Ontario Power Generation (OPG) is undertaking preliminary evaluations of the potential refurbishment of Pickering Units 5 to 8, as well as Darlington Units 1 to 4. These projects could result in refurbishment outages in the 2013 to 2017 time frame for Pickering, and later for Darlington. These potential projects form a key part of the Energy Supply and Demand Strategy currently under consideration by the Ontario Power Authority. AECL is supporting OPG to establish the basis for Retubing and continued plant life operation.