Document: NUREG-0800
Document ID: fea61ff0-f344-4101-adfb-590e3d9dfafe
Document Type: srp
Title: Draft Revision 6 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159A946.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
ety of the software-controlled safety system, but are primarily concerned with the internal operation of the software. The safety characteristic, however, is primarily concerned with the effect of the software on system hazards and the measures taken to control those hazards. Security - The establishment of a Secure Development and Operational Environment (SDOE) for digital safety systems to: (1) to prevent undocumented, unneeded, and unwanted modifications and (2) to protect against a predictable set of undesirable acts (e.g., inadvertent operator actions or the undesirable behavior of connected systems) that could challenge the integrity, reliability, or functionality of a digital safety system during operations. RG 1.152 contains guidance for SDOE. Timing - The ability of the software system to achieve its timing objectives within the hardware constraints imposed by the computing system being used. A.3.2.2 Definition of Process Characteristics Completeness - Those attributes of the planning documents, implementation process documents and design outputs that provide full implementation of the functions required of the software. The functions which the software is required to perform are derived from the general functional requirements of the safety system, and the assignment of functional requirements to the software in the overall system design. (See also the definition of “Complete” in Clause 4.3.3 of IEEE Std 830, which is endorsed by RG 1.172.) Consistency - The degree of freedom from contradiction within a single document or among the different documents and components. There are two aspects to consistency. Internal consistency denotes the consistency within the different parts of a component for example, a software design output is internally consistent if no set of design elements are mutually contradictory. External consistency denotes the consistency between one component and another for example, software requirements and the resulting code are