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Journal Articles

Secondary sodium fire measures in JSFR

Chikazawa, Yoshitaka; Kato, Atsushi*; Yamamoto, Tomohiko; Kubo, Shigenobu; Ohno, Shuji; Iwasaki, Mikinori*; Hara, Hiroyuki*; Shimakawa, Yoshio*; Sakaba, Hiroshi*

Nuclear Technology, 196(1), p.61 - 73, 2016/10

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

JSFR adopts double boundary for all sodium components. However, design measures are investigated for the secondary sodium fire inside the reactor building, which might be assumed as design extension conditions (DECs). Candidates of sodium fire measures in the secondary sodium systems such as sodium drain, nitrogen injection, pressure release valve, catch pan and leak sodium drain system have been compared from the view point of safety. Wide range of sodium fires in the steam generator room and air cooler have been analyzed evaluating performances of the candidate sodium fire measures.

Journal Articles

Numerical study on influence of Ohnesorge number and Reynolds number on the jet breakup behavior using the lattice Boltzmann method

Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kanagawa, Tetsuya*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05

For the safety design in which heat is properly removed from the molten fuel after the core disruptive accident in a sodium-cooled fast reactor, the estimation of the breakup behavior of molten fuel discharged into the coolant like a jet is desired. In order to investigate the influence of viscocity on the jet behavior, we simulated a jet discharged into a coolant using the three-dimensional lattice Boltzmann model for two-phase fluid, and examined the influence of Ohnesorge number and Reynolds number on the jet behavior. As a result, we made clear that it is necessary to consider viscosity of the coolant as well as that of the jet for the estimation of jet behavior.

Journal Articles

Performance evaluation on secondary sodium fire measures in JSFR

Chikazawa, Yoshitaka; Kato, Atsushi; Yamamoto, Tomohiko; Kubo, Shigenobu; Iwasaki, Mikinori*; Hara, Hiroyuki*; Shimakawa, Yoshio*; Sakaba, Hiroshi*

Proceedings of 2014 International Congress on the Advances in Nuclear Power Plants (ICAPP 2014) (CD-ROM), p.523 - 530, 2014/04

JSFR adopts double boundary for all sodium components. However, design measures are investigated for the secondary sodium fire inside the reactor building, which might be assumed as design extension conditions (DECs). Candidates of sodium fire measures in the secondary sodium systems such as sodium drain, nitrogen injection, pressure release valve, catch pan and leak sodium drain system have been compared from the view point of safety. Wide range of sodium fires in the steam generator room have been analyzed evaluating performances of the candidate sodium fire measures.

Journal Articles

Evaluation of jet breakup behavior by the lattice Boltzmann HCZ model, 1; Evaluation of jet breakup length

Matsuo, Eiji*; Abe, Yutaka*; Iwasawa, Yuzuru*; Ebihara, Kenichi; Kaneko, Akiko*; Sakaba, Hiroshi*; Koyama, Kazuya*

Dai-18-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.75 - 76, 2013/06

When supposing a core distractive accident (CDA) in a sodium-cooled fast reactor (SFR), it is necessary to understand the breakup behavior of the molten core material jet into coolant. Thus, the jet breakup was simulated by the lattice Boltzmann (LB) HCZ model. First, the applicability to jet breakup of the LBHCZ model was verified by comparing the simulation result to our experimental data. Next, from sensitive analyses by the simulation, it was found that the jet breakup length is in good agreement with Epstein's correlation when hydrodynamic fragmentation is a dominant phenomenon of the jet breakup.

Journal Articles

Evaluation of jet breakup behavior by the lattice Boltzmann HCZ model, 2; Effect of ambient fluid field on jet breakup

Iwasawa, Yuzuru*; Abe, Yutaka*; Matsuo, Eiji*; Ebihara, Kenichi; Kaneko, Akiko*; Sakaba, Hiroshi*; Koyama, Kazuya*

Dai-18-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.77 - 78, 2013/06

When supposing a core distractive accident (CDA) in a sodium-cooled fast reactor (SFR), it is necessary to understand the breakup behavior of the molten core material jet into coolant. In order to examine the effect of ambient fluid around the jet, the surface and fragmentation behavior was investigated using the lattice Boltzmann (LB) HCZ model. As a result, it was confirmed that the mechanism of the jet breakup behavior is one proposed by Epstein when hydrodynamic fragmentation is the dominant phenomenon for the jet break up.

