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Porcheron, E.*; Leblois, Y.*; Journeau, C.*; Delacroix, J.*; Molina, D.*; Suteau, C.*; Berlemont, R.*; Bouland, A.*; Lallot, Y.*; Roulet, D.*; et al.
Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR2022) (Internet), 5 Pages, 2022/10
One of the important challenges for the decommissioning of the damaged reactors of the Fukushima Daiichi Nuclear Power Station (1F) is the fuel debris retrieval. The URASOL project, which is undertaken by a French consortium consisting of ONET Technologies, CEA, and IRSN for JAEA/CLADS, is dedicated to acquiring basic scientific data on the generation and characteristics of radioactive aerosols from the thermal or mechanical processing of fuel debris simulant. Heating process undertaken in the VITAE facility simulates some representative conditions of thermal cutting by LASER. For mechanical cutting, the core boring technique is implemented in the FUJISAN facility. Fuel debris simulants have been developed for inactive and active trials. The aerosols are characterized in terms of mass concentration, real time number concentration, mass size distribution, morphology, and chemical properties. The chemical characterization aims at identifying potential radioactive particles released and the associated size distribution, both of which are important information for assessing possible safety and radioprotection measures during the fuel debris retrieval operations at 1F.
Yoshida, Kazuo; Tamaki, Hitoshi; Hiyama, Mina*
JAEA-Research 2021-005, 25 Pages, 2021/08
JAEA-Research-2021-005.pdf:2.91MB
An accident of evaporation to dryness by boiling of high level liquid waste (HLLW) is postulated as one of the severe accidents caused by the loss of cooling function at a fuel reprocessing plant. In this case, volatile radioactive materials, such as ruthenium (Ru) are released from the tanks with water and nitric-acid mixed vapor into atmosphere. Accurate quantitative estimation of released Ru is one of the important issues for risk assessment of those facilities. To resolve this issue, an empirical correlation equation of Ru mass transfer coefficient across the vapor-liquid surface, which can be useful for quantitative simulation of Ru mitigating behavior, has been obtained from data analyses of small-scale experiments conducted to clarify gaseous Ru migrating behavior under steam-condensing condition. A simulation study has been also carried out with a hypothetical typical facility building successfully to demonstrate the feasibility of quantitative estimation of amount of Ru migrating in the facility using the obtained correlation equation implemented in SCHERN computer code which simulates chemical behaviors of nitrogen oxide based on the condition also simulated thermal-hydraulic computer code.
Maruyama, Yu; Yoshida, Kazuo
Nihon Genshiryoku Gakkai-Shi ATOMO
, 63(7), p.517 - 522, 2021/07
no abstracts in English
Collaborative Laboratories for Advanced Decommissioning Science; Kyushu University*
JAEA-Review 2019-039, 104 Pages, 2020/03
JAEA-Review-2019-039.pdf:5.57MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Research and Development of Transparent Materials for Radiation Shield using Nanoparticles". The present study aims to reduce radiation exposure of workers in debris retrieval/analysis and reduce deterioration of optical and electronic systems in remote cameras. For these purposes, we develop transparent radiation shield by making the shield materials into nanoparticles, and dispersing/solidifying them in epoxy resin. By making B
C and W into nanoparticles, we will also develop a radiation shield that shields both neutrons and gamma-rays, and also suppresses secondary gamma-rays produced from neutrons.
Kasahara, Seiji; Imai, Yoshiyuki; Suzuki, Koichi*; Iwatsuki, Jin; Terada, Atsuhiko; Yan, X.
Nuclear Engineering and Design, 329, p.213 - 222, 2018/04
Times Cited Count：21 Percentile：90.78(Nuclear Science & Technology)A conceptual design of a practical large scale plant of the thermochemical water splitting iodine-sulfur (IS) process flowsheet was carried out as a heat application of JAEA's commercial high temperature gas cooled reactor GTHTR300C plant design. Innovative techniques proposed by JAEA were applied for improvement of hydrogen production thermal efficiency; depressurized flash concentration H
SO using waste heat from Bunsen reaction, prevention of HSO vaporization from a distillation column by introduction of HSO solution from a flash bottom, and I condensation heat recovery in an HI distillation column. Hydrogen of about 31,900 Nm
/h would be produced by 170 MW heat from the GTHTR300C. A thermal efficiency of 50.2% would be achievable with incorporation of the innovative techniques and high performance HI concentration and decomposition components and heat exchangers expected in future R&D.
