Whiteshell Laboratories (WL) has provided research facilities for the Cana­dian nuclear sector since the early 1960s. In 1997, AECL decided to discon­tinue research programs and operations at the facility, and in 1999 began to prepare plans for the safe and effective decommissioning of the WL site.

The major structures located on the WL site include the organic-cooled WR-1 research reactor (in storage with surveillance since 1995), the shielded facilities, research laboratories, and liquid and solid RAW management areas and facilities, including the concrete canister storage facility for the dry storage of research reactor fuel. In preparation for decommissioning, a comprehensive environmental assessment was successfully completed (AECL, 2001), and the CNSC issued a decommissioning licence for the WL site which came into effect on 1 January 2003. The CNSC has approved a

detailed decommissioning plan for the site, which provides information, as required, under the Class I Nuclear Facilities Regulations.

Initially, the decommissioning activities have been focused on decontami­nating and modifying nuclear facilities, laboratories and the associated service systems and removing redundant buildings to reduce risk and oper­ating costs. As buildings are prepared for final decommissioning, enabling facilities are being constructed to handle and store contaminated wastes that will arise from decommissioning (Koroll et al., 2009). Other work is ongoing in support of commitments made during the environmental assessment, including ongoing confirmation of the hydrogeological conditions of the waste management area on the site, fitness-for-service studies and an updated groundwater monitoring plan. Some areas within the waste management area were identified for early remediation within the overall site plan, including the fuel-bearing (in-ground) standpipes (Stepanik et al., 2011). The current plan has the major nuclear facilities being finally decommissioned/ dismantled in the 2020-2035 timeframe, consistent with the planned avail­ability of final long-term waste management facilities. These plans undergo reassessment as new cost and schedule information becomes available. It is anticipated that the site will be under institutional control for an extended period following decommissioning of the site infrastructure.