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Kato, Atsushi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Miyagawa, Takayuki*; Uchita, Masato*; Suzuno, Tetsuji*; Endo, Junji*; Kubo, Koji*; Murakami, Hisatomo*; Uzawa, Masayuki*; et al.
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 11 Pages, 2022/04
The authors are carrying out conceptual design studies for a pool-type sodium-cooled fast reactor. There are main challenges such as measures against severe earthquake in Japan, thermal hydraulic in a reactor vessel (RV), a decay heat removal system design. When the JP-pool SFR of 650 MWe is installed in Japan, it shall be designed against the severe seismic conditions. Additionally, a newly three-dimensional seismic isolation system is under development.
Chikazawa, Yoshitaka; Kato, Atsushi; Nabeshima, Kunihiko; Otaka, Masahiko; Uzawa, Masayuki*; Ikari, Risako*; Iwasaki, Mikinori*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05
Design study and evaluation for SDC and safety SDG on the BOP of the demonstration JSFR including fuel handling system, power supply system, component cooling water system, building arrangement are reported. For the fuel handling system, enhancement of storage cooling system has been investigated adding diversified cooling systems. For the power supply, existing emergency power supply system has been reinforced and alternative emergency power supply system is added. For the component cooling system and air conditioning, requirements and relation between safety grade components are investigated. Additionally for the component cooling system, design impact when adding decay heat removal system by sea water has been investigated. For reactor building, over view of evaluation on the external events and design policy for distributed arrangement is reported. Those design study and evaluation provides background information of SDC and SDG.
Kato, Atsushi; Chikazawa, Yoshitaka; Uzawa, Masayuki*; Kaneko, Fumiaki*; Ide, Akihiro*
Nuclear Technology, 189(1), p.30 - 44, 2015/01
Times Cited Count：1 Percentile：9.74(Nuclear Science & Technology)Responding to the Fukushima Dai-ichi Nuclear Power Plant (1F-NPP) accident, robustness of the fuel handling system (FHS) in Japan sodium-cooled fast reactor (JSFR) against the earthquake and the tsunami is studied for 2010 design version. In the earthquake estimation, the margin of seismic resistance and the sloshing in Ex-vessel fuel storage tank (EVST) against the earthquake of the 1F-envelop condition was estimated. In terms of the tsunami evaluation, the scenario to lead fuel subassemblies into the stable cooling state and the potential of the cooling system are introduced in case of the loss of emergency power supply. As a result, it showed that JSFR FHS in the original design already had the potential to prevent the release of radioactive material. Additionally, some design improvements of the EVST cooling system was introduced.
Chikazawa, Yoshitaka; Kato, Atsushi; Obata, Hiroyuki*; Uzawa, Masayuki*; Koga, Kazuhiro*; Chishiro, Ryo*
Journal of Nuclear Science and Technology, 51(4), p.437 - 447, 2014/04
Times Cited Count：1 Percentile：8.88(Nuclear Science & Technology)A simplified fuel handling system design for the demonstration JSFR has been proposed. FaCT phase I results of key technology evaluations on a pantograph fuel handling machine, a fuel transfer pot with two core component positions, dry spent fuel cleaning and minor actinide-bearing fresh fuel shipping cask are being developed. Experimental and analytical efforts have shown that key technologies to develop simplified fuel handling system are matured enough to proceed large scale sodium experiments and conceptual design study for the demonstration JSFR.
Otaka, Masahiko; Kato, Atsushi; Chikazawa, Yoshitaka; Uzawa, Masayuki*; Ide, Akihiro*; Kaneko, Fumiaki*; Hara, Hiroyuki*
Proceedings of 2014 International Congress on the Advances in Nuclear Power Plants (ICAPP 2014) (CD-ROM), p.607 - 615, 2014/04
Responding to the TEPCO's Fukushima Dai-ichi Nuclear Power Station accident, the design study was carried out to enhance cooling function of fuel handling system for Japan sodium-cooled fast reactor (JSFR). Design measures to maintain an FHS cooling function even in case of Design Extension Conditions are studied; such as alternative cooling systems which are independent and diversified from design basis cooling systems. Based on effectiveness evaluations, it was confirmed that these measures have adequate availability against the postulated design extension conditions.
