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Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modelingSakuma, Kazuyuki; Malins, A.; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Nakanishi, Takahiro; Mori, Koji*; Tada, Kazuhiro*; Kobayashi, Takamaru*; Kitamura, Akihiro; et al.
Journal of Environmental Radioactivity, 182, p.44 - 51, 2018/02
Times Cited Count：11 Percentile：37.6(Environmental Sciences)The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and Cs redistribution within the catchment. Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies. Forested areas far from the channels only made a minor contribution to Cs input to watercourses, total erosion of between 0.001-0.1 mm from May 2011 to December 2015. The 2.3-6.9% y
decrease in the amount of Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y), along with a migration downwards into subsoil and a small amount of export. The amount of Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas.
Tada, Kenichi; Kikuchi, Takeo*; Sakino, Takao; Suyama, Kenya
Journal of Nuclear Science and Technology, 55(2), p.138 - 150, 2018/02
Times Cited Count：3 Percentile：30.05(Nuclear Science & Technology)The criticality safety of the fuel debris in Fukushima Daiichi Nuclear Power Plant is one of the most important issues and the adoption of the burnup credit is desired for the criticality analysis. The assay data of used nuclear fuel irradiated in 2F2 is evaluated to validate SWAT4.0 for BWR fuel burnup problem. The calculation results revealed that number density of many heavy nuclides and FPs showed good agreement with the experimental data except for 
U, 
Np, 
Pu and Sm isotopes. The cause of the difference is assumption of the initial number density and void ratio and overestimation of the capture cross section of Np. The C/E-1 values do not depend on the types of fuel rods (UO
or UO-GdO
) and it is similar to that for the PWR fuel. These results indicate that SWAT4.0 appropriately analyzes the isotopic composition of the BWR fuel and it has sufficient accuracy to be adopted in the burnup credit evaluation of the fuel debris.
Mihara, Takeshi; Udagawa, Yutaka; Amaya, Masaki
Journal of Nuclear Science and Technology, 55(2), p.151 - 159, 2018/02
Times Cited Count：10 Percentile：67.52(Nuclear Science & Technology)Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Takada, Hiroshi
Journal of Nuclear Science and Technology, 55(2), p.160 - 168, 2018/02
Times Cited Count：5 Percentile：46.12(Nuclear Science & Technology)The mercury target vessel used for the spallation neutron source in J-PARC has multi-walled structure made of stainless steel type 316L, which comprises a mercury vessel and a water shroud. In 2015, water leak incidents from the water shroud occurred while the mercury target was operated with a proton beam power of 500 kW. Several investigations were conducted to identify the cause of failure. The results of the visual inspections, mockup tests, and analytical evaluations suggested that the water leak was caused by the combination of two factors. One was the diffusion bonding failure due to the large thermal stress induced by welding of the bolt head, which fixes the mercury vessel and the water shroud, during the fabrication process. The other was the thermal fatigue failure of the seal weld due to the repetitive beam trip during the operating period. These target failures point to the importance of eliminating initial defects from welding lines and to secure the rigidity and reliability of welded structures. The next mercury target was fabricated with an improved design which adopted parts of monolithic structure machined by wire EDM to reduce welding lines, and intensified inspections to eliminate the initial defects. The operation with the improved target is planned to be started in October 2017.
Pyeon, C. H.*; Vu, T. M.*; Yamanaka, Masao*; Sugawara, Takanori; Iwamoto, Hiroki; Nishihara, Kenji; Kim, S. H.*; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 55(2), p.190 - 198, 2018/02
Times Cited Count：16 Percentile：85.18(Nuclear Science & Technology)At the Kyoto University Critical Assembly, a series of reaction rate experiments is conducted on the accelerator-driven system (ADS) with spallation neutrons generated by the combined use of 100 MeV protons and a lead and bismuth target in the subcritical state. The reaction rates are measured by the foil activation method to obtain neutron spectrum information on ADS. Numerical calculations are performed with MCNP6.1 and JENDL/HE-2007 for high-energy protons and spallation process, JENDL-4.0 for transport and JENDL/D-99 for reaction rates. The reaction rates depend on subcriticality is revealed by the accuracy of the C/E (calculation/experiment) values. Nonetheless, the accuracy of the reaction rates at high-energy thresholds remains an important issue in the fixed-source calculations.
Sugawara, Takanori; Katano, Ryota; Tsujimoto, Kazufumi
Annals of Nuclear Energy, 111, p.449 - 459, 2018/01
Times Cited Count：13 Percentile：79.66(Nuclear Science & Technology)This study aims to review the ADS design based on the outcome for the last dozen years and to investigate the impact of impurities in the transmutation cycle on the ADS neutronics design. The impact of impurities in the transmutation cycle is investigated for the reviewed reference design. For the uranium from the partitioning, the accompaniment of 20 wt.% U against the Pu weight is acceptable although the MA transmutation amount will be decreased slightly. For the rare earth (RE) from the partitioning, the accompaniment of 5 wt.% RE against the MA weight is allowable. In the reprocessing, the decontamination factor, DF=10 for RE is enough from the viewpoint of the neutronics design. The impact of the fuel composition accuracy is also investigated. The uncertainty of the ZrN ratio against the MA fuel should be less than 0.2% to minimize a surplus proton beam current due to the uncertainty.
