### Abstract

Original language | English |
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Title of host publication | Proceedings of the 2nd CSNI Specialist Meeting on Simulators and Plant Analysers |

Place of Publication | Espoo |

Publisher | VTT Technical Research Centre of Finland |

Pages | 378-389 |

ISBN (Print) | 951-38-5269-5 |

Publication status | Published - 1999 |

MoE publication type | A4 Article in a conference publication |

Event | 2nd CSNI Specialist Meeting on Simulators and Plant Analysers - Espoo, Finland Duration: 29 Sep 1997 → 2 Oct 1997 |

### Publication series

Series | VTT Symposium |
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Number | 194 |

ISSN | 0357-9387 |

### Conference

Conference | 2nd CSNI Specialist Meeting on Simulators and Plant Analysers |
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Country | Finland |

City | Espoo |

Period | 29/09/97 → 2/10/97 |

### Fingerprint

### Cite this

*Proceedings of the 2nd CSNI Specialist Meeting on Simulators and Plant Analysers*(pp. 378-389). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 194

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*Proceedings of the 2nd CSNI Specialist Meeting on Simulators and Plant Analysers.*VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 194, pp. 378-389, 2nd CSNI Specialist Meeting on Simulators and Plant Analysers, Espoo, Finland, 29/09/97.

**Evaluation of two-fluid and drift flux thermohydraulics in APROS code environment.** / Miettinen, Jaakko; Karppinen, Ismo; Hänninen, Markku; Ylijoki, Jukka.

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review

TY - GEN

T1 - Evaluation of two-fluid and drift flux thermohydraulics in APROS code environment

AU - Miettinen, Jaakko

AU - Karppinen, Ismo

AU - Hänninen, Markku

AU - Ylijoki, Jukka

PY - 1999

Y1 - 1999

N2 - The characteristics of the thermohydraulic solutions in APROS are considered for the nuclear power plant modelling. The thermohydraulic model of the APROS plant analyzer includes three levels of solutions, homogeneous 3-equation model, 5-equation drift flux model and 6-equation two-fluid model. In practical modelling of versatile process systems different approaches are selected for different types of the power plant sections. The 3-equation model is used for turbines and auxiliary systems. The 5-equation model and 6-equation model are alternative models for main process sections of the primary and secondary sides. The 5-equation model has been typically selected for the real time applications and the 6-equation model for the safety analysis applications. The validation needs for both approaches are the same. Because the change of the solution mode is an easy task in APROS, the validation tasks are typically performed in parallel for 5-equation and 6-equation models. By calculating in parallel with both models systematic errors in solutions may be pointed out. The testing against both separate effects tests and integral tests is an essential part in the thermohydraulics. In different plant applications different physical features are important. The analysis requirements vary from one application to another. When nodalizations together with increased computer speed are growing up, the earlier validation cases may be insufficient. That is why the content of the code has to be known in detail. Such an expertise in the code development has to be gained that properties of the code against other thermohydraulics codes are known.

AB - The characteristics of the thermohydraulic solutions in APROS are considered for the nuclear power plant modelling. The thermohydraulic model of the APROS plant analyzer includes three levels of solutions, homogeneous 3-equation model, 5-equation drift flux model and 6-equation two-fluid model. In practical modelling of versatile process systems different approaches are selected for different types of the power plant sections. The 3-equation model is used for turbines and auxiliary systems. The 5-equation model and 6-equation model are alternative models for main process sections of the primary and secondary sides. The 5-equation model has been typically selected for the real time applications and the 6-equation model for the safety analysis applications. The validation needs for both approaches are the same. Because the change of the solution mode is an easy task in APROS, the validation tasks are typically performed in parallel for 5-equation and 6-equation models. By calculating in parallel with both models systematic errors in solutions may be pointed out. The testing against both separate effects tests and integral tests is an essential part in the thermohydraulics. In different plant applications different physical features are important. The analysis requirements vary from one application to another. When nodalizations together with increased computer speed are growing up, the earlier validation cases may be insufficient. That is why the content of the code has to be known in detail. Such an expertise in the code development has to be gained that properties of the code against other thermohydraulics codes are known.

M3 - Conference article in proceedings

SN - 951-38-5269-5

T3 - VTT Symposium

SP - 378

EP - 389

BT - Proceedings of the 2nd CSNI Specialist Meeting on Simulators and Plant Analysers

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -