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Nakayama, Shinsuke; Iwamoto, Osamu; Watanabe, Yukinobu*; Ogata, Kazuyuki*
no journal, ,
Intensive neutron sources using deuteron accelerators have been proposed for various applications such as irradiation testing of fusion reactor materials and production of medical radioisotopes. To contribute to the design study of such neutron sources, a deuteron reaction data file for light nuclei (Li-6,7, Be-9, C-12,13), JENDL/DEU-2020 was developed. In addition, the validation of it was performed by the simulation with the Monte Carlo transport codes such as PHITS. As a result, the simulation using JENDL/DEU-2020 reproduced the measured thick-target neutron yields better than those using the deuteron sub-library of TENDL and the reaction models implemented in PHITS, respectively.
Ozu, Akira; Maeda, Makoto; Komeda, Masao; Toh, Yosuke
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yamamura, Sota*; Yoshida, Hiroyuki; Abe, Yutaka*
no journal, ,
Specific measurement methods have been developed to understand multi-phase thermal-hydraulic behavior. By using these methods, we can obtain time series two and 3-dimensional spatial interface data of phases. These data are useful for providing validation data for advanced simulation methods based on multi-fluid computation fluid dynamics. For example, to understand FCI (fuel coolant interaction) behavior, specific measurements for fragments (dispersed phase) generated from the jet were measured, and interface and size of fragments were successfully evaluated. However, 3-dimensional data for velocity was not assessed, because there is no tracking method for individual dispersed phases like a tracking method of PTV (particle tracking velocimetry), which using time series 2-dimensional data. In this paper, we developed the dispersoid phase tracking method based on time series 3-dimensional interface data. To check the applicability of this method for 3-dimensional interface data, we used detailed two-phase simulation data by using TPFIT. In these data, there are 3-dimensional data of both interface and velocity distribution. Then, we can evaluate the correct dispersed phase velocity, and we can consider the accuracy of the developed method precisely. In this paper, we applied the developed method to simplified two-phase flow. The simplified flow means not to include coalescence and fragmentation of dispersoids. As a result, the tracking of one dispersoid performed successfully, but a standard deviation of the measuring error increased with the decrease of cell number of the dispersoid.
Terada, Hiroaki; Nagai, Haruyasu; Tsuzuki, Katsunori; Kadowaki, Masanao; Furuno, Akiko
no journal, ,
We have developed a method for estimation of source term of radioactive materials released into the atmosphere in nuclear accidents by comprehensive comparison of atmospheric dispersion simulations with different spatial scales and various types of environmental measurements. By applying this method to the Fukushima Daiichi Nuclear Power Station accident, the release rate estimated by the previous study was optimized and the effectiveness was examined.
Kono, Taiki*; Fujio, Kazuki*; Minato, Futoshi; Ishizuka, Chikako*; Chiba, Satoshi*
no journal, ,
no abstracts in English
Minato, Futoshi
no journal, ,
no abstracts in English
Nb at J-PARC 
MLF ANNRI and derivation of resonance parametersEndo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki
no journal, ,
no abstracts in English
C under different steam flow ratePham, V. H.; Nagae, Yuji; Kurata, Masaki; Ishibashi, Ryo*
no journal, ,
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi
no journal, ,
no abstracts in English
Shikaze, Yoshiaki; Shimazoe, Kenji*
no journal, ,
no abstracts in English
Sato, Tetsuro*; Yoshimura, Kazuya; Sato, Rina; Kanaizuka, Seiichi*; Sanada, Yukihisa; Ando, Masaki; Saito, Kimiaki
no journal, ,
From FY2014, researches on estimation of exposure dose when residents return to areas where evacuation orders have been canceled by interviewing living behavior routes and measuring air dose rates covering the entire routes have been carried out. We will report the specifications and the accuracy of exposure dose simulator developed in this study.
Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki
no journal, ,
no abstracts in English
Yoshida, Hiroko*; Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya
no journal, ,
no abstracts in English
Takano, Kazuya; Kato, Atsushi; Uchita, Masato*; Murakami, Hisatomo*
no journal, ,
Control rods of pool-type SFR are not fixed radially in the control rod guide tubes. Relative offset between control rods and around in-vessel structures occurs in an earthquake situation. The relative offset could lead three-point restraint of the control rods and difficulty of their insertion. In the present study, the seismic offset was quantitively evaluated and was compared with the criteria of the three-point restraint in the current design of pool-type SFR with 600 MWe. As the evaluated offset is below the criteria, the three-point restraint in an earthquake can be prevented in the current design of pool-type SFR. In addition, several measures were examined to increase the margin of control rods insertability.
Kimura, Atsushi
no journal, ,
no abstracts in English
Ono, Masato; Shimazaki, Yosuke; Ishitsuka, Etsuo; Iigaki, Kazuhiko
no journal, ,
The seismic design classification of HTTR was conservatively classified when HTTR was constructed, however the seismic design classification was reviewed with focus on the safety features based on the technical knowledge obtained from operations and calculations. The seismic design classification is one of the issues of checking conformity reviewed by the Nuclear Regulatory Agency.
Imoto, Jumpei; Nakajima, Kunihisa; Osaka, Masahiko
no journal, ,
CsOH chemisorption onto stainless steel surface is suggested to occur during a light water reactor severe accident and CsFeO
could be formed. In order to elucidate such a Cs chemisorption behavior, it is necessary to examine chemical reaction behavior with iron oxides formed on the stainless steel surface. In this study, chemical reaction behavior between CsOH and iron oxide was investigated by using mixed powders of cesium hydroxide monohydrate and iron oxides, i.e., goethite (
-FeOOH), hematite (-FeO
), and magnetite(FeO
). As the result, it was found that goethite and hematite were more reactive with CsOH than magnetite.
Suzuki, Eriko; Nakajima, Kunihisa; Miwa, Shuhei; Osaka, Masahiko; Hashimoto, Naoyuki*; Isobe, Shigehito*
no journal, ,
In order to study the cesium (Cs) chemisorption behavior onto stainless steel (SUS) under severe accident conditions, the chemical form and distribution of Cs compounds formed inside of the SUS oxide layer were investigated based on the microscopic observation such as TEM/EDS. As a result, it was revealed that chemical forms of Cs compounds varies along chemisorption temperature and depth from the SUS oxide layer surface.
Yoneyama, Kai*; Sato, Isamu*; Matsuura, Haruaki*; Koshigoe, Koki*; Miyahara, Naoya*; Kurihara, Norihiko*; Suzuki, Eriko; Osaka, Masahiko
no journal, ,
For the rational management of radioactive concrete waste generated in the decommissioning of LWR severe accident, the influence of mortar and aggregate on Cs penetration behavior based on the Cs penetration test using mortar, aggregate and concrete. While the distribution and diffusion coefficients of aggregate were smaller than that of mortar, the diffusion coefficient of concrete, which contained aggregates, was smaller than that of mortar. This result suggests that the boundary surfaces between aggregate and mortar could affect the Cs penetration behavior.
Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Fukasawa, Tomonori*; Fukui, Kunihiro*; Kitazawa, Toshihide*
no journal, ,
In the process of the spent fuel reprocessing, a mixture of uranyl nitrate and plutonium nitrate is converted to a mixed oxide powder by the microwave heating direct denitration method. In the case of assuming the heterogeneous cycle in the Na-cooled fast reactor, it is required to denitrate a solution containing mainly MA for which microwave heating denitration characteristics have not been clarified, therefore, it is necessary to obtain microwave heating denitration characteristics data for metal nitrate mixed aqueous solutions. In this study, microwave heating denitration characteristics of copper nitrate and nickel nitrate mixed solution and the complex relative permittivity of the final and intermediate products were evaluated. It was clarified that the mixing ratio and the microwave energy loss of metal oxides as final products remarkably affect the denitration characteristics.