Takahara, Shogo; Watanabe, Masatoshi*; Hirouchi, Jun; Iijima, Masashi*; Munakata, Masahiro
Health Physics, 114(1), p.64 - 72, 2018/01
Times Cited Count：2 Percentile：20.93(Environmental Sciences)Kobata, Masaaki; Okane, Tetsuo; Nakajima, Kunihisa; Suzuki, Eriko; Owada, Kenji; Kobayashi, Keisuke*; Yamagami, Hiroshi; Osaka, Masahiko
Journal of Nuclear Materials, 498, p.387 - 394, 2018/01
Times Cited Count：17 Percentile：86.67(Materials Science, Multidisciplinary)In this study, for the understandings of Cesium (Cs) adsorption behavior on structure materials in severe accidents at a light water nuclear reactor, the chemical state of Cs and its distribution on the surface of SUS304 stainless steel (SS) with different Si concentration were investigated by hard X-ray photoelectron spectroscopy (HAXPES) and scanning electron microscope / energy dispersive X-ray spectroscopy (SEM/EDX). As a result, it was found that Cs is selectively adsorbed at the site where Si distributes with high concentration. CsFeSiO
is a dominant Cs products in the case of low Si content, mainly formed, while CsSiO
and CsSiO
are formed in addition to CsFeSiO in the case of high Si content. The chemical forms of the Cs compounds produced in the adsorption process on the SS surface has a close correlation with the concentration and chemical states of Si originally included in SS.
-ray imager mounted on a multicopter droneSato, Yuki; Ozawa, Shingo*; Terasaka, Yuta; Kaburagi, Masaaki; Tanifuji, Yuta; Kawabata, Kuniaki; Miyamura, Hiroko; Izumi, Ryo*; Suzuki, Toshikazu*; Torii, Tatsuo
Journal of Nuclear Science and Technology, 55(1), p.90 - 96, 2018/01
Times Cited Count：43 Percentile：98.03(Nuclear Science & Technology)Tanaka, Taiki*; Narikiyo, Yoshihiro*; Morita, Kosuke*; Fujita, Kunihiro*; Kaji, Daiya*; Morimoto, Koji*; Yamaki, Sayaka*; Wakabayashi, Yasuo*; Tanaka, Kengo*; Takeyama, Mirei*; et al.
Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01
Times Cited Count：18 Percentile：74.47(Physics, Multidisciplinary)Excitation functions of quasielastic scattering cross sections for the 
Ca + 
Pb, 
Ti + Pb, and Ca + 
Cm reactions were successfully measured by using the gas-filled recoil-ion separator GARIS. Fusion barrier distributions were extracted from these data, and compared with the coupled-channels calculations. It was found that the peak energies of the barrier distributions for the Ca + Pb and Ti + Pb systems coincide with those of the 2n evaporation channel cross sections for the systems, while that of the Ca + Cm is located slightly below the 4n evaporation ones. This results provide us helpful information to predict the optimum beam energy to synthesize superheavy nuclei.
Sonoda, Tetsu*; Iimura, Hideki; Reponen, M.*; Wada, Michiharu*; Katayama, Ichiro*; Sonnenschein, V.*; Takamatsu, Takahide*; Tomita, Hideki*; Kojima, Takao*
Nuclear Instruments and Methods in Physics Research A, 877, p.118 - 123, 2018/01
Times Cited Count：4 Percentile：38.58(Instruments & Instrumentation)In order to produce low-energy RI beams at RIKEN RIBF, a laser ion source, PALIS, is under construction. This ion source is based on resonance ionization of RI atoms captured in Ar gas. Because the ion source is located 70m away from lasers, we have developed an optical system for laser beam transport. This system can be controlled remotely when the ion source is not accessible because of high radiation level. The position of laser beam after transport is reasonably stable, and the transport efficiency is about 50%.
Fukushima, Masahiro; Goda, J.*; Bounds, J.*; Cutler, T.*; Grove, T.*; Hutchinson, J.*; James, M.*; McKenzie, G.*; Sanchez, R.*; Oizumi, Akito; et al.
Nuclear Science and Engineering, 189, p.93 - 99, 2018/01
Times Cited Count：9 Percentile：67.52(Nuclear Science & Technology)To validate lead (Pb) nuclear cross sections, a series of integral experiments to measure lead void reactivity worths was conducted in a high-enriched uranium (HEU)/Pb system and a low enriched uranium (LEU)/Pb system using the Comet Critical Assembly at NCERC. The critical experiments were designed to provide complementary data sets having different sensitivities to scattering cross sections of lead. The larger amount of the U present in the LEU/Pb core increases the neutron importance above 1 MeV compared with the HEU/Pb core. Since removal of lead from the core shifts the neutron spectrum to the higher energy region, positive lead void reactivity worths were observed in the LEU/Pb core while negative values were observed in the HEU/Pb core. Experimental analyses for the lead void reactivity worths were performed with the Monte Carlo calculation code MCNP6.1 together with nuclear data libraries, JENDL 4.0 and ENDF/B VII.1. The calculation values were found to overestimate the experimental ones for the HEU/Pb core while being consistent for the LEU/Pb core.
Yokota, Terufumi
Physica A, 490, p.458 - 464, 2018/01
Times Cited Count：0 Percentile：0(Physics, Multidisciplinary)Andreyev, A. N.; Nishio, Katsuhisa; Schmidt, K.-H.*
Reports on Progress in Physics, 81(1), p.016301_1 - 016301_61, 2018/01
Times Cited Count：125 Percentile：91.8(Physics, Multidisciplinary)Aoki, So; Kondo, Keietsu; Kaji, Yoshiyuki; Yamamoto, Masahiro
Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, Vol.2, p.663 - 672, 2018/00
Times Cited Count：2 Percentile：58(Materials Science, Multidisciplinary)The objective of this study was to clarify effect of long-term thermal aging on SCC initiation susceptibility in low carbon austenitic stainless steels. Specimens used were Type 304L and 316L steels. Both steels were cold rolled to 20% thickness reduction (CW) and then followed by long-term thermal aging at 288
C for 14,000 h (LTA). Crevice Bent Beam (CBB) test was carried out to estimate the SCC initiation susceptibility under BWR simulated water condition at high temperature. The present results of the CBB tests showed that 304L CW + LTA exhibited no SCC susceptibility. In contrast, the SCC initiation susceptibility of 316L increased by the combination of cold rolling and long-term thermal aging. To understand these results, evaluation on the changes in microchemistry, microstructure and mechanical properties induced by the CW and LTA treatment has been developed, and their correlation with the SCC initiation susceptibility is discussed.
