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Journal Articles

Numerical evaluation of sodium-water reaction based on engineering approach with particle method

Kosaka, Wataru; Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Jang, S.*

Proceedings of 28th International Conference on Nuclear Engineering; Nuclear Energy the Future Zero Carbon Power (ICONE 28) (Internet), 6 Pages, 2021/08

For safety assessment or design of a steam generator (SG) of a sodium-cooled fast reactor, it is important to evaluate the effects of a multiphase flow involving sodium-water reaction. If pressurized water/water-vapor leaks from a tube, it forms a corrosive, high-temperature, and high-velocity jet, and may cause failure of the adjacent tubes. The occurrence of tube failure on many tubes will lead to failure of the boundary between the primary and secondary cooling loops. The numerical analysis code, LEAP-III, has been developed to evaluate water leak rate considering the effects of the above-mentioned phenomena with short computational time. In some cases, however, the current LEAP-III provides excessive conservativeness due to its temperature distribution evaluation model. In order to reduce this excess, we have developed a new Lagrange particle method with several engineering approaches. We also performed test analyses which simulate time development of the vapor jet with chemical reaction in a SG. The results of the developed method were compared with ones of the multi-dimensional multiphase thermal hydraulic analysis code, SERAPHIM which considers compressibility and chemical reaction. Through the test analyses, the basic capability of the developed method was confirmed.

Journal Articles

Advancement of elemental analytical model in LEAP-III code for tube failure propagation

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Li, J.*; Jang, S.*

Mechanical Engineering Journal (Internet), 7(3), p.19-00548_1 - 19-00548_11, 2020/06

Evaluation of occurrence possibility of tube failure propagation under sodium-water reaction accident is an important issue. In this study, a numerical analysis method to predict occurrence of failure propagation by overheating rupture was constructed to expand application range of an existing computer code. Applicability of the method was constructed through the numerical analysis of the experiment on water vapor discharging in liquid sodium. To improve the evaluation accuracy for the temperature distribution, a Lagrangian particle model for simulating reacting jet was also developed as an alternative method and its basic function was confirmed.

Journal Articles

Development of numerical analysis code LEAP-III for tube failure propagation

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Ohshima, Hiroyuki

Nihon Kikai Gakkai Rombunshu (Internet), 86(883), p.19-00353_1 - 19-00353_6, 2020/03

Evaluation of occurrence possibility of tube failure propagation under sodium-water reaction accident is an important issue. In this study, a numerical analysis method to predict occurrence of failure propagation by overheating rupture was constructed to expand application range of an existing computer code. Applicability of the method was constructed through the numerical analysis of the experiment on water vapor discharging in liquid sodium.

Journal Articles

Advancement of elemental analysis model in LEAP-III code for tube failure propagation

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Li, J.*; Jang, S.*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05

A numerical analysis model to predict occurrence of tube failure propagation by overheating rupture in steam generators of sodium-cooled fast reactors was developed. Applicability of the model was demonstrated through the numerical analysis of the experiment on water vapor discharging in liquid sodium. To improve an accuracy of a sodium-side temperature evaluation, a Lagrangian particle model for simulating the reacting jet was also developed. The numerical results by the program unit of this model showed that the discharged gaseous particles spread with a particle-particle and particle-tube interaction.

Journal Articles

Improvement of steam generator tube failure propagation analysis code LEAP for evaluation of overheating rupture

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Kurihara, Akikazu; Hamada, Hirotsugu; Ohshima, Hiroyuki

Journal of Nuclear Science and Technology, 56(2), p.201 - 209, 2019/02

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

Evaluation of occurrence possibility of tube failure propagation under sodium-water reaction accident is an important issue. In this study, a numerical analysis method to predict occurrence of failure propagation by overheating rupture was developed to expand application range of an existing computer code. Applicability of the method was demonstrated through the numerical analysis of the experiment on water vapor discharging in liquid sodium.

Journal Articles

Development of numerical analysis method for tube failure propagation under sodium-water reaction accident

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Ohshima, Hiroyuki

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 6 Pages, 2018/11

Evaluation of occurrence possibility of tube failure propagation under sodium-water reaction accident is an important issue. In this study, a numerical analysis method to predict occurrence of failure propagation by overheating rupture was constructed to expand application range of an existing computer code. Applicability of the method was constructed through the numerical analysis of the experiment on water vapor discharging in liquid sodium.

