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Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Zhang, S.*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Naito, Masanori*; Shirakawa, Noriyuki*; et al.
Proceedings of 2009 International Congress on Advances in Nuclear Power Plants (ICAPP '09) (CD-ROM), 1 Pages, 2009/05
A computer code, named COMPASS, is developed for multi-physics analysis of core disruptive accidents of sodium-cooled fast reactors (SFRs). A meshless method, called MPS method, is employed since complex thermal-hydraulics and structural problems with various phase change processes have to be analyzed. Verification for separeted basic processes and validation for practical phenomena are carried out. COMPASS is also expected to investigate molten fuel discharge to avoid re-criticality in large size SFR cores. Both MOX and metal fuels are considered. Eutectic reactions between the metal fuel and the cladding material are investigated by phase diagram calculation, classical and first-principles molecular dynamics. Basic studies relevant to the numerical methods support the code development of COMPASS. Parallel processing is implemented by OpenMP to treat large-scale problems. A visualization tool is also prepared by using AVS.
Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Zhang, S.*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Naito, Masanori*; Shirakawa, Noriyuki*; et al.
Proceedings of IAEA Topical Meeting on Advanced Safety Assessment Methods for Nuclear Reactors (CD-ROM), 9 Pages, 2007/10
A computer code, named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis), is being developed for various complex phenomena of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). Theoretical studies are performed about a unified algorithm for compressible and incompressible flows, fluid flow with solid debris, and algorithm improvement for free surface flows. Code verification and validation procedures are established by exploiting the past experiences in those of SIMMER-III code. COMPASS will be used for separated phenomena in CDAs, while the whole core will be analyzed by SIMMER-III. COMPASS is expected to clarify the detailed process in duct wall failure and fuel discharge to avoid re-criticality during CDAs in large size SFRs.
Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Shirakawa, Noriyuki*; Hosoda, Seigo*; Araki, Kazuhiro*; et al.
Proceedings of 5th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-5), p.472 - 479, 2006/11
A 5-year research project started in FY2005 in the framework of Innovative Nuclear Research and Development Program funded by the Ministry of Education, Culture, Sports, Science and Technology in Japan. A computer code, named COMPASS (Computer Code with Moving Particle Semi-implicit for Reactor Safety Analysis), is being developed using the Moving Particle Semi-implicit (MPS) method for various complex phenomena of severe accidents in fast breeder reactors. Both MOX and metal fuels are considered. Eutectic reactions between the metal fuel and the cladding material are being investigated by molecular dynamics and molecular orbital methods. The molten metal flow with solidification was analyzed by MPS. The elastic analysis of a hexagonal wrapper tube was analyzed by the MPS method as well. The results were compared with an experiment and an calculation using an commercial code. Eutectic reactions were calculated by molecular dynamics and compared with the references. We found that the combination of the above numerical methods was useful for multi-physics and multi-scale phenomena of core disruptive accidents in fast breeder reactors.
Koshizuka, Seiichi*; Liu, J.*; Morita, Koji*; Arima, Tatsumi*; Zhang, S.*; Tobita, Yoshiharu; Yamano, Hidemasa; Ito, Takahiro*; Naito, Masanori*; Shirakawa, Noriyuki*; et al.
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A computer code is developed based on a particle method technology in order to simulate in detail various phenomana in core disruptive accidents in fast reactors. This report is a summary of progress during FY2006 in a five-year project of the code development.