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Phan, L. H. S.*; Ohara, Yohei*; Kawata, Ryo*; Liu, X.*; Liu, W.*; Morita, Koji*; Guo, L.*; Kamiyama, Kenji; Tagami, Hirotaka
Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 12 Pages, 2018/10
Self-leveling behavior of core fuel debris beds is one of the key phenomena for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). The SIMMER code has been developed for CDA analysis of SFRs, and the code has been successfully applied to numerical simulations for key thermal-hydraulic phenomena involved in CDAs as well as reactor safety assessment. However, in SIMMER's fluid-dynamics model, it is always difficult to represent the strong interactions between solid particles as well as the discrete particle characteristics. To solve this problem, a new method has been developed by combining the multi-fluid model of the SIMMER code with the discrete element method (DEM) for the solid phase to reasonably simulate the particle behaviors as well as the fluid-particle interactions in multi-phase flows. In this study, in order to validate the multi-fluid model of the SIMMER code coupled with DEM, numerical simulations were performed on a series of self-leveling experiments using a gas injection method in cylindrical particle beds. The effects of friction coefficient on the simulation results were investigated by sensitivity analysis. Though more extensive validations are needed, the reasonable agreement between simulation results and corresponding experimental data preliminarily demonstrates the potential ability of the present method in simulating the self-leveling behaviors of debris bed. It is expected that the SIMMER code coupled with DEM is a prospective computational tool for analysis of safety issues related to solid particle debris bed in SFRs.
Kawata, Ryo*; Ohara, Yohei*; Sheikh, Md. A. R.*; Liu, X.*; Matsumoto, Tatsuya*; Morita, Koji*; Guo, L.*; Kamiyama, Kenji; Suzuki, Toru
Proceedings of 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) (USB Flash Drive), 14 Pages, 2017/09
Kawata, Koji; Matsuki, Takuo*; Miyahara, Shinya
JAEA-Review 2011-046, 42 Pages, 2012/02
JAEA-Review-2011-046.pdf:2.41MB
Sodium spray fire tests at an initial sodium temperature of 250
C were conducted under the atmospheric conditions of air and 3% oxygen containing nitrogen to determine both the sodium burning rate and the aerosol release fraction.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Kawata, Koji
Saikuru Kiko Giho, (25), 113- Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Futagami, Satoshi; Nishimura, Masahiro; Kawata, Koji; Ishikawa, Hiroyasu; Miyahara, Shinya
PNC TN9410 98-074, 154 Pages, 1998/08
Supposing sodium leak accident from a IHTS pipe in FBR, sodium pool combusion test Run-F7 series is under way to know liner peak temperature and to study sodium pool growth and combustion behavior in the case of small-scale sodium leaks (0.01ton/hr) in an air atmosphere. This report consists of a result of Run-F7-1 (Feb,17,1998) and Run-F7-2 (Apr, 21, 1998) : In these tests, sodium temperature and sodium leak rates are the same (about 0.01ton/hr), but the height of leak point was changed. The test was performed using FRAT-1 (Fission Product and Radioactive Aerosol Release Test Rig . volume : 3m
) of SAPFIRE (Safety Phenomenology Tests on Sodium Leak, Fire and Aerosols) facility. A burning pan (diameter : about 1000 mm, thickness : 6 mm) made of carbon steel (SM400B) to simulate floor steal liner was installed in FRAT-1. a 5kg of sodium was leaked at the leak rate of 0.01ton/hr under the temperature of 507C from the height of 0.1m and 1.5m (Run-F7-1 and Run-F7-2, respectively) during 30minutes when air was continued to feed into the cell. From the results, the following conclusion were drawn concerning the liner peak temperature, and sodium pool growth and combustion behavior, in the small-scale (0.01ton/hr) sodium leak: (1)In this case (1eak rate 0.01ton/hr), burning pan thermocouple measured 616C at approximately 33minutes in Run-F7-1, and 675C at 33minutes in Run-F7-2. therefore, the height of leak point has an effect on liner peak temperature. (2)Post test observation clarified that the deposits covered an area of about 0.3m in both tests. Sodium pool growth velocity during experiments were also similar. therefore, the height of leak point doesn't have a notable effect on sodium pool growth. (3)In both tests, burning rate of a unit area was 16kg-Na/mhr. (4)Analysis of the chemical composition of the deposits on the burning pan revealed that the main compounds were sodium oxides, but sodium dioxide and ...
Niwa, Hajime; Kawata, Norio; Ieda, Yoshiaki; Sato, Ikken; Ohno, Shuji; Uto, Nariaki; Miyahara, Shinya; Kondo, Satoru; Kamide, Hideki; Yamaguchi, Akira; et al.
PNC TN9410 94-154, 317 Pages, 1995/03
None
Ohno, Shuji; Kawata, Koji; Morikawa, Satoshi; Himeno, Yoshiaki
PNC TN9410 91-029, 11 Pages, 1991/01
Code development and experimental researches have been carried out for more realistic evaluation of the sodium fire accidents in the FBRs. A three-dimensional sodium fire analysis code,SOLFAS, is under development, SOLFAS consists of many calculational models for the detailedsodium fire analysis. Among the models,those of turbulent heat-mass transfer in an atmospheric gas,sodium pool combustion, and thermal conduction in heat structures havebeen developed to date. The gas solver including the turbulence model was verified with the sample calculations. Combustion rates of a low temperature sodium pool in a low oxygen concentration atmosphere and those of a sodium columnar fire in an air atmosphere were obtained from the experiments conducted in the SAPFIRE facility at PNC. Derived empirical formulae of the sodium combustion rate will contribute to the code development in the near future.
Kawata, Tsuyoshi; Kojima, Hiroshi; Kanamaru, Yoshiyuki; Wakayama, Yoshinori
no journal, ,
no abstracts in English
Kawata, Ryo*; Ohara, Yohei*; Fujimoto, Takuya*; Nishida, Satoshi*; Morita, Koji*; Guo, L.*; Tagami, Hirotaka; Suzuki, Toru
no journal, ,
no abstracts in English
Kawata, Ryo*; Ohara, Yohei*; Fujimoto, Takuya*; Nishida, Satoshi*; Morita, Koji*; Guo, L.*; Tagami, Hirotaka; Suzuki, Toru
no journal, ,
no abstracts in English
