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Aoshima, Atsushi; Suzuki, Yoshiharu; Namekawa, Takashi
Nihon Genshiryoku Gakkai-Shi ATOMO
, 55(12), p.733 - 736, 2013/12
no abstracts in English
Aoshima, Atsushi; Ueno, Tsutomu; Shiotsuki, Masao
Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 9 Pages, 2008/05
In TVF, concentrated high radioactive liquid waste produced in TRP has been vitrified since 1995. Because of very corrosive condition of melting glass, design life of a melter is limited five years and it requires interruption of plant operation and generation of high radioactive solid waste for melter change. To improve this situation, prolongation of melter design life time by increasing corrosion resistance of structural material is required strongly. Effective removal of noble metal from a melter is also required because accumulated noble metal cause shortening lifetime of a melter. So, JAEA tried to develop a melter which equipped with ability of high corrosion resistance and control temperature distribution for noble metal easy drain out. Mechanical removal technology of remained noble metal rich glass also used if necessary. Low temperature glassing technology and advance removal of noble metal from concentrated high radioactive liquid are also be studying.
Aoshima, Atsushi; Ueno, Tsutomu; Shiotsuki, Masao
Proceedings of European Nuclear Conference 2007 (ENC 2007) (CD-ROM), 5 Pages, 2007/09
Tokai Vitrification Facility (TVF) started hot operation in 1996 and produced 241 canisters as of June 2007. Through TVF operation, JAEA had much experience and accumulated much technical know-how which indicated that management for noble metal accumulation in a melter was key technology for smooth plant operation. JAEA should continue service operation based on a vitrification contract with the Japanese utilities because there remains about two third of High Active Liquid Waste (HALW) produced in the reprocessing service operation of Tokai Reprocessing Plant (TRP). TVF melter is designed in condition of five years life time because of very corrosive characteristic of melted glass. Five years design life time is equivalent to 500 canisters production in TVF. Because estimated number of canisters which will be produced in the future is over 500 canisters, exchange of the present melter is necessary. From these situations, JAEA decided basic strategy to increase stability of the existing melter operation and develop an advanced new melter for replacement in future which has largely prolonged life time and high noble metal drain ability. To attain these targets, JAEA extracted necessary key technologies to assemble into a ten years road map and started development. This development has been progressing on schedule.
Shiotsuki, Masao; Aoshima, Atsushi; Nomura, Shigeo
Proceedings of International Waste Management Symposium 2006 (WM '06) (CD-ROM), 10 Pages, 2006/02
Achievement of reliable technologies on solidification and disposal of the HLW from future fuel cycle systems such for high burnup LWR, Pu-thermal (MOX), fast breeder reactor (FBR) and their transient stages is one of the most important issues to establish such advanced fuel cycle systems. In this paper, applicability and flexibility of the current vitrification technology for LWR fuel cycle to HLW from the future fuel cycle systems were reviewed by examining characteristics of the HLWs. The current developed vitrification technology is expected to have an advantage for applying to the solidification process of the HLW generated from future fuel cycle systems with some modification/optimization of the melting condition, etc. Moreover, it is thought that the advance aqueous reprocessing system developed for future FBR cycle has the potential which can contribute to the further reducing the number/volume of the HLW. It is also confirmed that development efforts on countermeasure for accumulation of noble metals, which JAEA has been carrying out aiming to accomplishing more stable and reliable operation of the vitrification process and extending the melter's life, will be able to contribute in the future fuel cycle system furthermore.
Aoshima, Atsushi; Tanaka, Kazuhiko
Proceedings of International Waste Management Symposium 2005 (WM '05) (CD-ROM), 10 Pages, 2005/03
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Aoshima, Atsushi; Tanaka, Kazuhiko ; Kozaka, Tetsuo
Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 6 Pages, 2004/00
no abstracts in English
Morita, Yasuji; Tachimori, Shoichi; Koma, Yoshikazu*; Aoshima, Atsushi*
JAERI-Research 2002-017, 20 Pages, 2002/08
JAERI-Research-2002-017.pdf:1.32MB
The present report describes the results of a joint study between Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Energy Research Institute (JAERI) on actinide separation process from high-level liquid waste. The purpose of the joint study is to point out common subjects in process development by an overall evaluation of each actinide separation process: TRUEX/SETFICS Process studied in JNC and DIDPA Extraction Process studied in JAERI. The result of the evaluation showed that both processes have common subjects to be studied in sub-processes such as treatment step for spent solvent or DTPA waste solution and solvent washing step for recycling, although the main process is different from each other. It is necessary to develop the sub-processes and to test the whole process including the sub-processes. Two essential requirements: the cost reduction and the minimization of secondary wastes, are very important in future research and development for more rational and effective actinide separation process.
