Document: NUREG-0800
Document ID: 1b73c7c7-6991-449e-9bea-daaea39fefa5
Document Type: srp
Title: INSTRUMENTATION AND CONTROLS - INTRODUCTION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550076.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.1
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CFR Title: 

Content:
action is taken prior to, or to prevent accidents. Interlock systems important to safety are discussed in Section 7.6 of the SAR. F. Control systems are used in normal operations and in control plant processes that have a significant impact on plant safety but are not relied on to perform safety functions following anticipated operational occurrences or accidents. Control systems are reviewed to assure that they conform to acceptance criteria and guidelines, that the controlled variables can be maintained within prescribed operating ranges, and that effects of operation or failure of these systems are bounded by the accident analyses in Chapter 15 of the SAR. Control systems are discussed in Section 7.7 of the SAR. 7.1-3 Revision 5 - March 2007 G. Diverse I&C systems are provided expressly for diverse backup of the RTS and ESFAS. Diverse I&C systems account for the possibility of common-cause failures in protection systems. The diverse I&C systems category includes the anticipated transient without scram (ATWS) mitigation system, as required by 10 CFR 50.62. For plants with digital computer-based instrumentation and controls, diverse I&C systems may also include hard-wired manual controls, diverse displays, and diverse actuation systems specifically installed to meet the guidance of the Staff Requirements Memorandum (SRM) on SECY-93-087, "Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor (ALWR) Designs." This SRM describes the NRC position on diversity and defense-in-depth. Diverse I&C systems are discussed in Section 7.8 of the SAR. H. Data communication systems transmit signals between systems and between components of systems and include analog and digital multiplexers as well as non-multiplexed transmission. When such systems are included in a design, they support one or more of the categories of systems described above. They may also support I&C functions addressed in other sections of the SAR. Data