THE YUCCA MOUNTAIN PERFORMANCE CONFIRMATION PROGRAM

The Performance Confirmation (PC) Program for Yucca Mountain is responsive to the risk-informed, performance-based approach of 10 CFR 63, Subpart F.  It is designed to test the adequacy of assumptions, data, and analyses that support the findings used to permit construction of the repository and direct subsequent waste emplacement operations.

There are two objectives for the PC Program. First, the program provides information, where practicable, to confirm that subsurface conditions encountered and changes in those conditions during construction and waste emplacement operations are within assumed limits. Second, the program provides information to evaluate if the natural and engineered systems and components that were designed or assumed to operate as barriers after permanent closure are functioning as intended. 

The repository system is composed of two natural barriers and one Engineered Barrier System that are important to waste isolation and have been characterized and designed to work together to prevent or reduce the movement of water or radionuclides, or prevent the release or substantially reduce the release rate of radionuclides.

Performance confirmation began during the characterization of the Yucca Mountain site and will continue during repository construction and through emplacement of waste, only concluding when repository closure is licensed.  Performance confirmation tests that will continue from activities that were performed as a part of site characterization, with appropriately modified work scopes, are as follows: precipitation monitoring; seepage monitoring; subsurface water and rock testing; unsaturated zone testing; saturated zone monitoring; saturated zone alluvium testing; subsurface mapping; seismicity monitoring; construction effect monitoring; corrosion testing; and waste form testing.  New activities that will begin during construction or operations phases include:  saturated zone fault zone hydrology testing; thermally accelerated drift near-field monitoring; dust buildup monitoring; thermally accelerated drift environment monitoring; thermally accelerated drift thermal-mechanical effects monitoring; seal testing; waste package monitoring; and corrosion testing of thermally accelerated drift samples.