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Tamura, Koji*; Toyama, Shinichi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 61(5), p.413 - 415, 2019/05
In decommissioning of nuclear reactors, it is necessary to disassemble the nuclear reactor structure. In addition to the conventional cutting method, the laser method has many advantages such as remote controllability and no need for replacement parts such as blades, which can be a powerful choice. Nuclear reactor structure such as a pressure vessel are made of steel materials with a thickness exceeding 100 mm, and the laser method has poor knowledge and experience in cutting such thick steel materials. Therefore, as a result of trial cutting of steel materials under various cutting conditions with the high power fiber laser which is progressively available nowadays, it has been demonstrated that laser cutting is also possible for thick plates such as those used in nuclear reactors, and cutting of thick steel plates. We also developed the cutting technology using remote control using a robot in order to apply it to the decommissioning of thick steel cutting on the spot.
Muramatsu, Toshiharu; Yamada, Tomonori; Hanari, Toshihide; Takebe, Toshihiko; Nguyen, P. L.; Matsunaga, Yukihiro
JAEA-Research 2014-018, 41 Pages, 2014/09
JAEA-Research-2014-018.pdf:42.21MB
In decommissioning works of the Fukushima Daiichi Nuclear Power Plants, it is required that fuel debris solidifying mixed materials of fuels and in-vessel structures should be removed. The fuel debris is considered to have characteristics, such as indefinite shapes, porous bodies, multi-compositions, higher hardness, etc. from the knowledge in the U.S. and the Three Mile Island nuclear power plant. Laser lights are characterized by higher power density, local processability, remote controllabilitiy, etc. and can be performed thermal cutting and crushing-up for various materials which does not depend on fracture toughness. This report describes a research program and research activities in FY2013 aiming at developing removal system of fuel debris by the use of laser lights.
laser interferometerChiba, Shinichi; Kawano, Yasunori; Tsuchiya, Katsuhiko; Inoue, Akira*
JAERI-Research 2001-050, 59 Pages, 2001/11
JAERI-Research-2001-050.pdf:15.28MB
no abstracts in English
Jitsukawa, T.*; Tojo, T.*; Takagi, M.*; Sudo, H.*
PNC TJ8674 95-001, 68 Pages, 1995/02
no abstracts in English
Tsutani, Sadahiro*; Takeshita, Hiroshi*; Edajima, Toshikazu*; Motooka, Masafumi*
PNC TJ8224 93-001, 128 Pages, 1993/06
no abstracts in English
Tanaka, Yoji*; Nakasawa, Otohiko*; Sugumoto, Hiroshi*; Takeshita, Hiroshi*
PNC TJ8224 92-002, 33 Pages, 1992/03
no abstracts in English
Tanaka, Yoji*; Nakasawa, Otohiko*; Sugumoto, Hiroshi*; Takeshita, Hiroshi*
PNC TJ8224 92-001, 108 Pages, 1992/03
no abstracts in English
Seki, Seiichi; ; ; ; Aoki, Isao
PNC TN8440 91-014, 5 Pages, 1991/06
None
; Haga, Kazuo
PNC TN9410 91-205, 55 Pages, 1991/05
A transportable reactor has been studied in one of activities of frontier research in PNC. Since the reactor is going to be used at an secluded place in the earth, on the surface of the moon or at the deep sea bottom, the operation of the reactor requires wireless communications. Based on the present status of technology, a preliminary study has been performed in this report on a wireless operation method of the reactors on the moon and at the deep sea bottom. A wireless operation system of the reactor on the moon is supposed to exist technically on the extension of a present space communication system and a difficult problem does not seem to remain at the development stage of the wireless operation system. Concerning the wireless operation system of the reactor at the deep sea bottom, a few problems remain to be solved in the field of acoustic communications in sea water. However they seem to be solved technically in future. It takes about three seconds for an electric wave to go and come back between the reactor on the moon and the earth. It takes also about four seconds for an acoustic wave to reach the reactor at the deep sea bottom from the sea surface. Therefore, urgent control of the reactor by wireless communications is impossible in both cases. The urgent control must be performed by the reactors themselves.
Seimiya, Hiroshi; Yamada, Kazuo; Kuroha, Mitsuhiko; Saito, Makoto; Tomikawa, Hirofumi; Saito, Toru*; Hagiya, Shinichi*
PNC TN8410 90-082, 90 Pages, 1990/09
None