Document: NUREG-0800
Document ID: 757b676a-0f71-4094-8677-ca3a50743281
Document Type: srp
Title: Revision 7 – August 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A344.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
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Content:
nt of DI&C-ISG-02, “Task Working Group No. 2: Diversity and Defense-in-Depth Issues Interim Staff Guidance,” Revision 2. This interim staff guidance (ISG) was developed with extensive review of D3 issues including both internal review within the NRC and external input through public meetings with representatives from industry, vendors, and the general public. In summary, while the NRC considers (software) CCF in digital systems to be beyond design basis, NPPs should be protected against the effects of anticipated operational occurrences (AOOs) and postulated accidents with a concurrent CCF in the digital protection system. 1. Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(h), “Protection and Safety Systems,” requires compliance with Institute of Electrical & Electronics Engineers (IEEE) Standard (Std) 603-1991, “IEEE Standard Criteria for Safety Systems for Nuclear Power Generating Stations,” and the correction sheet dated January 30, 1995. For NPPs with construction permits (CPs) issued before January 1, 1971, the applicant may elect to comply instead with its plant-specific licensing basis. For NPPs with CPs issued between January 1, 1971, and May 13, 1999, the applicant may elect to comply instead with the requirements stated in IEEE Std 279-1971, “Criteria for Protection Systems for Nuclear Power Generating Stations.” IEEE Std 603-1991, Clause 5.1, requires in part that “safety systems shall perform all safety functions required for a design-basis event (DBE) in the presence of any single detectable failure within the safety systems concurrent with all identifiable, but non-detectable failures.” BTP 7-19-3 Revision 7 – August 2016 IEEE Std 603-1991, Clause 6.2, “Manual Control,” requires in part that means shall be provided in the control room to implement manual initiation at the division level of the automatically initiated protective actions. IEEE Std 603-1991, Clause 7.2, “Manual Control,” requires