Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tada, Kenichi; Nagaya, Yasunobu; Taninaka, Hiroshi; Yokoyama, Kenji; Okita, Shoichiro; Oizumi, Akito; Fukushima, Masahiro; Nakayama, Shinsuke
Journal of Nuclear Science and Technology, 21 Pages, 2023/04
Times Cited Count：6 Percentile：98.92(Nuclear Science & Technology)The new version of the Japanese evaluated nuclear data library, JENDL-5, was released in December 2021. This paper demonstrates the validation of JENDL-5 for fission reactor applications. Benchmark calculations are performed with the continuous-energy Monte Carlo codes MVP and MCNP and the deterministic code system MARBLE. The benchmark calculation results indicate that the performance of JENDL-5 for fission reactor applications is better than that of the former library JENDL-4.0.
Iwamoto, Osamu; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke; Abe, Yutaka*; Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; et al.
Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01
Times Cited Count：64 Percentile：99.99(Nuclear Science & Technology)Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
Times Cited Count：3 Percentile：15.82(Environmental Sciences)The dry and wet depositions of atmospheric ammonia (NH
) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
Np and 
Am by accelerator-driven system at Kyoto University Critical AssemblyPyeon, C. H.*; Yamanaka, Masao*; Oizumi, Akito; Fukushima, Masahiro; Chiba, Go*; Watanabe, Kenichi*; Endo, Tomohiro*; Van Rooijen, W. G.*; Hashimoto, Kengo*; Sakon, Atsushi*; et al.
Journal of Nuclear Science and Technology, 56(8), p.684 - 689, 2019/08
Times Cited Count：12 Percentile：80.27(Nuclear Science & Technology)This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (Np) and americium-241 (Am), and capture reactions of Np. Subcritical irradiation of Np and Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (Np or Am) and reference (uranium-235) foils. The first nuclear transmutation of Np and Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events.
Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.
Journal of Nuclear Science and Technology, 52(2), p.282 - 293, 2015/02
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)We have developed a void reactivity evaluation method by using modified conversion ratio measurements in a light water reactor (LWR) critical lattice. Assembly-wise void reactivity is evaluated from the "finite neutron multiplication factor", 
, deduced from the modified conversion ratio of each fuel rod. The distributions of modified conversion ratio and on a reduced-moderation LWR lattice, for which the improvement of negative void reactivity is a serious issue, were measured. Measured values were analyzed with a continuous-energy Monte Carlo method. The measurements and analyses agreed within the measurement uncertainty. The developed method is useful for validating the nuclear design methodology concerning void reactivity.
Yamagishi, Isao; Nagaishi, Ryuji; Kato, Chiaki; Morita, Keisuke; Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro; Sato, Hiroyuki; Nishihara, Kenji; Tsubata, Yasuhiro; et al.
Journal of Nuclear Science and Technology, 51(7-8), p.1044 - 1053, 2014/07
Times Cited Count：19 Percentile：78.38(Nuclear Science & Technology)For safe storage of zeolite wastes generated by treatment of radioactive saline water at the Fukushima Daiichi Nuclear Power Station, properties of the Herschelite adsorbent were studied and its adsorption vessel was evaluated for hydrogen production and corrosion. Hydrogen production depends on its water level and dissolved species because hydrogen is oxidized by radicals in water. It is possible to evaluate hydrogen production rate in Herschelite submerged in seawater or pure water by taking into account of the depth effect of the water. The reference vessel of decay heat 504 W with or without residual pure water was evaluated for the hydrogen concentration by thermal hydraulic analysis using obtained fundamental properties. Maximum hydrogen concentration was below the lower explosive limit (4 %). The steady-state corrosion potential of a stainless steel 316L increased with absorbed dose rate but its increase was repressed by the presence of Herschelite. At 750 Gy/h and 
60
C which were values evaluated at the bottom of the vessel of 504 W, the localized corrosion of SUS316L contacted with Herschelite would not immediately occur under 20,000 ppm of Cl
concentration.
Fukushima, Masahiro; Ishikawa, Makoto; Numata, Kazuyuki*; Jin, Tomoyuki*; Kugo, Teruhiko
Nuclear Data Sheets, 118, p.405 - 409, 2014/04
Times Cited Count：0 Percentile：0.02(Physics, Nuclear)Yoshimura, Kazuya; Onda, Yuichi*; Fukushima, Takehiko*
Scientific Reports (Internet), 4, p.4514_1 - 4514_6, 2014/03
Times Cited Count：30 Percentile：65.09(Multidisciplinary Sciences)Yoshioka, Kenichi*; Kikuchi, Tsukasa*; Gunji, Satoshi*; Kumanomido, Hironori*; Mitsuhashi, Ishi*; Umano, Takuya*; Yamaoka, Mitsuaki*; Okajima, Shigeaki; Fukushima, Masahiro; Nagaya, Yasunobu; et al.
