Document: NUREG-0800
Document ID: 1c54f5f9-dd57-4543-a00d-1597061af2e0
Document Type: srp
Title: SEISMIC CLASSIFICATION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1608/ML16084A812.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.2.1
CFR Part: 
CFR Title: 

Content:
c classification process and a sampling of risk- significant systems and mechanical components to validate that the applicant has an appropriate classification process in place. 9. GDC 2 requires SSCs that are important to safety be designed to withstand earthquakes. To support compliance with GDC 2, such SSCs should be appropriately classified to ensure that they are designed to withstand earthquakes. In addition to safety-related SSCs, nonsafety-related SSCs are to be designed to withstand earthquakes if they perform an important to safety function. The extent that these nonsafety-related SSCs are to be classified and designed for earthquakes depends on the specific need to be functional or to preclude their failure, consistent with risk insights. The risk informed approach that utilizes the probabilistic risk assessment (PRA) can be utilized to supplement and enhance the deterministic approach in order to identify these nonsafety-related SSCs that are credited in the PRA. Where industry consensus standards for seismic classification are consistent with NRC regulations, they may be acceptable for licensing purposes. 10. Various approaches, such as the regulatory treatment of nonsafety systems (RTNSS) process, may be considered to designate appropriate seismic requirements, including industry consensus standards and regulatory guidance. The RTNSS process is described in detail in an NRC memorandum from Dennis M. Crutchfield entitled “Consolidation of SECY-94-084 and SE CY-95-132,” dated July 24, 1995 (ADAMS Accession No. ML003708048), which consolidates approved policy positions from the two subject Commission papers and their associated Staff Requirements Memoranda. The RTNSS process is generally applied to passive designs and is considered for advanced reactors on a case by case basis. The designer will impose design requirements and classifications for these SSCs commensurate with their risk significance. For example, in SECY-96-128 and its associated SRM,