Document: NUREG-0800
Document ID: 00471f3b-36d9-4ce3-af70-d4dac9bb0e67
Document Type: srp
Title: Draft Revision 6 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159A809.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
tion of each of the existing sensors in the common flow path to its laboratory response time test data, and also to the laboratory response time test data for the reference sensor. Correlation between LCSR test results for the existing sensors and LCSR test results for the reference sensor may be used to establish the correlation with the reference RTD laboratory test data. As-Found/As-Left Surveillance Data The applicant or licensee should maintain a database of the “as-left” and “as-found” calibration and response time tests for each sensor. To monitor systematic drift or degradation, at each refueling cycle, or as required by the plant’s technical specifications, a newly calibrated RTD or a new RTD with recent calibration data should be installed at representative location(s) determined by analysis. The cross-correlation to the reference RTD(s) should be monitored using “as found “and” “as left” data records. Test data and analysis should identify and account for differences in isothermal conditions and demonstrate that the drift is random and is within an acceptable band as determined by setpoint analyses, and that systematic drift is not exhibited. If historical data reveals potential drift problems which would exceed the allowable values of temperature drift in testing for any sensor then the applicant or licensee should verify the calibration of the deviating sensor(s) and identify appropriate corrective action. Analysis to project RTD drift should be available for all RTDs within the protection system. Control/Protection Interaction and Common-Cause Failure during In-Situ Testing If the applicant or licensee uses test equipment common to redundant channels, qualified isolation should be provided to preclude single-failure effects on redundant channels or unacceptable protection/control interactions. 4. Review Procedures The protection system design basis should be examined to identify the requirements for RTD accuracy and time response.