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JAEA Reports

Accident consequence analysis for JMTR as a decommission facilities

Nagata, Hiroshi; Omori, Takazumi; Maeda, Eita; Otsuka, Kaoru; Nakano, Hiroko; Hanakawa, Hiroki; Ide, Hiroshi

JAEA-Review 2023-033, 40 Pages, 2024/01

JAEA-Review-2023-033.pdf:1.39MB

Japan Materials Testing Reactor (JMTR) was decided as a one of decommission facilities in April 2017. In order to submit the decommissioning plan to the Nuclear Regulation Authority, the type of accident assumed in the first stage of the decommissioning plan was selected, and the public exposure dose was evaluated. A fuel handling accident and a fire accident during storage of waste were selected as assumed accidents in the first stage of the decommissioning plan. An evaluation of the public exposure dose from the radioactive materials released into the atmosphere due to these accidents was estimated to be a maximum of 0.019 mSv (due to a fire accident during storage of waste). This estimated value was found to be sufficiently smaller than the judging criteria (5 mSv), and not to pose a significant risk of radiation exposure to the general public.

Journal Articles

Materials science and fuel technologies of uranium and plutonium mixed oxide

Kato, Masato; Machida, Masahiko; Hirooka, Shun; Nakamichi, Shinya; Ikusawa, Yoshihisa; Nakamura, Hiroki; Kobayashi, Keita; Ozawa, Takayuki; Maeda, Koji; Sasaki, Shinji; et al.

Materials Science and Fuel Technologies of Uranium and Plutonium mixed Oxide, 171 Pages, 2022/10

Innovative and advanced nuclear reactors using plutonium fuel has been developed in each country. In order to develop a new nuclear fuel, irradiation tests are indispensable, and it is necessary to demonstrate the performance and safety of nuclear fuels. If we can develop a technology that accurately simulates irradiation behavior as a technology that complements the irradiation test, the cost, time, and labor involved in nuclear fuel research and development will be greatly reduced. And safety and reliability can be significantly improved through simulation of nuclear fuel irradiation behavior. In order to evaluate the performance of nuclear fuel, it is necessary to know the physical and chemical properties of the fuel at high temperatures. And it is indispensable to develop a behavior model that describes various phenomena that occur during irradiation. In previous research and development, empirical methods with fitting parameters have been used in many parts of model development. However, empirical techniques can give very different results in areas where there is no data. Therefore, the purpose of this study is to construct a scientific descriptive model that can extrapolate the basic characteristics of fuel to the composition and temperature, and to develop an irradiation behavior analysis code to which the model is applied.

Journal Articles

A Knowledge-sharing activity on the environmental radiation monitoring results affected by the Fukushima-Daiichi Nuclear Power Plant Accident at Tokai-Oarai area in Ibaraki Prefecture

Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.

Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06

After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, $$^{134}$$Cs/$$^{137}$$Cs activity ratio, and so on. In this report, the results of the dose rate and $$^{137}$$Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.

Journal Articles

Spallation and fragmentation cross sections for 168 MeV/nucleon $$^{136}$$Xe ions on proton, deuteron, and carbon targets

Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.

Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06

 Times Cited Count:7 Percentile:55.09(Physics, Nuclear)

The spallation and fragmentation reactions of $$^{136}$$Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:10 Percentile:56.67(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Production and separation of astatine isotopes in the $$^7$$Li + $$^{nat}$$Pb reaction

Nishinaka, Ichiro; Yokoyama, Akihiko*; Washiyama, Koshin*; Maeda, Eita*; Watanabe, Shigeki; Hashimoto, Kazuyuki; Ishioka, Noriko; Makii, Hiroyuki; Toyoshima, Atsushi; Yamada, Norihiro*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 304(3), p.1077 - 1083, 2015/06

 Times Cited Count:10 Percentile:60.46(Chemistry, Analytical)

Production cross sections of astatine isotopes $$^{207-211}$$At in the 29-57 MeV $$^7$$Li induced reaction with $$^{nat}$$Pb target have been measured by $$alpha$$- and $$gamma$$-ray spectrometry. Excitation functions of production cross sections have been compared with a statistical model calculation to study the reaction mechanism of $$^7$$Li + $$^{nat}$$Pb. Considerably small experimental cross sections of $$^{210}$$At and $$^{209}$$At compared with the calculation were clearly observed at incident energies higher than 44 MeV, indicating that the effects of breakup reaction play a role. A chemical separation of astatine from an irradiated lead target has been studied with a dry-distillation method. A complementary way to produce astatine isotopes has been developed.

Journal Articles

Extraction of astatine isotopes for development of radiopharmaceuticals using a $$^{211}$$Rn-$$^{211}$$At generator

Maeda, Eita*; Yokoyama, Akihiko*; Taniguchi, Takumi*; Washiyama, Koshin*; Nishinaka, Ichiro

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1465 - 1468, 2015/02

 Times Cited Count:12 Percentile:67.00(Chemistry, Analytical)

The $$^{211}$$At isotope has gathered attention as a promising $$alpha$$-emitter for radionuclide therapy. We report the dependence of the distribution ratio of astatine on the concentration of HCl, and on the polarity of the organic solvent. The results will be useful for development of the $$^{211}$$Rn-$$^{211}$$At generator.

