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Yamaguchi, Akiko; Kurihara, Yuichi*; Nagata, Kojiro*; Tanaka, Kazuya; Higaki, Shogo*; Kobayashi, Toru; Tanida, Hajime; Ohara, Yoshiyuki*; Yokoyama, Keiichi; Yaita, Tsuyoshi; et al.
Journal of Colloid and Interface Science, 661, p.317 - 332, 2024/05
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)no abstracts in English
Machida, Masahiko; Yamada, Susumu; Kim, M.; Okumura, Masahiko; Miyamura, Hiroko; Shikaze, Yoshiaki; Sato, Tomoki*; Numata, Yoshiaki*; Tobita, Yasuhiro*; Yamaguchi, Takashi; et al.
RIST News, (69), p.2 - 18, 2023/09
The contamination of radioactive materials leaked from the reactor has resulted in numerous hot spots in the Fukushima Daiichi Nuclear Power Station (1F) building, posing obstacles to its decommissioning. In order to solve this problem, JAEA has conducted research and development of the digital technique for inverse estimation of radiation source distribution and countermeasures against the estimated source in virtual space for two years from 2021 based on the subsidy program "Project of Decommissioning and Contaminated Water Management" performed by the funds from the Ministry of Economy, Trade and Industry. In this article, we introduce the results of the project and the plan of the renewal project started in April 2023. For the former project, we report the derivative method for LASSO method considering the complex structure inside the building and the character of the source and show the result of the inverse estimation using the method in the real reactor building. Moreover, we explain the platform software "3D-ADRES-Indoor" which integrates these achievements. Finally, we introduce the plan of the latter project.
molecular dynamics simulations reveal the hydration structure of the radium(II) ionYamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08
Times Cited Count：9 Percentile：69.8(Multidisciplinary Sciences)no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
Hosha Kagaku, (45), p.28 - 30, 2022/03
no abstracts in English
Sato, Tatsuhiko; Niita, Koji*; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Okumura, Keisuke; et al.
EPJ Web of Conferences, 153, p.06008_1 - 06008_6, 2017/09
Times Cited Count：6 Percentile：95.14(Nuclear Science & Technology)Particle and Heavy Ion Transport code System, PHITS, has been developed under the collaboration of several institutes in Japan and Europe. It can deal with the transport of nearly all particles up to 1 TeV (per nucleon for ion) using various nuclear reaction models and data libraries. More than 2,500 researchers and technicians have used the code for a variety of applications such as accelerator design, radiation shielding and protection, medical physics, and space and geosciences. This paper briefly summarizes physics models and functions newly implemented in PHITS between versions 2.52 and 2.82.
Kitamura, Akihiro; Kurikami, Hiroshi; Sakuma, Kazuyuki; Malins, A.; Okumura, Masahiko; Machida, Masahiko; Mori, Koji*; Tada, Kazuhiro*; Tawara, Yasuhiro*; Kobayashi, Takamaru*; et al.
Earth Surface Processes and Landforms, 41(12), p.1708 - 1726, 2016/09
Times Cited Count：16 Percentile：52.3(Geography, Physical)Sediment erosion and transport processes that are considered to be important in predicting the future radioactive material distribution through sediment-sorbed form in Fukushima Prefecture are simulated. Since large portion of the sediment is considered to be supplied into the rivers, it is important to trace their migration process in terms of each river basin. We choose five river basins, namely the Odaka, the Ukedo, the Maeda, the Kuma, and the Tomioka, from north to south, because of their importance in contamination aspects and prediction studies. The results are summarized as comprehensive dataset of sediment migration for particular river basins in typical typhoon events that account for the most of annual soil erosion. Detail calculations implemented for the amount of sediment supplied in to the river, deposited on river and dam beds, and exported to the ocean.
Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuda, Norihiro; Iwase, Hiroshi*; et al.
JAEA-Conf 2016-004, p.63 - 69, 2016/09
A general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through the collaboration of several institutes. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. PHITS users apply the code to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research. This presentation briefly summarizes the physics models implemented in PHITS, and introduces some new models such as muon-induced nuclear reaction model and a 
de-excitation model EBITEM. We will also present the radiation damage cross sections for materials, PKA spectra and kerma factors calculated by PHITS under the IAEA-CRP activity titled "Primary radiation damage cross section."
Okumura, Keisuke; Kojima, Kensuke; Tanaka, Kenichi*
JAEA-Conf 2015-003, p.43 - 47, 2016/03
In the safety assessment concerning disposal of radioactive wastes generated in the decommissioning of nuclear facilities, it is necessary to evaluate the radionuclide inventory produced by the activation of structured materials. For this purpose, we have to pay much attention to the activation of many impurities irradiated in various neutron spectra depending on their positions and materials. Therefore, accurate activation cross-section data are necessary for many nuclides and reactions. A new multi-group neutron activation cross-section library (MAXS) was developed based on the recent nuclear data JENDL-4.0 and JEFF-3.0/A to apply it to the activation calculations for the decommissioning of nuclear facilities. The library contains cross-sections and isomeric ratios for many reactions such as (n,), (n,f), (n,2n), (n,3n), (n,p), (n,
), (n,d), (n,t), (n,n), (n,np), and so on, for 779 nuclides, in the 199-energy group structure of VITAMIN-B6.