Journal of Nuclear Science and Technology, 50(6), p.606 - 614, 2013/06
Times Cited Count：1 Percentile：10.69(Nuclear Science & Technology)We have developed an intra-pellet neutron flux and conversion ratio distribution measurement method. A foil activation method with special foils was used for the neutron flux distribution measurement. A 
-ray spectrum analysis method with special collimators was used for the conversion ratio distribution measurement. Using the developed methods, intra-pellet neutron flux distributions and conversion ratio distributions were measured in critical experiments on a reduced-moderation LWR. Measured values were analyzed with a deterministic method and a Monte Carlo method. The neutron flux distribution measurements and analyses agreed within the range of 1% to 2%. The conversion ratio distribution measurements and analyses were consistent with each other. We found that the measurement methods are useful for the validation of neutron behavior in a fuel pellet, which is known as micro reactor physics.
Ouchi, Masaru; Takebe, Shinichi; Kawatsuma, Shinji; Fukushima, Tadashi*
JAEA-Review 2012-019, 186 Pages, 2013/02
JAEA-Review-2012-019.pdf:11.86MB
We have reviewed information about justification for establishing uranium bearing waste acceptance for near surface disposal (trench and concrete pit disposals) in foreign countries, to intend to discuss clearance level and disposal of uranium bearing waste in Japan. Most of EU countries have adopted the unconditional clearance level 1 Bq/g described in EU Guidance RP 122 Part 1 and IAEA Safety Guide RS-G-1.7 for uranium wastes. And in the case of special landfill burial, the conditional clearance level about 10 Bq/g (equivalent to exemption level) has been adopted in Germany, Sweden and UK.
Matsunami, Noriaki*; Fukushima, Junichi*; Sataka, Masao; Okayasu, Satoru; Sugai, Hiroyuki; Kakiuchida, Hiroshi*
Nuclear Instruments and Methods in Physics Research B, 268(19), p.3071 - 3075, 2010/10
Times Cited Count：13 Percentile：65.22(Instruments & Instrumentation)no abstracts in English
Ueda, Nobuyuki*; Fukushima, Masahiro; Okajima, Shigeaki; Takeda, Toshikazu*; Kitada, Takanori*; Nauchi, Yasushi*; Kinoshita, Izumi*; Matsumura, Tetsuo*
Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), p.9493_1 - 9493_9, 2009/05
A series of critical experiments were carried out in the JAEA fast critical facility (FCA) named FCA XXIII cores with placing emphases on the reflector reactivity worth and the sodium void reactivity which are especially important from the view point of safety features of the 4S. The analyses of those physics mockup experiments have been carried out by the neutron transport calculation methods with continuous energy Monte Carlo code MVP and 70 energy-group discrete ordinate P0-S8 transport code DANTSYS using libraries processed from JENDL-3.3 data file. The results showed that combination of the stochastic and deterministic transport calculation methods (Monte Carlo and Sn) provided good prediction bases for criticality, reflector worth, sodium void reactivity, reaction rate ratios and absorber reactivity worth for the 4S nuclear design.
Hatanaka, Koichiro; Shigeta, Naotaka; Fukushima, Tatsuo
Proceedings of 2008 International High-Level Radioactive Waste Management Conference (IHLRWM 2008) (CD-ROM), p.101 - 108, 2008/09
The surface-based investigation (Phase I) in the Horonobe URL project has been conducted from March, 2001 until the end of the year 2005 as shown in Figure 1. Throughout the Phase I investigation, the concepts of geosynthesis and iterative assessment of the stepwise investigations were introduced towards characterization of the geological environment in the area including Horonobe URL site and the applicability was confirmed. The achievement of the Phase I investigation was summarized in the year 2006 and the relevant progress reports were published in March, 2007. In this paper, the concepts based on the geosynthesis methodology and its iterative application throughout stepwise investigations applied in the Horonobe URL project are discussed and summarized.
Hatanaka, Koichiro; Morioka, Hiroshi*; Fukushima, Tatsuo
Proceedings of 2008 International High-Level Radioactive Waste Management Conference (IHLRWM 2008) (CD-ROM), p.250 - 257, 2008/09
In this paper, the procedure for planning design/construction of the underground facilities developed in Phase I of Horonobe URL project, and current status of the actual construction in Phase II based on the design and relevant engineering technology developed in Phase I are briefly described.
Fukushima, Masahiro; Okajima, Shigeaki; Mori, Takamasa; Takeda, Toshikazu*; Kinoshita, Izumi*
Proceedings of International Conference on the Physics of Reactors, Nuclear Power; A Sustainable Resource (PHYSOR 2008) (CD-ROM), 7 Pages, 2008/09
The criticality was measured in a series of mock-up cores simulated small fast reactor with massive reflector at FCA facility of JAEA in order to evaluate the prediction accuracy of the current analysis code system. In the analyses, the effective cross sections were obtained by using an ultra-fine group cell calculation code. The JENDL-3.3 cross section library was used. The core calculations for the criticality were performed by using a three-dimensional S
transport code. Conventional calculations with a standard 70 energy group structure and under the P
transport approximation overestimated the experimental values up to 1.5%
/. Furthermore, the calculation parameters were investigated concerning the fine energy group structure and the higher Legendre order of anisotropic scattering cross section. Consequently, the calculation accuracy for the criticality was improved by about 1%/ with a 140 energy group structure and under the P approximation.