Oral presentation

Contamination at Plutonium Fuel Research Facility of Oarai Research and Development Center; Evaluation of the activity median aerodynamic diameter of plutonium and americium particles by using imaging plates

Yasumune, Takashi; Kato, Yoshinari; Maeda, Eita; Miyauchi, Hideaki; Hashimoto, Makoto; Takasaki, Koji

no journal, , 

no abstracts in English

Oral presentation

A Comparison between neutron diffraction and EBSD images for a TlBr crystal

Watanabe, Kenichi*; Hitomi, Keitaro*; Nogami, Mitsuhiro*; Maeda, Shigetaka; Ito, Chikara; Tanno, Takashi; Onabe, Hideaki*

no journal, , 

TlBr is a compound semiconductor with a high atomic number, high density and a wide bandgap, and is being developed as a gamma-ray detector material that can be operated at room temperature and has high detection efficiency. There is neutron diffraction in order to establish a crystal quality evaluation method for improving the yield in device fabrication, but the facilities that can be implemented are limited to large facilities such as J-PARC. The Electron Backscatter Diffraction (EBSD) image, which is one of the electron beam diffractions, can be obtained with an electron microscope, but only the information on the crystal surface can be obtained. In this study, the crystal orientation image was acquired for the TlBr crystal by neutron Bragg dip imaging, which is one of the neutron diffractions, and EBSD. By comparing both images, the applicability to a simple EBSD crystal quality evaluation method was examined.

Oral presentation

Observation of crystal origentation distribution of TlBr in crystal growth direction

Watanabe, Kenichi*; Hitomi, Keitaro*; Nogami, Mitsuhiro*; Maeda, Shigetaka; Onabe, Hideaki*

no journal, , 

TlBr is a compound semiconductor with a high atomic number and density, and a wide bandgap. TlBr detector is being developed as a gamma-ray detector material that can operate at room temperature and has high detection efficiency. The current issue is to improve the yield in device manufacturing, and it is required to establish a process that can stably manufacture high quality devices. The crystal growth process is one of the most important processes in producing a good quality detector, and it is very important to understand how crystals are grown. This time, we tried to obtain knowledge about crystal growth by observing the crystal orientation distribution in the crystal growth direction.

Oral presentation

Installation of KURAMA-II for on-site monitoring

Maeda, Eita; Hashimoto, Makoto; Nohara, Naofumi; Muto, Yasunobu; Yamada, Junya; Hamaguchi, Takumi; Inoue, Yuki

no journal, , 

no abstracts in English

Oral presentation

Production of astatine radioisotopes in the $$^7$$Li+$$^{nat}$$Pb reaction and simple chemical separation of astatine

Nishinaka, Ichiro; Yokoyama, Akihiko*; Washiyama, Koshin*; Amano, Ryohei*; Ri, Keiko*; Yamada, Norihiro*; Ishiguro, Rika*; Maeda, Eita*; Makii, Hiroyuki; Hashimoto, Kazuyuki; et al.

no journal, , 

We have started to study production and utilization of an $$alpha$$ radioactive nuclide $$^{211}$$At which is a prospective candidate for targeted alpha radiotherapy. We determined production cross sections of astatine radioisotopes in the reaction of 29-48 MeV $$^7$$Li+$$^{nat}$$Pb by $$alpha$$-ray and $$gamma$$-ray spectrometry at the tandem accelerator of JAEA-Tokai. Besides, we developed a simple dry-chemical method for separation of astatine.

Oral presentation

Introduction of KURAMA-II with wireless communication "ZETA" for monitoring nuclear operators

Igarashi, Yu; Hamaguchi, Takumi; Maeda, Eita; Yamada, Junya; Muto, Yasunobu; Nohara, Naofumi

no journal, , 

At the Oarai Research Institute of the Japan Atomic Energy Agency, a portable KURAMA equipped with a data transmission function using an autonomous network based on the ZETA standard was permanently installed in the vicinity of the MP, and a system for observing radiation doses around the site boundary was developed. In this presentation, the background to the redundancy of post-measurement monitoring, which is the purpose of this system installation, and the fixed-point observation data for about one year will be reported.

