Document: NUREG-0800
Document ID: c3be7591-d074-48a8-bb9c-4dcdfccd0ddf
Document Type: srp
Title: Draft Revision 6 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159A959.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
ds of failures than traditional analog systems are. Self-testing and watchdog timers should reduce the time to detect and identify failures. Computer self-testing is most effective at detecting random hardware failures. The characteristics of digital systems should be considered in the review of technical specification surveillance features. Architectural differences between digital and analog systems warrant careful consideration during the review of surveillance test provisions. Furthermore, the concepts used to determine test intervals for hardware-based systems do not apply directly to the software used in digital computer-based I&C systems. Therefore, previous reliability analysis used to establish test intervals will address the effects of software usage. Similar reviews are performed as necessary to verify the self-test and periodic test provisions for nonsafety systems. 2. Information to be Reviewed Applicant or licensee's technical description of surveillance and self-test features, single-failure analyses, failure modes and effects analyses, and plant technical specifications should be reviewed. BTP 7-17-5 Draft Revision 6 – August 2015 3. Acceptance Criteria Surveillance test and self-test features for digital computer-based protection systems should conform to the guidance of RG 1.22 and RG 1.118. Bypasses necessary to enable testing should conform to the guidance of RG 1.47. Failure Detection Failures detected by hardware, software, and surveillance testing should be consistent with the failure detectability assumptions of the single-failure analysis and the failure modes and effects analysis. Self-Test Features Digital computer-based I&C systems should include self-test features to confirm computer system operation on system initialization. Digital computer-based I&C systems should generally include continuous self-testing. Some small, stand-alone, embedded digital computers may not need self-testing. Typical self-tests include monitoring memory and