Kugo, Teruhiko; Ando, Masaki; Kojima, Kensuke; Fukushima, Masahiro; Mori, Takamasa; Nakano, Yoshihiro; Okajima, Shigeaki; Kitada, Takanori*; Takeda, Toshikazu*
Journal of Nuclear Science and Technology, 45(4), p.288 - 303, 2008/04
Times Cited Count：6 Percentile：40.09(Nuclear Science & Technology)The effectiveness of the extended bias factor methods, the LC and PE methods, is numerically investigated by applying them to a breeding light water reactor core as a target core with use of FCA-XXII-1 critical experiments. The present study numerically verifies the features of the extended bias factor methods. Both the methods can improve the prediction accuracy the most by using all the experiments. The PE method always improves the prediction accuracy with any combination of experiments. The PE method is always superior to the LC method for improvement of the prediction accuracy. From the present study, the followings are found. The experiments on multiplication factor are more applicable to a reaction rate ratio of 
U capture to 
Pu fission (C28/F49) of the target core than the experiments on C28/F49. Combinations of the experiments on multiplication factor is more effective to a void reactivity of the target core than those of the experiments on void reactivity though those on void reactivity are superior to those on multiplication factors in the case of using a single experiment. From these results, we conclude that the experiments on multiplication factor are more effective than the other experiments for all the neutronic characteristics of the target core. From these results, it is concluded that the PE method is promising to complement full mockup experiments for various future nuclear systems by using a number of existing and future benchmark experiments.
Kobune, Masafumi*; Fukushima, Koji*; Yamaji, Toru*; Tada, Hideto*; Yazawa, Tetsuo*; Fujisawa, Hironori*; Shimizu, Masaru*; Nishihata, Yasuo; Matsumura, Daiju; Mizuki, Junichiro; et al.
Journal of Applied Physics, 101(7), p.074110_1 - 074110_6, 2007/04
Times Cited Count：8 Percentile：33.28(Physics, Applied)no abstracts in English
Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Kunimaru, Takanori; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; Hama, Katsuhiro; Matsui, Hiroya; et al.
JAEA-Research 2007-044, 434 Pages, 2007/03
JAEA-Research-2007-044.pdf:54.58MBJAEA-Research-2007-044(errata).pdf:0.08MB
The Horonobe URL Project started in 2000. Research and development activities are planned over three phases, that will span a total duration of about 20 years: the 1st surface-based investigarion phase (6 years), the 2nd URL construction phase (8 years) and rhe 3rd operation phase (12 years). Geological, geophysical, geo-mechanical, hydrogeological, and hydro-geochemical investigations have been carried out during the surface-based investigation.
Ishii, Eiichi; Fukushima, Tatsuo
Oyo Chishitsu, 47(5), p.280 - 291, 2006/12
Because some fractures might be water conducting features in rocks, it is necessary to consider sufficiently the fractures, for development of a geological model. In this study, we have tried to understand geological characteristics and formative processes of faults in Neogene siliceous rocks, based on results of outcrop observation, boring-core observation, and borehole-wall observation, in order to develop an investigation technique for water conducting features. In addition, we have tried to estimate permeability of faults and to develop a geological conceptual model including water conducting features. The results of this study suggest the follow: Concerning faults without filling minerals and hydro-thermal alteration in Neogene siliceous rocks including fold structures, (1) in order to classify the faults, an attention of relation between fault direction and fold axis/bedding direction, of displacement sense, and of displacement is effective. (2) in order to understand the formative process of the faults, an observation of crosscutting relations of faults, an analysis of relationship between faulting and folding, and an inference of stress conditions of faulting by fault striation analysis are effective. (3) in order to estimate hydro-geological property, an observation of redox front along faults near the surface, and an analysis of fault density, of formative process of faults, and of relation between fault direction and stress axis are effective.
Seya, Masami; Hatanaka, Koichiro; Fukushima, Tatsuo
Sato Kogyo Gijutsu Kenkyushoho, (31), p.49 - 56, 2006/11
Although the atomic energy is utilized as effective energy source, treatment and disposal of high-level radioactive waste are important issues to be solved. In Japan, the high-level radioactive waste is planned to be disposed off in deep underground and R&D programs for the treatment and the disposal of the high-level radioactive waste are underway by Japan Atomic Energy Agency(JAEA) and other research institutes. The Horonobe Underground Research Laboratory Project is one of the research projects of JAEA to establish the scientific and technical basis in sedimentary rocks at Horonobe-cho, Hokkaido. In this report we introduce the outline and current status of the Horonobe Underground Reasearch Laboratory Project.
