Decommissioning program and future plan for Research Hot Laboratory, 3

Shiina, Hidenori; Ono, Katsuto; Nishi, Masahiro; Uno, Kiryu; Kanazawa, Hiroyuki; Oi, Ryuichi; Nihei, Yasuo

Dekomisshoningu Giho, (61), p.29 - 38, 2020/03

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_61.pdf

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) was constructed in 1961, as the first one in Japan, to perform the examinations of irradiated fuels and materials. RHL consists of 10 heavy concrete cells and 38 lead cells. RHL contributed to research and development program in or out of JAEA for the investigation of irradiation behavior for fuels and nuclear materials. However, RHL is the one of target as the rationalization program for decrepit facilities in former Tokai institute. Therefore the decommissioning works of RHL started on April 2003. The dismantling of 12 lead cells has been progressing since 2010. The dismantling procedure of lead cells was performed in the following order. The peripheral equipment in lead cells were removed and contamination survey of the inner surface of the cells. Then, the backside shield doors were extracted. The lifting frame for the isolation tent was set on the cells. After that, the ceiling plates, isolation walls and lead blocks were removed. The strippable paint was used to remove permeable contamination on the inner surface of structural steel of the cells. The dismantling work will be continued to mention the efficiency of decommissioning works and reduction of radioactive waste with ensuring safety.

Decommissioning program of Research Hot Laboratory in JAEA; Technical review of dismantling works for the lead cells, 2

Shiina, Hidenori; Ono, Katsuto; Nishi, Masahiro; Nihei, Yasuo

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 7 Pages, 2017/00

http://hotlab.sckcen.be/proceedings

The Research Hot Laboratory (RHL) in Japan Atomic Energy Agency (JAEA) is the first facility in Japan for the post irradiation examination (PIE) on reactor fuels and structural materials, which had contributed to advancement of the fuels and materials since 1961. The building of RHL consists of two stories above ground and a basement, in which 10 heavy concrete and 38 lead cells were installed. In RHL, all operations for PIE had been completed in 2003. Then the decommissioning program has been implemented in order to promote the rationalization of research facilities in JAEA. As the first step of the program, PIE apparatuses and irradiated samples were removed from the cells, which have been managed as radioactive wastes. The dismantling of lead cells was initiated in 2005. At present 26 lead cells are successfully dismantled. This paper shows technical review of dismantling operations for the lead cells.

Replacement technique for front acrylic panels of a large size glove box using bag-in / bag-out method

Endo, Shinya; Numata, Masami; Ichise, Kenichi; Nishi, Masahiro; Komiya, Tomokazu; Sakuraba, Naotoshi; Usami, Koji; Tomita, Takeshi

Proceedings of 46th Annual Meeting of "Hot Laboratories and Remote Handling" Working Group (HOTLAB 2009) (CD-ROM), 6 Pages, 2009/09

For safety operation and maintenance of the large size glove box, the degraded acrylic panels of the box must be replaced by the new panels. As the conventional replacement technique, the decontamination of the glove box and installation of isolation tent are necessary to prevent the leak of contamination, because airtight condition of the box is broken down during replacement process. Therefore, the prerequisite works are required considerable manpower. The new replacement technique using bag-in / bag-out method was developed by JAEA. In this technique, for keeping the airtight condition of the box, the inside of degraded panel is covered with an airtight panel and the outside is covered over the large bag which is used to replace the acrylic panels. As the benefits of this technique, the prerequisite works are not required and the manpower is less than a third of the conventional technique.

Development of advanced neutron radiography for inspection on irradiated fuels and materials, 3; Examination of neutron imaging plate and computed tomography methods on unirradiated fuel rod

Yasuda, Ryo; Matsubayashi, Masahito; Nakata, Masahito; Harada, Katsuya; Amano, Hidetoshi; Ando, Hitoshi*; Sasajima, Fumio; Nishi, Masahiro; Horiguchi, Yoji

JAERI-Tech 2002-001, 23 Pages, 2002/02

JAERI-Tech-2002-001.pdf:3.79MB

Advanced neutron radiography techniques such as neutron imaging plate (NIP) and Computed Tomography (CT) methods have been investigated the practicality for Post Irradiation Examination (PIE). In this work, an unirradiated fuel rod was examined by NIP and CT methods in order to collect the fundamental data for applying these techniques to PIE.The fuel rod is composed of seven-enriched UO2 pellet and two-natural UO2 pellet that are loaded into a Zircaloy tube. There are somewhat difference in the size and shape among those UO2 pellets. A transmitted and cross-sectional images were obtained by NIP and CT methods, respectively.In the NIP image, the difference in the size, shape, and enrichment among the UO2 pellets is obviously recognized. In the case of CT method, the images clearly show the detailed shape of the cross section in the pellets, in addition, the difference in the enrichment between the natural and enriched pellets is recognized.

Irradiation behavior of microspheres of U-Zr alloys

Ogawa, Toru; *; Ito, Akinori; ; Sekino, Hajime; Nishi, Masahiro; Ishikawa, Akiyoshi; Akabori, Mitsuo

Journal of Alloys and Compounds, 271-273, p.670 - 675, 1998/00

https://doi.org/10.1016/S0925-8388(98)00184-4

no abstracts in English

Oxide layer-thickness measurement on fuel cladding for high burnup HBWR fuel rods using eddy current method (Non-destructive examination)

Nakata, Masahito; Amano, Hidetoshi; ; Nishi, Masahiro; Nakamura, Jinichi; Furuta, Teruo; ;

HPR-345, 0, 9 Pages, 1995/00

no abstracts in English

Development of volume reduction equipment for radioactive waste

Ichise, Kenichi; Sakuraba, Naotoshi; Suzuki, Kazuhiro; Miyata, Seiichi; Komiya, Tomokazu; Nishi, Masahiro; Kitagawa, Isamu; Numata, Masami

no journal, , 

As a part of measures to reduce radioactive wastes, which are generated during operation and maintenance of Waste Safety Testing Facility (WASTEF), we developed volume reduction equipment for and wastes. In this presentation, we report manufacture of an experimental model, its operativeness & verification of reduction effect in a mock-up test, improvements, and application to actual radioactive wastes.

Decommissioning program of research hot laboratory in JAEA; Technical review of dismantling works for the lead cells

Shiina, Hidenori; Nozawa, Yukio; Ono, Katsuto; Nishi, Masahiro; Koya, Toshio; Ishikawa, Akiyoshi

no journal, , 

http://hotlab.sckcen.be/en/Proceedings