Probabilistic seismic hazard analysis for Kakrapar

Authors: William K Mohanty Akhilesh K Verma

Publish Date: 2013/06/07

Volume: 69, Issue: 1, Pages: 919-952

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Abstract

Seismic ground motion caused by earthquakes mainly affects the constructions and structures around its area of influence In this context the probabilistic seismic hazard analysis PSHA is a scientific step towards the safety analysis of any major construction such as nuclear power plant Thus the present study focused to estimate seismic hazard level at different probabilities for Kakrapar nuclear power plant located in the Western India The hazard curves for the study area are developed following the procedure of PSHA suggested by Cornell–McGuire Three source zones NarmadaTapti zone NTZ Rann of Kuchchh ROK and west passive margin WPM are classified on the basis of seismicity and tectonic setting of the study area The estimated maximum magnitude m max for NTZ ROK and WPM are 69 ± 057 65 ± 064 and 61 ± 064 respectively Logic tree approach has been used for the development of hazard curves to account the epistemic uncertainties associated with the analysis For maximum credible earthquake MCE ie the probability of exceedance of 2  in 50 years return period of ~2500 years the peak spectral acceleration ie PSA at 02 s expected around 5 km of the Kakrapar nuclear power plant site is 023 g from all source zones however at exact site location it is 018 g The PSA values due to NTZ ROK and WPM based on MCE are 022 0065 and 0052 g respectively In case of designbased earthquake DBE ie 50  probability in 50 years return period of ~110 years the calculated maximum spectral acceleration SA from all source zones is about 0045 g The PSA distribution for the DBE from the NTZ has reached a maximum value of 0042 g however PSA for ROK and WPM is considerably low with a maximum value of 0022 and 0021 g respectively Considering the MCE and DBE the estimated PSA at 02 s has a highest value of ~023 g from all source zones Spectral accelerations SAs correspond to different periods are presented and SA plots for NTZ zone can be considered as response spectra for the KAPS site Deaggregation of PSHA in the present study is also discussed PGA values reported in seismic zonation map and global seismic hazard analysis program around the present study area range from 005 to 02 g which is slightly lower than the peak acceleration obtained in this study The results of this study would facilitate in the performance of the sitespecific seismic probabilistic safety analysisThe authors are thankful to Dr Andrzej Kijko for providing the computer program for the estimation of maximum magnitude Authors are also acknowledged the Nuclear Power Corporation of India Limited NPCIL Department of Atomic Energy Government of India for the financial support for the present study We are grateful to Dr G Srinivas Smt Rajee Guptan and Smt AK Vijaya Probabilistic Safety Analysis PSA section Directorate of Reactor Safety Analysis NPCIL for their timetotime suggestions on this work The suggestions and critical comments by Dr G Srinivas during the preparation of the manuscript are highly appreciated We would also like to express our great appreciation of the comments and suggestions received from two anonymous reviewers whose painstaking reviews have led to substantial modification of our ideas and improvement of the manuscript

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