Quintessa has developed a custom portfolio selection tool, CHANSELA (Channel Selection Assistant), for EDF Energy (formerly British Energy), which takes account of a wide range of factors to support decisions on which selection of channels of Advanced Gas Cooled Reactors (AGRs) should be inspected to support continued safe operation.

Decisions on which channels to inspect at outages are complex as different types of channel provide different information on the core condition.  It is important that the reasons for the choice of channels for inspection are clearly documented and the information gained at each inspection is systematically assessed.

CHANSELA aids this process in a number of ways.  Firstly, it allows the user to visualise historical information about the reactor on a core map; for example, channel bow, brick shrinkage and feature information.  The user can also elect to view channels or bricks that adhere to specific rules, for example those channels that are located at the edge of the reactor, have a high burn-up and have not been inspected since 2005.  After the user has used such rules to specify the exact information that is desired from a particular inspection, and any constraints or preferences that may influence the selection of particular channels, CHANSELA will automatically suggest the combination of channels that provides the maximal amount of information.  The user also has the option of picking their own portfolio of channels for inspection, seeing how well this scores in terms of information obtained, and comparing to the optimal portfolio or other user-defined portfolios.  The software allows every stage of the process to be documented, providing a clear and transparent audit trail.

This software employs some novel concepts including a genetic algorithm for optimising channel selections and flexible methods for providing queries to the software.