ADORE: Alternative detector layout optimization for ROP system of CANDU reactors

In CANDU® reactor design, the regional overpower protection (ROP) systems protect the reactor against overpower in the fuel which could reduce the safety margin-to-dryout. Specifically for the CANDU® 600 MW (CANDU 6) design, there are two ROP systems in the core, one for each fast-acting shutdown systems. Each ROP system includes a number of fast-responding, self-powered flux detectors suitably distributed throughout the core within vertical and horizontal assemblies. The placement of these ROP detectors is a challenging discrete optimization problem. The DLO (detector layout optimization) module of ROVER-F code was used to design the existing ROP detector layout of CANDU 6 reactors. In the past couple of years, a new methodology for designing the detector layout for the ROP system, called DETPLASA algorithm, has been developed. This method utilizes the simulated annealing (SA) technique to optimize the placement of the detectors in the core. This algorithm was developed to overcome the shortcoming of DLO method to produce a detector layout configuration when the size of the problem is large. An alternative method has been recently developed for solving the ROP detector placement problem. This method is called ADORE (Alternative Detector layout Optimization for REgional overpower protection system). Although technically any stochastic optimization technique can be utilized, presently this method utilizes the SA technique as its optimization engine. This paper presents an overview of ADORE methodology and provides some numerical results from its execution.

► This paper presents an alternative method for performing the regional overpower protection (ROP) detector layout optimization for CANDU reactors.
► It has been demonstrated that the new method can produce detector layouts which satisfy the desired trip set point.
► The robustness of the method has been tested against various sizes of ROP system.