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Journal Articles

Temporal change in atmospheric radiocesium during the first seven years after the Fukushima Dai-ich Nuclear Power Plant accident

Abe, Tomohisa; Yoshimura, Kazuya; Sanada, Yukihisa

Aerosol and Air Quality Research, 21(7), p.200636_1 -  200636_11, 2021/07

 Times Cited Count:0 Percentile:0(Environmental Sciences)

Journal Articles

Radiation monitoring and evaluation of exposure doses to lift the evacuation orders for the zones designated for reconstruction and recovery

Sanada, Yukihisa; Kurikami, Hiroshi; Funaki, Hironori; Yoshimura, Kazuya; Abe, Tomohisa; Ishida, Mutsushi*; Tanimori, Soichiro*; Sato, Rina

Nihon Genshiryoku Gakkai Wabun Rombunshi, 20(2), p.62 - 73, 2021/06

Japanese government starts to consider radiation protection in the "specific reconstruction reproduction base area" of which evacuation order will be lifted by 2023. It is essential to grab the present situations of radiation contamination and evaluate exposure dose in the area to realize the plan. Many surveys have evaluated the distributions of air dose rate and exposure dose has been estimated based on the results since the Fukushima Daiichi Nuclear Power Plant accident. Nevertheless, more detailed information on exposure is needed for the areas because its radiation level is relatively high. That is also to help make prudent evaluation plan. This study aimed to evaluate the detailed contamination situation there and estimate exposure dose with considering areal circumstances. Investigations were carried out for (1) airborne survey of air dose rate using an unmanned helicopter (2) evaluation of airborne radiocesium and (3) estimation of external/internal effective doses for typical activity patterns assumed.

JAEA Reports

The Data-base of the radiation monitoring in Fukushima based on the comprehensive radiation monitoring plan

Abe, Tomohisa; Ogiya, Takashi*; Shibata, Katsuya*; Hanawa, Tatsuaki*; Sanada, Yukihisa

JAEA-Data/Code 2020-004, 280 Pages, 2020/08

JAEA-Data-Code-2020-004.pdf:3.91MB

After the accidents at Fukushima Daiichi Nuclear Power Station (FDNPS), Japan Atomic Energy Agency has carried on survey for distribution situation of radiation materials under the direction of the Ministry of Education, Culture, Sports, Science and Technology (later the Nuclear Regulatory Agency) from June 2011 to FY2019. This report is mainly summarized as data-base of air dose rate, integrated dose and radionuclide concentration of some types of environmental sample (airborne dust, soil, pine needles) in the radiation monitoring in Fukushima Prefecture (20 km far from FDNPS). The results of radiation monitoring were analyzed for temporal change at each measurement site under the unification format. Furthermore, the effective half-life and the dispersion at each location and sample were evaluated based on these big data.

Journal Articles

Study on optimizing microwave heating denitration method and powder characteristics of uranium trioxide

Segawa, Tomomi; Kawaguchi, Koichi; Kato, Yoshiyuki; Ishii, Katsunori; Suzuki, Masahiro; Fujita, Shunya*; Kobayashi, Shohei*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 9 Pages, 2019/05

A solution of plutonium nitrate and uranyl nitrate is converted into a mixed oxide by microwave heating denitration method. In the present study, for improving the efficiency of microwave heating and achieving high-temperature uniformity to produce homogeneous UO$$_{3}$$ powder, the microwave heating test of potassium chloride and uranyl nitrate solution, and numerical simulation analysis were conducted. The potassium chloride agar was adjusted to the dielectric loss, which is close to that of the uranyl nitrate solution and the optimum support table height was estimated to be 50 mm for denitration of the uranyl nitrate solution by microwave heating. The adiabator improved the efficiency of microwave heating denitration. Moreover, the powder yield was improved by using the adiabator owing to ease of scraping of the denitration product from the bottom of the denitration vessel.

Journal Articles

Micro-PIXE analysis study of ferrite products synthesized from simulated radioactive liquid waste containing chemical hazardous elements

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Nakazawa, Osamu; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-16; QST Takasaki Annual Report 2017, P. 140, 2019/03

no abstracts in English

Journal Articles

Mechanism of flashing phenomena by microwave heating and influence of high dielectric constant solution

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*; Segawa, Tomomi; Kato, Yoshiyuki; Kawaguchi, Koichi; Ishii, Katsunori

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 7 Pages, 2018/11

Mixed uranium oxide and plutonium oxide powder is produced from uranyl nitrate and plutonium nitrate mixed solution by the microwave heating denitration method in the spent fuel reprocessing process. Since the microwave heating method is accompanied by a boiling phenomenon, it is necessary to fully grasp the operating conditions in order to avoid flashing and spilling in the mass production of denitrification technology for the future. In this research, it was clarified that the heat transfer coefficient became lower as the dielectric constant increased. The dominant factor of the blowing up phenomena is supposed to be generation of the innumerable bubble rather than bubble's growth.

