PSI - Issue 73

Juraj Králik et al. / Procedia Structural Integrity 73 (2025) 73–80 Juraj Králik/ Structural Integrity Procedia 00 (2025) 000–000

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4. Conlusion This paper presents the experimental and numerical analysis of the influence of NPP buildings to wind impact on the NPP buildings and ventilation chimney in locality Jaslovské Bohunice (EBO V2). The extreme wind loads were defined for mean return period equal to one per 10 4 years in accordance with IAEA and NRA SR requirements for NPP structures. In the past, the wind loads were defined on base of Eurocode recommendations. The comparison of the wind pressure coefficient c pe are presented here. The fundamental problem with the wind resistance of nuclear power plant structures was that the actual wind pressures were indifferent compared to the simple Eurocode model. The original NPP projects were based on simplified instructions for distributing wind loads on simple building shapes (cuboid, cylinder, etc.) as well as gable roofs. This article has shown that in the case of a variable assembly of buildings of different shapes, the distribution of pressures and negative pressures acting on the walls and roofs of the buildings is significantly affected. The same problems affect the chimney located near the NPP buildings. In accordance with the IAEA (2003) requirements for increasing the safety and reliability of NPP facilities, more attention will need to be paid to investigating the impact of extreme winds on NPP facilities. Acknowledgements The project was realized with the financial support of the Slovak Grant National Agency VEGA 1/0155/23. References Hubova, O. et al., 2020. Experimental determination of wind effects on NPP buildings in BLWT STU wind tunnel, Rep. 2020015, STU Bratislava. IAEA, 2003. Safety Standards, External Events Excluding Earthquakes in the Design of Nuclear Power Plants, No. NS-G-1.5, Vienna. JCSS, 2011. JCSS Probabilistic Model Code. Zurich. www.jcss.byg.dtu.dk. Kawulok, M. et al. 2023. Hyperbolic Paraboloid Tensile Structure—Numerical CFD Simulation of Wind Flow in RWIND Software. Buildings. MDPI Open Access Publishing, 13(3), s. 1-14. ISSN 2075-5309. Kološ, I. et al. 2019. Evaluation of turbulence models for flow over a thermally loaded hill. Journal of Numerical Analysis, Industrial and Applied Mathematics. European Society of Computational Methods in Sciences and Engineering, 13(3-4), s. 10-19. ISSN 1790-8140. Králik, J. 2009. Safety and Reliability of Nuclear Power Buildings in Slovakia. Earthquake-Impact-Explosion. Monograph. Ed. STU Bratislava, 307pp. Králik, J. and Králik, J. jr. 2020. Numerical simulation of the extreme wind impact on EBO V2 buildings in Jaslovské Bohunice, Rep. 0086*I3 EBOV2- EWL-FLUENT.2020, P & C Bratislava. Králik, J. et al. 2020. Risk analysis of the structures under extreme climatic and accident situations, earthquake and the simulation of the terroris- tic attacks. Safety and reliability of the nuclear power plants. VEGA 1/0453/20, MŠVVŠ SR. Králik, J. and Králik, J. jr., 2022. Fragility analysis of the safety of NPP ventilating chimney under extreme wind impact considering the influence of NPP buildings to wind impact. In: ICNAAM 2022, September, Thessaloniki, Greece. Michalcova, V. et al., 2017. Numerical Models of Wind Effects on Temperature Loaded Object. In: Key engineering materials. Vol. 738. Drunken Zurich: TTP, pp. 69-78. ISBN 978-3-0357-1114-1. Menter, F.R., Lechner, R., Ansys Grman GmbH, Matyushenko, A. 2020. Best Practice: Generalized k- ω Two-Equation Turbulence Model in Ansys CFD (GEKO). NTS, ST. Petersburg. NRA SR, 2011. The stress tests for Nuclear Power Plants Slovakia, Bratislava. NUREG/CR-4839, 1992. Methods for External Event Screening Quantification: Risk Methods Integration and Evaluation Program (RMIEP) Methods Development, Report, U.S. Nuclear Regulatory Commission. SHMU, 2012. Summary report SHMÚ for locality Jaslovské Bohunice, Bratislava. STN EN 1991-1-4, 2007. Structural loading. Part 1-4 General loading – Wind loading. SUTN Bratislava. Wilcox, D.C. 2008. Formulation of the k-omega Turbulence Model Revisited. In: AIAA Journal, Vol. 46, No. 11, pp. 2823-2838, DOI: 10.2514/1.36541. ANSYS Inc. 2024. Theory Manual. Edition. SAS IP, Inc. ANSYS Inc. 2024. Ansys Fluent Theory Guide. Ed. SAS IP, Inc.