Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.
JAEA-Review 2021-020, 42 Pages, 2021/10
JAEA-Review-2021-020.pdf:2.95MB
The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.
Shinohara, Masanori; Sawahata, Hiroaki; Kawamoto, Taiki; Motegi, Toshihiro; Saito, Kenji; Takada, Shoji; Yoshida, Naoaki; Isozaki, Ryosuke; Katsuyama, Kozo
JAEA-Technology 2012-025, 31 Pages, 2012/08
JAEA-Technology-2012-025.pdf:4.69MB
An event, in which one of WRMs were disabled to detect the neutron flux in the reactor core, occurred during the period of reactor shut down of HTTR in March, 2010. The actual life time of WRM was unexpectedly shorter than the past developed life time. Investigation of the cause of the outage of WRM toward the recovery of the life time up to the developed life is one of the issues to develop the technology basis of High Temperature Gas cooled Reactor (HTGR). Then, a post irradiation examination was planned to specify the damaged part causing the event in the WRM was also planned. For the investigation, the X-ray computed tomography scanner in Fuels Monitoring Facility (FMF). This report describes the preliminary investigation on the cause of outage of the WRM. The results of study for transportation method of the irradiated WRM from HTTR to FMF is also reported with the record to complete the transport operation.
Isozaki, Ryosuke; Katsuyama, Kozo; Tanaka, Kosuke; Sato, Isamu; Usuki, Toshiyuki; Sekio, Yoshihiro; Hayashi, Takehiro; Tokoro, Daishiro*
no journal, ,
no abstracts in English
Isozaki, Ryosuke; Mizukoshi, Yasutaka; Katsuyama, Kozo; Kodaka, Hideo
no journal, ,
no abstracts in English
Takahashi, Koji; Abe, Ganji; Isozaki, Masami; Ikeda, Ryosuke; Oda, Yasuhisa; Kajiwara, Ken; Sakamoto, Keishi; Kobayashi, Noriyuki*; Iida, Hiromasa*; Komatsuzaki, Manabu*; et al.
no journal, ,
It was analytically obtained that electron cyclotron current drive efficency at 
=0.4
0.6 can be doubled modifying the steering function of millimeter wave launching from the equatorial port from toroidally to poloidally. The design modification of the ITER equatorial launcher enhancing ECCD function is implemented. The millimeter wave design satisfying transmission efficiency more than 99% with the required ploidal beam steering capability is successfully obtained and reflected to the launcher structural design. The millimeter wave design optimization, BSM design modification to allow the required polidal beam steering capability and so on are reported in detail at the conference.
Takahashi, Koji; Abe, Ganji; Isozaki, Masami; Kobayashi, Noriyuki*; Shidara, Hiroyuki; Oda, Yasuhisa; Ikeda, Ryosuke; Kobayashi, Takayuki; Moriyama, Shinichi; Sakamoto, Keishi
no journal, ,
An ITER equatorial EC launcher has been designed to inject a 170 GHz, 20 MW millimeter wave beam to plasma with poloidal steering functionality in order to obtain more driven current at the peripheral region of plasma. The millimeter wave design to accomplish the high transmission efficiency more than 99% and to compliant with the requirement on heat load on the mirror s and beam size at the resonance location of plasma has been successfully developed. The mock-up to simulate the millimeter wave propagation in the launcher based on the design modification of the beam path is fabricated and the low power experiment is in progress. The field pattern measurement at the mock-up outlet indicates the validity of the design optimization of mirror's and the waveguide set-up. The design of the millimeter wave beam path for poloidal steering launcher and the experiments of the launcher mock-up are reported in detail at the workshop.
Shidara, Hiroyuki; Takahashi, Koji; Komatsuzaki, Manabu*; Isozaki, Masami; Kobayashi, Noriyuki*; Abe, Teruo*; Abe, Ganji; Oda, Yasuhisa; Ikeda, Ryosuke; Kobayashi, Takayuki; et al.
no journal, ,
In order to validate the millimeter wave design procedure, the EL mock-up has been constructed and the low power test has been carried out by using mW-level low power RF oscillators. The test has been carried out with critical four edged beams instead of all eight beams in the upper waveguide unit. The measured data has been compared with design at several important locations in the launcher and after the launcher exit with steering mirror angle changed. The comparison of the measured beams propagation and the design shows good agreement for the beam sizes and the beam orientation performance. The quantitative evaluations has been carried out and the design procedure's reasonability has been confirmed.
Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
no journal, ,
no abstracts in English
Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Yonezawa, Ryoma; Suzuki, Hisashi; Mizukoshi, Yasutaka; Sakamoto, Naoki
no journal, ,
The five post-irradiation examination facilities in the Oarai Research and Development Institute of the Japan Atomic Energy Agency have been operated for over 40 years in order to investigate the irradiation performance and physicochemical characteristics of nuclear fuels and materials for fast reactors. The equipments associated with these facilities have been managed to maintain secure from the problems that occurred in the process of aging. Therefore, we established a safety assessment method for aging facilities in 2002, and we have been conducting maintenance management of facilities since then. In this study, designing risk assessment flow is considered in order to solve the issues detected as a result of analysis based on the experience of the repairment during the periodic safety review monitoring.
Isozaki, Ryosuke; Sakamoto, Naoki
no journal, ,
no abstracts in English
Isozaki, Ryosuke; Tamaoki, Yuichi; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Suzuki, Hisashi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
no journal, ,
no abstracts in English
Sawahata, Satoshi; Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Suzuki, Hisashi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
no journal, ,
no abstracts in English