For the U . S . Nuclear Regulatory Commission ’ S Key Technical Issue Agreements : an Integrated Approach

The Nuclear Waste Policy Act required the U.S. Nuclear Regulatory Commission (NRC) to comment on the Yucca Mountain Site Recommendation relative to the sufficiency of the Project’s information to support a potential license application. As part of the NRC’s associated review process a series of meetings held between August, 2000 and September, 2001, the U.S. Department of Energy (DOE) and the NRC established 293 agreements to address NRC’s questions and information needs relative to Key Technical Issues related to postclosure performance and preclosure safety and operations of a geologic repository for high-level spent fuel and nuclear waste at Yucca Mountain, Nevada. These Key Technical Issues (KTIs) are: Container Life and Source Term; Evolution of the Near Field Environment; Igneous Activity; Repository Design and Thermal Mechanical Effects; Radionuclide Transport; Structural Deformation and Seismicity; Thermal Effects on Flow; Total System Performance Assessment Integration; Unsaturated and Saturated Flow under Isothermal Conditions; and Preclosure Issues. Since the KTI agreements were established, DOE and NRC have had a series of interactions focused on resolution in order to facilitate NRC acceptance and review of DOE’s license application for construction authorization, currently scheduled in December 2004. In fact, these agreements have been an effective way to focus program resources and attention on those issues most important to licensing the geologic repository. DOE’s original approach to issue resolution involved submittal of documentation on single or small groups of related KTI agreements. However, recognizing that addressing each agreement in isolation was not as effective as a more comprehensive approach, in 2003 DOE significantly revised its issue resolution methodology by developing resolution documents that group the KTI agreements in an integrated holistic view of the repository system’s natural and engineered components. The majority of the original KTI agreements will be addressed in these groups, which are: 1) Climate and Infiltration; 2) Unsaturated Zone Flow; 3) Water Seeping into Drifts; 4) Mechanical Degradation and Seismic Effects; 5) In-Drift Chemical Environment; 6) Waste Package and Drip Shield Corrosion; 7) In-Package Environment and Waste Form Degradation and Solubility; 8) Colloid Transport; 9) Engineered Barrier System Transport; 10) Unsaturated Zone Transport; 11) Saturated Zone Flow and Transport; 12) Biosphere Transport; 13) Volcanic Events; and, 14) Low-Probability Seismic Events. This revised approach is consistent with the U.S. Nuclear Regulatory Commission’s Yucca Mountain Review Plan [1] and the regulatory requirements at 10 CFR Part 63 [2]. Documentation addressing the remaining KTI agreements is scheduled to be submitted to the NRC by August 2004.