Implementing Adaptive Phased Management 2024-28

This diagram shows a conceptual layout for the surface facilities, as well as an approximate area of 1,500 acres (600 hectares) for the underground services area and placement rooms in the deep geological repository at one of the repository sites under consideration. The proposed site in the Wabigoon Lake Ojibway Nation-Ignace area is located in crystalline rock, while the proposed site in the Saugeen Ojibway Nation-South Bruce area is in sedimentary rock.

The deep geological repository uses a multiple-barrier system designed to safely contain and isolate used nuclear fuel over the very long term. Constructed more than 500 metres below ground, the repository will consist of a network of placement rooms that will store the used nuclear fuel. This approach aligns with international best practices.

At the surface, there will be facilities where the used fuel is received, inspected and repackaged into purpose-built containers encased in a buffer box of bentonite clay before being transferred to the main shaft for underground placement. Work is underway on the design of the repository surface facilities, including the Used Fuel Packaging Plant.

The repository underground will be accessed through three shafts, which will be located within a single centralized and secure services area. This services area will also include an underground demonstration facility for testing of the future engineered barrier emplacement equipment. The layout also includes multiple access tunnels that enable the placement rooms to be situated in areas with a suitable host rock. The buffer boxes, with the used fuel containers inside, will be arranged in the horizontal placement rooms, and any spaces left over will be backfilled with granular bentonite pellets or chips.

We will continue to evolve the design of the repository using the site-specific information we obtain from additional site characterization after site selection, with an objective to develop the updated repository design for the construction licence around 2031.

We will also adapt to changes in technology, experience and learnings from nuclear waste management programs in other countries, and decisions about nuclear power generation that could change the volume or type of fuel to be managed such as small modular reactors (SMRs). For more information about how the NWMO will account for future decisions about nuclear generation in Canada, please see the section Keeping abreast of the external landscape and adapting to change.

As of the end of 2023, the repository design is sized to account for the existing inventory of used fuel, as well as projected inventories from planned reactor life extensions and refurbishments of operating reactors. Additionally, both potential sites have the capability for expansion of the underground to accommodate additional inventory.