Nakamura, Shoji; Toh, Yosuke; Kimura, Atsushi; Hatsukawa, Yuichi*; Harada, Hideo
Journal of Nuclear Science and Technology, 59(7), p.851 - 865, 2022/07
The present study performed integral experiments of I using a fast-neutron source reactor "YAYOI" of the University of Tokyo to validate evaluated nuclear data libraries. The iodine-129 sample and flux monitors were irradiated by fast neutrons in the Glory hole of the YAYOI reactor. Reaction rates of I were obtained by measurement of decay gamma-rays emitted from I. The validity of the fast-neutron flux spectrum in the Glory hole was confirmed by the ratios of the reaction rates of flux monitors. The experimental reaction rate of I was compared with that calculated with both the fast-neutron flux spectrum and evaluated nuclear data libraries. The present study revealed that the evaluated nuclear data of I cited in JENDL-4.0 should be reduced as much as 18% in neutron energies ranging from 10 keV to 3 MeV, and supported the reported data by Noguere below 100 keV.
Nakamura, Shoji; Hatsukawa, Yuichi*; Kimura, Atsushi; Toh, Yosuke; Harada, Hideo
Journal of Nuclear Science and Technology, 58(12), p.1318 - 1329, 2021/12
The present study performed fast-neutron capture cross-section measurement of Tc by an activation method using a fast-neutron source reactor "YAYOI" of the University of Tokyo. Technetium-99 samples were irradiated with reactor neutrons using a pneumatic system. Reaction rates of Tc were obtained by measuring decay gamma rays emitted from Tc. The neutron flux at an irradiation position was monitored with gold foils. The fast-neutron capture cross section of Tc at neutron energy of 85 keV was derived as 0.4320.023 barn by using the reaction rates of Tc, evaluated cross-section data and the fast-neutron flux spectrum of the YAYOI reactor. The present study agreed with the evaluated nuclear data library JENDL-4.0.
Kawase, Shoichiro*; Kimura, Atsushi; Harada, Hideo; Iwamoto, Nobuyuki; Iwamoto, Osamu; Nakamura, Shoji; Segawa, Mariko; Toh, Yosuke
Journal of Nuclear Science and Technology, 58(7), p.764 - 786, 2021/07
Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Aoi, Nori*; Azaiez, F.*; Furutaka, Kazuyoshi; Hatsukawa, Yuichi; Kimura, Atsushi; Kisamori, Keiichi*; Kobayashi, Motoki*; et al.
Physical Review C, 103(3), p.034327_1 - 034327_8, 2021/03
Takai, Shizuka; Kimura, Hideo*; Uchikoshi, Emiko*; Munakata, Masahiro; Takeda, Seiji
JAEA-Data/Code 2020-007, 174 Pages, 2020/09
The MIG2DF computer code is a computer program that simulates groundwater flow and radionuclide transport in porous media for the safety assessment of radioactive waste disposal. The original version of MIG2DF was released in 1992. The original code employs a two-dimensional (vertical or horizontal cross-section, or an axisymmetric configuration) finite-element method to approximate the governing equations for density-dependent saturated-unsaturated groundwater flow and radionuclide transport. Meanwhile, for geological disposal of radioactive wastes, landscape evolution such as uplift and erosion needs to be assessed as a long-term geological and climate events, considering site conditions. In coastal areas, the impact to groundwater flow by change of salinity distribution to sea level change also needs to be considered. To deal with these events in the assessment, we have revised the original version of MIG2DF and developed the external program which enables MIG2DF to consider unsteady landscape evolution. In these developments, this report describes an upgrade of MIG2DF (Version 2) and presents the configuration, equations, methods, and verification. This reports also give the explanation external programs of MIG2DF: PASS-TRAC (the particle tracking code), PASS-PRE (the code for dataset preparation), and PASS-POST (the post-processing visualization system).
Dupont, E.*; Bossant, M.*; Capote, R.*; Carlson, A. D.*; Danon, Y.*; Fleming, M.*; Ge, Z.*; Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; et al.
EPJ Web of Conferences, 239, p.15005_1 - 15005_4, 2020/09
Kimura, Hideo; Takita, Hayato
JAEA-Technology 2020-002, 50 Pages, 2020/05
Japan Atomic Energy Agency is strongly promoting business process re-engineering (BPR) of the entire organization in order to achieve more efficient, centralized and IT-style work. As part of this BPR, we have been studying the introduction of robotic process automation (RPA), which has been making remarkable progress in recent years, in order to further streamline and improve efficiency mainly for administrative work. In order to implement an appropriate RPA, the characteristics of each RPA software were clarified by investigating the functions of major RPA software and developing sample robots. Furthermore, we categorized various tasks that are expected to utilize RPA software and examined the application of RPA software to each business pattern.
Takai, Shizuka; Shimada, Asako; Sawaguchi, Takuma; Takeda, Seiji; Kimura, Hideo
Radiation Protection Dosimetry, 188(1), p.1 - 7, 2020/01
After the Fukushima Nuclear Power Plant accident, most of radiocesium-contaminated soil generated from decontamination activities outside Fukushima prefecture has been stored at decontamination sites such as schools, parks and residential lands (storage at sites) according to the Decontamination Guidelines. However, additional exposure due to the present storage has not been evaluated. Moreover, entering storage sites, which is not restricted for storage at sites, was not considered in safety assessment conducted in the guidelines. To continue the storage and confirm the effectiveness, understanding of present possible exposures is important. In this study, we evaluated exposure doses for residents and users of storage sites based on the present situation. As a result, annual doses due to residence were 10 to 10 mSv y and doses due to annual entries were of the order of 10 mSv y. Hence, we confirmed that the exposure due to present storage outside Fukushima is significantly less than 1 mSv y.