Kato, Atsushi; Chikazawa, Yoshitaka; Uzawa, Masayuki*
Proceedings of 2012 International Congress on Advances in Nuclear Power Plants (ICAPP '12) (CD-ROM), p.475 - 482, 2012/06
Responding to the Fukushima Dai-ichi Nuclear Power Plant (1F-NPP) accident, the earthquake and the tsunami proof of the fuel handling system (FHS) in Japan Sodium-cooled Fast Reactor (JSFR) is studied. In the earthquake proof estimation, the margin of seismic resistance against the earthquake of the 1F-envelop condition and the sloshing behavior in the EVST is estimated. In terms of the tsunami proof, the scenario to lead fuel subassemblies into the stable cooling state and the potential of the cooling system is introduced in case of loss of the emergency power supply. As a result, it is clear that JSFR FHS originally could already be prepared to have the potential to prevent the release of radioactive material.
Chikazawa, Yoshitaka; Uzawa, Masayuki*; Usui, Shinichi*; Tozawa, Katsuhiro*; Kotake, Shoji
Nuclear Technology, 177(3), p.293 - 302, 2012/03
Times Cited Count：3 Percentile：24.98(Nuclear Science & Technology)JSFR is a concept of a commercial sodium-cooled fast reactor which has been being studied in Fast Reactor Cycle Technology Development (FaCT) project since 2006. For the JSFR fuel handling, various fuel handling systems (FHSs) were investigated and an advanced FHS with an ex-vessel storage tank (EVST) has been selected. The other FHS concepts investigated are evolutional FHSs without an EVST. The result has indicated that the construction cost of the evolutional systems do not reduce the construction cost dramatically, which is mainly due to additional safety measures required higher decay heat handling in gas atmosphere and due to the necessity of separated fresh and failed fuel storage. From an economical point of view, a longer plant outage of the evolutional systems offsets its advantage of the lower construction cost. On the basis of the results of this comparative study, JSFR has selected the FHS with an EVST.
Nishiyama, Noboru; Kotake, Shoji*; Uzawa, Masayuki*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR 2009) (CD-ROM), 9 Pages, 2012/00
Japan Sodium-cooled Fast Reactor (JSFR) adopts a compact design to reduce construction cost as a commercialized reactor. A commercialized fast reactor is also expected to be excellent in operation and maintenance for high availability. From the study for JSFR, in-service inspection and repair program necessary for JSFR has been developed. Major component design has been improved considering ISI accommodation, and the required ISI devices have been specified according to the proposed ISI program. To increase maintainability of JSFR, such approaches are employed at the conceptual design stage.
Chikazawa, Yoshitaka; Kato, Atsushi; Obata, Hiroyuki*; Nishiyama, Noboru; Uzawa, Masayuki*; Tozawa, Katsuhiro*; Chishiro, Ryo*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 7 Pages, 2011/10
A preliminary design of the JSFR fuel handling system has been proposed. FaCT phase I results of key technology evaluations on preliminary safety assessment, a pantograph fuel handling machine, a sodium pot with two core component positions, dry spent fuel cleaning and minor actinide-bearing fresh fuel shipping cask are provided.
Chikazawa, Yoshitaka; Uzawa, Masayuki*; Usui, Shinichi*; Tozawa, Katsuhiro*; Kotake, Shoji
Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.10142_1 - 10142_9, 2010/06
Kato, Atsushi; Hirata, Shingo; Chikazawa, Yoshitaka; Uto, Nariaki; Obata, Hiroyuki*; Kotake, Shoji*; Uzawa, Masayuki*
Proceedings of 2010 International Congress on Advances in Nuclear Power Plants (ICAPP '10) (CD-ROM), p.692 - 699, 2010/06
In the JSFR design, a single rotating plug and an upper inner structure (UIS) with a vertically penetrating slit are proposed, so that the fuel handling machine (FHM) can access any subassembly by horizontal movement of the FHM arm in the slit space. As a result of a full-scale mockup test, excellent performance in normal operation has been shown. In this study, from the viewpoint of achieving reliability of the pantograph type FHM, behavior of the FHM mockup have been investigated under abnormal conditions.
O separation and dehydration characteristics of Y-type zeolite adsorbentIwai, Yasunori; Uzawa, Masayuki*; Yamanishi, Toshihiko
Fusion Science and Technology, 54(2), p.462 - 465, 2008/08
Times Cited Count：4 Percentile：29.49(Nuclear Science & Technology)Adsorber has been studied to apply in the first stage of water detritiation system processing more than 100 kg/h of high-level tritiated water generated in a future fusion plant. Zeolite is a suitable adsorbent since it is an inorganic matter having a large water capacity. Rapid dehydration characteristic as well as large HTO/HO separation factor is necessary for adsorber to minimize its size. Present experiments were focused on the effect of cation on HTO/HO separation and dehydration characteristics of Y-type zeolites. It was found that the isotope separation factors are around 1.1-1.2 under static conditions. As for dehydration, operating temperature fixs the movable water capacity of the zeolites and the capacity at room temperature is NaY 
CaY KY. HTO dehydration characteristics depend on the accumulated purge gas amount and the purge gas rate is less influential. It is found that pressure swing is an effective method for HTO dehydration.
Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; et al.
Nuclear Fusion, 47(12), p.1645 - 1651, 2007/12
Times Cited Count：4 Percentile：11.4(Physics, Fluids & Plasmas)The confinement and removal of tritium are the key subjects for safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell building, tritium is often released, as vapor and is in contact with the inner walls. Also those of an ITER tritium plant building will be exposed to tritium in an accident. However, the data are scarce, especially on the penetration of tritium into the concrete of the wall materials. The tritium released in the buildings is removed by the Atmosphere Detritiation Systems (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF
is used in ITER, and is expected to be released in an accident such as fire. Although the SF gas has the potential as a catalyst poison, the performance of ADS with the existence of SF has not been confirmed yet. Tritiated water is produced in the regeneration process of ADS, and is subsequently processed by the ITER Water Detritiation System (WDS). One of the key components of WDS is an electrolysis cell. The electrolysis cell is made of organic compounds, and there is no data on the durability of the cell exposed to tritium. To overcome these issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behavior in concrete; (2) effect of SF on performance of ADS; and (3) tritium durability of electrolysis cell of ITER-WDS.
Isobe, Kanetsugu; Uzawa, Masayuki*; Yamanishi, Toshihiko; Kurita, Koichi*
STI/PUB/1284 (CD-ROM), 7 Pages, 2007/04
The high-level tritium water is expected to be produced in the vacuum chamber and in a breeding blanket system. It is one of the key issues to recover tritium from the high-level tritium water from the viewpoint of tritium inventory control in the vacuum vessel as well as tritium recover as a fuel. A solid polymer electrolysis used in WDS (Water Detiritiation System) of ITER can not be applied for the high-level tritium water to avoid the radiation damage. A ceramic electrolysis would be only a method to recover tritium from the high-level tritium water. The water is decomposed by the reduction on the electrode in the electrolysis. Aiming to increase the efficiency of this process, we have developed effective electrode, such as platinum and yttria stabilized zirconia (Pt-YSZ) compound. In this study, we developed new two types of electrode containing cerium oxide (Ceria). One electrode has a double-layer structure used ceria as an inner layer and Pt-YSZ as an outer layer. The other electrode used the ceria as an additive element of Pt-YSZ electrode. Both electrodes show a higher performance than that of Pt-YSZ. Especially, the double layer electrode shows three times higher efficiency than that of Pt-YSZ electrode. In the comparison between Pt-YSZ electrode and the new electrodes, the characteristics of both the electrodes, such as impedance and a structure, were also studied.
Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
no abstracts in English
Yamanishi, Toshihiko; Hayashi, Takumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Uzawa, Masayuki*; Nishi, Masataka
Fusion Science and Technology, 48(1), p.63 - 66, 2005/07
Times Cited Count：6 Percentile：40.47(Nuclear Science & Technology)no abstracts in English
Fusaeda, Shigeki*; Uzawa, Masayuki*; *; Kasai, Masao*; Ishihara, Yoshinao*; *
PNC TJ1216 95-001, 47 Pages, 1995/02
None
Uto, Nariaki; Chikazawa, Yoshitaka; Kato, Atsushi; Uzawa, Masayuki*; Obata, Hiroyuki*
no journal, ,
The innovative fuel handling system concept of Japan Sodium-cooled Fast Reactor (JSFR) is aimed at contributing to reduction in construction cost and radioactive waste and improvement in plant availability. The concept is designed to meet predicted actual reactor conditions such as high output, large fuel inventory, increase in decay heat generated from spent fuel due to high burnup, increase in decay heat and activity of fresh fuel bearing miner actinide. This paper reports the result of applicability study of this concept to JSFR.
Chikazawa, Yoshitaka; Kato, Atsushi; Uzawa, Masayuki*; Tozawa, Katsuhiro*; Chishiro, Ryo*; Obata, Hiroyuki*; Nishiyama, Noboru
no journal, ,
no abstracts in English
Kato, Atsushi; Chikazawa, Yoshitaka; Uzawa, Masayuki*
no journal, ,
For spent fuels cooling, sodium-cooled fast reactor has the ex-vessel fuel storage tank (EVST) and the spent fuel storage pool which have the huge amount of nuclear materials. This mainly reports the cooling characteristics of these equipments in case of the station black out due to the earthquake and subsequent tsunami.
