Document: NUREG-0800
Document ID: 8c755ba5-45e1-492e-b36c-5fa2fa5b3e29
Document Type: srp
Title: Appendix 7-A
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500545.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
ed in the review: • The relationships between the safety limit, analytical limit, the allowable value, the setpoint, the as-found limit and the as-left limit. • The basis for selection of the trip setpoint. • The uncertainty terms that are addressed. • The method used to combine uncertainty terms. • Justification of statistical combination. • The relationship between instrument and process measurement units. • Data used to select the trip setpoint, including the source of the data. • Assumptions used to select the trip setpoint (e.g., ambient temperature limits for equipment calibration and operation, potential for harsh accident environment). • Instrument installation details and bias values that could affect the setpoint. • Correction factors used to determine the setpoint, e.g., pressure compensation to account for elevation difference between the trip measurement point and the sensor physical location. • Instrument test, calibration or vendor data, as-found and as-left; each instrument should be demonstrated to have random drift by empirical and field data. Evaluation results should be reflected appropriately in the uncertainty terms, including the setpoint methodology. The design, installation, calibration procedures, and calibration activities for specific channels may be inspected to gain further confidence that setpoint calculations are consistent with plant equipment and calibration procedures. NRC Inspection Manual Chapter 93807, "Systems Based Instrumentation and Control Inspection," provides guidance for such inspections. Rev. 4 — June 1997 Appendix 7-A BTP HICB-12-6 C. References ANSI/IEEE Std 279-1971. "Criteria for Protection Systems for Nuclear Power Generating Stations." ANSI/NCSL Std Z540-1-1994. "Calibration Laboratories and Measuring and Test Equipment - General Requirements." Draft Regulatory Guide DG-1045. Proposed Revision 3 to Regulatory Guide 1.105, "Instrument Setpoints for Safety Systems." Office of Nuclear