Integral experiment of I(n, ) using fast neutron source in the "YAYOI" reactor

Nakamura, Shoji; Toh, Yosuke; Kimura, Atsushi; Hatsukawa, Yuichi*; Harada, Hideo

Journal of Nuclear Science and Technology, 59(7), p.851 - 865, 2022/07

https://doi.org/10.1080/00223131.2021.2011794

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.

Neutron capture cross sections of curium isotopes measured with ANNRI at J-PARC

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

https://doi.org/10.1080/00223131.2020.1864492

Development of MIG2DF Version 2

Takai, Shizuka; Kimura, Hideo*; Uchikoshi, Emiko*; Munakata, Masahiro; Takeda, Seiji

JAEA-Data/Code 2020-007, 174 Pages, 2020/09

JAEA-Data-Code-2020-007.pdf:4.23MB

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).

Investigation of the function of RPA software and examination of its application to JAEA's work

Kimura, Hideo; Takita, Hayato

JAEA-Technology 2020-002, 50 Pages, 2020/05

JAEA-Technology-2020-002.pdf:5.03MB

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.

Measurement of the U(n, f) cross section relative to the Li(n, t) and B(n, ) standards from thermal to 170 keV neutron energy range at n_TOF

Amaducci, S.*; Harada, Hideo; Kimura, Atsushi; 118 of others*

European Physical Journal A, 55(7), p.120_1 - 120_19, 2019/07

https://doi.org/10.1140/epja/i2019-12802-7

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.

Technical report on the development of finance and contract information system Ver.4

Kimura, Hideo; Hikasa, Naoki*; Kugenuma, Yuji*; Doi, Toshiharu*; Kikuchi, Yoshitaka*

JAEA-Technology 2019-004, 25 Pages, 2019/05

JAEA-Technology-2019-004.pdf:3.02MB

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.

Cross section measurements of Gd(n,) induced by thermal and epithermal neutrons

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

https://doi.org/10.1140/epja/i2019-12692-7

Measurements of neutron total and capture cross sections of Am with ANNRI at J-PARC

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

AA2017-0628.pdf:2.06MB

https://doi.org/10.1080/00223131.2018.1485519

Integrating radiation protection criteria for radioactive waste management into remediation procedures in existing exposure situations after a nuclear accident

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

https://doi.org/10.1088/1361-6498/aaa155

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.

Technical developments for accurate determination of amount of samples used for TOF measurements

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

https://doi.org/10.1051/epjconf/201714603019

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.