Journal Articles

Mechanism of flashing phenomena induced by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*; Segawa, Tomomi; Yamada, Yoshikazu; Kato, Yoshiyuki; Ishii, Katsunori

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07

Mixed uranium oxide and plutonium oxide powder is produced from uranyl nitrate and plutonium nitrate mixed solution by the microwave heating denitration method in the spent fuel reprocessing process. Since the microwave heating method is accompanied by a boiling phenomenon, it is necessary to fully grasp the operating conditions in order to avoid flashing and spilling in the mass production of denitrification technology for the future. In this research, it was confirmed that a potassium chloride aqueous solution as a simulant of uranyl nitrate aqueous solution with high dielectric loss cause loss of microwave at the solution surface as the dielectric loss increased with the increase of KCl concentration by experimental and electromagnetic field analysis, and revealed that the change in the heating condition affects the generation of flushing.

Journal Articles

Application of ferrite process to radioactive waste; Study of ferrite product stability by micro-PIXE analysis

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-8; QST Takasaki Annual Report 2016, P. 61, 2018/03

no abstracts in English

Journal Articles

Flushing phenomena and flow structure by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Chonan, Fuminori*; Yuasa, Tomohisa*; Yamaki, Tatsunori*; Segawa, Tomomi; Yamada, Yoshikazu

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 8 Pages, 2017/07

From the observation results, in the process of flushing, the behaviors leading to flushing were classified divided into three types. First type is that first generation bubble from heating leads to flushing. Second type is that nucleate boiling continues during heating and stop, finally single bubble generates and leads to flushing. Third type is defined that gradual evaporation occurs without bubbles. It was revealed that the total quantities of heat released by flushing are approximately equal when assuming the flushing mechanism, it can be triggered that a large amount of micro bubbles are instantaneously generated and grew.

Journal Articles

Element distribution measurement in incineration ash using micro-PIXE analysis

Abe, Tomohisa; Shimazaki, Takejiro; Nakayama, Takuya; Osone, Osamu; Osugi, Takeshi; Nakazawa, Osamu; Yuri, Yosuke*; Yamada, Naoto*; Sato, Takahiro*

QST-M-2; QST Takasaki Annual Report 2015, P. 83, 2017/03

no abstracts in English

Journal Articles

Report on the weekend basic course for Division of Nuclear Fuel Cycle and Environment in fiscal year 2015

Taniguchi, Takumi; Abe, Tomohisa

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), p.73 - 74, 2016/06

The weekend basic course for Division of Nuclear Fuel Cycle and Environment was held on November 7 (Sat) and 8 (Sun) on 2015 at Tohoku University Aobayama Campus in Sendai City. Twenty-eight people from universities and companies attended the course, and seven lectures and group discussions were held. I will report the outline of this course and the contents of the group discussion.

Journal Articles

Formation of a uniform ion beam using multipole magnets

Yuri, Yosuke; Ishizaka, Tomohisa; Yuyama, Takahiro; Okumura, Susumu; Ishibori, Ikuo; Yokota, Wataru; Watanabe, Shinichi*; Kubono, Shigeru*; Oshiro, Yukimitsu*

Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.3895 - 3897, 2009/05

Journal Articles

Comprehensive cost estimation method for decommissioning

Kudo, Kenji; Kawatsuma, Shinji; Rindo, Hiroshi; Watabe, Kozo; Tomii, Hiroyuki; Shiraishi, Kunio; Yagi, Naoto; Fukushima, Tadashi; Zaitsu, Tomohisa

Proceedings of 14th International Conference on Nuclear Engineering (ICONE-14) (CD-ROM), 8 Pages, 2006/07

Japan Atomic Energy Research Institute (JAERI) played a leading role in basic research in the field of atomic energy research and development, while Japan Nuclear Cycle Development Institute (JNC) did a major role in FBR cycle development and high level waste disposal. Following the Government's decision in December 2001, JAERI and JNC was merged as of October 1st, 2005. The new organization, Japan Atomic Energy Agency (JAEA), is an institute for comprehensive R&D for atomic energy, and is the largest research and development institute among Governmental R&D organizations. Its missions are basic research on atomic energy, R&D for nuclear fuel cycle, decommissioning of own facilities and disposal of waste, contribution to safety and non-proliferation, etc. The JAEA owns a number of nuclear facilities: research reactors such as JRR-2 and Joyo, prototype reactors such as ATR "Fugen" and FBR "Monju", fuel cycle plants such as Uranium Enrichment Demonstration Plant at Ningyo-Toge, MOX fuel plants at Tokai, Reprocessing Plant at Tokai, and Hot Laboratories such as JRTF and FMF. As a part of preparation of the mergence, JNC and JAERI have jointly developed a comprehensive cost estimation method for decommissioning, based on decommissioning and refurbishing experiences of JAERI and JNC. This method involves more estimation parameters from typical decommissioning activities than before, so as to make it more reliable. JAERI and JNC have estimated the total cost for decommissioning by using this method, and concluded that the cost would be 600 billion yen (approx. 5 billion USD).

