Document: NUREG-0800
Document ID: 6209b3e7-917d-48d2-a299-4d1230aa5b51
Document Type: srp
Title: Revision 5 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550070.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
udes application modules, diagnostic modules, and other support modules. A watch-dog timer is normally set at the beginning of each cycle and reset at the end. If the cycle is not completed before the watch-dog timer period is complete, an error is generated. A basis should be provided that describes the cycle and demonstrates that the watch-dog timer is correctly implemented, the time required for the application modules does not exceed the allotted time given in the architecture timing budget, and diagnostic and other support modules will not cause the allotted time to be exceeded. Examples of solutions acceptable to the Staff may be found in the Safety Evaluation Reports for the Palo Verde Nuclear Generating Station, Units 1, 2, and 3, "Issuance of Amendments on the Core Protection Calculator System Upgrade," dated October 24, 2003, and the Siemens Power Corporation, Topical Report EMF-2110(NP), "Teleperm XS: A Digital Reactor Protection System," dated May 5, 2000. Use of Part-Scale Prototypes In systems that have not been implemented and tested on a full scale, expected system delays on scale-up should be calculated and shown to be less than limiting system response times (NUREG/CR-6083, Sections 2.1.3 and 2.1.4). A basis should be provided that describes the effects of adding sensors, divisions, communication links, controllers, computer nodes, or actuation devices required to scale the test system to full scale. Test data should confirm scaling as well as performance projections. Exceptions are considered anomalies or abnormal events. Prototypes designed to demonstrate scaling should include all significant architectural elements plus enough additional elements to show the scaling effects to be measured. BTP 7-21-9 Revision 5 - March 2007 4. Review Procedures Based on review of the available information and applicant/licensee commitments, the reviewer should reach a conclusion appropriate to the level of detail and type of submittal. For certified designs