Definition of component and structural fragility for use in the Seismic Safety Margins Research Program

The Seismic Safety Margins Research Program (SSMRP) is to estimate the conservatism in the Standard Review Plan seismic safety requirements and to develop improved seismic requirements. The approach to achieve these objectives is to develop probability methodology that more realistically estimates the behavior of nuclear power plants during an earthquake. The development of fragility descriptions for components, systems, and structures is a necessary part of this approach, and the Components and Structural Fragilities Project of the SSMRP is responsible for developing these descriptions. The SSMRP will comprise several phases. Phase 1 is addressed at this time, and will focus specifically on the Zion 1 plant and site. (orig.)