Journal Articles

Advancement of numerical analysis method for tube failure propagation

Uchibori, Akihiro; Takata, Takashi; Yanagisawa, Hideki*; Li, J.*; Jang, S.*

Proceedings of 2018 ANS Winter Meeting and Nuclear Technology Expo; Embedded Topical International Topical Meeting on Advances in Thermal Hydraulics (ATH 2018) (USB Flash Drive), p.1289 - 1294, 2018/11

Evaluation of occurrence possibility of tube failure propagation under sodium-water reaction accident is an important issue. In this study, a numerical analysis method to predict occurrence of failure propagation by overheating rupture was constructed to expand application range of an existing computer code. Applicability of the method was constructed through the numerical analysis of the experiment on water vapor discharging in liquid sodium. To improve the evaluation accuracy for the temperature distribution, a Lagrangian particle model for simulating reacting jet was also developed as an alternative method and its basic function was confirmed.

JAEA Reports

Development of LEAP-III code for evaluation of long-time event progress under tube failure accident in steam generators

Uchibori, Akihiro; Yanagisawa, Hideki*; Takata, Takashi; Kurihara, Akikazu; Hamada, Hirotsugu; Ohshima, Hiroyuki

JAEA-Research 2017-007, 61 Pages, 2017/07

JAEA-Research-2017-007.pdf:4.3MB

For safety assessment of a steam generator of sodium-cooled fast reactors, it is necessary to evaluate the possibility of occurring tube failure propagation and of water leak rate under sodium-water reaction accident. In the previous studies, a computer code called LEAP-II calculating a wastage-type failure propagation and the water leak rate during long-time event progress was developed. In this study, a numerical method to evaluate the possibility of occurring overheating rupture was introduced into the LEAP-II code to expand application range of this code. The completed code is called LEAP-III. The test analysis on a tube bundle configuration demonstrated that the overheating rupture model could provide conservative prediction.

Journal Articles

Heat transfer characteristics inside an adjacent tube thermally-affected by sodium-water reaction in steam generator of sodium-cooled commercial fast reactor

Kurihara, Akikazu; Umeda, Ryota; Yanagisawa, Hideki*; Ohshima, Hiroyuki

Dai-16-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.9 - 10, 2011/06

In the case of sodium-water reaction accident in a steam generator of sodium-cooled fast reactors (FRs), adjacent heat transfer tubes may be damaged due to high temperature environment of the reaction field. For the purpose of understanding the overheating tube rupture mechanism, an experimental study has been performed to clarify waterside heat transfer characteristics during up-flow in a vertical tube under the real plant part-load operation conditions in which safety margin is least. A test tube was heated rapidly and the time averaged heat flux was estimated using an inverse solution. It was conformed that the heat transfer on the wall changed from nucleate boiling to transient-film boiling all over the heating section and dried-out surface spread from downstream toward upstream. We improved the heat transfer correlations applied to RELAP5 code and made sure the adequacy of these correlations to evaluate tube overheating.

Journal Articles

Reduction of electron concentration in Lightly N-Doped n-Type 4H-SiC epilayers by 200 keV electron irradiation

Matsuura, Hideharu*; Yanagisawa, Hideki*; Nishino, Kozo*; Nojiri, Takunori*; Myojin, Yoshiko*; Matsuyama, Yukei*; Onoda, Shinobu; Oshima, Takeshi

Open Applied Physics Journal (Internet), 4, p.37 - 40, 2011/05

Journal Articles

Reduction in majority-carrier concentration in N-doped or Al-doped 4H-SiC epilayer by electron irradiation

Matsuura, Hideharu*; Yanagisawa, Hideki*; Nishino, Kozo*; Nojiri, Takunori*; Onoda, Shinobu; Oshima, Takeshi

Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.89 - 91, 2010/10

JAEA Reports

Numerical methods on flow instabilities in steam generator

Yoshikawa, Ryuji; Hamada, Hirotsugu; Ohshima, Hiroyuki; Yanagisawa, Hideki*

JAEA-Research 2008-058, 29 Pages, 2008/06

JAEA-Research-2008-058.pdf:1.31MB

In Japan Atomic Energy Agency, investigations on heat transfer characteristics of steam generator are being performed for the development of Sodium-cooled Fast Breeder Reactor. In this report, the numerical methods were studied for two-phase flow instability analysis in steam generator. For numerical simulation purpose, the flow instability analysis code was developed with homogeneous equilibrium model on single heat transfer tube. The special algorithm to calculate inlet flow rate with inlet pressure, outlet pressure and heat flux as boundary conditions for the density-wave instability analysis has been established. The flow instability in single tube was successfully simulated with homogeneous equilibrium model. Then the drift-flux model including the effects of subcooled boiling and two phase slip was adopted to improve the accuracy. The capability of drift-flux model for simulating density-wave instability in single tube was confirmed.

