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Journal Articles

R&D strategy on mid- and long-term behavior of fuel debris

Yano, Kimihiko; Kitagaki, Toru; Washiya, Tadahiro; Miyamoto, Yasuaki; Ogawa, Toru

Progress in Nuclear Science and Technology (Internet), 5, p.225 - 228, 2018/11

According to the roadmap for decommissioning of Fukushima Daiichi NPS, fuel debris retrieval will start from 2021, after a decade from fuel debris generation. Fuel debris will stay in the reactors until the end of defueling. In addition, it is not hard to anticipate that storage is necessary for fuel debris removed from reactors. In order to consider such a post-accident operation for fuel debris, it is indispensable to discuss the states and characteristics of fuel debris during several decades. Therefore, JAEA directed R&D strategy on mid- and long-term behavior of fuel debris tentatively and is making a start of fundamental studies on this issue in corporation with the domestic universities and other research institutes.

Journal Articles

Outline and activities of test facility at Collaborative Laboratories for Advanced Decommissioning Science, Japan Atomic Energy Agency

Miyamoto, Yasuaki

Nihon Robotto Gakkai-Shi, 36(7), p.464 - 467, 2018/09

I introduced the activities of Collaborative Laboratories for Advanced Decommissioning Science, the summary of the CLADS Main Building and main result.

Journal Articles

Research and development activities for cleanup of the Fukushima Daiichi Nuclear Power Station

Sasaki, Toshiki; Kaminishi, Shuji*; Miyamoto, Yasuaki; Funasaka, Hideyuki

Materials Research Society Symposium Proceedings, Vol.1518, p.257 - 268, 2013/10

BB2012-2567.pdf:1.85MB

The Fukushima Daiichi Nuclear Power Station accident and restoration works have produced significant volume of radioactive waste. The waste has very different characteristics from usual radioactive waste produced in nuclear power stations and it requires extensive research and development for management of the waste. R&D works such as radionuclide analysis of the waste, hydrogen generation/diffusion analysis of a storage vessel, corrosion evaluation of storage vessels, etc. have been performed for characterization and safe storage of the waste. The detailed R&D plan for processing and disposal waste will be established by the end of FY2012.

Journal Articles

Research and development on waste management for the Fukushima Daiichi NPS by JAEA

Koma, Yoshikazu; Ashida, Takashi; Meguro, Yoshihiro; Miyamoto, Yasuaki; Sasaki, Toshiki; Yamagishi, Isao; Kameo, Yutaka; Terada, Atsuhiko; Hiyama, Toshiaki; Koyama, Tomozo; et al.

Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.736 - 743, 2013/09

Fukushima Daiichi Nuclear Power Station (F1NPS), TEPCO, was severely damaged with the hydrogen explosions caused by losing their cooling functions due to the earthquake and the tsunami occurred on March 11, 2011. Radioactive wastes generated from the current FINPS and future their decommission and demolition are greater huge amount than those from general reactors and nuclear fuel facilities. Toward accomplishing safe and reasonable management of the wastes, great effort of R&Ds has been strongly required and performed in bringing together the knowledge and experience of all of Japan. This report outlines the current status of the R&Ds performed in JAEA.

JAEA Reports

Stabilization of simulated radioactive lead waste and simulated low level radioactive liquid waste using reformed sulfur (Joint research)

Sone, Tomoyuki; Sasaki, Toshiki; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Inoue, Haruka*; Kihara, Tsuyoshi*; Takei, Yoshihisa*; Tatekawa, Takaiki*; Fukaya, Masaaki*; Iriya, Keishiro*; et al.

JAEA-Technology 2008-032, 25 Pages, 2008/03

JAEA-Technology-2008-032.pdf:5.54MB

Reformed sulfur (RS) is superior in water interception and acid resistance compared with cement. Therefore solidified wastes with RS should have the high resistance to leaching. Unconfined compressive strength test and leaching test using solidified simulated wastes containing lead contaminated with radioactive nuclides (Lead waste) with RS and solidified simulated low level radioactive liquid waste (LLLW) with RS were conducted to examine the applicability of reformed sulfur solidification method (RSSM) as solidification technique of Lead waste and LLLW. The results of these studies show that RSSM is effective technique for stabilization of lead compared with cement solidification method because solidified lead with RS has much stronger resistance to leaching of lead than solidified lead with cement. It also show that the applicability of RSSM as solidification technique of the waste containing lead oxide and LLLW is low because the resistance to leaching of solidified lead oxide with RS and of solidified simulated LLLW with RS were equal to or lower than those of solidified products with cement respectively.

