1 Second Generation Waste Package Design Study Prepared by

The design of waste packages currently proposed for YMP is highly conservative. The candidate materials of construction of the waste packages and drip shields while highly corrosion resistant are extremely expensive and components made from these materials will require complex and expensive fabrication methods to assure their integrity. A proposed, second generation operating concept and waste package design, is intended to permit more efficient and less costly operation of the repository while maintaining waste package integrity. Major reductions in waste package costs can be realized by increasing the number of fuel assemblies stored in each waste package, eliminating the reference titanium drip shield and fabricating the outer container from low alloy “weathering ” steels. These steels have outstanding resistance to general corrosion and are localized corrosion. The second generation waste package is proposed for implementation after the initial licensing and operation of the reference Yucca Mountain design. Implementation would follow a regulatory process analogous to that used to implement plant life extensions and power uprates of commercial light water nuclear reactors. The proposed concept capitalizes on the benefits of hot, dry storage to minimize potential for contact and corrosion of the waste package metallic surface by liquid electrolytes. The merits and feasibility of this approach have been investigated analytically at UNR (1, 2) and testing of th