setting approaches for rocks for the performance assessment of geological disposal; Application for granitic rocksTachi, Yukio; Suyama, Tadahiro*; Shibutani, Sanae*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(2), p.109 - 133, 2017/12
For performance assessment (PA), the distribution coefficient (K) need to be determined taking into account the specific PA conditions, including geochemical variability or uncertainty. The K setting approach for rocks was developed by integrating three methods; (i) direct use of measured K data extracted from the sorption database, (ii) semi-quantitative estimation by scaling differences between experimental and PA conditions, and (iii) thermodynamic sorption models. This approach was tested for granitic rock by comparing K values and their uncertainties of Cs and Am. The results indicated that K can be quantitatively evaluated by all approaches when adequate data and models are available. The K dataset for safety-relevant 25 radionuclides was developed based on the direct use of measured data, and compared with the recent K dataset in European PA projects. This K setting approaches allowed to estimate the K values and their uncertainties under the expected site conditions.
Muramatsu, Toshiharu
Hikari Araiansu, 28(12), p.31 - 35, 2017/12
no abstracts in English
Ishii, Eiichi
International Journal of Rock Mechanics and Mining Sciences, 100, p.10 - 22, 2017/12
Times Cited Count：7 Percentile：39.89(Engineering, Geological)The highest transmissivity of fractures in a rock mass is crucial for conservative assessment of a site for radioactive waste disposal. However, it is not realistic to measure that of all possible fractures in a site. Previous studies indicated that the highest potential transmissivities of fractures in fault zones can be predicted by a rock mechanical indicator, ductility index (DI). Noting that the mechanism of formation and preservation of pore structures in fault-zone fractures may be the same as that of pore structures in discrete shear fractures. This study investigated whether or not the DI model is applicable to discrete shear fracture systems, using geological and hydrological data of discrete shear fractures in a Neogene diatomaceous mudstone (Koetoi Formation). As a result, the data set obtained by this study well fits the existing data sets of the DI model, suggesting that the DI mode is applicable to discrete shear fracture systems as well as fault zones.
Kawamura, Hideyuki; Furuno, Akiko; Kobayashi, Takuya; In, Teiji*; Nakayama, Tomoharu*; Ishikawa, Yoichi*; Miyazawa, Yasumasa*; Usui, Norihisa*
Journal of Environmental Radioactivity, 180, p.36 - 58, 2017/12
Times Cited Count：11 Percentile：35.55(Environmental Sciences)This study simulates the oceanic dispersion of Fukushima-derived Cs-137 by an oceanic dispersion model and multiple oceanic general circulation models. The models relatively well reproduced the observed Cs-137 concentrations in the coastal, offshore, and open oceans. Multiple simulations in the coastal, offshore, and open oceans consistently suggested that Cs-137 dispersed along the coast in the north-south direction during the first few months post-disaster, and were subsequently dispersed offshore by the Kuroshio Current and Kuroshio Extension. Quantification of the Cs-137 amounts suggested that Cs-137 actively dispersed from the coastal and offshore oceans to the open ocean, and from the surface layer to the deeper layers in the North Pacific.
Komiyama, Daisuke; Amaya, Masaki
Journal of Nuclear Science and Technology, 54(12), p.1338 - 1344, 2017/12
Times Cited Count：1 Percentile：10.62(Nuclear Science & Technology)Kinase, Sakae; Takahashi, Tomoyuki*; Saito, Kimiaki
Journal of Nuclear Science and Technology, 54(12), p.1345 - 1354, 2017/12
Times Cited Count：26 Percentile：92.78(Nuclear Science & Technology)
Li ion beamsNishinaka, Ichiro*; Yokoyama, Akihiko*; Washiyama, Koshin*; Makii, Hiroyuki; Hashimoto, Kazuyuki*
Journal of Radioanalytical and Nuclear Chemistry, 314(3), p.1947 - 1965, 2017/12
Times Cited Count：2 Percentile：19.65(Chemistry, Analytical)Production cross sections of iodine, tellurium and antimony radionuclides in the 24-59 MeV Li + 
Sn reaction have been measured by the conventional stacked foil technique with -ray spectrometry. Excitation functions of the production cross sections were compared with a statistical model calculation. The contributions of complete and incomplete fusion in the production of observed radionuclides are discussed from the view points of production routes in the nuclide chart and decays for iodine, tellurium and antimony nuclides. The integral yields of 
I were deduced from the calculated excitation functions in the Li induced reactions on Sn isotopes in view of the production of medically important 
I. The results are discussed by comparing with literature values in the other reactions.
Takahatake, Yoko; Shibata, Atsuhiro; Nomura, Kazunori; Sato, Tsutomu*
Minerals (Internet), 7(12), p.247_1 - 247_13, 2017/12
Times Cited Count：9 Percentile：47.71(Geochemistry & Geophysics)Hydrous sodium titanate (SrTreat) is able to remove radioactive Sr from Radioactive contaminated water at Fukushima Daiichi Nuclear Power station (F1NPS). Knowing the amount of radioactive nuclides in the used SrTreat is important for an effective disposal and deposition of the F1NPS waste. This study investigated changes in the ability of SrTreat to sorb Sr during its use, and to understand the causes of changes in the sorbing. After exposure to a simulated treated water for 99 h, the surface structure of the SrTreat was changed, and the percentage of sorbed Sr and the buffer capacity for protons decreased. When the amount of radioactive nuclides contained in the used SrTreat is calculated from the sorption data of the as received SrTreat.
