The Use of Prolog for Computerized Technical Specifications

The task of deciding whether a particular nuclear plant condition is in compliance with its Technical Specifications is, in principle, algorithmic. However, the implicit algorithm is so complex and the required level of confidence in code validity is so high that traditional methods of computerized analysis have proven unsatisfactory. PROLOG provides a close match to the explicit semantic structure of the written specifications, a good tool for analysis of the implicit subsystem operability trees and, by virtue of its declarative style and imbedded logical structure, greatly simplifies the problem of code validation. LCOM, a PROLOG representation of a subset of BWR Technical Specifications, was developed to explore the applicability of PROLOG in this problem domain and to provide benchmark data for full-scale implementations. The declarative style and built-in unification mechanism of PROLOG does substantially simplify the process of program construction and validation. Extrapolations indicate processing times for a complete Tech Spec implementation of ≳ 1 minute in systems capable of ≲ 20 KLIPS.