; Sataka, Masao; Hanashima, Susumu; Nakamura, Masahiko; Kabumoto, Hiroshi; Kutsukake, Kenichi
Dai-23-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu , p.65-68(2011) ; (JAEA-J 09464)

39001201
Basic study on surface chemical combination between beryllium metal and hydrogen isotope gas (in Japanese)
Tsuchiya, Kunihiko
Heisei-22-Nendo Toyama Daigaku Kyodo Kenkyu Seika Hokokusho , p.31-32(2011) ; (JAEA-J 09465) [link]

39001202
Dosimetry systems and absorbed dose measurement (in Japanese)
Kojima, Takuji
Herusukea Seihin No Mekkin Oyobi Mekkin Hosho , p.122-125(2011) ; (JAEA-J 09466)

39001203
Plasticity collapse strength of stainless piping subjected to combined tension and bending (in Japanese)
Matsubara, Masaaki*; Hayashi, Tatsuya*; Suzuki, Masato*; Shiraishi, Taisuke*; Sakamoto, Kenji*; Wakai, Takashi
Nippon Kikai Gakkai M&M 2011 Zairyo Rikigaku Kanfarensu Koen Rombunshu (CD-ROM) , 2p.(2011) ; (JAEA-J 09467)

In this study, we investigated the influence of two or more flaws on the collapse strength of austenitic stainless steel piping to improve the safety of a nuclear power plant. The multiple flaws may be more often than single flaw. Therefore, it is important to evaluate the collapse strength of the piping with multiple flaws. Piping with a single flaw and multiple flaws were used in the examination. Collapse strength of the piping is verified under the combination condition of tension and bending. It aims to model from multiple flaws to the single flaw for simplification of the. As a result, (1) It is possible to evaluate the collapse strength by identifying the multiple flaws as the single flaw conservatively. (2) On each load condition, the parallel notches on piping can be accounted to be the single notch.

39001204
A Temperature dependent multi-linear cyclic plasticity model (in Japanese)
Iwata, Koji
Nippon Kikai Gakkai M&M 2011 Zairyo Rikigaku Kanfarensu Koen Rombunshu (CD-ROM) , 3p.(2011) ; (JAEA-J 09468)

39001205
Metal ion adsorbent synthesized by radiation-induced graft polymerization (in Japanese)
Tamada, Masao
Reametaru, Kisho Kinzoku Risaikuru Gijutsu No Saisentan , p.95-104(2011) ; (JAEA-J 09477)

Graft polymerization is a radiation processing which cam impart desired functional group into a trunk polymer. When a nonwoven fabric is selected as the trunk polymer of the graft polymerization, a fibrous metal adsorbent can be synthesized. The resulting fibrous adsorbent realizes extremely high flow rate in the metal ion adsorption. This adsorbent is applicable for the recover of uranium from seawater and the collection of scandium from hot spring water. In the case of uranium recovery from seawater, 1 kg of yellow cake was collected successfully at Aomori area. A novel mooring system of braid type adsorbent was developed to reduce the recovery cost of uranium from seawater. Experimental collection of scandium from the hot spring water has been carried out at Kusatsu Onsen in Gunma prefecture. The development of scandium collection technology will induce its new versatile usages.

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