Kato, Junya; Miyauchi, Atsushi; Aoshima, Atsushi; Shiotsuki, Masao; Yamashita, Teruo; Nakajima, Masayoshi; Morikawa, Yo; Miura, Akihiko; Fukui, Toshiki*; Yamasaki, Akito*; et al.
no journal, ,
no abstracts in English
Aoshima, Atsushi; Tanaka, Kazuhiko
no journal, ,
no abstracts in English
Shimbara, Shigehiro; Fujiwara, Koji; Kozaka, Tetsuo; Ueno, Tsutomu; Aoshima, Atsushi
no journal, ,
no abstracts in English
Ishida, Michihiko; Suto, Toshiyuki; Inano, Masatoshi; Aoshima, Atsushi
no journal, ,
In the Tokai Reprocessing Plant (TRP), process safety has been evaluated since the fire and explosion incident of the bituminization facility in 1997. In this report, both deterministic and probabilistic safety assessment approaches of the TRP are summarized.
Ishida, Michihiko; Suto, Toshiyuki; Inano, Masatoshi; Aoshima, Atsushi; Muramatsu, Ken; Ueda, Yoshinori*
no journal, ,
A study to evaluate component failure rates for a reprocessing plant has started at the Japan Atomic Energy Agency (JAEA). The study is sponsored by the Japan Nuclear Energy Safety Organization (JNES) as a contract research. The Tokai Reprocessing plant(TRP) has been operating over 30 years since 1977. Maintenance records of plant components have been accumulated and compiled in the Tokai Reprocessing Plant Maintenance Support System (TORMASS). Since the TORMASS was thought to be an effective source to pick up component failure information, the evaluation work of component failure rates started at 2005 based on the maintenance records in the TORMASS. By the end of 2006, failure rates for 17 types of 392 components had been evaluated. This result is expected to contribute to building up generic database for reprocessing plant component failure rates in order to promote the utilization of the risk information for reprocessing plants in Japan.
Aoshima, Atsushi; Shiotsuki, Masao; Yamashita, Teruo
no journal, ,
TVF is unique operating vitrification facility in Japan constructed to vitrify HALW from TRP. In TVF, the total number of produced canisters is 247 and about 80% of HALW generated so far still remains in TRP. In TVF, a ceramic type melter was adopted of which design life time is set five years by structural material corrosion. Present melter is the second generation and future exchange of the second melter is inevitable. For the third melter, JAEA has been developing an advanced melter concept with prolonged design life time of twenty years and better noble metal drainability. This concept features two new technologies; skull layer and reverse viscosity operation mode. The former intends to decrease corrosion rate of refractory by forming low temperature glass zone on the surface. The latter intends to decrease viscosity of glass along wall lower than that of inside to remove accumulated noble metalby glass flow along wall. For both technologies, temperature control is a key point.
Ishida, Michihiko; Inano, Masatoshi; Aoshima, Atsushi; Suto, Toshiyuki; Muramatsu, Ken; Ueda, Yoshinori*
no journal, ,
Component failure rates are one of the most important inputs for PSA. Although there are many component failure rates databases for NPPs, there are few for a reprocessing plant. Therefore, in order to perform reliable PSA of a reprocessing plant, it is important to establish the failure rate database based on the actual plant maintenance data. The Tokai Reprocessing Plant (TRP) has been operating over 30 years since 1977. Maintenance records of plant components have been accumulated and compiled in the Tokai Reprocessing Plant Maintenance Support System (TORMASS). A basic study has started in the JAEA from 2005 by using the TORMASS data to contribute the development of reliable component failure rates. The outlines of the component failure estimation are summarized.
Nakano, Takafumi; Inano, Masatoshi; Aoshima, Atsushi
no journal, ,
no abstracts in English