Journal Articles

Development of thermal hydraulic computer code for steam-water flow in steam generator of fast breeder reactor

Yoshikawa, Ryuji; Hamada, Hirotsugu; Ohshima, Hiroyuki; Yanagisawa, Hideki*

Dai-13-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.495 - 496, 2008/06

In Japan Atomic Energy Agency, investigations on heat transfer characteristics of steam generator are being performed for the development of commercialized sodium-cooled fast breeder reactor. In this study, the computer code for flow instability analysis in single heat transfer tube was developed with drift-flux model which included the effects of subcooled boiling and two phase slip. The special algorithm to calculate inlet flow rate with inlet pressure, outlet pressure and heat flux as boundary conditions for the density-wave instability analysis has been established. The subcooled model was verified by calculating the void fraction distribution of steady heat transfer flow. The capability of drift flux model for simulating density-wave instability in single tube was confirmed.

Oral presentation

Changes of acceptor density in Al-doped 6H-SiC epilayer by 200 keV electron irradiation

Yanagisawa, Hideki*; Izawa, Keisuke*; Matsuura, Hideharu*; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Increase of hole concentration in Al-doped 6H-SiC epilayer by 100 keV electron irradiation or annealing

Yanagisawa, Hideki*; Nishino, Kozo*; Nojiri, Takunori*; Matsuura, Hideharu*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Change of acceptor densities in Al-doped 4H-SiC by displacement of C atoms

Nishino, Kozo*; Yanagisawa, Hideki*; Nojiri, Takunori*; Matsuura, Hideharu*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Heat transfer characteristics inside tube caused by sodium-water reaction in FBR steam generator

Kurihara, Akikazu; Ohshima, Hiroyuki; Yanagisawa, Hideki*

no journal, , 

Sodium reacts chemically with water in case of unexpected tube failure of steam generator (SG) in fast breeder reactor (FBR), exoergic reaction produced reaction field with high temperature and high corrosive (sodium-water reaction). Adjacent tubes are exposed to the reaction field and have possibility of overheating rupture by inner pressure with reduction of material strength. It is integral to predict the event with high accuracy that we understand characteristics of heat transfer inside tube in detail. Rapid heating experiment equivalent to sodium-water reaction has been carried out under high pressure, low mass flow rate and high subcooling, Heat flux and temperature on inner wall were estimated correctly by inverse problem solution. As the result of present study, we confirm heat transfer characteristics inside tube qualitatively.

Oral presentation

Heat transfer characteristics inside tube caused by sodium-water reaction in FBR steam generators

Kurihara, Akikazu; Ohshima, Hiroyuki; Yanagisawa, Hideki*

no journal, , 

In case of unexpected tube failure of steam generator (SG) in JSFR, adjacent tubes are exposed to the reaction field and have possibility of overheating rupture by inner pressure with reduction of material strength. It is integral to predict the event with high accuracy that we understand characteristics of heat transfer inside tube in detail. Rapid heating experiment equivalent to sodium-water reaction has been carried out under high pressure, low mass flow rate and high subcooling, Heat flux and temperature on inner wall were estimated correctly by inverse problem solution. As the result of present study, we confirm heat transfer characteristics inside tube qualitatively.

Oral presentation

Radiation resistance of Al-doped 4H-SiC epilayer to 200keV electron irradiation

Nojiri, Takunori*; Nishino, Kozo*; Yanagisawa, Hideki*; Matsuura, Hideharu*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

Oral presentation

Change in hole concentration in Al-doped 6H-SiC by electron irradiation and thermal annealing

Matsuura, Hideharu*; Yanagisawa, Hideki*; Nishino, Kozo*; Myojin, Yoshiko*; Nojiri, Takunori*; Matsuyama, Yukei*; Onoda, Shinobu; Oshima, Takeshi

no journal, , 

no abstracts in English

23 (Records 1-20 displayed on this page)