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
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their safety function in the event of an anticipated operational occurrence. 2. Relevant Guidance IEEE Std 603-1991 requires in part that the safety system design basis include the following: • The increment allotted for inaccuracies, calibration uncertainties, and errors. • The overall response times of the safety system used in establishing the setpoint allowable value. • The basis to demonstrate that the assumed values used for instrumentation inaccuracy, calibration uncertainties and error, and time response are acceptable and reasonable. Performance of an RTD is characterized by its accuracy and response time. Accuracy is a measure of how well the RTD indicates a static temperature, and response time indicates how quickly the RTD can sense a temperature change. NUREG/CR-5560, “Aging of Nuclear Plant Resistance Temperature Detectors,” asserts that the calibration and response time of RTDs are affected by aging even within design conditions, but that the aging is manageable by periodic tests performed at each refueling interval. Electric Power Research Institute (EPRI) TR-106453-3925, “Temperature Sensor Evaluation,” provides additional information on RTD performance. 3. Purpose The purpose of this BTP is to provide guidance for NRC reviewers to verify that the previously cited regulatory bases and standards are met by an applicant's submittal. This BTP has two objectives: • Confirm that calibration inaccuracies, uncertainties, and errors associated with a proposed cross-calibration method are consistent with design basis and setpoint analysis assumptions, and • Confirm that a proposed cross-calibration method is adequate to confirm that RTD response times are consistent with accident analysis assumptions. 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