Ozu, Akira; Komeda, Masao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Nakashima, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(12), p.700 - 704, 2017/12
no abstracts in English
Okita, Taira*; Itakura, Mitsuhiro
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(12), p.712 - 716, 2017/12
Molecular simulations for nuclear materials aim to reproduce atomistic-scale phenomena induced by irradiation and infer the change in material properties. In the present work, recent progress in this field is presented. In particular, the following three topics are explained: (1) Quantification of lattice defects formation process induced by fast neutron collision. (2) Identification of dislocation-channeling mechanism induced by interactions between defect clusters and dislocations. (3) Modeling of the three dimensional movement of defect clusters using molecular dynamics and kinetic Monte Carlo simulations.
Hirose, Kentaro; Nishio, Katsuhisa; Tanaka, Shoya*; L
guillon, R.*; Makii, Hiroyuki; Nishinaka, Ichiro*; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Vermeulen, M. J.; et al.
Physical Review Letters, 119(22), p.222501_1 - 222501_6, 2017/12
Times Cited Count：50 Percentile：91.08(Physics, Multidisciplinary)Fission-fragment mass distributions were measured for 
U, 
Np and 
Pu populated in the excitation-energy range from 10 to 60 MeV by multi-nucleon transfer channels in the reaction 
O + U at the JAEA tandem facility. Among them, the data for 
U and 
Np were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multi-chance fission.
Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
Al
; New polymorphic phase in Al-Pd-Sc systemPospisil, J.; Haga, Yoshinori; Nakajima, Kunihisa; Ishikawa, Norito; C
sa
ov
, I.*; Tateiwa, Naoyuki; Yamamoto, Etsuji; Yamamura, Tomoo*
Solid State Communications, 268, p.12 - 14, 2017/12
Times Cited Count：0 Percentile：0(Physics, Condensed Matter)Narita, Hirokazu*; Maeda, Motoki*; Tokoro, Chiharu*; Suzuki, Tomoya*; Tanaka, Mikiya*; Motokawa, Ryuhei; Shiwaku, Hideaki; Yaita, Tsuyoshi
Analytical Sciences, 33(11), p.1305 - 1309, 2017/11
Times Cited Count：11 Percentile：40.7(Chemistry, Analytical)Naganawa, Hirochika
Bunseki Kagaku, 66(11), p.797 - 808, 2017/11
Times Cited Count：6 Percentile：22.86(Chemistry, Analytical)A new liquid-liquid extraction method, called the emulsion-flow method, has recently been developed at Japan Atomic Energy Agency (JAEA). The emulsion-flow method, where low cost, simplicity, high efficiency, compactness, safety, and eco-friendly go together, has attracted attention, and has been expected to bring innovation to liquid-liquid extraction technologies. Compared with conventional industrial apparatuses, an emulsion-flow apparatus successfully combines the lowest cost superior to a spray column and the highest performance (the highest efficiency and the highest processing speed) comparable to a centrifugal extractor. Furthermore, the emulsion-flow method can also be used for collecting particulate components by utilizing their aggregation onto a liquid-liquid interface and for purifying water polluted by oil with its remarkable phase-separating ability.
Ikushima, Kazuki*; Shibahara, Masakazu*; Nishikawa, Satoru*; Furukawa, Takashi*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi
E-Journal of Advanced Maintenance (Internet), 9(3), p.NT87_1 - NT87_5, 2017/11
Minato, Futoshi; Fukui, Tokuro
EPJ Web of Conferences, 163, p.00037_1 - 00037_5, 2017/11
Times Cited Count：2 Percentile：78.04(Nuclear Science & Technology)The capture reaction can be divided into two parts, that is the compound and direct processes. For most stable nuclei, the compound process occupies a large part of the neutron capture cross section. However, it has been pointed out that the direct process comes to play a comparable role to the compound one at a low energy in light and neutron-rich nuclei, where the number of resonance state at the neutron threshold energy is relatively small. In addition, there is an interference term between the direct and compound processes. However, it is usually neglected for most nuclei, because either of the compound or the direct process is more important than the other, its contribution becomes negligible. However, some experiment data have given an implication of the existence of the interference effect, and Mengoni and Otsuka reported that the experimental results of capture cross section can be described by taking into account it. It is then natural as a next step to have a concern whether the interference effect comes to play a role for neutron-rich nuclei as well. We therefore calculate the neutron capture reaction for neutron-rich nuclei and study the interference effect on it. We will present some results for neutron-rich nuclei and the interference effect becomes important.
Nishio, Katsuhisa; Hirose, Kentaro; Vermeulen, M. J.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Sato, Tetsuya; Nagame, Yuichiro; et al.
EPJ Web of Conferences, 163, p.00041_1 - 00041_6, 2017/11
Times Cited Count：1 Percentile：61.21(Nuclear Science & Technology)Sugawara, Takanori; Iwamoto, Hiroki; Tsujimoto, Kazufumi
NEA/NSC/R(2017)3, p.149 - 159, 2017/11
In this study, new beam window concept for accelerator-driven system (ADS) is investigated by changing the design condition. The most important factor for the beam window design is the proton beam current, and the design condition will be mitigated if the proton beam current will be reduced. To reduce the proton beam current, a subcriticality adjustment rod which was a BC control rod was employed and neutronics calculations were performed by ADS3D code. The results of the neutronics calculation indicated that the proton beam current was reduced from 20mA to 10mA by the installation of the subcriticality adjustment rods. Based on the mitigated calculation condition, the investigation of the beam window was performed by the particle transport analysis by PHITS code, the thermal hydraulics analysis by STAR-CCM+ code and the structural analysis by ANSYS code. Through these coupled analyses, more feasible beam window concept which was the hemispherical shape, the outer diameter = 470mm, the thickness at the top = 4.0mm and factor of safety =12, was presented.
Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Okuda, Kazufumi*; Makishima, Kazuo*; Sato, Mitsuteru*; Sato, Yosuke*; Nakano, Toshio*; et al.
Nature, 551(7681), p.481 - 484, 2017/11
Times Cited Count：116 Percentile：97.64(Multidisciplinary Sciences)Miyasaka, Satoshi*; Unome, Sota*; Tamura, Ayako*; Ito, Yoshiaki*; Ishizaki, Azusa; Sanada, Yukihisa
Nihon Rimoto Senshingu Gakkai Dai-63-Kai (Heisei-29-Nendo Shuki) Gakujutsu Koenkai Rombunshu (CD-ROM), p.81 - 84, 2017/11
Information of snow depth is important to improve the airborne radiation measurement in the winter. The snow depth is enable to estimate by the aerial photograph which is obtained at the same time with the radiation measurement before and after the snowfall. We attempted optimization parameters which used to make a Digital Surface Model (DSM) using Structure from Motion (SfM) method for estimation of the snow depth. As a result, to enable to measure precisely the snow depth was indicated. However, the estimated snow depth in the forest area was relatively not so accurate because fallen leaves and a tree move were prevented to measure DSM precisely.
Fukui, Tokuro*; Minato, Futoshi
Physical Review C, 96(5), p.054608_1 - 054608_8, 2017/11
Times Cited Count：4 Percentile：27.61(Physics, Nuclear)Nishio, Katsuhisa; Hirose, Kentaro; Lguillon, R.*; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Chiba, Satoshi*; Aritomo, Yoshihiro*; Tanaka, Shoya*; et al.
Proceedings of 6th International Conference on Fission and Properties of Neutron-rich Nuclei (ICFN-6), p.590 - 597, 2017/11
Okano, Yasushi; Yamano, Hidemasa
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 3 Pages, 2017/11
Forest fire hazard assessment methodologies using a logic tree have been applied for the evaluation of combination hazard curves of a forest fire with lightning as an initiator of a forest fire and with a strong wind being independent from a forest fire. The complex shape of the combinational hazard curve of forest fire and lighting is due to that both lightning and high velocity wind tend to appear under unstable weather conditions, and there is correlation between two hazards. The evaluated combinational hazard curve of forest fire and strong wind for the instantaneous wind velocity over 80 m/s has extremely small frequency in the range below 10
/year.
Arai, Kensaku*; Katsuyama, Jinya; Li, Y.
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 8 Pages, 2017/11
Probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed to assess structural integrity of aged reactor pressure vessels (RPVs) of light water nuclear power plants by Japan Atomic Energy Agency (JAEA). PASCAL is able to obtain failure frequency such as through-wall cracking frequency (TWCF) of RPVs under several transients including pressurized thermal shock (PTS) event. On the other hand, FAVOR was developed to perform almost the same analysis by Oak Ridge National Laboratory (ORNL) under United States Nuclear Regulatory Commission (USNRC) funding and has been utilized in the US nuclear regulation. To improve the reliability of PFM analysis results of PASCAL, benchmark analyses between PASCAL and FAVOR were performed. This paper provides results of the benchmark analyses using analysis conditions and parameters of the US 3-loop pressurized water reactor (PWR) nuclear power plant. Furthermore, sensitivity analyses relating to differences of analysis models (ex. Embrittlement correlation model) between Japan and the US were also conducted.
Yamano, Hidemasa; Naruto, Kenichi*; Kurisaka, Kenichi; Nishino, Hiroyuki; Okano, Yasushi
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 3 Pages, 2017/11
Spent fuels are transferred from a reactor core to a spent fuel pool through an external vessel storage tank (EVST) filled with sodium in sodium-cooled fast reactors in Japan (JSFR). The objective of this study is to identify dominant accident sequences leading to fuel failure by conducting PRA for EVST. The EVST heat removal system in JSFR consists of four independent loops with for primary and secondary ones. Based on the JSFR design information, this study has identified initiating events, event and /fault tree analyses, human reliability analysis, and quantification of accident sequences. Fuel damage frequency of the EVST was evaluated approx. 10
/year in this paper. The main contributor of the fuel damage frequency is the loss of heat removal function of the cooling system. The dominant initiating event was the loss of one circuit of normal heat removal operation.
Kumagai, Yuta
Radioisotopes, 66(11), p.537 - 541, 2017/11
Radiation effects on the mixtures of inorganic oxides and water have been investigated for understanding radiation chemistry in solid-liquid systems. A number of studies revealed that energy deposition on solid phase stimulates reactions at the interface. This energy/charge transfer has been demonstrated by experiments to affect early stage of the radiation-induced reaction. However, the interfacial reactions subsequent to the energy/charge transfer require further studies. Here, we will see gaps between the basic understanding on the early stage and radiation effects in solid-liquid systems connected to applications, taking zeolite/water and uranium oxide/water interfaces for examples. Understanding of the interfacial reactions subsequent to the energy/charge transfer would bridge the gaps and enable to predict the radiation effects in applications.
Hirade, Tetsuya
Radioisotopes, 66(11), p.587 - 593, 2017/11
Positron, anti-particle of electron, annihilates with the lifetime of 100ps to several ns in condensed matter. The energy of the mass of both particles emits as two -rays. The annihilation rate of energy of -rays indicate information just before the annihilation. Positrons have some possibility of reaction with excess electrons to form Positronium (Ps). Ps formation occur within ~ps, therefore Ps formation can be a probe of very fast reactions. Moreover, long lived triplet Ps can have reaction with reactive species until the lifetime of ~ns. Here, methods of positron annihilation research for radiation chemistry and some researches done by positron annihilation methods are introduced.
