Fault Displacement Hazard Analysis Based on Probabilistic Seismic Hazard Analysis for Specific Nuclear Sites

Tamás János Katona,Erzsébet Győri,László Tóth

doi:10.3390/app11157162

Tamás János Katona, Erzsébet Győri + Show 1 more

Open Access

https://doi.org/10.3390/app11157162

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Abstract

Permanent ground displacements/deformations caused by earthquakes can seriously challenge the safety of the nuclear power plants. The state-of-the-art hazard analysis methods provide a fault displacement hazard curve, i.e., the annual probability of given measure of displacement will be exceeded. The evaluation of ground displacement hazard requires great effort, empirical evidence, and sufficient data for the characterization of the fault activity and capability to cause permanent surface displacement. There are practical cases when the fault at the site area revealed to be active, and, despite this, there are no sufficient data for the evaluation of permanent ground displacements hazard and for judging on the safety significance of permanent ground displacement. For these cases, a methodology is proposed that is based on the seismotectonic modelling and results of the probabilistic seismic hazard analysis. The method provides conservative assessment of the annual probability of fault displacement that allows the decision whether permanent displacement hazard is relevant to nuclear power plant safety. The feasibility and applicability of the method is demonstrated for the Paks site, Hungary.

Highlights

Fault displacement hazard has been a crucial siting issue from the beginning of the construction of commercial nuclear power plants
The above considerations on the conservativeness are valid for the estimation of the mean hazard curve for the contribution of the distributed faulting
A procedure has been developed for the evaluation hazard curves of the on-fault displacement as well as for the contribution of distributed faulting that is based on PSHA disaggregation results

Summary

Introduction

Fault displacement hazard has been a crucial siting issue from the beginning of the construction of commercial nuclear power plants. According to older regulatory approach the site should be abandoned, if a fault near the site judged for capable to cause permanent surface displacement. The attributes for capability of the faults to generate surface displacement are as follows [2,3]):. (1) Evidence of significant past movement or movements of a recurring nature within such a period that it is reasonable to conclude that further movements at or near the surface may occur. This time interval is fixed by the regulations. The significance should be qualified considering the effect surface movement on the integrity and function of safety related structures of nuclear power plant, i.e., the significance is matter of nuclear engineering rather than geoscience

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