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Seki, Masakazu; Maekawa, Tomoyuki; Izawa, Kazuhiko; Sono, Hiroki
JAEA-Technology 2017-038, 52 Pages, 2018/03
JAEA-Technology-2017-038.pdf:4.6MB
The Japan Atomic Energy Agency is conducting a reactor modification project of the Static Experiment Critical Facility (STACY). In the modification, STACY is to be converted from a thermal reactor using solution fuel into that using fuel rods and light water moderator. Reactivity of the modified STACY core is controlled by the water level fed in the core tank as well as the present STACY. In order to verify the basic design of the water feed and drain system of the modified STACY, we constructed a mockup test apparatus with almost the same structure and specifications as the modified STACY. In the mockup test, performance checks were pursued regarding limitation of maximum flow of water feeding, adjustment of the flow rate of water feeding, stop of water feeding and others. This report describes the outline and results of the mock-up test of the water feed and drain system of the modified STACY.
Maekawa, Kazuhiko*; Yoshimura, Tadahiro*; Kikuchi, Toshiaki*; Hoshino, Yasushi*; Munekata, Hideki*; Shimizu, Makoto*
JNC TJ9420 2005-004, 284 Pages, 2005/02
JNC-TJ9420-2005-004.pdf:11.56MB
In feasibility studies on commercialized FBR cycle system, comprehensive system investigation and properties evaluation for candidate FBR cycle systems have been implemented through view point of safety, economics, environmental burden reduction, non-proliferation resistivity, etc. As part of these studies, an investigation of small scale sphere-pac fuel fabrication plant with external gelation process was conducted. Until last fiscal year, equipment layout in cells and overall layout design of the 200t-HM/y scale fuel fabrication plant were conducted as well as schematical design studies on main equipments in gelation and reagent recovery processes of the plant. System property data concerning economics and environmental burden reduction of fuel fabrication plant was also acquired. In this fiscal year, the processes from vibropacking to fuel assemblies storage were added to the investigation range, and a conceptual design of whole fuel fabrication plant was studied as well as deepening the design study on main equipments. The conceptual design study was mainly conducted for small 50t-HM/y scale plant and a revising investigation was done for 200t-HM/y scale Plant. Taking the planed comparative evaluation with pellet fuel fabrication system into account, design of equipments which should be equivalent with pellet system, especially in post-vibropacking processes, were standardized in each system. Based on these design studies, system properties data concerning economics and environmental burden reduction of the plant was also acquired. In comparison with existing design, the cell height was lowered on condition that plug type pneumatic system was adopted and fuel fabrication building was downsized by applying rationalized layout design of pellet system to post-vibropacking processes. Reduction of reagent usage at gelation process and rationalization of sintering and O/M controlling processes etc., are foremost tasks.
Maekawa, Kazuhiko*; Yoshimura, Tadahiro*; Hoshino, Yasushi*; Munekata, Hideki*; Tamaki, Yoshihisa*
JNC TJ9420 2005-003, 280 Pages, 2005/02
JNC-TJ9420-2005-003.pdf:4.73MB
In feasibility studies on commercialized FBR cycle system, a comprehensive system investigation and properties evaluation for candidate FBR cycle systems has been implemented through view point of safety, economics, environmental burden reduction, non-proliferation resistively, etc. As part of these studies, an investigation into rationalization of low decontamination pellet fuel fabrication plant configuration, and a study on characteristics evaluation techniques which focused on plant operating rate and waste generation was conducted. Until last fiscal year, a characteristics evaluation simulator which calculates plant operating rate and waste generation by input failure frequency data and periodic replacement data of every equipment or component was developed, and characteristics comparison between multiple fuel fabrication systems was done by applying it. Character of each fuel fabrication system, concerning system stability represented by waste generation, was shown and challenges in characteristics evaluation were made clear. In this fiscal year, programs of the simulator were modified to reflect plant designs correctly by describing campaign operation and batch treatment in the plant in order to make more quantitative calculation possible. On the other hand, in response to the challenges in the characteristics evaluation of last fiscal year, the system properties data based on a certain standard were acquired in conceptual design study and database were created with view of inter-system comparison. As the results of comparison between pellet system and sphere-pac system using simulator, it was suggested that system stability of pellet system is higher than sphere-pac system, and pellet system is also better in environmental burden reduction, because waste generation of sphere-pac system is apparently larger than pellet system.