Kasahara, Seiji; Kubo, Shinji; Hino, Ryutaro; Onuki, Kaoru; Nomura, Mikihiro*; Nakao, Shinichi*
Proceedings of AIChE 2005 Spring National Meeting (CD-ROM), 8 Pages, 2005/04
Japan Atomic Energy Research Institute (JAERI) has been conducting the research and development on the thermochemical water-splitting IS process for effective hydrogen production using nuclear heat of close to 1000 
C that can be supplied from High Temperature Gas-cooled Reactor (HTGR). The activity covers the studies on the process control for the continuous hydrogen production, the process improvements in the HI decomposition procedure and the preliminary screening of corrosion resistant materials of construction. Present status of the study is presented, especially, focusing on the process flowsheeting study concerning the application of membrane process for the HI processing.
Iwamura, Takamichi; Okubo, Tsutomu; Akie, Hiroshi; Kugo, Teruhiko; Yonomoto, Taisuke; Kureta, Masatoshi; Ishikawa, Nobuyuki; Nagaya, Yasunobu; Araya, Fumimasa; Okajima, Shigeaki; et al.
JAERI-Research 2004-008, 383 Pages, 2004/06
JAERI-Research-2004-008.pdf:21.49MB
The present report contains the achievement of "Research and Development on Reduced-Moderation Light Water Reactor with Passive Safety Features", which was performed by Japan Atomic Energy Research Institute (JAERI), Hitachi Ltd., Japan Atomic Power Company and Tokyo Institute of Technology in FY2000-2002 as the innovative and viable nuclear energy technology (IVNET) development project operated by the Institute of Applied Energy (IAE). In the present project, the reduced-moderation water reactor (RMWR) has been developed to ensure sustainable energy supply and to solve the recent problems of nuclear power and nuclear fuel cycle, such as economical competitiveness, effective use of plutonium and reduction of spent fuel storage. The RMWR can attain the favorable characteristics such as high burnup, long operation cycle, multiple recycling of plutonium (Pu) and effective utilization of uranium resources based on accumulated LWR technologies.
Nomura, Mikihiro; Kasahara, Seiji; Onuki, Kaoru
JAERI-Research 2002-039, 24 Pages, 2003/01
JAERI-Research-2002-039.pdf:1.01MB
Thermal efficiency to produce hydrogen from water through the IS process was evaluated by a viewpoint of thermodynamics. Thermal efficiency is decided by a temperature from a heat source and limited by the works calculated by the Carnot efficiency for any hydrogen production methods. The maximum thermal efficiency is 81.3% for a thermal cycle between 1123K and 733K. The thermal efficiency of the IS process was evaluated by G-T diagrams of each reactions and separation processes. The maximum value is 78.2% without considering the works for separations of acids from water. However, the effects of the works for separations on thermal efficiency are essential for the IS process, because Gibbs energies of separations of acids from water are always positive. The thermal efficiency could be changed from 53.5% to 76.6% by the calculation with or without the separation processes.
Abe, Yutaka*
JAERI-Tech 2002-011, 70 Pages, 2002/03
JAERI-Tech-2002-011.pdf:5.62MB
no abstracts in English
Nariai, Hideki*
JAERI-Tech 2002-009, 60 Pages, 2002/03
JAERI-Tech-2002-009.pdf:7.73MB
no abstracts in English
*; ;
JAERI-M 90-082, 44 Pages, 1990/05
no abstracts in English
; Shimizu, Saburo; Nakajima, Hayato; Ikezoe, Yasumasa;
Int.J.Hydrogen Energy, 9(5), p.391 - 396, 1984/00
Times Cited Count：5 Percentile：72.66(Chemistry, Physical)no abstracts in English
Nakajima, Hayato; Shimizu, Saburo; ; Ikezoe, Yasumasa;
Nihon Kagakkai-Shi, 8, p.1257 - 1261, 1984/00
no abstracts in English
; Shimizu, Saburo; Nakajima, Hayato; Ikezoe, Yasumasa;
Bulletin of the Chemical Society of Japan, 56, p.3294 - 3296, 1983/00
Times Cited Count：2 Percentile：24.03(Chemistry, Multidisciplinary)no abstracts in English
