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Ohashi, Yusuke; Shimaike, Masamitsu; Matsumoto, Takashi; Takahashi, Nobuo; Yokoyama, Kaoru; Morimoto, Yasuyuki
Nuclear Technology, 209(5), p.777 - 786, 2023/05
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)At the Ningyo-Toge Center, technical development related to uranium refining conversion and enrichment has been completed, and decommissioning of these facilities has begun. The error between the quantity of dismantled materials estimated from the facility design drawings and the actual quantity of dismantled materials was minimal when averaging over the entire Uranium Refining and Conversion Plant and Uranium Enrichment Engineering Facility, which results indicated that the preliminary estimate of the quantity of dismantled materials for decommissioning was reasonable. Most of the dismantled materials, which have no contamination history and are properly managed were able to be carried out to recyclers as non-radioactive waste (NR). In addition, the possibility of evaluating the uranium concentration of clearance level in dismantled objects was confirmed through gamma-ray measurement tests using mock-up waste.
Yamane, Ikumi; Takahashi, Nobuo; Sawayama, Kengo; Nishiwaki, Hiroki; Matsumoto, Takashi; Ogawa, Jumpei; Nomura, Mitsuo; Arima, Tatsumi*
JAEA-Technology 2021-038, 18 Pages, 2022/02
JAEA-Technology-2021-038.pdf:1.61MB
We have dismantled uranium enrichment facilities in Ningyo-toge Environmental Engineering Center since their operation finished in 2001, and the total amount of metallic wastes is estimated to be about 130 thousand tons. Eighty percent of them can be disposed as nonradioactive waste (NR), but there are some steel parts possibly uranium-contaminated. We need removing painted surface of such steels and radiologically surveying to dispose them as NRs. Though painted surfaces have been conventionally removed through hand working with grinders, this manual work requires installation of green house, protective clothing, and full-face mask, in order to prevent dispersion and inhalation of airborne dusts. We desire further developments of surface cleaning techniques to reduce time, cost, workload, and secondary waste generation caused by excessive grinding. Therefore, in this study, we focused on the laser cleaning technology used for the separation and removal of paint films at construction sites. In order to improve the coating separation and removal technology for NR objects, we evaluated the coating separation and removal performance of NR steel surface by laser cleaning system, observed the coating scattering behavior by high-speed camera and investigated the coating recovery method, evaluated the laser separation and removal performance of steel surface powder, and thermodynamically evaluated the uranium compounds on steel surface. We additionally evaluated the feasibility of laser cleaning techniques in our works basing on these results, and discussed future work plans for further developments of laser cleaning techniques.
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Haga, Yoshinori; Sugai, Takashi*; Matsumoto, Yuji*; Yamamoto, Etsuji
JPS Conference Proceedings (Internet), 29, p.013003_1 - 013003_5, 2020/02
Matsumoto, Takashi; Takahashi, Nobuo; Hayashibara, Kenichi; Ishimori, Yuu; Mita, Yutaka; Kakiya, Hideyoshi
JAEA-Technology 2016-020, 80 Pages, 2016/11
JAEA-Technology-2016-020.pdf:17.8MB
The Enrichment Engineering Facility of the Ningyo-toge Environmental Engineering Center was constructed in order to establish the technological basis of plant engineering for uranium enrichment in Japan. Uranium enrichment tests, using natural and reprocessed uranium, were carried out from 1979 to 1989 with two types of centrifuges in the facility. According to the decommissioning plan of the facility, UF
handling equipment and supplemental equipment in these plants are intended to be dismantled by 2019 in order to make vacant spaces for future projects use, for example, inventory investigation, precipitation treatment, etc. This report shows the current state of the decommissioning project in the second-half of the fiscal year of 2014.
Matsumoto, Takashi; Morimoto, Yasuyuki; Takahashi, Nobuo; Takata, Masaharu; Yoshida, Hideaki; Nakashima, Shinichi; Ishimori, Yuu
JAEA-Technology 2015-036, 60 Pages, 2016/01
JAEA-Technology-2015-036.pdf:9.15MB
The Enrichment Engineering Facilities of the Ningyo-toge Environmental Engineering Center was constructed in order to establish the technical basis of the uranium enrichment plant in Japan. Uranium enrichment tests, using natural and reprocessed uranium, were carried out from 1979 to 1990 at two types of plants in the facilities. UF handling equipment and Supplemental equipment in these plants are intended to be dismantled by 2019 in order to make places for future projects, for example, inventory investigation, precipitation treatment, etc. This report shows the basic plan of this decommissioning project and presents the current state of dismantling in the first-half of the fiscal year of 2014, with indicating its schedule, procedure, situation, results, and so on. The dismantled materials generated amounted to 37 mesh containers and 199 drums, and the secondary waste generated amounted to 271.4 kg.
; ; Tsuboi, Takashi; E.R.Vance*; B.D.Begg*; K.P.Hart*
Materials Research Society Symposium Proceedings, Vol.353, 0, p.1405 - 1412, 1995/00
no abstracts in English
-decay damage effects in curium-doped titanate ceramic containing sodium-free high-level nuclear waste; ; M.W.A.Stewart*; Tsuboi, Takashi; *; E.R.Vance*; K.P.Hart*; Togashi, Yoshihiro; Kanazawa, Hiroyuki; C.J.Ball*; et al.
Journal of the American Ceramic Society, 77(9), p.2255 - 2264, 1994/00
Times Cited Count：30 Percentile：80.45(Materials Science, Ceramics)no abstracts in English
Mita, Yutaka; Matsumura, Toshihiro; Sugitsue, Noritake; Yamaguchi, Hiromi; Sano, Akira*; Naito, Susumu*; Maekawa, Tatsuyuki*; Yoshimura, Yukio*; Matsumoto, Takashi*
no journal, ,
By using Ionized Air Type Measurement Apparatus which was designed to measure clearance level of dismantled large-scale things which generate from nuclear plants, after chemical decontaminating machinery and materials which are used in plants, we experimented on a real-scale measurement of clearance level of them. We evaluated performance of detection and confirm applicability as a system of measurement of clearance level.
