PROBABILISTIC ROP DETECTOR LAYOUT OPTIMIZATION USING SIMULATED ANNEALING TECHNIQUE FOR CANDU~? REACTORS

摘要

The Regional Overpower Protection (ROP) systems protect CANDU~? reactors against overpower in the fuel that could reduce the safety margin-to-dryout. The overpower could originate from localized power peaking within the core or a general increase in the core power level. In the CANDU 6 design, there are two ROP systems in the core, one for each of the two fast-acting shutdown systems. Each ROP system consists of a number of fast-responding, self-powered flux detectors suitably distributed throughout the core within vertical or horizontal assemblies. A new approach for designing the detector layout for the ROP system was recently introduced. The new method, called the DETPLASA algorithm, utilizes the simulated annealing (SA) technique to optimize the placement of the detectors in the core. The DETPLASA algorithm was originally developed as a tool for the deterministic design stage of the ROP system. Further developments have been performed to the algorithm to incorporate the probabilistic trip setpoint evaluation. This paper presents the new and improved DETPLASA algorithm along with some numerical examples to illustrate its performance.