Amaducci, S.*; Harada, Hideo; Kimura, Atsushi; 118 of others*
European Physical Journal A, 55(7), p.120_1 - 120_19, 2019/07
The U(n, f) cross section was measured at n_TOF relative to Li(n, t) and B(n, ), in a wide energy range (25 meV170 keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. The present results indicate that the cross section in the 918 keV neutron energy range is indeed overestimated by almost 5% in the recently released evaluated data files ENDF/B-VIII.0 and JEFF3.3. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. From the present data, a value of 249.71.4(stat)0.94(syst) b eV has been extracted for the cross section integral between 7.8 and 11 eV, confirming the value of 247.53 b eV recently established as a standard.
Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06
Kimura, Hideo; Hikasa, Naoki*; Kugenuma, Yuji*; Doi, Toshiharu*; Kikuchi, Yoshitaka*
JAEA-Technology 2019-004, 25 Pages, 2019/05
JAEA has developed the "Financial and contract information system" for effective and efficient accomplishment of the mission-critical tasks. Because the development of the next system was necessary with the end in the support time limit of the current system, we carried out the development of the next system in 2018. While the addition of the electronic approval function or the adoption of the latest package software largely performed a functional enhancement until now by applying distributed systems construction technique based on the separation procurement that we devised progressively, in development, we extremely realized procurement with the low cost.
Hagiwara, Kaito*; Yano, Takatomi*; Das, P. K.*; Lorenz, S.*; Ou, Iwa*; Sakuda, Makoto*; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki; Harada, Hideo; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.023D01_1 - 023D01_26, 2019/02
Mastromarco, M.*; Manna, A.*; Aberle, O.*; Andrzejewski, J.*; Harada, Hideo; Kimura, Atsushi; n_TOF Collaboration*; 116 of others*
European Physical Journal A, 55(1), p.9_1 - 9_20, 2019/01
Nakamura, Shoji; Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Takamiya, Koichi*; Fujii, Toshiyuki*
Journal of Nuclear Science and Technology, 56(1), p.123 - 129, 2019/01
Accurate data of -ray emission probabilities are frequently needed when one quantitatively determines the amount of isotope by -ray measurements or obtains neutron capture cross-sections using them. Americium-243, one of the most important minor actinides, produces Am after neutron capture. The 744-keV -ray decaying from the ground state of Am has a relatively large -ray emission probability c.a. 66%, however, its uncertainty is as large as 29%. The uncertainty of the -ray emission probability leads to a major factor of the systematic uncertainty on determining an amount of isotope, and therefore the -ray emission probability was measured by using an activation method and an examined level structure of Cm. In this study, the emission probability of 744-keV ray was derived as 66.51.1%, and its uncertainty was improved from 29% to 2%.
Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10
Damone, L.*; Barbagallo, M.*; Mastromarco, M.*; Cosentino, L.*; Harada, Hideo; Kimura, Atsushi; n_TOF Collaboration*; 152 of others*
Physical Review Letters, 121(4), p.042701_1 - 042701_7, 2018/07
Sugiyama, Daisuke*; Kimura, Hideo; Tachikawa, Hirokazu*; Iimoto, Takeshi*; Kawata, Yosuke*; Ogino, Haruyuki*; Okoshi, Minoru*
Journal of Radiological Protection, 38(1), p.456 - 462, 2018/03
Experience after the accident at the Fukushima Daiichi Nuclear Power Station has shown that there is a need to establish radiation protection criteria for radioactive waste management consistent with the criteria adopted for the remediation of existing exposure situations. A stepwise approach to setting such criteria is proposed. Initially, a reference level for annual effective dose from waste management activities in the range 1-10 mSv should be set, with the reference level being less than the reference level for ambient dose. Subsequently, the reference level for annual effective dose from waste management activities should be reduced in one or more steps to achieve a final target value of 1 mSv. The dose criteria at each stage should be determined with relevant stakeholder involvement. Illustrative case studies show how this stepwise approach might be applied in practice.
Kimura, Atsushi; Harada, Hideo; Kunieda, Satoshi; Katabuchi, Tatsuya*
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(11), p.654 - 658, 2017/11
no abstracts in English
Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Kimura, Atsushi; Iwamoto, Osamu; Harada, Hideo; Takamiya, Koichi*; Hori, Junichi*
EPJ Web of Conferences, 146, p.03019_1 - 03019_4, 2017/09
The research project entitled "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started to improve the reliability of the neutron cross section date of MAs. In order to obtain accurate cross section data, it is indispensable to determine the amount of MA sample accurately and non-destructively. However, the uncertainty concerning the amount of sample is not assured in some cases. Therefore, as a part of the AIMAC project, this study is aimed to development the technique for accurate determination of the amount of samples by two different methods: -ray spectroscopic method and calorimetric method. This contribution presents the developed techniques together with results obtained by two independent techniques.
Kimura, Atsushi; Harada, Hideo; Nakamura, Shoji; Toh, Yosuke; Igashira, Masayuki*; Katabuchi, Tatsuya*; Mizumoto, Motoharu*; Hori, Junichi*
EPJ Web of Conferences, 146, p.11031_1 - 11031_4, 2017/09