Prepared for the United States Department of Energy, Office of Civilian Radioactive Waste Management, Yucca Mountain Site Characterization Project under Contract DE-AC04-76DP00789
Authors: M. P. Hardy (AAI) and S. J. Bauer (Sandia National Laboratories)
A methodology and preliminary application for designing repository openings to withstand vibratory ground motion is presented. The methodology first establishes the design basis ground motion based on the usage category, performance goals, and hazard exceedance guidelines and incorporates those motions into the more general drift design methodology. The repository drift design methodology includes the effects of the in situ stresses and the thermal loads generated from the heat released from the nuclear waste packages. Empirical and analytical methods for design for seismic loading are reviewed, and it is concluded that analytical methods provide the only means method to adequately incorporate the effects of seismic and thermal loads on design. Quasi-static and dynamic analysis methods are discussed. The example application to the potential repository at the Yucca Mountain site illustrates, by using the quasi-static method, that the seismic loads in combination with the thermal loads can be significant in the design of the ground support/reinforcement system in some locations. Under present expected conditions, the seismic loads themselves are not excessive and can be accommodated in the design by available ground support/reinforcement systems. However, in the waste emplacement drift where the thermal loads are high, the potential and additional seismic loads could require novel ground support/reinforcement designs and maintenance.