GEOLOGY IN LICENSING NEW NUCLEAR POWER FACILITIES AT THE V.C. SUMMER NUCLEAR STATION (VCSNS) SITE, SOUTH CAROLINA, BY THE U.S. NUCLEAR REGULATORY COMMISSION (NRC) (Invited Presentation)

Requirements in the Code of Federal Regulations and guidance in NRC regulatory guides specify the importance of geologic characterization of sites for new nuclear power facilities. During the NRC’s regulatory process, started in March 2008 and leading to licensing of the VCSNS site for construction and operation of two Westinghouse AP1000 units in March 2012, NRC geologists reviewed parts of the VCSNS Final Safety Analysis Report (FSAR) related to basic geologic and seismic information and surface faulting; conducted site audits and Quality Assurance (QA) inspections to examine geologic features in the field; prepared a Final Safety Evaluation Report (FSER) presenting review and audit results; briefed the Advisory Committee on Reactor Safety regarding those results; and provided sworn testimony in mandatory public hearings to defend conclusions about site suitability based on review, audit, and inspection results. NRC geologists also identified a geologic mapping License Condition as the responsibility of the VCSNS licensee in the FSER, which required detailed geologic mapping of the excavation for the Unit 3 nuclear island structure; evaluation of geologic features discovered in excavations for safety-related structures other than the nuclear island; and notification of the Office of New Reactors once the excavations were ready for NRC staff to examine. The licensee committed to conducting the geologic mapping in the FSAR and mapped rock units, tectonic structures, and geologic features in the walls and floors of Unit 3 excavations for safety-related structures in detail. During the site audits and QA inspections, NRC geologists reviewed the geologic maps and associated data prepared to address the License Condition; examined the mapped tectonic structures, geologic features, and foundation bedrock units in the field; and evaluated geometry and field relationships of tectonic structures, including data constraining time of development, lithologies, and relationships between site-specific and regional tectonic structures. Based on these extensive activities, NRC geologists assessed the potential for tectonic and non-tectonic surface deformation at the VCSNS site and independently verified that no capable (i.e., Quaternary) tectonic structures occur that may adversely affect site suitability.