Document: NUREG-0800
Document ID: 0acce825-b76b-42b8-abac-5dd1ef880f21
Document Type: srp
Title: Diversity and
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A085.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.9
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CFR Title: 

Content:
tation. The scope and depth of the inspection should be consistent with the extent and complexity of the proposed digital system and the potential safety impact of system failure. For simple, limited, low-impact retrofits to existing systems, the process audit may be a very limited-scope “desk audit” of selected examples of process documentation. The review of extensive digital I&C systems, such as replacement of the protection and control systems, should involve detailed reviews of a wide range of software process documentation. Ideally, these reviews would occur in process audits of several of the life-cycle phases, as indicated in Figure 7.0-A-5 of this appendix. The audit of a given set of life-cycle activities and the inspection of products generated by those activities, as discussed in Subsection C.3.7 below, may be combined into a single audit. One effective audit technique is the string audit. Reviewers examine the implementation of a randomly selected, statistically significant sample of software development process requirements and functional requirements and confirm that they are implemented throughout the life-cycle. Appendix 7.0-A-16 Revision 6 – August 2016 For new reactor applications, the licensee’s implementation of the lifecycle activities will be verified through the construction inspection program. For applications under 10 CFR Part 52, appropriate ITAAC should be in identified in the application to verify implementation of the lifecycle activities. SRP Section 14.3.5, “Instrumentation and Controls - Inspections, Tests, Analyses, and Acceptance Criteria,” provides acceptance criteria for software lifecycle ITAAC. 3.7 Audit of Software Life-Cycle Process Design Outputs The products of a design process include the design outputs that describe the technical requirements of systems and components and the systems and components themselves. The review of digital systems should include inspection of these products on an audit basis to