Document: NUREG-0800
Document ID: a2598df1-7ec6-43a6-9d2a-d8210d1f944f
Document Type: srp
Title: through 7.9. Additional information relevant to the review process can be found in the references in
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500461.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.1
CFR Part: 
CFR Title: 

Content:
e characteristics. If software is involved in computer internal data communication, the review should proceed as described above under data communication systems. C.3.3. Review of Defense-in-Depth and Diversity I&C safety systems incorporating digital computer technology in the reactor protection system or ESFAS must comply with the NRC position on D-in-D&D described in the Staff Requirements Memorandum on SECY-93-087, "Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor (ALWR) Designs." Figure 7.0-A-4 illustrates the process for review of the system-level D-in-D&D features to determine compliance with the position. BTP HICB-19 describes in detail the regulatory bases, material to be reviewed, acceptance criteria, and review process. For simple modifications, such as incorporating a single digital function into an otherwise analog I&C system, the D-in-D&D analysis may be very simple. Extensive and detailed analyses may be required for completely integrated computer-based reactor protection and control systems. C.3.4. Review of Software Life Cycle Process Planning The Staff's conclusion regarding the quality and reliability of digital computer systems will be based upon confirmation of the following points: 1. Plant and overall I&C system requirements are correctly decomposed into the digital I&C system requirements for each digital I&C system under review. Critical hardware and software characteristics are identified. 2. A development process is specified and documented such that implementation of the process gives a high degree of confidence that the functional requirements will be or are implemented in the computer system. The life cycle process plan describes a coordinated engineering process in which design outputs at each planned stage of the design process are verified to implement the input requirements of the stage. 3. The specified process and products, including design outputs, are designed to be inspected at