Journal Articles

Influence of fragmentation on jet breakup behaviour

Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kuroda, Taihei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Ito, Kazuhiro*; Nariai, Hideki*

Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 12 Pages, 2013/05

In the safety design of a Fast Breeder Reactor(FBR), when it is supposed that a Core Disruptive Accident(CDA) occurs, it is strongly required that molten core materials are completely solidified and are cooled down by sodium coolant in a reactor vessel. In this study, we injected molten alloy and transparent fluid, which are a simulant of the molten core material, into water, which is a simulant of the coolant. In this study, we injected molten alloy and transparent fluid, which simulate the molten core material, into water, which simulates the coolant. In the experiment, we observed the jet breakup behavior of them using a high speed video camera, and compared the observe images with the previous theories. In addition, we simulated numerically the qualitative behavior of the liquid jet using a two-phase fluid model of the lattice Boltzmann method.

Journal Articles

Evaluation of sodium combustion in the JSFR SCCV

Kato, Atsushi; Chikazawa, Yoshitaka; Yamamoto, Tomohiko; Ohno, Shuji; Kubo, Shigenobu; Sakaba, Hiroshi*; Akiyama, Yo*; Iwasaki, Mikinori*

Proceedings of 2013 International Congress on Advances in Nuclear Power Plants (ICAPP 2013) (USB Flash Drive), 9 Pages, 2013/04

After the accident of TEPCO's Fukushima Dai-ichi Nuclear Power Plant, evaluations of severe events beyond the design basis on a NPP are focused. As one of those activities, wide range of sodium combustion and hydrogen generation potentials have been analyzed to investigate potential consequences on SCCV. Structural and boundary integrity of SCCV have been evaluated from sodium combustion analyses for pressure and temperature loads. Hydrogen generation has also been evaluated as potential loads of SCCV.

JAEA Reports

MK-III Modification work of heat transport system in JOYO; Dismantling and sodium cleaning of secondary cooling system components

Ishii, Takayuki; Isozaki, Kazunori; Ashida, Takashi; Minakawa, Satoru; Terakado, Tsuguo; Nogami, Hiroshi*; Kakurai, Katsuhiko*; Ueda, Soji*; Kawahara, Hirotaka; Ichige, Satoshi; et al.

JNC TN9410 2002-013, 86 Pages, 2002/11

JNC-TN9410-2002-013.pdf:68.29MB

The MK-III project has been proceeding to improve the irradiation capability of the experimental fast reactor JOY0. The MK-III project has three major purposes such as increase high neutron flux, improvement of plant availability factor and upgrading in irradiation techniques. Thermal output by core transformation for high neutron flux was increased from 100MWt to 140MWt. The main components in the cooling system such as IHX(Intermediate Heat Exchanger) and DHX(Dump Heat Exchanger) were replaced in MK-III modification in order to increase heat removal capability. Heat transfer capacity of IHX was increased from 50MWt/Unit to 70MWt/Unit and that of DHX was increased from 25MWt/Unit to 35MWt/Unit. These components replacement has been safety completed from october 30, 2000 through September 21, 2001. This report summarizes the way, results and safety measures about dismantling of no sodium adhered components and such as DHX blower and sodium cleaning of sodium components such as the DHX, the pipes connected with DHX and secondary side of IHX. Dismantling and sodium cleaning of secondary cooling system components were performed safely and efficiently as almost planned. The total amount of removed sodium was about 13.5kg.

Oral presentation

Counter-flow diffusion reaction of water and sodium evaporated from liquid pool

Yamaguchi, Akira*; Takata, Takashi*; Ohshima, Hiroyuki; Deguchi, Yoshihiro*; Sakaba, Hiroshi*

no journal, , 

no abstracts in English

Oral presentation

Report of subcommittee of thermal hydraulics evaluation in reactor core and component

Kataoka, Isao*; Narabayashi, Tadashi*; Sakaba, Hiroshi*; Yoshida, Hiroyuki; Nishida, Koji*; Hotta, Akitoshi*

no journal, , 

no abstracts in English

Oral presentation

Evaluation of SCCV integrity under hypothetical sodium combustion, 1; Sodium combustion evaluation

Yamamoto, Tomohiko; Kato, Atsushi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Sakaba, Hiroshi*; Sakashita, Takeshi*

no journal, , 

JSFR is planning to adopt a steel plate reinforced concrete (SC) structure for containment vessel (CV). This paper describes the analyses of hypothetical sodium combustion and load condition in the CV.

