Graded approach to setpoint calculation programs Conference Paper uri icon


  • When ISA Standard S67.04, `Setpoints for Nuclear Safety-Related Instrumentation,' was originally written, it was directed at those instrument channels which were used for reactor protection and engineered safety features actuation. Over time the standard, and more recently the corresponding Recommended Practice (RP), have been utilized for setpoint calculations for instrument channels other than those for which they were originally envisioned. There appears to be a growing belief within the industry that the level of detail required by the Standard and Recommended Practice should be applied to all setpoint calculations. This paper provides recommendations for a graded approach for use of the requirements and guidelines from these documents based on safety significance of the instrument channel and/or the original basis for the setpoint. That is, all elements of the Standard and the RP may not be appropriate for all setpoint calculations. Please note that, while both authors are members of the S67.04 and S67.15 committees and the paper refers to and quotes from the S67.04 Part I and dRP67.04 Part II, this paper represents the authors thoughts and ideas with regard to a graded approach to setpoint calculations and at the time of submission has not been endorsed by either committee.

author list (cited authors)

  • Webb, R. C., & Beuchel, B. E.

publication date

  • December 1992