FaCT Phase-I evaluation on the advanced aqueous reprocessing process, 4; Solvent extraction simplified for FBR fuel reprocessing

Koma, Yoshikazu; Ogino, Hideki; Sakamoto, Atsushi; Nakabayashi, Hiroki; Shibata, Atsuhiro; Nakahara, Masaumi; Washiya, Tadahiro

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12

Fast Reactor Cycle Technology Development Project (FaCT Project); A Design study on an engineering-scale hot test facility (Interim report)

Nakamura, Hirofumi; Nagai, Toshihisa; Suto, Toshiyuki; Kosaka, Ichiro; Nakazaki, Katsutoshi; Suto, Shinya; Nakamura, Tomotaka; Nakabayashi, Hiroki; Hayashi, Naoto; Sumida, Daisaku

JAEA-Technology 2008-077, 276 Pages, 2008/12

JAEA-Technology-2008-077.pdf:25.66MB

Japan Atomic Energy Agency (JAEA) has been conducting "Fast Reactor Cycle Technology Development Project (FaCT Project)" for the purposes of researching and developing the technologies for the fast breeder reactor cycle commercialization since Japanese fiscal year (JFY) 2007. Based on the above R&D program for reprocessing system, the engineering-scale hot test would provide demonstration data on the specification, operation and maintenance of the adapted innovative technologies, system and plant. And more, these results would be fed to the design of the demonstration facility planning on the FaCT project road map. This report is the interim report of design studies about the engineering-scale hot test facility and includes not only design of the equipment and facility, but also consideration for design principle, requirements and facility basic planning.

Heat evaluation examination of fuel assembly

Suto, Shinya; Nakabayashi, Hiroki; Yao, Kaoru*

JAEA-Technology 2007-029, 73 Pages, 2007/03

JAEA-Technology-2007-029.pdf:11.39MB

The cooling examination was executed by using the simulated fuel assembly to obtain the basic data of the most effective cooling system in the laser disassembling process of the spent fuel assembly of prototype fast breeder reactor "Monju". As a result, the following have been understood. (1) Before the laser disassembling (there is not any duct tube cutting), it is possible to cool enough by the amount of the wind of 20m/h or more flowing from the handling head side. (2) After the laser disassembling begins (duct tube is cut), 1kW or more of the heat generation cannot be cooled by ventilation from the handling head side. (3) Cooling by the flow across fuel pin is required during laser disassembling. The basic data of the cooling system was obtained from these examination results. However, for cooling across fuel pin during the laser disassembling, it is necessary to examine shape of the side cooling nozzle, spraying angle, and flow velocity at the nozzle exit, etc. enough.

A Study of the criticality safety design for the metal fuel recycle system, 2

Nakabayashi, Hiroki; Kurisaka, Kenichi; Sato, Koji; Niwa, Hajime; Aoki, Kazuo*

JAEA-Technology 2006-027, 119 Pages, 2006/03

JAEA-Technology-2006-027.pdf:9.02MB

This report describes a study about the criticality safety design for the large-scale electrorefiner, which is designed in the activities of "The Design Study of Metal Fuel Recycle System (2002)", under the collaboration with Central Research Institute of Electric Power Industry, and the continuation of "A Study of the Criticality Safety Design for the Metal Fuel Recycle System", which was published at September 2003. The report includes a detail design and quantitative criticality parameter limits based on "the mass control supported with chemical form control" concept which is proposed in "A Study of the Criticality Safety Design for the Metal Fuel Recycle System". Furthermore procedures to determine these limits are presented in the report. Next we studied contingencies anticipated under the critical control and executed quantitative criticality safety analyses of models based on these abnormal conditions. The analytical result shows adequate safety margins are existed in the criticality safety design even if many of these contingencies could occur. Moreover we propose a concept of material transfer and production control system, we call it as "Operation by wire", which all equipment and handling machines are electrified and the control system provides completely automated process control and operation. The control system eliminates human errors and violations like over batching error or transfer error in the commercial scale metal fuel recycle system with complicated operation procedures.

