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Pu
O
powder using master sintering curve theoryNakamichi, Shinya; Sunaoshi, Takeo*; Hirooka, Shun; Vauchy, R.; Murakami, Tatsutoshi
Journal of Nuclear Materials, 595, p.155072_1 - 155072_11, 2024/07
Miwa, Kazuji; Takeda, Seiji; Iimoto, Takeshi*
Radiation Protection Dosimetry, 184(3-4), p.372 - 375, 2019/10
Times Cited Count：0 Percentile：0.01(Environmental Sciences)The Ministry of the Environment has indicated the policy of recycling the contaminated soil generated by decontamination activity after the Fukushima accident. By recycling to coastal reclamation which is one of effective recycling application, dissolved radiocesium and absorbed radiocesium on soil particles will flow out to the ocean by construction, therefore evaluating radiocesium transition in ocean considering the both types of radiocesium is important for safety assessment. In this study, the radiocesium outflow during constructing and after constructing is modeled, and radiocesium transition in ocean is evaluated by Sediment model suggested in OECD/NEA. The adaptability of sediment model is confirmed by reproducing evaluation of the coastal area of Fukushima. We incorporate the sediment model to PASCLR2 code system to evaluate the doses from radiocesium in ocean.
Miyahara, Kaname; Ohara, Toshimasa*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 59(5), p.282 - 286, 2017/05
This review highlights JAEA and NIES's challenges for enhancing Fukushima environmental resilience based on carrying out multifaceted research working with many public and private sector organizations and academia.
Ohara, Toshimasa*; Miyahara, Kaname
Global Environmental Research (Internet), 20(1&2), p.3 - 13, 2017/03
Toward the environmental regeneration in Fukushima Prefecture and other areas after the Fukushima Daiichi Nuclear Power Station accidents, JAEA and NIES working with many public and private sector organizations and academia have carried out multifaceted research that will help to restore the environment of affected areas. These challenging efforts need to be further strengthened.
Arifi, E.*; Ishimatsu, Koichi*; Iizasa, Shinya*; Namihira, Takao*; Sakamoto, Hiroyuki*; Tachi, Yukio; Kato, Hiroyasu*; Shigeishi, Mitsuhiro*
Construction and Building Materials, 67(Part B), p.192 - 196, 2014/09
Times Cited Count：5 Percentile：25.91(Construction & Building Technology)The Fukushima Dai-ichi Nuclear Plant accident has resulted in a large amount of radioactively contaminated concrete. The possible application of the pulsed power discharge to reduce the amount of contaminated concrete as radioactive waste was investigated. The contaminated concrete was decontaminated by separating contaminated matrix from uncontaminated coarse aggregate under pulsed power discharge process. In this study, a stable Cs isotope was used to simulate radioactively contaminated concrete. As a result, while the volume of reclaimed aggregate from contaminated concrete could be reproduced was up to 60%, nevertheless Cs detected in the reclaimed aggregate was only approximately 3%. Thus most of the Cs were dissolved in water during the discharge process. It is expected that the pulsed power could reduce the contaminated concrete waste by reusing aggregate. Further investigations are requested to test the applicability of this method under the realistic conditions close to the actual waste.
Uchikawa, Sadao; Okubo, Tsutomu; Kugo, Teruhiko; Akie, Hiroshi; Nakano, Yoshihiro; Onuki, Akira; Iwamura, Takamichi
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
no abstracts in English
Iwamura, Takamichi; Uchikawa, Sadao; Okubo, Tsutomu; Kugo, Teruhiko; Akie, Hiroshi; Nakatsuka, Toru
Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 8 Pages, 2005/05
In order to ensure sustainable energy supply in the future based on the matured Light Water Reactor (LWR) and coming LWR-Mixed Oxide (MOX) technologies, a concept of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been investigated in Japan Atomic Energy Research Institute (JAERI). The concept consists of two parts in the chronological sequence. The first part realizes a high conversion type core concept, which is basically intended to keep the smooth technical continuity from current LWR without significant gaps in technical point of view. The second part represents the Reduced-Moderation Water Reactor (RMWR) core concept, which realizes a high conversion ratio over 1.0 being useful for the long-term sustainable energy supply through plutonium multiple recycling based on the well-experienced LWR technologies. The key point is that the two core concepts utilize the compatible and the same size fuel assemblies, and hence, the former concept can proceed to the latter in the same reactor system, based flexibly on the fuel cycle circumstances.
Okubo, Tsutomu
Konsoryu, 17(3), p.228 - 235, 2003/09
The Reduced-Moderation Water Reactor is supposed to realize plutonium multiple recycling, and furthermore, plutonium breeding cycle, based on the well-established Light Water Reactor technologies. In the present paper, the overview of the design study is presented and the related R&D issues are introduced, especially focusing on the thermal hydraulic activities.
