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Kato, Atsushi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Miyagawa, Takayuki*; Uchita, Masato*; Suzuno, Tetsuji*; Endo, Junji*; Kubo, Koji*; Murakami, Hisatomo*; Uzawa, Masayuki*; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 11 Pages, 2022/04
The authors are carrying out conceptual design studies for a pool-type sodium-cooled fast reactor. There are main challenges such as measures against severe earthquake in Japan, thermal hydraulic in a reactor vessel (RV), a decay heat removal system design. When the JP-pool SFR of 650 MWe is installed in Japan, it shall be designed against the severe seismic conditions. Additionally, a newly three-dimensional seismic isolation system is under development.
Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.
JAEA-Technology 2021-001, 144 Pages, 2021/08
Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count:13 Percentile:99.06(Quantum Science & Technology)Mukai, Yasunobu; Nakamura, Hironobu; Nakamichi, Hideo; Kurita, Tsutomu; Noguchi, Yoshihiko*; Tamura, Takayuki*; Ikegame, Ko*; Shimizu, Junji*
Proceedings of INMM 56th Annual Meeting (Internet), 9 Pages, 2015/07
The PIMS used at Rokkasho Reprocessing Plant can quantify plutonium amount in each process vessel located inside glovebox by means of neutron measurement. Since the PIMS is not used for the neutron coincidence counting, it is very important to maintain that those constants meet the actual process condition. PIMS was calibrated in 2006, and then JNFL has been started to measure the Pu amount directly in each glovebox for the purpose of facility NMA. However, it was found that PIMS counting was unexpectedly and continuously increased during long time of inter-campaign. In order to find out the main cause, JAEA and JNFL jointly conducted several investigations. In the investigations, correctness of system parameters and relevant constants, behavior of the neutron generation when MOX powder is stored in actual glovebox for a long time (to see O/M and moisture change) and the behavior focused on the relation between MOX powder and light element using inside glovebox (fluorine is included in the PTFE which is used in many gloveboxes as packing of instruments) were experimentally confirmed using MOX powder in PCDF. As a result, since the same behavior happened in the actual PIMS was confirmed in the testing environment in which MOX powder coexists with fluorine, it is concluded that the main potential cause of PIMS is the increasing of the probability of (, ) reactions by a contact between PTFE and MOX powder.
Omori, Junji; Koizumi, Norikiyo; Shimizu, Tatsuya; Okuno, Kiyoshi; Hasegawa, Mitsuru*
JAEA-Technology 2009-046, 60 Pages, 2009/09
In the winding pack (WP) of the ITER TF coil, cover plates (CPs) are welded to radial plate (RP) after placing the conductors into the RP groove to fix it. The dimensions of the RP are 15 m high and 9 m wide, while its required tolerances are very severe such as flatness of 2 mm and in-plane deformation of about 2.5 mm. It is therefore necessary to reduce the deformation of the RP by CP welding. In order to estimate the weld deformation, a 1 m RP mock-up was fabricated and weld deformations were measured. From the test results, inherent strains have been obtained and the weld deformations of the full scale RP have been estimated. The RP deformations could be within the tolerances by the CP welding thickness of 2.5 mm in inboard region and 1.0 mm in outboard region. In addition, an alternative design, which improve the fabricability of the WP, was proposed. The analyses for the alternative design is performed and the results show the deformations could be reduced more.
Shimizu, Katsusuke*; Onozuka, Masanori*; Usui, Yukinori*; Urata, Kazuhiro*; Tsujita, Yoshihiro*; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Omori, Junji; Shibanuma, Kiyoshi
Fusion Engineering and Design, 82(15-24), p.2081 - 2088, 2007/10
Times Cited Count:5 Percentile:37.19(Nuclear Science & Technology)To confirm the manufacturing and assembly process of the ITER vacuum vessel (VV), a series of related tests has been conducted. (1) Using a full-scale partial mock-up, fabrication methods are to be examined to determine feasibility. (2) To simulate a series of field-joint assembly operations, a test stand was built. (3) To provide an appropriate shield gas supply on the back side of the outer shell during field-joint welding, three types of back-seal structures have been tested. (4) The applicability of UT methods for volumetric inspection has been investigated. (5) Applicability of Liquid Penetrant Testing as a surface examination for the VV interior surface (i.e. ultra-vacuum side) has been investigated.
Omori, Junji; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Shibanuma, Kiyoshi; Sago, Hiromi*; Shimizu, Katsusuke*; Onozuka, Masanori*
no journal, ,
no abstracts in English
Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Omori, Junji; Shibanuma, Kiyoshi; Onozuka, Masanori*; Shimizu, Katsusuke*
no journal, ,
no abstracts in English
Onozuka, Masanori*; Shimizu, Katsusuke*; Usui, Yukinori*; Urata, Kazuhiro*; Namiki, Masao*; Tsujita, Yoshihiro*; Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Omori, Junji; et al.
no journal, ,
no abstracts in English
Shimizu, Yasuo*; Dobashi, Kunio*; Kusakabe, Takahiko*; Nagamine, Takeaki*; Oikawa, Masakazu*; Sato, Takahiro; Haga, Junji*; Okubo, Takeru; Ishii, Yasuyuki; Kamiya, Tomihiro; et al.
no journal, ,
no abstracts in English
Koizumi, Norikiyo; Nakajima, Hideo; Matsui, Kunihiro; Takano, Katsutoshi; Hemmi, Tsutomu; Omori, Junji; Shimizu, Tatsuya; Okuno, Kiyoshi
no journal, ,
no abstracts in English
Shimizu, Masahiro*; Endo, Junji*; Chikazawa, Yoshitaka; Kubo, Shigenobu
no journal, ,
no abstracts in English