scope:

This recommended practice provides guidance for the implementation of ANSI/ISA-67.04.01- 2006 in the following areas:

a) Methodologies, including sample equations to calculate total channel uncertainty;

b) Common assumptions and practices in instrument uncertainty calculations;

c) Equations for estimating uncertainties for commonly used analog and digital modules;

d) Methods to determine the impact of commonly encountered effects on instrument uncertainty;

e) Application of instrument channel uncertainty in setpoint determination;

f) Sources and interpretation of data for uncertainty calculations;

g) Discussion of the interface between setpoint determination and plant operating procedures, calibration procedures, and accident analysis;

h) Documentation requirements.

Purpose

The purpose of this recommended practice is to present guidelines and examples of methods for the implementation of ANSI/ISA-67.04.01-2006 in order to facilitate the performance of instrument uncertainty calculations and setpoint determination for safety-related instrument setpoints in nuclear power plants.