New state-of-the-art regulatory document has been developed and implemented in Ukraine to present requirements for seismic hazard assessment of nuclear power plant (NPP) sites and seismic resistance of nuclear power units taking into account lessons learnt from the accident at Fukushima-1 NPP. One of the new important regulatory requirements in this document is the extension of the list of mandatory load combinations, which should be considered in assessing seismic resistance of unit components.
Advantages and disadvantages of the algorithm proposed by the operating organization to determine the necessity to consider some load combinations in assessing the seismic resistance of pipelines and thermomechanical equipment based on previously performed seismic strength calculations have been analyzed in the paper. The pipelines as well as the thermomechanical equipment of Zaporizhzhya NPP Unit 3, for which seismic strength evaluation was calculated, have been considered.
The results of expert seismic calculations of YP13S02 valve of ZNPP-1 and ZNPP-3 have been provided. The paper presents the comparative analysis of the floor response spectra for the lower, middle and high elevations of ZNPP-3 containment with the corresponding floor response spectra of other Ukrainian NPPs and conclusions.
The possibility for disseminating results obtained by the operating organization for ZNPP-3 to other units of the Ukrainian NPPs has been analyzed.
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