Document: NUREG-0800
Document ID: 21b37b7c-b45c-4247-b4a5-c2f28df75be4
Document Type: srp
Title: INSTRUMENTATION AND CONTROLS (Tier 1)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070663.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.5
CFR Part: 
CFR Title: 

Content:
d evaluated. Detailed supporting information is in DCD Tier 2 Chapters 7 and 14.3. In lieu of having a completed I&C design for review, the reviewer must base the safety determination on an acceptable process for the design of the I&C systems, and related design acceptance criteria (DAC). The DAC are described further in Appendix A of this SRP Chapter. The issues discussed in the DAC should include the design of the safety system and plant protection system controls, development and qualification processes for I&C hardware and software, and design features that provide I&C system diversity as protection against common mode failures and address defense-in-depth considerations. These issues and their relationships to other systems of the design should be described in Tier 1. Figures may be used for this at a block diagram level. The description of the logic and control should address automatic decision-making and trip logic functions, and manual initiation functions associated with the safety actions of the safety-related systems. Instrumentation and control equipment may include microprocessor-based, software-controlled signal processors that perform signal conditioning, setpoint comparison, trip logic, system initiation and reset, self-test, calibration, and bypass functions. The signal processors associated with a particular safety-related system are usually considered to be an integral part of that system. Some I&C systems may be shared (such as a multiplexor system) and may be addressed in SSAR as a separate system. The safety determination and, therefore, the requirements that a separately described I&C system must meet will be determined by the safety significance of the systems that it is supporting. Tier 1 should address the development and qualification processes for I&C equipment. The discussion should include (1) design processes and acceptance criteria to be used for safety-related systems using programmable microprocessor-based control equipment, (2) a