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
CFR Part: 
CFR Title: 

Content:
Section 3.2.1, “Software Requirements Specification,” and Section 4.2.1, “Software Requirements Specifications,” contain relevant guidance. An SRS that exhibits the functional and the software development process characteristics listed below should be produced. B.3.3.1.1 Functional Characteristics of SRS For each of the functional characteristics, the requirements imposed by the system requirements and system design on the software for that characteristic should be contained in the SRS. Functional characteristics addressed by the SRS include accuracy, functionality, reliability, robustness, safety, security, and timing. BTP 7.14-54 Revision 6 - August 2016 Accuracy means that accuracy requirements should be provided for each input and each output variable. Accuracy requirements should be stated numerically, and appropriate physical units and error bounds should be supplied. Accuracy requirements should include a description of data type and data size for each input and output variable. Functionality means that the operations that must be performed for each mode of operation are completely specified. Functions should be specified in terms of inputs to the function, transformations to be carried out by the function, and outputs generated by the function. Reliability means that all requirements for fault tolerance and failure modes are fully specified for each operating mode. Software requirements for handling both hardware and software failures should be provided, including requirements for analysis of and recovery from computer system failures. Requirements for on-line in-service testing and diagnostics should be provided. Robustness means that the behavior of the software in the presence of unexpected, incorrect, anomalous and improper: (1) input, (2) hardware behavior, or (3) software behavior is fully specified. Of particular concern is the behavior of the software in the presence of unexpectedly high or low rates of message traffic. Safety means that the