Document: NUREG-0800
Document ID: 81c8f1c3-ae6a-49e5-8289-f33ef409c663
Document Type: srp
Title: Revision 6 - August 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A240.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
times are consistent with accident analysis assumptions. BTP 7-13-4 Revision 6 – August 2016 B. BRANCH TECHNICAL POSITION 1. Introduction To ensure adequate performance of the RTD, its accuracy and response time should be verified at appropriate intervals. For reactor coolant system (RCS) RTD sensors, practical considerations may limit the extent and methods prudent for in-situ calibration and testing. Periodic removal and re-installation of RTDs solely to support verification of calibration or response time could potentially introduce errors due to installation and increasing personnel exposure. In addition, it may not be feasible or prudent to achieve the range of isothermal conditions in the RCS for in-situ verification of the complete calibration range of the RTDs. Nevertheless, the applicant/licensee should provide assurance that the calibration and response time for each RTD has not significantly changed due to aging or degradation of the sensor and its installation. One method acceptable to the staff is to periodically provide an installed reference RTD that has been recently calibrated and response-time tested. The remaining “similar” RTDs may be cross-correlated to the reference RTD to identify any significant degradation in performance. The “similar” RTDs are those which can be shown to be subject to sufficiently similar temperature and flow conditions in the RCS. While this method does not provide for complete calibration verification of each RTD over its range, the staff has found the method adequate for timely detection of drift or degradation of RTDs, provided that the guidance herein is applied. This guidance addresses the following topics: • Traceability of the installed reference RTD to laboratory calibration data • Acceptable methods for in-situ testing of RTDs • Response time testing • “As-found” and “as-left” surveillance data • Control/protection interaction or common-cause failure during in-situ testing 2.