AECL’s CRL site is large (-4000 ha) and diverse and contains many struc­tures and features, some dating back to the beginning of the site ’s first establishment in 1944. The site is expected to continue in operation as a licensed nuclear site, with a wide range of nuclear research and develop­ment and operation activities being conducted for many years to come. Any contaminated facilities or contaminated lands and radioactive wastes that have been produced during prior operations or decommissioning activities constitute the legacy liabilities that are now managed through the NLLP, described above in Section 19.2.2.

The decommissioning model for the CRL site, including the waste man­agement areas, is described in a comprehensive preliminary decommission­ing plan (CPDP) (Miller, 2010). The strategy developed is for a number of individual decommissioning projects for the site’s various components over time rather than a single project for the site as a whole at some time in the future, designated as the end of operational life. Priorities for decommis­sioning projects are established based on health, safety, security and envi­ronmental risks, and also take into consideration operational requirements and business priorities (Stephens, 2009). The individual decommissioning projects in the CRL site CPDP document are grouped into seven planning envelopes (PE), where each PE is a grouping that has a degree of similarity, which lends itself to the application of common planning assumptions. Plan­ning envelopes 1-4 are for above-ground structures, PE 5 is for distributed services, PE 6 is for affected lands, and PE 7 is for waste management areas. The individual projects will, in general, take each respective structure or feature to a documented end-state while the site as a whole continues in operation. Some projects will be implemented at the end of the site’s opera­tional life to qualify the site for a period of institutional control, the refer­ence being 300 years (2100-2400). During the institutional control period, selected parts of the site may be turned over for industrial re-use in accord­ance with then-current laws and regulations. Work is currently under way to develop an overall, co-ordinated environmental restoration strategy for the CRL site which is integrated with the plans for decommissioning the physical structures and available waste management facilities, and which is in the most cost — and risk — effective manner as determined by the various stakeholders.