For 40 years, nuclear generation has provided about half of Ontario’s electricity. It has an excellent safety record. And it’s reliable, affordable power with virtually no greenhouse gas emissions. But it produces a small amount of radioactive waste that has to be managed. OPG has managed that waste safely, in an environmentally sound manner since it first began operation. And, OPG is working to make sure Ontario has a safe, permanent solution to manage nuclear waste. One aspect of this has been developing a place to store low and intermediate‑level waste, such as products and components used in the reactor building that may have collected some radiation during use. Over the past 10 years, OPG has studied and consulted on the creation of a deep geologic repository (DGR) to meet this need.

What is the Deep Geologic Repository (DGR)?

One of the safest places to store low and intermediate‑level nuclear waste is in a deep geologic repository (DGR). The proposed DGR would be located at the secure Bruce nuclear site in Kincardine, Ontario.

What is low and intermediate‑level nuclear waste?

Low‑level waste includes items used at nuclear facilities, like mop heads, gloves, clothes and floor sweepings. Intermediate‑level waste includes used filters and resins, and reactor components.


Ontario Power Generation has safely transported, processed and stored its nuclear waste for more than 40 years. Low and intermediate‑level waste has been safely transported to and stored at the Western Waste Management Facility (WWMF), located at the secure Bruce nuclear site. In 2001, a long‑term management option was requested by the Municipality of Kincardine. With the support of Bruce County municipalities and communities, OPG has proposed to construct and operate a deep geologic repository (DGR) on its existing Bruce nuclear site that would safely isolate low and intermediate‑level waste deep underground. The DGR would be located 680 metres below ground, in 450 million year‑old, stable rock formations.

Low‑level waste consists of minimally radioactive materials such as mop heads, rags, paper towels, floor sweepings and protective clothing used in nuclear stations during routine operation and maintenance. These items are packed in plastic bags, placed in sealed containers, and loaded onto secure transport trailers for shipping to the WWMF for processing and storage. The low‑level waste is sorted at the facility and stored as is, compacted or incinerated.

Intermediate‑level waste consists mostly of resins and filters, and used reactor components. These items are loaded into specially reinforced and shielded transportation packages certified by the Canadian Nuclear Safety Commission. Currently, this waste is also safely stored at the WWMF.

The Deep Geologic Repository (DGR) is 680 metres underground. That’s 130 metres deeper than the CN Tower.


Isolated from the environment

The DGR will be located more than a kilometre away from any part of Lake Huron and will have no impact on the surrounding environment.


Impenetrable rock

The solid rock formations around the DGR will limit the movement of radioactivity to extremely slow rates.


Very favourable geologic features make the site of the proposed DGR one of the best possible locations for storing low and intermediate‑level waste.

  • It's located in a thick formation of sedimentary rock, which was laid down in an ancient ocean between 390 and 540 million years ago.
  • Multiple formations of flat bedrock (hundreds of millions of years old) lie beneath the Bruce site. It’s an extremely stable geologic formation that’s survived mountain‑building and multiple glaciers.
  • The rock at 680 metres deep was purposely chosen. It’s mechanically strong, has very low permeability, is virtually dry and is surrounded by rocks that prevent almost anything from passing through them.

Protecting the surrounding environment

Protected beneath solid rock

Multiple natural barriers of solid, stable rock safely protect and isolate Lake Huron from the DGR.

Safe & stable

The rock around the proposed DGR is ancient and has survived mountain‑building and multiple glaciers.

Experts predict the rock will remain stable for hundreds of millions of years.


The natural geologic features around the proposed DGR site will ensure the stored waste would remain isolated and contained.

Teams of geologists have documented why the features of the rock are ideal:

  • It’s predictable. Horizontally layered, undeformed sedimentary shale and limestone formations are spread over large distances.
  • It’s a natural barrier with extremely low permeability.
  • It’s stable. The DGR is located in a seismically quiet area comparable to the Canadian Shield.
  • It’s isolated far from water. The near surface and groundwater aquifers are well isolated from the proposed DGR.

There is a minute amount of water in the rock surrounding the site. But after careful study, scientists found the water is ancient and has properties of evaporated seawater. This means it has not been in contact with the surface for hundreds of millions of years.

OPG has done its homework.

Who has studied the DGR?

The proposed DGR has been proven very safe through numerous studies and analyses conducted by engineers, geologists, geoscientists and hydrologists.

Who confirmed the research results?

Teams of scientists and recognized experts from around the world have confirmed the DGR can safely store the waste.

Independent reviews say it’s safe.

Numerous independent reviews agree with the findings in the study.


It’s not just OPG that has studied the proposed DGR site to make sure it’s very safe.

Here’s a list of the numerous organizations and individuals who have contributed to the successful completion of site characterization activities and geosynthesis.

AECOM Canada Ltd.

Descriptive Geosphere Site Model
Geofirma Engineering Ltd.

Technical Oversight
Geoscience Review Group
  • Jacques Delay (Andra)
  • Joe Pearson
Andreas Gautschi (Nagra)
Derek Martin (University of Alberta)

Specialists & Consultants
Itasca – Geology, 3DGFM, Geomechanical Stability Analysis
Worthington Groundwater – Karst
Fracture Systems Ltd. – EDZ
AMEC Geomatrix Inc. – Seismic Hazard Assessment
Hydro Resolutions – in‑situ hydraulic testing

Canadian and International Universities
University of Toronto – glacial systems modelling
University of Waterloo – hydrogeological modelling, geology, hydrogeochemistry
University of Ottawa – groundwater and porewater chemistry, porewater extraction techniques
University of New Brunswick – diffusion testing and method development, hydrogeochemistry
University of Alberta - geomechanics
University of Bern – groundwater and porewater geochemistry, porewater extraction techniques
University of Washington – glacial erosion
Pennsylvania State University – cap rock integrity
Monash University – outcrop fracture mapping

The Deep Geologic Repository (DGR)

Nuclear power produces large amounts of clean electricity that keeps our air free of smog and greenhouse gas emissions while powering our homes, hospitals and businesses. But there are bi‑products that must be well managed. OPG has always been committed to the safe management of nuclear waste. A safe, permanent storage place for low and intermediate‑level waste is one more step in ensuring this responsible management continues long after our operations cease. Scientists have confirmed the proposed DGR can safely and permanently store low and intermediate‑level nuclear waste in a manner that protects the surrounding environment. Numerous independent reviews agree. This is one more step in protecting our environment, today and for future generations.