Kojima, Kensuke; Okumura, Keisuke; Kosako, Kazuaki*; Torii, Kazutaka*
JAEA-Research 2015-019, 90 Pages, 2016/01
JAEA-Research-2015-019.pdf:1.95MB
At the decommissioning of light water reactors (LWRs), it is important to evaluate an amount of radioactivity in the ex-core structures such as a reactor containment vessel, radiation shieldings, and so on. It is thought that the leakage neutron spectra in these radioactivation regions, which strongly affect the induced radioactivity, would be changed by different reactor core configurations such as fuel assembly loading pattern and fuel burnups. This study was intended to evaluate these effects. For the purpose, firstly, partial neutron currents on the core surfaces were calculated for some core configurations. Then, the leakage neutron flux spectra in major radioactivation regions were calculated based on the provided currents. Finally, influence of the core configurations upon the neutron flux spectra was evaluated. As a result, it has been found that the influence is small on the spectrum shapes of neutron fluxes. However, it is necessary to pay attention to the facts that intensities of the leakage neutron fluxes are changed by the configurations and that intensities and spectrum shapes of the leakage neutron fluxes are changed depending on the angular direction around the core.
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Furuta, Takuya; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; et al.
Annals of Nuclear Energy, 82, p.110 - 115, 2015/08
Times Cited Count：35 Percentile：94.59(Nuclear Science & Technology)The general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through a collaboration of several institutes in Japan and Europe. The Japan Atomic Energy Agency is responsible for managing the entire project. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. This paper briefly summarizes the physics models implemented in PHITS, and introduces some important functions useful for particular purposes, such as an event generator mode and beam transport functions.
Iwamoto, Yosuke; Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Furuta, Takuya; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; et al.
JAEA-Conf 2014-002, p.69 - 74, 2015/02
A general purpose Monte Carlo Particle and Heavy Ion Transport code System, PHITS, is being developed through the collaboration of several institutes in Japan and Europe. PHITS can deal with the transport of nearly all particles, including neutrons, protons, heavy ions, photons, and electrons, over wide energy ranges using various nuclear reaction models and data libraries. All components of PHITS such as its source, executable and data-library files are assembled in one package and then distributed to many countries. More than 1,000 researchers apply the code to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research. This presentation briefly summarizes the physics models implemented in PHITS, and introduces some important functions for specific applications, such as an event generator mode and a radiation damage calculation function.
Yamamoto, Kento; Okumura, Keisuke; Kojima, Kensuke; Okamoto, Tsutomu
Nuclear Back-end and Transmutation Technology for Waste Disposal, p.233 - 249, 2015/00
To improve the prediction accuracy of concentrations of activation products (APs) in the field of nuclear back-end, it is important to investigate the elements and the nuclear reactions leading to generation of APs. To clarify quantitatively the source elements and the nuclear reactions dominating generation of APs, sensitivity analyses of initial compositions and cross sections were conducted using ORIGEN2.2 code and ORLIBJ40, which is a set of the 1-group cross section libraries based on JENDL-4.0. Activations of cladding tubes, end-plugs and spacers of fuel assemblies and channel boxes in BWR, whose materials are zirconium alloy, stainless steel, and nickel-chromium-based alloy, were analyzed. The results clarified quantitatively the source elements and the nuclear reactions dominating generation of APs. It was remarkable that the dominant generation pathways were clarified even for the nuclides generated through complicated pathways. In conclusion, the results of sensitivity analyses could be utilized to select the objective of elements for measurements of impurities in the materials and of nuclear data for improvement of accuracy.
Kojima, Kensuke; Okumura, Keisuke
Proceedings of International Conference on the Physics of Reactors; The Role of Reactor Physics toward a Sustainable Future (PHYSOR 2014) (CD-ROM), 9 Pages, 2014/09
The MOSRA system has been developing to improve the applicability of the neutronic characteristic analyses. The cell calculation module MOSRA-SRAC is a core module of MOSRA, and applicability tests for realistic problems are required. As a test, we joined the benchmark "Burnup Credit Criticality Benchmark Phase IIIC." The benchmark requested the neutronic characteristics for a BWR fuel assembly with gadolinium, which had been used in the TEPCO's Fukushima Daiichi Nuclear Power Station. Because of a restriction of MOSRA-SRAC, the geometry was partially homogenized. To verify the module's applicability including the homogenization effects, the multiplication factor and the nuclide compositions were compared with the well-validated code MVP-BURN. As the results, the applicability of MSORA-SRAC for the assembly was verified. Additionally, it was also shown that the homogenization effects were smaller than the difference due to the calculation methods.
