On Optimal Assignment of Cold Standby Components for Multi-Channel Safety Interlocks

Abstract Since hardware failures are inevitable but random events, the reliabilities of safety interlocks can be closely tied to their structures and maintenance programs. Our primary objectives in this work are to devise corrective and preventive maintenance policies under the support of cold standbys and to derive the general formulations for computing the availabilities of alarm and shutdown subsystems based on their Markov diagrams. An interlock superstructure is also developed to facilitate the search for the best interlock designs and maintenance plans with the genetic algorithm (GA). One example is provided to demonstrate the feasibility and effectiveness of the proposed optimization approach.