The Deep Geological Repository (DGR) that our community is in the running to host is known as an Adaptive Phased Management (APM) Project. This means that the project will be implemented in phases over a period of time. It also means that as the science changes and questions and concerns are raised, the NWMO will adapt or change the way their processes accordingly. See below for a timeline of the Project. Read on for more information about the DGR and a Timeline.
Everyone in Canada (and the world) is responsible for used nuclear fuel. We need to find a safe way to store used nuclear fuel, and a Deep Geological Repository (DGR) is being proposed. You may be familiar with what a DGR is, or you may just be learning. Part of the DGR is the multibarrier system. Read below for more information on the multi barrier system and the Deep Geoglical Repository.
Barrier #1: The Nuclear Fuel Pellet
- uranium dioxide pellet
- hard, high density ceramic
- does not dissolve
- resistance to wear/tear & high temps
Barrier #2: Fuel Rod & Fuel Bundle
- each rod has pellets within it and is sealed
- the rods are composed of strong corrosion resistant metal called Zircaloy
- the rods are then put into bundles
Barrier #3: Used Nuclear Fuel Container
- containers are made from steel and a corrosion resistant copper coating
- this prevents radioactivity from escaping
- fuel bundles are placed inside a carbon steel pipe
- engineered to remain in tact and keep the used nuclear fuel isolated until radioactivity reachers levels of natural uranium
- holds 48 use fuel bundles
- spherical head welded on
- shape designed to withstand pressure
Barrier #4: Bentonite Clay
- this clay is a stable, natural formation from hundreds of millions of years ago
- powerful barrier to water flow
- swells when exposed water, creating a seal
- chemical properties isolate the unlikely event that radioactivity tries to escape.
- each fuel container will be encased in highly compacted bentonite clay buffer box
- each buffer box placed and separated from the next with bentonite spacer blocks, stacked in two layers
- 6-10 metre thick compacted bentonite seal
- 10-12 metre thick concrete bulkhead use to seal entrance to each placement room.
Barrier #5: The Geosphere
- the natural barrier of the granite rock at the site is part of why Ignace is still in the site selection process
- protects repository from disruptive natural events, water flow, and human intrusion
- repository will be approximately 500 meters underground
- the deeper its buried, the least amount of fractures in the rock which disrupts waterflow. See the waterflow/rock fracture diagram under the Environment page.