Journal Articles

Innovative alpha radioactivity monitor for clearance level inspection based on ionized air transport technology; CFD-simulated and experimental ion transport efficiencies for uranium-attached pipes

Hirata, Yosuke*; Nakahara, Katsuhiko*; Sano, Akira*; Sato, Mitsuyoshi*; Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

Journal of Power and Energy Systems (Internet), 2(2), p.561 - 572, 2008/00

Journal Articles

Thermal pretreatment for TRU waste sorting

Sasaki, Toshiki; Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi

Proceedings of International Waste Management Symposium 2008 (WM '08) (CD-ROM), 8 Pages, 2008/00

Japan Atomic Energy Agency conducted a study on thermal treatment of TRU waste to develop a removal technology for materials that are forbidden to dispose of. The thermal pretreatment in which hot nitrogen and/or air is introduced to the waste is a process of removing combustibles, liquids, and low melting point metals from PVC wrapped TRU waste. In this study, thermal pretreatment of simulated waste was conducted using a desktop thermal treatment vessel and a laboratory scale thermal pretreatment system. Combustibles such as papers, PVC, oil, etc. were removed and low melting point metals such as zinc, lead, and aluminum were separated from the simulated waste by the thermal pretreatment.

Journal Articles

Innovative alpha-radioactivity monitor for clearance level inspection based on ionized air transportation technology, 1; Comparison with mass spectral analysis using uranium-attached samples

Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Sano, Akira*; Naito, Susumu*; Sumida, Akio*; Izumi, Mikio*; Maekawa, Tatsuyuki*; Sato, Mitsuyoshi*; Nambu, Kenichi*; et al.

Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 6 Pages, 2007/04

no abstracts in English

Journal Articles

Innovative alpha radioactivity monitor for clearance level inspection based on ionized air transport technology, 2; CFD-simulated and experimental ion transport efficiencies for uranium-attached pipes

Hirata, Yosuke*; Nakahara, Katsuhiko*; Sano, Akira*; Sato, Mitsuyoshi*; Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Nambu, Kenichi*; Takahashi, Hiroyuki*; Oda, Akinori*

Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 6 Pages, 2007/04

no abstracts in English

Journal Articles

Ion current prediction model considering columnar recombination in alpha radioactivity measurement using ionized air transportation

Naito, Susumu*; Hirata, Yosuke*; Izumi, Mikio*; Sano, Akira*; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi

Journal of Nuclear Science and Technology, 44(2), p.121 - 128, 2007/02

 Times Cited Count:1 Percentile:12.05(Nuclear Science & Technology)

A reinforced ion current prediction model in the alpha radioactivity measurement using ionized air transportation was presented. Although our previous model explained a qualitative trend of the measured ion current values, their absolute values were considerably overestimated. In order to explain them quantitatively, the model was reinforced in consideration of columnar recombination. It was found that our new model explains the considerable ion loss in the initial stage of ion diffusion and narrows the gap between the predicted and measured ion current values. This model also indicated a prospective suppression of ion loss due to columnar recombination by spraying a high-speed air flow on the contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, the theoretical relationship between alpha radioactivity and ion current was clarified quantitatively in laminar flow and turbulent pipe flow.

JAEA Reports

Experimental investigation of melting treatment of nonflammable solid wastes in a canister with a high-frequency induction furnace

Ozawa, Tatsuya; Miyamoto, Yasuaki; Suto, Makoto; Aoyama, Yoshio; Yamaguchi, Hiromi

JAEA-Technology 2006-050, 88 Pages, 2006/11

JAEA-Technology-2006-050.pdf:14.49MB

Melting treatment is one of the volume reduction processes for nonflammable radioactive solid wastes. Though it is applied to the volume reduction process for the low-level radioactive wastes generated at nuclear power plants, it still has technical problems to be solved. The results of our previous investigation of existing melting treatment facilities and conceptual design of the melting treatment system for transuranic waste, made these technical problems clear. To solve them, we have been carrying out the experiments of melting treatment of the simulated transuranic wastes which are nonflammable solid wastes. This report describes the progress in investigating these problems, as well as the results of recent experiments.

Journal Articles

Particle modeling of transport of $$alpha$$-ray generated ion clusters in air

Tong, L.*; Nambu, Kenichi*; Hirata, Yosuke*; Izumi, Mikio*; Miyamoto, Yasuaki; Yamaguchi, Hiromi

Japanese Journal of Applied Physics, Part 1, 45(10B), p.8217 - 8220, 2006/10

 Times Cited Count:0 Percentile:0(Physics, Applied)

A particle model is developed using the test-particle Monte Carlo method to study the transport properties of alpha-ray generated ion clusters in a flow of air. The simulated transport properties provide a theoretical basis for designing the alpha radioactivity measurement system. An accurate ion-molecule collision model is proposed to simulate the collisions between ion and air molecule. The recombination between positive and negative ions is simulated using Nanu and Denpoh method [J. Phys. Soc. Jpn. 67(1998) 1288]. The calculations are performed from low gas pressures of 0.001 and 0.01 atm to high gas pressures of 0.1 and 1 atm in a circular pipe. The simulation presents such a steady state ion transport that the generation of ions reaches a quasi-equilibrium with the loss of ions, absorbed by a measuring sensor and lost on the pipe wall.