Nagaishi, Ryuji
Radioisotopes, 66(11), p.601 - 610, 2017/11
no abstracts in English
Clark, A. J.*; Denman, M. R.*; Takata, Takashi; Ohshima, Hiroyuki
SAND2017-12409, 39 Pages, 2017/11
Two sodium spray fire experiments performed by Sandia National Laboratories (SNL) were used for a code-to-code comparison between CONTAIN-LMR and SPHINCS. Both computer codes are used for modeling sodium accidents in sodium fast reactors. The comparison between the two codes provides insights into the ability of both codes to model sodium spray fires. The SNL T3 and T4 experiments are 20 kg sodium spray fires with sodium spray temperatures of 200C and 500C, respectively. The vessel in the SNL T4 experiment experienced a rapid pressurization that caused of the instrumentation ports to fail during the sodium spray. Despite these unforeseen difficulties, both codes were shown in good agreement with the experiments. SPHINCS showed better long-term agreement with the SNL T3 experiment than CONTAIN-LMR. The unexpected port failure during the SNL T4 experiment presented modelling challenges.
Harjo, S.; Tsuchida, Noriyuki*; Abe, Jun*; Gong, W.*
Scientific Reports (Internet), 7(1), p.15149_1 - 15149_11, 2017/11
Times Cited Count：100 Percentile：93.84(Multidisciplinary Sciences)Terada, Kentaro*; Sato, Akira*; Ninomiya, Kazuhiko*; Kawashima, Yoshitaka*; Shimomura, Koichiro*; Yoshida, Go*; Kawai, Yosuke*; Osawa, Takahito; Tachibana, Shogo*
Scientific Reports (Internet), 7(1), p.15478_1 - 15478_6, 2017/11
Times Cited Count：21 Percentile：68.68(Multidisciplinary Sciences)Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities. Here we report the first non-destructive elemental analysis of a carbonaceous chondrite using one of the world-leading intense direct current muon beam source (MuSIC; MUon Science Innovative Channel). We successfully detected characteristic muonic X-rays of Mg, Si, Fe, O, S and C from Jbilet Winselwan CM chondrite, of which carbon content is about 2 wt percent, and the obtained elemental abundance pattern was consistent with that of CM chondrites.
Kobayashi, Tatsuya*; Ito, Kimitaka*; Ido, Takeshi*; Kamiya, Kensaku*; Ito, Sanae*; Miura, Yukitoshi; Nagashima, Yoshihiko*; Fujisawa, Akihide*; Inagaki, Shigeru*; Ida, Katsumi*
Scientific Reports (Internet), 7(1), p.14971_1 - 14971_8, 2017/11
Times Cited Count：22 Percentile：78.98(Multidisciplinary Sciences)Tanaka, Kazuya; Kaplan, D. I.*; Onuki, Toshihiko
Applied Geochemistry, 85(Part B), p.119 - 120, 2017/10
Times Cited Count：0 Percentile：0.3(Geochemistry & Geophysics)We have prepared a special issue for Applied Geochemistry entitled "Transformation and Fate of Natural and Anthropogenic Radionuclides in the Environments". Here, we present 13 peer-reviewed articles on the general theme of natural and anthropogenic radionuclides in different environments. At the same time, these articles cover various topics of field research on the distribution of radionuclides, as well as laboratory experiments on adsorption and redox chemistry of these. The articles have been written by the attendees of the session at the Goldschmidt 2016 held in Yokohama, Japan, and by other authors who submitted their manuscripts to Applied Geochemistry focusing on the theme of the special issue.
Horiike, Takumi*; Dotsuta, Yuma*; Nakano, Yuriko*; Ochiai, Asumi*; Utsunomiya, Satoshi*; Onuki, Toshihiko; Yamashita, Mitsuo*
Applied and Environmental Microbiology, 83(20), p.e00855-17_1 - e00855-17_11, 2017/10
Times Cited Count：18 Percentile：58.91(Biotechnology & Applied Microbiology)Radioactive strontium (
Sr) leaked into the ocean from the Fukushima Daiichi Nuclear Power Plant after the nuclear accident. Since the removal of Sr using general adsorbents is not efficient at high salinity, this study investigated removal of soluble Sr from a saline solution by biogenic carbonate minerals. An isolate, Bacillus sp. strain TK2d, from marine sediment removed more than 99 % of Sr in a saline solution. Sr adsorbed at the cell surface and then carbonate minerals containing Sr developed outside the cells.
Zr(
)
Zr cross section from the surrogate ratio method and its effect on 
-process nucleosynthesisYan, S. Q.*; Li, Z. H.*; Wang, Y. B.*; Nishio, Katsuhisa; Lugaro, M.*; Karakas, A. I.*; Makii, Hiroyuki; Mohr, P.*; Su, J.*; Li, Y. J.*; et al.
Astrophysical Journal, 848(2), p.98_1 - 98_8, 2017/10
Times Cited Count：5 Percentile：21.48(Astronomy & Astrophysics)Tanifuji, Yuta
Genshiryoku Nenkan 2018, p.96 - 97, 2017/10
no abstracts in English
Yanagisawa, Tsutomu*; Usami, Shin; Maeda, Seiichiro
Genshiryoku Nenkan 2018, p.90 - 95, 2017/10
no abstracts in English
by tuning nematicity and magnetism in FeSe
S
superconductorsMatsuura, Kohei*; Mizukami, Yuta*; Arai, Yuki*; Sugimura, Yuichi*; Maejima, Naoyuki*; Machida, Akihiko*; Watanuki, Tetsu*; Fukuda, Tatsuo; Yajima, Takeshi*; Hiroi, Zenji*; et al.