Maekawa, Kazuhiko*; Yoshimura, Tadahiro*; Hoshino, Yasushi*; Munekata, Hideki*; Tamaki, Yoshihisa*
JNC TJ9420 2005-002, 221 Pages, 2005/02
JNC-TJ9420-2005-002.pdf:7.16MB
In feasibility studies on commercialized FBR cyde system, a comprehensive system investigation and properties evaluation for candidate FBR cycle systems has been implemented through view point of safety, economics, environmental burden reduction, non-proliferation resistivity, etc. As part of these studies, an investigation into rationalization of low decontamination pellet fuel fabrication plant configuration was carried out Until last fiscal year, conceptual design studies of the fuel fabrication plant in 200t-HM/y scale were conducted, and system properties data concerning economics and environmental burden reduction of fuel fabrication plant was acquired. In addition to this, 50t-HM/y scale plant was also schematically studied. In this fiscal year, a rationalization study on conceptual design of 50t-HM/y scale plant was conducted with main aim of economic improvement, and the 200t-HM/y scale plant design was revised based on the recent R&D progress. The system properties data concerning economics and environmental burden reduction of fuel fabrication plant was also acquired. In both case of the 50t-HM/y and 200t-HM/y scale plant, it was suggested that the equipment costs were reduced in several percentages because of reduction of maintenance equipments and cut in line number at the pellet fabrication process although granulation process for denitration converted powder and O/M control process for pellets were added. System properties data for comparative evaluation of candidate fuel fabrication systems was also prepared.
Katanishi, Shoji; Kunitomi, Kazuhiko; Tsuji, Nobumasa*; Maekawa, Isamu*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.257 - 267, 2004/09
no abstracts in English
Maekawa, Kazuhiko*
JNC TJ8400 2003-034, 284 Pages, 2003/02
JNC-TJ8400-2003-034.pdf:15.43MB
The main points of this research were ; (1)It was examined that the relationship between the groundwater chemistry and the topography/geography/geology of the sampling point. (2)It was shown that the groundwater chemistry in the depth which corresponded to the shallow land disposal and intermediate depth disposal was possible to be classified into some groups by Principal Component Analysis and Cluster Analysis. (3)It was shown that the appropriate models for shallow groundwater chemistry was possible to be suggested. (4)The influence processes from water chemistry to the parameter used for a performance assessment calculation were identified by the analysis of existing FEPs. (5)In the TRU waste disposal system, the influence processes judged that importance was low obviously was selected.
Maekawa, Kazuhiko*
JNC TJ8400 2002-055, 165 Pages, 2002/03
JNC-TJ8400-2002-055.pdf:31.47MB
The main points of this research were ; (1)The points of the groundwater chemistry were reported according to the properties of TRU waste. They were pH, Eh, Cl
, CO
/HCO
, SO
, Mg
. (2)The model of groundwater chemistry for geological disposal of TRU waste may be set by the model for HLW. (3)The programs to construct the model at the depth of shallow land disposal and intermediate depth disposal were cleared. The measures for constructing the model were presented. The measures were to assemble the chemical data according to the topography and geology and to investigate the groundwater chemistry in the field. (4)FEPs related to the chemical evolution of ground water in a shallow land burial, a disposal about 100m depth and a geological disposal for TRU wastes were described. (5)Degradation of the cementitious materials with time were highlighted as the important interaction in the FEPs to predicting the chemical evolution around the repository (6)The means of solving the issues related to the chemical evolution of ground water were presented. The method of doing were to set the key interaction in the FEPs in order by bottom-up aproch.
Kasuga, Shoji*; Kubota, Kenichi*; Okamoto, Futoshi*; Maekawa, Isamu*; Furihata, Noboru*; Saito, Masanao*; Kido, Yuji*; Ohashi, Hirofumi; Tachibana, Yukio; Kunitomi, Kazuhiko
no journal, ,
Conceptual design of a small-sized HTGR for electricity generation and district heating has been conducted by JAEA with support of Japanese vendors: Toshiba Corporation, Fuji Electric, Kawasaki Heavy Industries, Nuclear Fuel Industries, Shimizu Corporation, and Marubeni Utility Services. System design as well as nuclear design of the first core of HTR50S using the same CFPs as the HTTR has been performed and the nuclear design shows upgraded performance of the reactor compared with the HTTR.
Izawa, Kazuhiko; Maekawa, Tomoyuki; Aoyama, Yasuo; Sono, Hiroki; Ogawa, Kazuhiko; Yanagisawa, Hiroshi; Miyoshi, Yoshinori
no journal, ,
no abstracts in English
Maekawa, Tomoyuki; Seki, Masakazu; Sumiya, Masato; Araki, Shohei; Murakami, Takahiko; Hasegawa, Kenta; Yoshikawa, Tomoki; Mori, Takashi*; Ishii, Junichi; Kobayashi, Fuyumi; et al.
no journal, ,
As previously reported, to clarify critical characteristics of fuel debris, the Static Experiment Critical Facility (STACY) is being converted to the heterogenous thermal system using fuel rods and light water moderator from the homogenous system using solution fuel. Seismic reinforcement of the support structure of the core tank started in 2022. This report presents progress on manufacture and construction of the modified STACY in 2021 and 2022.
