Document: NUREG-0800
Document ID: 4f141c71-35ca-4353-9047-a13efe6d56b7
Document Type: srp
Title: Revision 6 - August 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A308.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
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CFR Title: 

Content:
in a given implementation. Traceability - The degree to which each element of one life cycle product can be traced forward to one or more elements of a successor life cycle product, and can be traced backwards to one or more elements of a predecessor life cycle product. Traceability is central to the production of complex systems to ensure all requirements are implemented, checked and tested. (See also the definition of “Traceable” in Clause 4.3.8 of IEEE Std 830, which is endorsed by RG 1.172.) Unambiguity - The degree to which each element of a product, and of all elements taken together, have only one interpretation. (See also the definition of “Unambiguous” in Clause 4.3.2 of IEEE Std 830, which is endorsed by RG 1.172.) Verifiability - The degree to which a software planning document, implementation process document or design output is stated or provided in such a way as to facilitate the establishment of verification criteria and the performance of analyses, reviews, or tests to determine whether those criteria have been met. (See also the definition of “Verifiable” in Clause 4.3.6 of IEEE Std 830, which is endorsed by RG 1.172.) BTP 7.14-9 Revision 6 - August 2016 B. BRANCH TECHNICAL POSITION B.1 IntroductionError! Bookmark not defined. Digital I&C safety systems must be designed, fabricated, installed, and tested to quality standards commensurate with the importance of the safety functions to be performed. Implementation of an acceptable software life cycle provides the necessary software quality. Digital I&C systems can share code, data transmission, data, and process equipment to a greater degree than analog systems. Although this sharing is the basis for many of the advantages of digital systems, it also raises a key concern: a design using shared data or code has the potential to propagate a common-cause or common-mode failure via software errors, thus defeating the redundancy achieved by the hardware architectural structure. Greater sharing