Oral presentation

Design approach for LOHRS type event based on the safety design criteria for Generation-IV SFR, 3; Adequacy evaluation of candidates

Kubo, Shigenobu; Chikazawa, Yoshitaka; Shimakawa, Yoshio*; Endo, Junji*; Sakaba, Hiroshi*

no journal, , 

Design study of a decay heat removal system to comply with the safety design criteria for the Generation-IV SFR has been carried out. This paper reports adequacy evaluation of candidates for design requirements.

Oral presentation

Reliability evaluation on passive shutdown system for JSFR

Yamada, Yumi*; Tokizaki, Minako*; Shimakawa, Yoshio*; Yamano, Hidemasa; Kubo, Shigenobu; Sakaba, Hiroshi*

no journal, , 

JSFR demonstration reactor employes SASS: Self Actuated Shutdown System as passive reactor shutdown system, probability of the loss of function is demanded through reliability evaluation to demoonstrate level 1PSA for this plant. Unreliability of SASS in representative abnormal transient without scram (ATWS) event was evaluated using developed method for reliability evaluation.

Oral presentation

Collaboration with Republic of Kazakhstan regarding development of HTGR, 3; Collaboration of development of oxidation-resistant graphite material for HTGR

Shibata, Taiju; Sumita, Junya; Nagata, Hiroshi; Saito, Takashi; Tsuchiya, Kunihiko; Sakaba, Nariaki; Osaki, Hiroki*; Kato, Hideki*; Fujitsuka, Kunihiro*; Muto, Takenori*; et al.

no journal, , 

no abstracts in English

Oral presentation

Analysis on measures of secondary sodium leak for JSFR

Chikazawa, Yoshitaka; Kato, Atsushi; Yamamoto, Tomohiko; Iwasaki, Mikinori*; Hara, Hiroyuki*; Shimakawa, Yoshio*; Sakaba, Hiroshi*

no journal, , 

JSFR has double wall sodium boundary to mitigate influence of sodium leak. In this studyk, efficiency of measures are evaluated assuming double boundary failure in severe condition.

Oral presentation

Study on quench behavior at core disruptive accident for fast breeder reactor, 23; Simulation of breakup behavior of liquid jet by lattice Boltzmann method

Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*

no journal, , 

Since there is a possibility that molten core is spouted out into coolant in the case of the core disruptive accident of a fast breeder reactor, it is important to predict the jet breakup length, which is the distance that the jet reaches, for proper cooling. The previous report discusses the adaptability of the simulation by the lattice Boltzmann model to the experiment of liquid jet by comparing to the experiment with air entrainment which is not considered in the model. In this presentation, we discussed the mechanism of jet breakup by comparing the simulation to the experiment without air entrainment. As a result, the model reproduced the jet behavior without air entrainment well, and the dimensionless number regarding the jet breakup length was almost same with that of the experiment. In addition, according to the flow velocity distribution obtained from the simulation, it was confirmed that vortexes at the leading-edge of the jet promote the jet breakup.

Oral presentation

Study on quench behavior at core disruptive accident for fast breeder reactor, 27; Numerical study on effect of viscosity on jet breakup behavior in liquid-liquid system using the lattice Boltzmann method

Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kanagawa, Tetsuya*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*

no journal, , 

no abstracts in English

Oral presentation

Application of dynamic PRA to the design optimization of sodium-cooled fast reactors

Kato, Atsushi; Ide, Akihiro*; Shibata, Akihiro*; Ishizaki, Miku*; Tanaka, Futoshi*; Sakaba, Hiroshi*; Nishizaki, Chihiro*; Sawairi, Tsuyoshi*

no journal, , 

Sodium fast reactor needs long time decay heat removal compared with Light water reactor. This reports trial evaluation of dynamic PRA application on Sodium cooled fast reactor in terms of decay heat. Thanks to this application, dominant risk factor could be cleared out.

18 (Records 1-18 displayed on this page)
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