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| Titel |
Towards the Seismic Hazard Reassessment of Paks NPP (Hungary) Site: Seismicity and Sensitivity Studies |
| VerfasserIn |
László Tóth, Péter Mónus, Erzsébet Győri, Gyula Grenerczy, Tamas Janos Katona, Márta Kiszely |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103525
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| Publikation (Nr.) |
 EGU/EGU2015-2939.pdf |
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| Zusammenfassung |
| In context of extension of Paks Nuclear Power Plant by new units, a comprehensive site
seismic hazard evaluation program has been developed that is already approved by the
Hungarian Authorities. This includes a 3D seismic survey, drilling of several deep boreholes,
extensive geological mapping, and geophysical investigations at the site and its vicinity, as
well as on near regional, and regional scale. Furthermore, all relevant techniques of modern
space geodesy (GPS, PSInSAR) will be also utilized to construct a new seismotectonic
model. The implementation of the project is still in progress. In the presentation,
some important elements of the new seismic hazard assessment are highlighted, and
some results obtained in the preliminary phase of the program are presented and
discussed.
The first and most important component of the program is the compilation of the
seismological database that is developed on different time scale zooming on different event
recurrence rates such as paleo-earthquakes (10-1/a).
In 1995, Paks NPP installed and started to operate a sensitive microseismic monitoring
network capable for locating earthquakes as small as magnitude 2.0 within about 100 km of
the NPP site. During the two decades of operation, the microseismic monitoring network
located some 2,000 earthquakes within the region of latitude 45.5 – 49 N and longitude 16 –
23 E. Out of the total number of events, 130 earthquakes were reported as “felt
events”. The largest earthquake was an event of ML 4.8, causing significant damage in
the epicenter area. The results of microseismic monitoring provide valuable data
for seismotectonic modelling and results in more accurate earthquake recurrence
equations.
The first modern PSHA of Paks NPP site was carried out in 1995. Complex site
characterization project was implemented and hazard curves had been evaluated for 10-3 –
10-5 annual frequency. As a follow-up, PSHA results have been reviewed and updated in the
frame of periodic safety reviews, and hazard characterization of the site has been confirmed.
The hazard curves have been extended to lower probability events, as it is required by the
probabilistic safety analysis. These earlier projects resulted in 0.22-0.26 g and 0.43-0.54 g
mean PGA at 104 and 105 return periods. The site effect and liquefaction probability
have also been evaluated. As it is expected for the site of soft soil conditions, the
amplification is greater at shorter periods for the lower amplitude ground motion of 104
return period compared to the longer periods for the higher amplitude of the 105
year level ground motion. Further studies will be based on the improved regional
seismotectonic model, state-of-the-art hazard evaluation software, and better knowledge of
the local soil conditions. The presented preliminary results can demonstrate the
adequacy of the planned program and highlight the progress in the hazard assessment. |
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