Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ishikawa, Akihisa; Tanaka, Hiroki*; Nakamura, Satoshi*; Kumada, Hiroaki*; Sakurai, Yoshinori*; Watanabe, Kenichi*; Yoshihashi, Sachiko*; Tanagami, Yuki*; Uritani, Akira*; Kiyanagi, Yoshiaki*
Journal of Radiation Research (Internet), 65(6), p.765 - 775, 2024/11
Times Cited Count:0 Percentile:0.00(Biology)Emura, Yuki; Matsuba, Kenichi; Kikuchi, Shin; Yamano, Hidemasa
Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 8 Pages, 2024/11
Emura, Yuki; Takai, Toshihide; Kikuchi, Shin; Kamiyama, Kenji; Yamano, Hidemasa; Yokoyama, Hiroki*; Sakamoto, Kan*
Journal of Nuclear Science and Technology, 61(7), p.911 - 920, 2024/07
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)Hayashi, Koichi*; Lederer, M.*; Fukumoto, Yohei*; Goto, Masashi*; Yamamoto, Yuta*; Happo, Naohisa*; Harada, Masahide; Inamura, Yasuhiro; Oikawa, Kenichi; Oyama, Kenji*; et al.
Applied Physics Letters, 120(13), p.132101_1 - 132101_6, 2022/03
Times Cited Count:3 Percentile:27.65(Physics, Applied)Hamamoto, Shimpei; Ho, H. Q.; Iigaki, Kazuhiko; Goto, Minoru; Shimazaki, Yosuke; Sawahata, Hiroaki; Ishitsuka, Etsuo
Nuclear Engineering and Design, 386, p.111564_1 - 111564_8, 2022/01
Times Cited Count:1 Percentile:16.36(Nuclear Science & Technology)The experience of Fukushima Daiichi Nuclear Power Plant accident caused by the great earthquake that occurred in eastern Japan in 2011 showed the importance of preparing for the loss of function of the engineered safety features. Increasing the strength of equipment to prevent loss of function in an accident is effective, but the possibility of loss of function remains. Therefore, it is important to have an alternative to lost functions in order to put the accident under control early. Thus, this study designed an alternative shutdown system, namely a portable backup shutdown system (PBSS), to make countermeasures in the event of a loss of shutdown function more robust without impairing economic efficiency of the High Temperature Gas-cooled Reactor (HTGR). The PBSS is portable and capable of being installed manually so that it can operate in a total loss of off-site electricity. Various neutron absorber materials for the PBSS were also considered from the viewpoints of technical and cost-effective properties. As results of optimization, the boron nitride (BN) was selected as it shows a good neutronic property as well as a reasonable cost in comparison with other materials.
Miwa, Shuhei; Miyahara, Naoya*; Nakajima, Kunihisa; Imoto, Jumpei; Suzuki, Eriko
Nihon Genshiryoku Gakkai-Shi ATOMO, 63(12), p.825 - 829, 2021/12
In the BWR severe accident, it was indicated that the control material boron significantly influences chemical behavior and transition behavior of cesium, which is important from the viewpoint of exposure, and it causes great uncertainty in the prediction of environmental release and distribution in the reactor. Therefore, in order to elucidate the important chemistry to be considered in severe accident analysis, we have developed the experimental setup that enables the evaluation of chemistry during transportation in the reactor, and evaluated cesium chemistry. Based on the results, we developed the chemistry database named ECUME composed of datasets and models that are the basis of chemical reaction analysis so that chemical behavior could be evaluated by severe accident analysis code.
Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa
Mechanical Engineering Journal (Internet), 8(4), p.20-00540_1 - 20-00540_11, 2021/08
In a core disruptive accident scenario, boron carbide, which is used as a control rod material, may melt below the melting temperature of stainless steel owing to the eutectic reaction with them. The eutectic mixture produced is assumed to extensively relocate in the degraded core, and this behavior plays an important role in significantly reducing the neutronic reactivity. However, these behaviors have never been simulated in previous severe accident analysis. To contribute to the improvement of the core disruptive accident analysis code, the thermophysical properties of the eutectic mixture in the solid state were measured, and regression equations that show the temperature (and boron carbide concentration) dependence are created.
Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken
JPS Conference Proceedings (Internet), 33, p.011075_1 - 011075_6, 2021/03
Ikebe, Yurie*; Oshima, Masumi*; Bamba, Shigeru*; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Toyoshima, Atsushi*; Bi, C.*; Seto, Hirofumi*; Amano, Hikaru*; et al.
Applied Radiation and Isotopes, 164, p.109106_1 - 109106_7, 2020/10
Times Cited Count:2 Percentile:18.47(Chemistry, Inorganic & Nuclear)Boron Neutron Capture Therapy (BNCT) is a radiotherapy for the treatment of intractable cancer. In BNCT precise determination of B concentration in whole blood sample before neutron irradiation is crucial for control of the neutron irradiation time and the neutron dosimetry. We have applied the Charged Particle Activation Analysis (CPAA) to non-destructive and accurate determination of
B concentration in whole blood sample. The experiment was performed at JAEA Tandem Accelerator using an 8 MeV proton beam. The 478 keV
ray of
Be produced in the
B(p,
)
Be reaction was used to quantify the
B, and
rays of
Co originating from the reaction with Fe in blood was used to normalize the
-ray intensity. The results demonstrated that the present CPAA method can be applied to the determination of the
B concentration in the blood sample.
