Document: NUREG-0800
Document ID: 5989239b-cda8-4832-8a1c-ff0c221fca34
Document Type: srp
Title: Draft Revision 6 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159A799.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
• 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. BTP 7-12-5 Draft Revision 6 – August 2015 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 turn, ensures that the transient will be avoided and/or terminated before the process parameters exceed the established safety limits. Similar calculations and reviews are performed as necessary to verify the setpoints for functions that are not related to a safety limit or for nonsafety