Oral presentation

Nuclear and radiochemical study of production and utilization of radioactive astatine isotopes in the Li + $$^{nat}$$Pb reaction

Nishinaka, Ichiro; Yokoyama, Akihiko*; Washiyama, Koshin*; Amano, Ryohei*; Maeda, Eita*; Yamada, Norihiro*; Makii, Hiroyuki; Watanabe, Shigeki; Ishioka, Noriko; Hashimoto, Kazuyuki

no journal, , 

Oral presentation

Nuclear and radiochemical study of production and utilization of radioactive astatine isotopes in the Li+$$^{nat}$$Pb reaction; Aim at the new cancer medical treatment by $$alpha$$-emitting radioisotopes

Nishinaka, Ichiro; Makii, Hiroyuki; Toyoshima, Atsushi; Yokoyama, Akihiko*; Washiyama, Koshin*; Amano, Ryohei*; Maeda, Eita*; Yamada, Norihiro*; Taniguchi, Takumi*; Watanabe, Shigeki; et al.

no journal, , 

no abstracts in English

Oral presentation

Production of $$^{211}$$At for alpha radiotherapy via $$^{209}$$Bi($$^7$$Li,5n)$$^{211}$$Rn

Nishinaka, Ichiro; Washiyama, Koshin*; Yokoyama, Akihiko*; Maeda, Eita*; Hashimoto, Kazuyuki; Makii, Hiroyuki

no journal, , 

A $$^{211}$$Rn/$$^{211}$$At generator has been proposed to supply a radiotracer $$^{211}$$At with a half-life (T$$_{1/2}$$ = 7.2 h) for medical applications. To establish a technology of the $$^{211}$$Rn/$$^{211}$$At generator, $$^{211}$$Rn (T$$_{1/2}$$ = 14.7 h) has to be produced through the $$^{209}$$Bi($$^7$$Li, 5n)$$^{211}$$Rn reaction without melting bismuth metal targets due to heat produced by the irradiation of 60 MeV $$^7$$Li ion beams. In this work, we have studied the effects of a He gas cooling system of an irradiation chamber constructed for the production of $$^{211}$$Rn. Irradiations were carried out at the JAEA tandem accelerator using the irradiation chamber equipped with the He gas cooling system. The results show that the He gas effectively cools the targets and the cooling efficiency is nearly independent of the pressure ($$>$$ 1 kPa) and the flow rate ($$sim$$20 L/min) of the He gas.

Oral presentation

Production of alpha-emitting radioisotopes using the cyclotron facilities at Osaka University and JAEA Takasaki, and the Tandem accelerator at Tokai, JAEA

Washiyama, Koshin*; Amano, Ryohei*; Maeda, Eita*; Yokoyama, Akihiko*; Nishinaka, Ichiro; Takahashi, Naruto*; Shinohara, Atsushi*; Watanabe, Shigeki; Ishioka, Noriko

no journal, , 

In order to use of an alpha emitter for targeted alpha therapy, we have started the production and the utilization of $$^{211}$$At using 30 MeV $$^4$$He particle in the $$^{209}$$Bi($$^4$$He, 2n)$$^{211}$$At nuclear reaction at cyclotron facilities of Osaka University and JAEA Takasaki. In addition to that, we have been developing a $$^{211}$$Rn/$$^{211}$$At generator to expand the availability of $$^{211}$$At to wide range of populations far away from cyclotron facilities. The results of studies on the At-chemistry for clinical use and on the development of the $$^{211}$$Rn/$$^{211}$$At generator will be presented. And a review of current status of targeted alpha therapy in Japan will be also introduced.

Oral presentation

Contamination at Plutonium Fuel Research Facility of Oarai Research and Development Center, 3; Measurement and data aggregation of radiation contamination for workers' dose evaluation

Kato, Yoshinari; Hashimoto, Makoto; Miyauchi, Hideaki; Yasumune, Takashi; Maeda, Eita; Takasaki, Koji; Yoshizawa, Michio; Momose, Takumaro

no journal, , 

no abstracts in English

Oral presentation

Study on environmental radiation monitoring results for nine years after the accident at THE TEPCO Fukushima Daiichi Nuclear Power Plant at JAEA Oarai Research and Development Institute

Inoue, Yuki; Yamada, Junya; Maeda, Eita; Hatakeyama, Takumi; Miyauchi, Hideaki; Hashimoto, Makoto

no journal, , 

no abstracts in English

Oral presentation

Production and utilization of radioactive astatine isotopes in the $$^7$$Li + $$^{nat}$$Pb reaction

Nishinaka, Ichiro; Yokoyama, Akihiko*; Washiyama, Koshin*; Amano, Ryohei*; Maeda, Eita*; Yamada, Norihiro*; Makii, Hiroyuki; Toyoshima, Atsushi; Watanabe, Shigeki; Ishioka, Noriko; et al.

no journal, , 

Production cross sections of astatine in 29-57 MeV $$^7$$Li + $$^{rm nat}$$Pb have been measured by $$alpha$$- and $$gamma$$-ray spectrometry. Excitation functions of production cross sections have been compared with a statistical model calculation to study the reaction mechanism of the $$^7$$Li + $$^{rm nat}$$Pb reaction. It indicates that the breakup of $$^7$$Li plays a rule in the $$^7$$Li + $$^{rm nat}$$Pb reaction. Besides, we have developed a dry-distillation method which separates carrier-free astatine from an irradiated lead target.

34 (Records 1-20 displayed on this page)