Abe, Yuta; Tsuchikawa, Yusuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Oishi, Yuji*; Kamiyama, Takashi*; Nagae, Yuji; Sato, Ikken
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
Hayashi, Kei*; Saito, Wataru*; Sugimoto, Kazuya*; Oyama, Kenji*; Hayashi, Koichi*; Happo, Naohisa*; Harada, Masahide; Oikawa, Kenichi; Inamura, Yasuhiro; Miyazaki, Yuzuru*
AIP Advances (Internet), 10(3), p.035115_1 - 035115_7, 2020/03
Times Cited Count:18 Percentile:68.71(Nanoscience & Nanotechnology)Miwa, Shuhei; Takase, Gaku; Imoto, Jumpei; Nishioka, Shunichiro; Miyahara, Naoya; Osaka, Masahiko
Journal of Nuclear Science and Technology, 57(3), p.291 - 300, 2020/03
Times Cited Count:9 Percentile:64.25(Nuclear Science & Technology)For the evaluation of transport behavior of control material boron in a severe accident of BWR from the viewpoint of chemical effects on cesium and iodine behavior, boron chemistry during transportation in the high temperature region above 400 K was experimentally investigated. The heating tests of boron oxide specimen were conducted using the dedicated experimental apparatus reproducing fission product release and transport in steam atmosphere. Released boron oxide vapor was deposited above 1,000 K by the condensation onto stainless steel. The boron deposits and/or vapors significantly reacted with stainless steel above 1,000 K and formed the stable iron-boron mixed oxide (FeO)BO
. These results indicate that released boron from degraded BWR control blade in a severe accident could remain in the high temperature region such as a Reactor Pressure Vessel. Based on these results, it can be said that the existence of boron deposits in the high temperature region would decrease the amount of transported cesium vapors from a Reactor Pressure Vessel due to possible formation of low volatile cesium borate compounds by the reaction of boron deposits with cesium vapors.
Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa
Nuclear Technology, 205(9), p.1164 - 1174, 2019/09
Times Cited Count:11 Percentile:71.09(Nuclear Science & Technology)Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.847 - 852, 2019/09
Miyahara, Naoya; Miwa, Shuhei; Horiguchi, Naoki; Sato, Isamu*; Osaka, Masahiko
Journal of Nuclear Science and Technology, 56(2), p.228 - 240, 2019/02
Times Cited Count:9 Percentile:64.25(Nuclear Science & Technology)In order to improve LWR source term under severe accident conditions, the first version of a fission product (FP) chemistry database named "ECUME" was developed. The ECUME is intended to include major chemical reactions and their effective kinetic constants for representative SA sequences. It is expected that the ECUME can serve as a fundamental basis from which FP chemical models in the SA analysis codes can be elaborated. The implemented chemical reactions in the first version were those for representative gas species in Cs-I-B-Mo-O-H system. The chemical reaction kinetic constants were evaluated from either literature data or calculated values using ab-initio calculations. The sample chemical reaction calculation using the presently constructed dataset showed meaningful kinetics effects at 1000 K. Comparison of the chemical equilibrium compositions by using the dataset with those by chemical equilibrium calculations has shown rather good consistency for the representative Cs-I-B-Mo-O-H species. From these results, it was concluded that the present dataset should be useful to evaluate FP chemistry in Cs-I-B-Mo-O-H system under LWA SA conditions.
Ochs, M.*; Vriens, B.*; Tachi, Yukio
Progress in Nuclear Science and Technology (Internet), 5, p.208 - 212, 2018/11
The clean-up activities related to the accident at the Fukushima Nuclear Power Plant give rise to several types of wastes containing cementitious materials, such as concrete. Further, the use of cement-based barriers may be considered, due to their favorable and stable chemical properties, including their ability to sorb or incorporate radionuclides. Wastes from Fukushima are expected to contain substances that can have perturbing effects on retention, especially organic complexing substances, boron, and chloride salts. The present study focuses on a methodology for quantifying the retention behaviour of UVI) and U(IV) in cement materials of different degradation and in the presence of organics, boron, and salts on the basis of available literature information. A stepwise approach is proposed and illustrated for Kd setting for U(VI) and U(IV).
Takai, Toshihide; Furukawa, Tomohiro; Yamano, Hidemasa
Proceedings of 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) (CD-ROM), p.1007 - 1013, 2018/04
Di Lemma, F. G.; Yamashita, Shinichiro; Miwa, Shuhei; Nakajima, Kunihisa; Osaka, Masahiko
Energy Procedia, 127, p.29 - 34, 2017/09
Times Cited Count:6 Percentile:93.93(Energy & Fuels)Chemical effects of molybdenum (Mo) and boron (B), which were considered to form compounds with Cs, on the Cs chemisorption were predicted using a chemical equilibrium calculation. It is seen that CsMoO
were formed in the chemisorbed compounds. On the other hand, little effects were observed for B. The results suggest that the effects of Mo should be considered for further experimental investigation.
Hidaka, Akihide; Yokoyama, Hiroya
Journal of Nuclear Science and Technology, 54(8), P. i, 2017/08
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)no abstracts in English