Historical Perspective Since Early Development Using Uniform Building Code Criteria

DOE-STD-1020-2002

Figure C-1 Consistent Specification of All

Seismic Design/Evaluation Criteria Elements

C.2

Basic Approach for Earthquake Design and Evaluation and

Meeting Target Performance Goals

C.2.1

Overall Approach for DOE Seismic Criteria

Historical Perspective Since Early Development Using Uniform Building Code Criteria

Structure/component performance is a function of: (1) the likelihood of hazard

occurrence and (2) the strength of the structure or equipment item. Consequently, seismic

performance depends not only on the earthquake probability used to specify design seismic

loading, but also on the degree of conservatism used in the design process as illustrated in Figure

C-2. For instance, if one wishes to achieve less than about 10-4 annual probability of onset of

loss of function, this goal can be achieved by using conservative design or evaluation approaches

for a natural phenomena hazard that has a more frequent annual probability of exceedance (such

as 10-3), or it can be achieved by using median-centered design or evaluation approaches (i.e.,

approaches that have no intentional conservative or unconservative bias) coupled with a 10-4

hazard definition. At least for the earthquake hazard, the former alternate has been the most

traditional. Conservative design or evaluation approaches are well-established, extensively

documented, and commonly practiced. Median design or evaluation approaches are currently

controversial, not well understood, and seldom practiced. Conservative design and evaluation

approaches are utilized for both conventional facilities (similar to DOE PC-1) and for nuclear

power plants (similar to DOE PC- 4). For consistency with these other uses, the approach in this

standard specifies the use of conservative design and evaluation procedures coupled with a

hazard definition consistent with these procedures.

C-4