Yamamoto, Kento; Okumura, Keisuke; Kojima, Kensuke; Okamoto, Tsutomu
JAEA-Research 2013-038, 88 Pages, 2014/02
JAEA-Research-2013-038.pdf:3.15MB
Accurate information on main generation pathways of activation products is important to improve the accuracy of predicting the concentrations of activation products. Using ORIGEN2 and ORLIBJ40, which is a set of the cross section libraries based on JENDL-4.0, the initial compositions and the cross sections which influence on the concentrations of activation products were clarified by executing the sensitivity analyses on them. Activations of cladding tubes, end-plugs and spacers of fuel assemblies and channel boxes, which were composed of Zircaloy, SUS304, and Inconel-718, were analyzed. The main generation pathways of some significant activation products were summarized from the results of sensitivity analyses.
Okumura, Keisuke; Kojima, Kensuke; Okamoto, Tsutomu; Hagura, Hiroyuki; Suyama, Kenya
JAEA-Conf 2013-002, p.15 - 20, 2013/10
Three-dimensional nuclide inventory and decay heat analysis were performed for the Fukushima Dai-ichi Power Plants (1F1, 1F2, 1F3) by using MOSRA system with JENDL-4.0 library. In the analysis, nuclide inventory for approximately 1400 nuclides were estimated in consideration of radial and axial burn-up and void distributions. Total decay heat and its distribution in each plant were estimated by the sum of all nuclide contributions. The obtained decay heat was compared with the results of simple evaluation formulas used in severe accident analyses. The results of the simple evaluation formulas agree with our results within 20%. For future decommissioning of commercial nuclear power plants, new activation cross-sections library for ORIGEN-S is also under development in the cooperative study program between JAEA and JAPCO. The present status and future plan are shown from view points of nuclear data and method.
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Noda, Shusaku; Ogawa, Tatsuhiko; Iwase, Hiroshi*; Nakashima, Hiroshi; Fukahori, Tokio; et al.
Journal of Nuclear Science and Technology, 50(9), p.913 - 923, 2013/09
Times Cited Count：564 Percentile：99.98(Nuclear Science & Technology)An upgraded version of the Particle and Heavy Ion Transport code System, PHITS 2.52, was developed and released to public. The new version has been greatly improved from the previous released version, PHITS 2.24, in terms of not only the code itself but also the contents of its package such as attached data libraries. Owing to these improvements, PHITS became a more powerful tool for particle transport simulation applicable to various research and development fields such as nuclear technology, accelerator design, medical physics, and cosmic-ray research.
Ishizaka, Tomohisa; Imai, Koji*; Yuri, Yosuke; Yuyama, Takahiro; Ishibori, Ikuo; Okumura, Susumu
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.594 - 596, 2013/08
no abstracts in English
Okumura, Keisuke; Sugino, Kazuteru; Kojima, Kensuke; Jin, Tomoyuki*; Okamoto, Tsutomu; Katakura, Junichi*
JAEA-Data/Code 2012-032, 148 Pages, 2013/03
JAEA-Data-Code-2012-032.pdf:6.99MB
A set of cross section libraries for the isotope generation and depletion calculation code ORIGEN2 was produced by using recent nuclear data JENDL-4.0. In this new library (ORLIBJ40), neutron-induced cross sections, fission product yields, isomeric ratios and half-lives were updated. ORLIBJ40 includes 24 libraries for typical UO
or MOX fuels of PWR and BWR. In addition, it includes 36 libraries for various fast reactor fuels. ORLIBJ40 was applied to the post irradiation examination analyses of LWR nuclear spent fuels. As a result, it was confirmed that improvements were achieved especially for inventory and radioactivity estimations of minor actinides (Am and Cm isotopes) and fission products sensitive to cross sections (Eu and Sm isotopes) and for long-lived fission products (
Se, etc.), compared with other existing ORIGEN2 libraries.
Ishizaka, Tomohisa; Imai, Koji*; Yuri, Yosuke; Yuyama, Takahiro; Ishibori, Ikuo; Okumura, Susumu
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 157, 2013/01
Sato, Tatsuhiko; Niita, Koji*; Matsuda, Norihiro; Hashimoto, Shintaro; Iwamoto, Yosuke; Noda, Shusaku; Ogawa, Tatsuhiko; Nakashima, Hiroshi; Fukahori, Tokio; Okumura, Keisuke; et al.
RIST News, (54), p.14 - 24, 2013/01
Features of the latest version of the PHITS code (version 2.52) is described.
