Kokusen, Junya; Akasaka, Shingo*; Shimizu, Osamu; Kanazawa, Hiroyuki; Honda, Junichi; Harada, Katsuya; Okamoto, Hisato
JAEA-Technology 2020-011, 70 Pages, 2020/10
The Uranium Enrichment Laboratory in the Japan Atomic Energy Agency (JAEA) was constructed in 1972 for the purpose of uranium enrichment research. The smoke emitting accident on 1989 and the fire accident on 1997 had been happened in this facility. The research on uranium enrichment was completed in JFY1998. The decommissioning work was started including the transfer of the nuclear fuel material to the other facility in JFY2012. The decommissioning work was completed in JFY2019 which are consisting of removing the hood, dismantlement of wall and ceiling with contamination caused by fire accident. The releasing the controlled area was performed after the confirmation of any contamination is not remained in the target area. The radioactive waste was generated while decommissioning, burnable and non-flammable are 1.7t and 69.5t respectively. The Laboratory will be used as a general facility for cold experiments.
Segawa, Yukari; Horita, Takuma; Kitatsuji, Yoshihiro; Kumagai, Yuta; Aoyagi, Noboru; Nakada, Masami; Otobe, Haruyoshi; Tamura, Yukito*; Okamoto, Hisato; Otomo, Takashi; et al.
JAEA-Technology 2016-039, 64 Pages, 2017/03
The laboratory building No.1 for the plutonium research program (Bldg. Pu1) was chosen as one of the facilities to decommission by Japan Atomic Energy Agency Reform in September, 2013. The research groups, users of Bldg. Pu1, were driven by necessity to remove used equipment and transport nuclear fuel to other facilities from Bldg. Pu1. Research Group for Radiochemistry proactively established the Used Equipment Removal Team for the smooth operation of the removal in April, 2015. The team classified six types of work into the nature of the operation, removal of used equipment, disposal of chemicals, stabilization of mercury, stabilization of nuclear fuel, transportation of nuclear fuel and radioisotope, and survey of contamination status inside the glove boxes. These works were completed in December, 2015. This report circumstantially shows six works process, with the exception of the approval of the changes on the usage of nuclear fuel in Bldg. Pu1 to help prospective decommission.
Terunuma, Akihiro; Mimura, Ryuji; Nagashima, Hisao; Aoyagi, Yoshitaka; Hirokawa, Katsunori*; Uta, Masato; Ishimori, Yuu; Kuwabara, Jun; Okamoto, Hisato; Kimura, Yasuhisa; et al.
JAEA-Review 2016-008, 98 Pages, 2016/07
Japan Atomic Energy Agency formulated the plan to achieve the medium-term target in the period of April 2010 to March 2015(hereinafter referred to as "the second medium-term plan"). JAEA determined the plan for the business operations of each year (hereinafter referred to as "the year plan"). This report is that the Sector of Decommissioning and Radioactive Waste Management has summarized the results of the decommissioning technology development and decommissioning of nuclear facilities which were carried out in the second medium-term plan.
Matsui, Hiroki; Okamoto, Hisato
JAEA-Technology 2014-015, 43 Pages, 2014/06
The remote controlled optical microscope installed in the lead cell at the Reactor Fuel Examination Facility in Japan Atomic Energy Agency has been upgraded to a higher performance unit to study the effect of the microstructural evolution in clad material on the high burn-up fuel behavior under the accident condition. The optical pass of the new microscope requires a new through hole in the shielding lead wall of the cell. To meet safety regulations, auxiliary lead shieldings were designed to cover the lost shielding function of the cell wall. Particle and Heavy Ion Transport Code System (PHITS) was used to calculate and determine the shape and setting positions of the shielding unit. Seismic assessments of the unit were also performed.
Umino, Akira; Saito, Mitsuo; Kanazawa, Hiroyuki; Koya, Toshio; Okamoto, Hisato; Sekino, Hajime*; Nishino, Yasuharu
Dekomisshoningu Giho, (32), p.2 - 12, 2005/09
The Research Hot Laboratory (RHL) in Japan Atomic Research Institute (JAERI) was constructed in 1961, as the first one in JAPAN, to perform the examinations of irradiated fuels and materials. RHL with two floors and a basement consists of 10 heavy concrete cells, and 38 lead cells (20 lead cells at present). The RHL had been contributed to research program in JAERI. However, RHL is the one of target 'A middle-range decommissioning plan for the facility in Tokai Research Establishment' as the rationalization program for decrepit facilities in JAERI. Therefore, all PIEs had been finished in March 2003 and the dismantling works of hot cells have been started. The 18 lead cells had been dismantled. The examinations performed in RHL will be succeeded to the RFEF and the WASTEF. The partial area of RHL facility will be used for the temporary storage of un-irradiated fuel samples used for our previous research works and radioactive device generated in proton accelerator facility (called J-PARC).
Fujimori, Shinichi; Okane, Tetsuo; Okamoto, Jun; Mamiya, Kazutoshi; Muramatsu, Yasuji; Fujimori, Atsushi*; Harima, Hisatomo*; Aoki, Dai*; Ikeda, Shugo*; Shishido, Hiroaki*; et al.
Physical Review B, 67(14), p.144507_1 - 144507_5, 2003/04
We have performed angle-resolved photoemission spectroscopy (~eV) and 3-4 resonant photoemission spectroscopy (~eV) studies on the layered cerium compounds CeIn (=Rh and Ir), which show competition between superconductivity and antiferromagnetism. The results suggest that the Ce~4 electrons in both compounds are nearly localized. We have found that although the Ce~4 electrons in the superconducting CeIrIn are more delocalized than those in the antiferromagnetic CeRhIn, their electronic structures are very similar to each other.
Yamaguchi, Tetsuji; Nakayama, Shinichi; Okamoto, Hisato
Radiochimica Acta, 90(12), p.863 - 868, 2003/01
no abstracts in English
Takano, Masahide; Ito, Akinori; Akabori, Mitsuo; Ogawa, Toru; Numata, Masami; Okamoto, Hisato
Journal of Nuclear Materials, 294(1-2), p.24 - 27, 2001/04
no abstracts in English