Document: NUREG-0800
Document ID: e427eac9-c153-4d33-b744-70711f982d6e
Document Type: srp
Title: B-9
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A091.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.1
CFR Part: 
CFR Title: 

Content:
system. Clause 4.7 of IEEE Std 279-1971, with regard to isolation devices and multiple failures resulting from a credible single event, is explained by example in Clause 4.2 of IEEE Std 279-1971. The applicant’s or licensee’s analysis should confirm that the requirements for control and protection system interaction are satisfied. 4.8. Derivation of System Inputs (IEEE Std 279-1971, Clause 4.8) A protection system that requires loss of flow protection would, for example, normally derive its signal from flow sensors. A design might use an indirect parameter such as a pressure signal or pump speed. However, the applicant/licensee should verify that any indirect parameter is a valid representation of the desired direct parameter for all events. Even a directly measured variable should be reviewed and its response to postulated events compared with the credit taken for the parameter in the events for which it provides protection. For both direct and indirect parameters, the applicant or licensee should verify that the characteristics (e.g., range, accuracy, resolution, response time) of the instruments that produce the protection system inputs are consistent with the analysis provided in Chapter 15 of the SAR.