Nature Communications (Internet), 8, p.1143_1 - 1143_6, 2017/10
Times Cited Count：80 Percentile：91.57(Multidisciplinary Sciences)
CrShizuma, Toshiyuki*; Hayakawa, Takehito*; Daito, Izuru*; Ogaki, Hideaki*; Miyamoto, Shuji*; Minato, Futoshi
Physical Review C, 96(4), p.044316_1 - 044316_10, 2017/10
Times Cited Count：9 Percentile：55.37(Physics, Nuclear)The low-lying dipole strength in Cr was measured in nuclear resonance fluorescence experiments using a quasi-monochromatic, linearly polarized photon beam. The parities of the excited dipole states were determined by the intensity asymmetry of resonantly scattered -rays with respect to the polarization plane of the incident photon beam. The summed magnetic dipole (M1) strength was determined as 
at excitation energies between 7.5 and 12.1 MeV; the summed electric dipole (E1) strength was obtained as 
fm
. The observed M1 and E1 strengths were compared via random phase approximation calculations using the Skyrme interaction. The effects of 2 particle-2 hole configuration mixing and tensor force on dipole strength distributions were investigated.
=28 and 
=50; Spectroscopy of 
ZnShand, C. M.*; Podolyk, Zs.*; G
rska, M.*; Doornenbal, P.*; Obertelli, A.*; Nowacki, F.*; Otsuka, T.*; Sieja, K.*; Tostevin, J. A.*; Tsunoda, T.*; et al.
Physics Letters B, 773, p.492 - 497, 2017/10
Times Cited Count：25 Percentile：87.36(Astronomy & Astrophysics)Chiba, Satoshi*; Wakabayashi, Toshio*; Tachi, Yoshiaki; Takaki, Naoyuki*; Terashima, Atsunori*; Okumura, Shin*; Yoshida, Tadashi*
Scientific Reports (Internet), 7(1), p.13961_1 - 13961_10, 2017/10
Times Cited Count：34 Percentile：96.31(Multidisciplinary Sciences)Transmutation of long-lived fission products (LLFPs: 
Se, 
Zr, 
Tc, 
Pd, 
I, and 
Cs) into short-lived or non-radioactive nuclides by fast neutron spectrum reactors without isotope separation has been proposed as a solution to the problem of radioactive wastes disposal. Despite investigation of many methods, such transmutation remains technologically difficult. To establish an effective and efficient transmutation system, we propose a novel neutron moderator material, yttrium deuteride (YD), to soften the neutron spectrum leaking from the reactor core. Neutron energy spectra and effective half-lives of LLFPs, transmutation rates, and support ratios were evaluated with the continuous-energy Monte Carlo code MVP-II/MVP-BURN and the JENDL-4.0 cross section library. With the YD moderator in the radial blanket and shield regions, effective half-lives drastically decreased from 10
to 10
years and the support ratios reached 1.0 for all six LLFPs. This successful development and implementation of a transmutation system for LLFPs without isotope separation contribute to developing a self-consuming cycle of LLFPs using fast spectrum reactors to reduce radioactive waste.
Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Thermal Science and Engineering, 25(4), p.65 - 74, 2017/10
no abstracts in English
Malins, A.; Machida, Masahiko; Niita, Koji*
EPJ Web of Conferences, 153, p.06001_1 - 06001_9, 2017/09
Times Cited Count：1 Percentile：61.21(Nuclear Science & Technology)-rays from neutron induced fission of U-235Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Orlandi, R.; Lguillon, R.; Ogawa, Tatsuhiko; Soldner, T.*; Hambsch, F.-J.*; Astier, A.*; Pollitt, A.*; et al.
EPJ Web of Conferences, 146, p.04036_1 - 04036_4, 2017/09
Times Cited Count：4 Percentile：90.81(Nuclear Science & Technology)The measurement of the prompt fission -ray spectrum (PFGS) is quite important to study the de-excitation process of neutron-rich fission fragments as well as to generate data required to design a generation-IV reactors. The PFGS measured for spontaneous fission of 
Cf shows a broad hump at energies more than 8 MeV. This is interpreted as a giant dipole resonance (GDR) of the fragments centered around 15 MeV. To understand how the GDR is populated in the fission process, one needs to measure the PFGS for the reactions with the mass yields different from the spontaneous fission of Cf, such as (n,f). The measurements of the PFGS for (n,f), however, are limited less than 9 MeV even in the recent experiment. This prompts us to make a new measurement to extend the know PFGS up to 20 MeV. The measurement has been carried out at the PF1B beam line of Institut Laue-Langevin. In this contribution we will present the results obtained the measurement.
Nishio, Katsuhisa; Hirose, Kentaro; Lguillon, R.*; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Smallcombe, J.*; Chiba, Satoshi*; Aritomo, Yoshihiro*; Tanaka, Shoya*; et al.
EPJ Web of Conferences, 146, p.04009_1 - 04009_6, 2017/09
Times Cited Count：3 Percentile：86.43(Nuclear Science & Technology)Matsuyama, Tsugufumi*; Suzuki, Tatsuhiko*; Migita, Yukie; Ishii, Kota*; Ueno, Satoshi*
Hoken Butsuri, 52(3), p.226 - 230, 2017/09
no abstracts in English
Takahashi, Yoshio*; Fan, Q.*; Suga, Hiroki*; Tanaka, Kazuya; Sakaguchi, Aya*; Takeichi, Yasuo*; Ono, Kanta*; Mase, Kazuhiko*; Kato, Kenji*; Kanivets, V. V.*
Scientific Reports (Internet), 7(1), p.12407_1 - 12407_11, 2017/09
Times Cited Count：28 Percentile：67.08(Multidisciplinary Sciences)We focused on factors controlling partition of radiocesium on particulate matters and sediments in rivers of Fukushima and Chernobyl. Radiocesium is more soluble in the Pripyat River (Chernobyl) due to weaker interaction of radiocesium with clay minerals caused by the inhibition effect of the adsorbed humic substances. In contrast, particulate matters and sediments in the Kuchibuto River (Fukushima) display high adsorption affinity with lesser inhibition effect of adsorbed humic substances. This difference is possibly governed by the geology and soil type of provenances surrounding both catchments.