Journal Articles

Radon concentration dependence of alpha radioactivity measurement using ionized air transportation

Naito, Susumu*; Sano, Akira*; Izumi, Mikio*; Noda, Etsuo*; Hayashi, Kazuo*; Sato, Mitsuyoshi*; Suto, Osamu; Miyamoto, Yasuaki; Kondo, Shinichi*; Iinuma, Koichi*; et al.

Nuclear Science Symposium Conference Record, 2005 IEEE, Vol.1, p.495 - 499, 2005/10

An alpha radioactivity monitor (alpha-clearance monitor) is being developed to measure alpha radioactivity of uranium contaminated waste with large and complex surfaces. It uses an alpha radioactivity measurement method by collecting the air ionized by alpha particles using an air stream and by measuring its ion current. One of the major problems of the alpha-clearance monitor is the background ion current mainly by radon in atmosphere ($$sim$$700 fA), which is much larger than ion current of an alpha particle (several fA). It strongly influences on the detection limit of alpha radioactivity. In order to improve the detection limit, we developed a method to monitor the radon concentration inside the monitor without the additional radon detector. In addition, the influencing factors on the detection limit: ion mobility and ion recombination coefficient were measured and evaluated on various environmental conditions (temperature, humidity and aerosol density).

Journal Articles

Stabilization of Lead in Low-Level Radioactive Waste Form Using Low-Alkalinity Cements

Sasaki, Toshiki; Miyamoto, Yasuaki; Fukumoto, Masahiro

Waste Management symposium 2005, Poster Session, 19b, 0 Pages, 2005/03

None

Journal Articles

Development of Melt Refining Decontamination Technology for Low Level Radioactive Metal Waste Contaminated with Uranium

Suto, Makoto; Miyamoto, Yasuaki; Fukumoto, Masahiro; Suto, Osamu

Journal of Physics and Chemistry of Solids, 66(2-4), p.608 - 611, 2005/00

None

Journal Articles

Stabilization of Lead in Low-Level Radioactive Waste Form Using Low-Alkalinity Cements

Sasaki, Toshiki; Miyamoto, Yasuaki; Fukumoto, Masahiro

Proceedings of Waste Management Symposium 2005, CD-ROM, 6p., 6 Pages, 2004/00

Leaching behavior of lead from waste forms solidified using low-alkalinity cements was studied to reduce the leachability of lead from low-level radioactive waste (LLRW) forms. The use of low-alkalinity cements effectively decreased the concentrations of lead in the leachates and the only sample that passed the leaching test of the landfill of hazardous industrial wastes was the lead sulfide solidified using calcium sulpho-aluminate cement blended silica fume.

JAEA Reports

Evaluation Report of the Melt Refining Decontamination Technology

Miyamoto, Yasuaki; Yamanaka, Tomohiro*; Aoyama, Makoto; Takahashi, Kuniaki; Suto, Osamu

JNC-TN8400 2003-044, 127 Pages, 2003/03

JNC-TN8400-2003-044.pdf:19.07MB

It examined for the uranium system metal wastes which can be expected a high decontamination performance by applying melt refining decontamination technology, and the decontamination performance by using a refractories melting furnace and a cold crucible induction melting furnace was confirmed. Moreover, evaluation about technical applicability, such as engineering characteristics by the examination using an engineering scale melting furnace, was carried out.

Journal Articles

Development of Melt Refining Decontamination Technology for Low Level Radioactive Metal Waste Contamonated with Uranium

Aoyama, Makoto; Miyamoto, Yasuaki; Suto, Osamu

Abstract, PB54, (pb54), 0 Pages, 2003/00

None

Journal Articles

None

; ; Koakutsu, Masayuki; ; Miyamoto, Yasuaki; Takeda, Seiichiro

Saikuru Kiko Giho, (16), 37- Pages, 2002/00

None

JAEA Reports

Present status of research on hydrogen energy and perspective of HTGR hydrogen production system

Miyamoto, Yoshiaki; Ogawa, Masuro; Akino, Norio; Shiina, Yasuaki; Inagaki, Yoshiyuki; Shimizu, Saburo; Onuki, Kaoru; Ishiyama, Shintaro; Katanishi, Shoji; Takeda, Tetsuaki; et al.

JAERI-Review 2001-006, 147 Pages, 2001/03

JAERI-Review-2001-006.pdf:9.2MB

no abstracts in English

45 (Records 1-20 displayed on this page)