Document: NUREG-0800
Document ID: 4b0fa4a0-ce32-4f59-9360-9426826a668c
Document Type: srp
Title: Rev. 4 — June 1997
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500496.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
uirements to confirm that I&C safety system power sources are adequate.) Transmission of signals between independent channels should be through isolation devices. BTP HICB-11 provides guidance for the application and qualification of isolation devices. 8. Section 4.7 — Control and Protection System Interaction Control and protection system interaction involves more than examining the electrical isolation and interconnection. The functional performance of control systems must be such that a control system cannot prevent proper action of a protection system. This section of ANSI/IEEE Std 279, with regard to isolation devices and multiple failures resulting from a credible single event, is explained by example in the document (See Section 4.2 of ANSI/IEEE Std 279). The applicant/licensee's analysis should confirm that the requirements for control and protection system interaction are satisfied. 9. Section 4.8 — Derivation of System Inputs 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/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. 10. Section 4.9 — Capability for Sensor Checks The most common method used to verify the availability of the input sensors is by cross checking between redundant channels that have available readout. When only two