Document: NUREG-0800
Document ID: c6dbe9ec-b58d-4a77-85ee-47b58571c3c0
Document Type: srp
Title: Revision 6 - August 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A200.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
hat situation, the as-found value must be compared with the previous as-left value. BTP 7-12-5 Revision 6 – August 2016 4. Purpose The purpose of this BTP is to provide guidance for the NRC staff to verify conformance with the previously cited regulatory bases and standards for instrument setpoints. This BTP has three objectives: • Verify that setpoint calculation methods are adequate to ensure that protective actions are initiated before the associated plant process parameters exceed their analytical limits. • Verify that setpoint calculation methods are adequate to ensure that control and monitoring setpoints are consistent with their requirements. • Confirm that the established calibration intervals and methods are consistent with safety analysis assumptions. B. BRANCH TECHNICAL POSITION 1. Introduction Instrumentation and control (I&C) safety systems control plant parameters to ensure that safety limits will not be exceeded under the most severe design-basis accident. Instrument setpoints and acceptable as-left and acceptable as-found bands for these I&C safety system functions are chosen so that potentially unsafe or damaging process excursions (transients) can be avoided and/or terminated before plant conditions exceed safety limits. Accident analyses establish the limits for critical process parameters. These analytical limits, as established by accident analyses, do not normally include considerations for the accuracy (uncertainty) of installed instrumentation. Additional analyses and procedures are necessary to ensure that the limiting trip setpoint of each safety control function is appropriate. Instrument channel uncertainties in these analyses are based on the characteristics of installed instrumentation, the environmental conditions present at the instrumentation’s installed locations, and process conditions. A properly established setpoint initiates a plant protective action before the process parameter exceeds its analytical limit. This, in