Document: NUREG-0800
Document ID: 56298a3a-bad0-4f4d-91c4-5fc5c1817434
Document Type: srp
Title: INTERLOCK SYSTEMS IMPORTANT TO SAFETY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0704/ML070460348.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.6
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of instrumentation and controls Secondary - None I. AREAS OF REVIEW The objective of the review is to confirm that design considerations such as redundancy, independence, single failures, qualification, bypasses, status indication, and testing are consistent with the design bases of these systems and commensurate with the importance of the safety functions to be performed. 1. This Standard Review Plan (SRP) section describes the review process and acceptance criteria for those interlock systems important to safety that operate to reduce the probability of occurrence of specific events, or to maintain safety systems in a state that assures their availability in an accident. These systems include: • Interlock systems to prevent over-pressurization of low-pressure systems (e.g., residual heat removal) when these systems are connected to high-pressure systems (e.g., primary coolant). • Interlocks to prevent over-pressurization of the primary coolant system during low-temperature operation of the reactor vessel. 7.6-2 Revision 5 - March 2007 • Valve interlocks to assure the availability of emergency core cooling system (ECCS) accumulators. • Interlocks to isolate safety systems from non-safety systems (e.g., seismic and non-seismic portions of auxiliary supporting systems), and interlocks to preclude inadvertent inter-ties between redundant or diverse safety systems where such inter-ties exist for the purposes of testing or maintenance. 2. Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC). For design certification (DC) and combined license (COL) reviews, the staff reviews the applicant's proposed ITAAC associated with the structures, systems, and components (SSCs) related to this SRP section in accordance with SRP Section 14.3, "Inspections, Tests, Analyses, and Acceptance Criteria." The staff recognizes that the review of ITAAC cannot be completed until after the rest of this