DOE 2000. - Waste Isolation Pilot Plant - U.S. Department of Energy

WIPP RH PSAR DOE/WIPP-03-3174 CHAPTER 2
From this figure, the most conservative calculated estimate of the 1000 year acceleration at the WIPP
facility is seen to be approximately 0.075g. The geologic and seismic assumptions leading to this
1000-year peak acceleration include the consideration of a Richter magnitude 5.5 earthquake at the site, a
6.0 magnitude earthquake on the Central Basin Platform, and a 7.8 magnitude earthquake in the Basin
and Range subregion. These magnitudes correspond roughly to equivalent epicentral intensity events of
VII, VIII and XI on the Modified Mercalli intensity scale. 8 These values, especially the first two, are
considered quite conservative, and the other parameters used in the 0.075g derivation are also very
conservatively chosen. For additional conservatism, a peak design acceleration of 0.1g is selected for the
WIPP facility DBE. The design response spectra for vertical and horizontal motions are taken from
Regulatory Guide 1.60 (U.S. Nuclear Regulatory Commission) 46 with the high frequency asymptote
scaled to this 0.1g peak acceleration value. These response spectra are shown in Figures 3.2-2 and 3.2-3.
This DBE and the risk analysis that serves an important role in its definition are directly applicable to
Design Class II and IIIA confinement structures and components at the WIPP Facility. Underground
structures and components are Design Class IIIB and as such are not subject to DBE. Mine experience
and studies on earthquake damage to underground facilities 47 show that tunnels, mines, wells, etc., are
not damaged for sites having peak accelerations at the surface below 0.2g.
Design Class IIIB underground facilities do not require the consideration of seismic effects based on the
above, and seismic load combinations with increased allowable stresses will not control the design.
2.5-19 January 24, 2003