Okoshi, Minoru
Dekomisshoningu Giho, (26), p.2 - 12, 2002/11
The concept of clearance has been introduced by the International Atomic Energy Agency in 1996 and is very useful for the management of very low-level solid materials generating from the decommissioning of nuclear facilities. Therefore, the European Commission (EC) derived the specific clearance levels for metals, buildings and building rubble in RP 89 and 113, respectively. The EC also derived the general clearance levels for all solid materials generating from the regulated facilities in RP 122. Comparing the clearance levels of Japan with the unrounded levels of EC, the differences of levels are small. The biggest difference is found in Fe-55 and the EC's clearance level is about one fifth of Japanese clearance level. This is caused because the EC considers the direct ingestion of cleared building rubble by children and used the conservative ingestion rate of it. EC's discussions related to the clearance levels are very useful for Japan to derive our own clearance levels and to clear materials from regulatory control.
Nakamura, Hisashi; Nakashima, Mikio
JAERI-Tech 2002-006, 58 Pages, 2002/03
JAERI-Tech-2002-006.pdf:2.56MB
Radiation exposure was estimated on production and utilization of recycled items using dismantling waste by assuming that their usage are restricted to nuclear facilities. The radiation exposure attributed to production of a steel-plate cast iron waste container, a receptacle for slag, and a drum reinforcement was calculated to be in the range of several 
Sv to several tens of Sv even in recycling contaminated metal waste of which radioactivity concentration of Co-60 is higher than the clearance level by a factor of two figures. It is also elucidated that casting of a multiple casting waste package meets the standards of dose equivalent rate for the transport of a radioactive package and the weight of the package will be able to kept around 20 tons for the convenience of the handling, in case of disposal of metal waste less than 37MBq/g with the steel-plate cast iron waste container. As the results, from the radiological exposure's point of view, it should be possible to use slightly contaminated metal for recycled items in waste management.
Iwamura, Takamichi; Okubo, Tsutomu; Shimada, Shoichiro*; Usui, Shuji*; Shirakawa, Toshihisa*; Nakatsuka, Toru; Kugo, Teruhiko; Akie, Hiroshi; Nakano, Yoshihiro; Wada, Shigeyuki*
JAERI-Research 99-058, p.61 - 0, 1999/11
JAERI-Research-99-058.pdf:3.3MB
no abstracts in English
-spectrometryKono, Nobuaki; Watanabe, Kazuo
JAERI-Research 98-023, 20 Pages, 1998/03
JAERI-Research-98-023.pdf:0.82MB
no abstracts in English
Nakamura, Hisashi; Shindo, Hideaki
Proc. of 3rd European Technical Seminar on Melting and Recycling of Metallic waste Materials, p.79 - 91, 1997/00
no abstracts in English
Uchiyama, Gunzo; Fujine, Sachio; Maeda, Mitsuru; Sugikawa, Susumu; Tsujino, Takeshi
Solvent Extr. Ion Exch., 13(1), p.59 - 82, 1995/00
Times Cited Count：1 Percentile：13.34(Chemistry, Multidisciplinary)no abstracts in English
Fujine, Sachio; Takano, Hideki; Sato, Osamu; Tone, Tatsuzo; Yamada, Takashi*; Kurosawa, Katsutoshi*
JAERI-M 93-157, 157 Pages, 1993/08
no abstracts in English
; ;
EPA-520/1-90-013, p.82 - 89, 1990/00
no abstracts in English
Okamoto, Tsuyoshi*; *; Nishimura, Hideo
JAERI-M 89-059, 18 Pages, 1989/05
no abstracts in English
Osaka, Shuichi*; Yoshida, Ryoichi*; Yamazaki, Yukiko*; Ikeda, Hiroyuki*
no journal, ,
Japan Nuclear Fuel Ltd. (JNFL) has constructed JNFL MOX Fuel Fabrication Plant (J-MOX) since 2010. The MIMAS process has been introduced in the powder mixing process from AREVA NC considering a lot of MOX fuel fabrication experiences at MELOX plant in France. The feed material of Pu for J-MOX is MH-MOX powder from Rokkasho Reprocessing Plant (RRP) in Japan. The MH-MOX powder is a mixed oxide consisting of 50 wt% plutonium oxide and 50 wt% uranium oxide produced by direct denitration of Pu and U nitric acid solution utilizing microwave heating (MH) technology which was developed by Japan Atomic Energy Agency (JAEA). The compatibility of the MH-MOX powder with the MIMAS process was positively evaluated and confirmed in our previous study. The MIMAS process has two mixing steps. In the first step, which is called "Primary Blend", the feed materials (MH-MOX powder, UO powder and recycled scrap powder) are mixed and homogeneous powder which contains approximately 30 wt% of Pu is obtained. In the second step, which is called "Secondary Blend", the primary blend powder is diluted with UO powder to a certain Pu content. This paper describes the influences of the UO powder and the recycled scrap powder on the MOX pellet density.