Journal Articles

Cost estimation method for decommissioning of nuclear facilities

Tomii, Hiroyuki; Matsuo, Kiyoshi*; Shiraishi, Kunio; Watabe, Kozo; Saiki, Hideo*; Kawatsuma, Shinji*; Rindo, Hiroshi*; Zaitsu, Tomohisa*

Dekomisshoningu Giho, (31), p.11 - 20, 2005/03

no abstracts in English

Journal Articles

Cost estimation method for decommissioning of nuclear facilities

Tomii, Hiroyuki*; Matsuo, Kiyoshi*; Shiraishi, Kunio*; Watabe, Kozo*; Saiki, Hideo; Kawatsuma, Shinji; Rindo, Hiroshi; Zaitsu, Tomohisa

Dekomisshoningu Giho, (31), p.11 - 20, 2005/03

Japanese Government decided that Japan Atomic Energy Research Institute ( JAERI ) and Japan Nuclear Cycle Development Institute ( JNC ) shall be consolidated to a New rganization as of October 2005, which organization would be an Institute for comprehensive research and development for atomic.Through the preparation for unification, JAERI and JNC have been developing the Decommissioning program for own facilities, estimating decommissioning cost and the amount of waste from the decommissioning, and developing Management Program. Planning the Decommissioning program, it is important to estimate decommissioning cost effectively, because JAERI and JNC retain about 230 nuclear facilities which are reactors, fuel cycle facilities and research facilities. Then the decommissioning cost estimation method has developed based on several dismantling and replacement experiences. This method has adopted more estimation fomulae for decommissioning various works than ever, so as to be more reliable. And decommissioning cost for the facilities has estimated under the common condition. This method would be improved, reflecting future nuclear facilities dismantling and replacement events.This paper shows the cost estimation method for nuclear facilities and cost evaluation result for about 230 facilities of both JAERI and JNC.

Journal Articles

Study of thermal annealing of vacancies in ion implanted 3C-SiC by positron annihilation

Oshima, Takeshi; Uedono, Akira*; Ito, Hisayoshi; Abe, Koji*; Suzuki, Ryoichi*; *; Aoki, Yasushi; Tanigawa, Shoichiro*; Yoshikawa, Masahito; Mikado, Tomohisa*; et al.

Mater. Sci. Forum, 264-268, p.745 - 748, 1998/00

no abstracts in English

Oral presentation

Synthesis of radiobrominated amino acid derivatives via silicon-bromine exchange reaction

Watanabe, Shigeki; Yamada, Keiichi*; Watanabe, Saki*; Oku, Hiroyuki*; Moriguchi, Tomohisa*; Shinozuka, Kazuo*; Ishioka, Noriko

no journal, , 

Oral presentation

Synthesis of silylated phenylalanine derivatives and radiobromine labeling via silicon-bromine exchange reaction

Watanabe, Saki*; Watanabe, Shigeki; Yamada, Keiichi*; Oku, Hiroyuki*; Moriguchi, Tomohisa*; Ishioka, Noriko; Shinozuka, Kazuo*

no journal, , 

no abstracts in English

Oral presentation

Application of Japanese experiences on radiation education to IAEA Asian project and its future development

Iimoto, Takeshi*; Kakefu, Tomohisa*; Takagi, Rieko*; Takahashi, Itaru*; Nakamura, Takashi*; Kito, Keiko*; Watanabe, Yoko; Yamashita, Kiyonobu

no journal, , 

no abstracts in English

Oral presentation

Basic study on microwave heating of mixture solution, 1; Heating phenomena of mixture solution with microwave irradiation

Chonan, Fuminori*; Abe, Yutaka*; Yuasa, Tomohisa*; Kaneko, Akiko*; Segawa, Tomomi; Yamada, Yoshikazu

no journal, , 

In a reprocessing process of nuclear fuel cycle, an uranium-plutonium mixed oxide (MOX) raw powder is converted from a mixture solution of uranyl nitrate and plutonium nitrate by the microwave heating denitration method (MH method). The MH method is applied to remove water and nitric acid from a metallic nitrate solution, and a metallic oxide is obtained. In order to improve the efficiency of MH method, optimizing the equipment and conditions is needed to prevent flushing of a mixture solution during microwave heating. In our group, we have been studied that the influence of height of supporter which placed under the mixture solution in the vessel on its heating phenomena. Also we have been analyzed simulation of electromagnetic field during microwave heating in microwave oven. From those results, we considered the appropriate height of supporter in the oven. It was clarified that height of supporter was one of the important parameter for the efficiency of microwave heating.

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