Document: NRC Regulatory Guide
Document ID: c7a40fcc-fc9d-4eb2-ad86-f9f5b0f04c82
Document Type: regulatory_guide
Title: Plant-Specific, Risk-Informed Decisionmaking:  Technical Specifications (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1920/ML19206A489.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.177
CFR Part: 
CFR Title: 

Content:
finition of Operable – Operability. Therefore, some judgment is needed in applying the guidance in the Inspection Manual Chapter 0326, “Operability Determinations” (Ref. 15). The staff gives the historical basis for this definition in Generic Letter (GL) 80-30, “Clarification of the Term ‘Operable’ as It Applies to Single Failure Criterion for Safety Systems Required by TS,” dated April 10, 1980 (Ref. 16). As stated in GL 80-30, the TS were formulated to preserve the single-failure criterion for systems that are relied upon in the safety analysis report. When the required redundancy is not maintained, the TS require action within a specified time. GL 80-30 calls the specified time to take action an “equipment out-of-service” time. This term is equivalent to the term “completion time” used in the STS. This limited time is a temporary relaxation of the single-failure criterion to take action so that the equipment can be restored to an operable status in accordance with the TS. DG-1287, Page 6 Since the issuance of GL 80-30, the NRC has issued various initial operating licenses, combined licenses, and amendments to licenses, each of which contains a definition of “operable” similar to the GL 80-30 definition. These definitions do not require a licensee to assume an additional failure when assessing operability of a degraded or nonfunctional safety system or component. Harmonization with International Standards The NRC’s goal is to harmonize its guidance with international standards. The International Atomic Energy Agency (IAEA) has established a series of safety guides and standards constituting a high level of safety for protecting people and the environment. The IAEA safety guides present international good practices to help users to achieve high levels of safety. The information in this RG is generally consistent with the principles in the below IAEA documents: • IAEA Safety Guide SSG-3, “Development and Application of Level 1