Lower-bound magnitude for probabilistic seismic hazard assessment

Technical Report · Sun Oct 01 04:00:00 EDT 1989

OSTI ID:5496794

McCann, Jr, M W; Reed, J W ^[1]

---

1. Benjamin (J.R.) and Associates, Inc., Mountain View, CA (USA)

This report provides technical information to determine the lower-bound earthquake magnitude (LBM) for use in probabilistic seismic hazard (PSH) computations that are applied to nuclear plant applications. The evaluations consider the seismologic characteristics of earthquake experience at similar facilities and insights from probabilistic risk analysis. The recommendations for LBM satisfy the two basic precepts: (1) there is a reasonable engineering assurance that the likelihood of damage due to earthquakes smaller than the LBM is negligible, and (2) any small risk due to earthquakes smaller than the LBM is compensated by conservatisms in PSH results for larger earthquakes. Theoretical and empirical ground motion studies demonstrate that ground shaking duration and spectral shape are a strong function of earthquake magnitude. Small earthquakes have short duration and spectral shapes centered at high frequencies as compared to nuclear power plant design spectra which are typical of moderate and large earthquakes. Analysis of earthquake experience data shows damage to heavy industrial facilities, taken as analogs to nuclear plant structures and components, occurs for earthquakes having moment magnitude M larger than 5.1. Probabilistic seismic risk and margins studies show nuclear plant structures and adequately anchored ductile components to be rugged for moderate-size earthquakes with broad design-type spectral shapes. They may, therefore, be considered rugged for small earthquakes. Finally, nonlinear analysis of the damage effectiveness of strong-motion recordings shows that potential damage does not occur for earthquakes smaller than about M5.6. These results support a conservative LBM of M5.0 for application to nuclear power plant PSH assessments. 144 refs., 78 figs., 34 tabs.

• Research Organization: Electric Power Research Inst., Palo Alto, CA (USA); Benjamin (J.R.) and Associates, Inc., Mountain View, CA (USA)
• Sponsoring Organization: EPRI
• OSTI ID: 5496794
• Report Number(s): EPRI-NP-6496
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220900* -- Nuclear Reactor Technology-- Reactor Safety
58 GEOSCIENCES
580201 -- Geophysics-- Seismology & Tectonics-- (1980-1989)
99 GENERAL AND MISCELLANEOUS
990230 -- Mathematics & Mathematical Models-- (1987-1989)
DAMAGE
DATA ACQUISITION
DATA ANALYSIS
DESIGN
DOCUMENT TYPES
EARTHQUAKE MAGNITUDE
EARTHQUAKES
GEOPHYSICS
GROUND MOTION
MATHEMATICAL MODELS
MITIGATION
MOTION
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
PROGRESS REPORT
REACTOR SAFETY
RECOMMENDATIONS
RISK ASSESSMENT
SAFETY
SEISMIC EFFECTS
SEISMIC EVENTS
SEISMOLOGY
THERMAL POWER PLANTS