Document: NRC Regulatory Guide
Document ID: 2459a562-8984-421c-8058-d096dbb9617c
Document Type: regulatory_guide
Title: Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to Their Safety Significance
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0314/ML031430373.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.201
CFR Part: 
CFR Title: 

Content:
r those SSCs with the potential for common cause failures. The IDP may want to use the following criteria to check whether the SSC is categorized appropriately, and for SSCs not explicitly modeled, by considering whether the SSC has an impact on the plant’s capability to: (i) Prevent or mitigate accident conditions, (ii) Reach and/or maintain safe shutdown conditions, (iii) Preserve the reactor coolant system pressure boundary integrity, (iv) Maintain containment integrity, or (v) Allow monitoring of post-accident conditions. 21. Section 10.2 For licensees that perform the optional step, “Detailed Engineering Review of HSS Components,” the same depth and rigor must be used in categorizing at the individual component level as was used for categorizing at the system functional level. Thus, if a SSC is determined by the categorization process to be safety-significant then it cannot be re- categorized LSS without re-performing the entire categorization process at the component level. However, if the component is not determined to be safety-significant by the detailed component level categorization process, then the following factors must be considered in determining if the SSC can be categorized LSS in addition to the identified NEI 00-04 considerations:  Safety function being satisfied by SSC operation  Level of redundancy existing at the plant to fulfill the SSC’s function  Ability to recover from a failure of the SSC 12  Performance history of the SSC  Use of the SSC in the Emergency Operating Procedures or Severe Accident Management Guidelines Further, the licensee or applicant, through the IDP, must document the basis for the classification of an SSC based on the above considerations, including the development of a SSC level categorization worksheet similar to that developed for the system-level results in Section 7. For SSCs not modeled explicitly in the PRA, the IDP could use the following guidance to determine if low safety significance is