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
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Content:
perating and overhead functions, with well-defined and strictly controlled interfaces between them. Any online maintenance features should be included. The hardware and software architecture should be reviewed to verify that there is no violation of other criteria such as single failure, channel separation, and separation between Class 1E and non-1E systems. The review should verify that no new hazards are introduced into the safety system as a result of the architecture configuration. Security means the establishment of a SDOE per RG 1.152. Timing means that the architectural design describes all timing limitations, the strategy for handling each, the required margins, and the method of measuring those margins. A timing specification should exist for each architectural element, in terms of minimum and maximum times for execution. Scheduling mechanisms and inter-process communication methods should be described. The architecture should be such that operations are performed in the correct sequence. SRP BTP 7-21 provides additional guidance on real-time performance. SRP Section 7.9 provides additional guidance on digital data communications systems. B.3.3.2.2 Process Characteristics of SAD The software development process characteristics that the SAD should exhibit include completeness, consistency, style, traceability, and verifiability. Completeness means that all the software requirements are satisfied in the architecture. The SAD should address all operating modes specified in the SRS, including initialization, operational, shut-down, maintenance, and test modes. Consistency means that each software architectural element is compatible with the SRS, the hardware architecture, documented descriptions and known properties of the operational and hardware environment, and other software elements. Timing specifications of each software element should be consistent with the specifications of the other elements with which it interacts and with the expected performance of