A Study of the Criticality Safety Design for the Metal Fuel Recycle System

Nakabayashi, Hiroki; Fujioka, Tsunaaki; Sato, Koji; Aoki, Kazuo*

JNC TN9400 2003-082, 67 Pages, 2003/09

JNC-TN9400-2003-082.pdf:3.02MB

This report accounts for a study about the criticality safety design for the large-scale electrorefiner, which is designed in the activities of "The Design Study of Metal Fuel Recycle System(2002)", under the collaboration with Central Research Institute od Electric Power Industry.

A conceptual study of the criticality safety design for pyrochemical reprocessing systems

Nakabayashi, Hiroki;

JNC TN9400 2001-072, 107 Pages, 2001/06

JNC-TN9400-2001-072.pdf:3.33MB

Pyrochemical reprocessing systems, which are based on the different physical principles from the existing aqueous reprocessing systems, are expected to be the more economical, more reductible of environmental impact and higher proliferation-resistant. Though many researches and experiments for the development of those systems have been done in many countries there are few studies on the criticality safety design. In this study, the criticality safety design are performed for three pyrochemical reprocessing systems, the metal electrorefining process which has been developed by the Argonne National Labolatory (ANL) in the U.S, the oxide electrowinning process which has been developed by the Research Institute of Atomic Reactors (RIAR) in Russia and the fluoride volatility process which has been developed by the ANL in the U.S, the Japan Atomic Energy Reserch Institute (JAERI) in Japan, etc. As a result of this study, the ordinal criticality safety management methods can directly be applied both to the electrowinning process and to the fluoride volatility process. However, for the electrorefiner vessel used in the metal-electrorefining process, the ordinal methods, in which the only one chemical state is supposed for the all fissile nuclide in the individual unit, cannot be applied directly because the different chemical states co-exist in the electrorefiner by the operation. It is proposed the different idea for this case in the study. And these results are useful to design any pyrochemical reprocessing plants. Because subcritical limits are determined by criticality data of simple models in this study, these limits should be reevaluated based on the detailed hardware design. Futhermore, the criticality safety evaluation with the contingency analysis must be performed to certify that the design has an adequate safety clearance to the anticipated anomaly events.

Study on Np behaviors in U-Pu-Np co-extraction process using PARC code

Asakura, Toshihide; Tsubata, Yasuhiro; Morita, Yasuji; Nakabayashi, Hiroki; Nagai, Toshihisa

no journal, , 

To contribute to optimize the simple solvent extraction process of NEXT process, PARC-L code simulation calculations of U-Pu-Np co-extraction process were performed, and the extraction/separation behaviors of Np were examined from the viewpoint of oxidation/reduction reaction rate of Np (V)-Np (VI) in relating to the nitrous acid concentration. The time-dependent change of Np valence state distribution in the feed solution was calculated. Assuming the composition of the feed solution as that obtained from the valence calculation, extraction calculations were performed.

Application of probability risk assessment in TRP and its capability to maintenance planning

Takase, Yuki; Miura, Yasushi; Nakabayashi, Hiroki

no journal, , 

Tokai Reprocessing plant (TRP), which temporarily suspended the reprocessing of spent fuel in 2007, moved to decommissioning in 2018 without restarting operations. Under the decommissioning situation, the high-level radioactive liquid waste generated in the past reprocessing operation is the highest potential risk in TRP. These high-level radioactive liquid wastes are stored in High Active Liquid Waste Storage Facility (HAW) and sequentially Vitrified in Tokai Vitrification Facility (TVF). The serious accident risk about evaporation accident of high radioactive liquid waste has been remained in both facilities. In this study, a loss of heat sink (LOHS) frequency of high radioactive liquid waste in HAW and TVF was assessed by Probability Risk Assessment (PRA). The risk information was extracted for the equipment of important of safety related system from the view point of maintaining the facility safety. Its capability to maintenance planning was evaluated.