Sakuma, Hiroshi*; Tachi, Yukio; Yotsuji, Kenji; Suehara, Shigeru*; Arima, Tatsumi*; Fujii, Naoki*; Kawamura, Katsuyuki*; Honda, Akira
Clays and Clay Minerals, 65(4), p.252 - 272, 2017/08
Times Cited Count：2 Percentile：16.51(Chemistry, Physical)Structure and stability of montmorillonite edge faces (110), (010), (100), and (130) of the layer charges y = 0.5 and 0.33 are investigated by the first-principles electronic calculations based on the density functional theory. Stacking and single layer models are tested for understanding the effect of stacking on the stability of montmorillonite edge faces. Most stacking layers stabilize the edge faces by making hydrogen bonds between the layers; therefore, the surface energy of stacking layers is reduced rather than the single layer model. This indicates that the surface energy of edge faces should be estimated depending on the swelling conditions. Lowest surface energies of (010) and (130) edge faces were realized by the presence of Mg ions on the edge faces. These edge faces have a strong adsorption site for cations due to local negative charge of the edges.
Nishimura, Akihiko; Takenaka, Yusuke*; Furusawa, Akinori; Torimoto, Kazuhiro; Ueda, Masashi; Fukuda, Naoaki*; Hirao, Kazuyuki*
E-Journal of Advanced Maintenance (Internet), 9(2), p.52 - 59, 2017/08
no abstracts in English
Hayashi, Koichi*; Oyama, Kenji*; Happo, Naohisa*; Matsushita, Tomohiro*; Hosokawa, Shinya*; Harada, Masahide; Inamura, Yasuhiro; Nitani, Hiroaki*; Shishido, Toetsu*; Yubuta, Kunio*
Science Advances (Internet), 3(8), p.e1700294_1 - e1700294_7, 2017/08
Igarashi, Masayasu*; Matsumoto, Tomohiro*; Yagihashi, Fujio*; Yamashita, Hiroshi*; Ohara, Takashi; Hanashima, Takayasu*; Nakao, Akiko*; Moyoshi, Taketo*; Sato, Kazuhiko*; Shimada, Shigeru*
Nature Communications (Internet), 8, p.140_1 - 140_8, 2017/07
Times Cited Count：25 Percentile：64.07(Multidisciplinary Sciences)Lacroix, V.*; Bouydo, A.*; Katsumata, Genshichiro*; Li, Y.; Hasegawa, Kunio
Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 7 Pages, 2017/07
Ijiri, Yuta*; Ono, Naoko*; Ukai, Shigeharu*; Yu, H.*; Otsuka, Satoshi; Abe, Yosuke; Matsukawa, Yoshitaka*
Philosophical Magazine, 97(13), p.1047 - 1056, 2017/02
Times Cited Count：2 Percentile：11.52(Materials Science, Multidisciplinary)The interaction between oxide particles and dislocations in a 9Cr-ODS ferritic steel is investigated by both static and in-situ TEM observation under dynamic straining conditions and room temperature. The measured obstacle strength (
) of the oxide particles was no greater than 0.80 and the average was 0.63. The dislocation loops around some coarsened particles were also observed. The calculated obstacle strength by a stress formula of the Orowan interaction is nearly equaled to the average experimental value. Not only cross-slip system but also the Orowan interaction should be considered as the main interaction mechanism between oxide particles and dislocation in 9Cr-ODS ferritic steel.
Nagoshi, Kohei*; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Takeuchi, Masayuki; Sato, Mutsumi*; Oikawa, Hiroshi*
Nihon Ion Kokan Gakkai-Shi, 28(1), p.11 - 18, 2017/01
no abstracts in English
B conversion layerMiyajima, Shigeyuki*; Shishido, Hiroaki*; Narukami, Yoshito*; Yoshioka, Naohito*; Fujimaki, Akira*; Hidaka, Mutsuo*; Oikawa, Kenichi; Harada, Masahide; Oku, Takayuki; Arai, Masatoshi*; et al.
Nuclear Instruments and Methods in Physics Research A, 842, p.71 - 75, 2017/01
Times Cited Count：13 Percentile：78.05(Instruments & Instrumentation)Tsuji, Masakuni*; Kobayashi, Shinji*; Mikake, Shinichiro; Sato, Toshinori; Matsui, Hiroya
Procedia Engineering, 191, p.543 - 550, 2017/00
Times Cited Count：11 Percentile：92.43(Mining & Mineral Processing)This paper shows the application of two post-grouting works to a gallery at 500 m depth of Mizunami Underground Research Laboratory in Japan. Three new grouting concepts were applied to the post-grouting works; a new grout material, a new injection system, and a new post-grouting zone. As for a grout material, "durable liquid-type colloidal silica grout (CSG)" was applied to seal the narrow fractures. As for an injection system, "complex dynamic grouting method" was applied to improve the penetrability of the grout material. The grouting works were successful in reducing the abundant water inflow from the rock mass with many fractures.
Yano, Naomine*; Yamada, Taro*; Hosoya, Takaaki*; Ohara, Takashi; Tanaka, Ichiro*; Kusaka, Katsuhiro*
Scientific Reports (Internet), 6, p.36628_1 - 36628_9, 2016/12
Times Cited Count：11 Percentile：61.6(Multidisciplinary Sciences)
