In-Depth: Dangers of Burying Nuclear Waste

Burying nuclear waste deep in the earth is an experiment. And once it is done, it will be very difficult to undo.

The nuclear industry in Canada likes to point to all the other countries that have been exploring the ideas of deep geological repositories for decades, as if this is evidence of success. But in fact, it would be more accurately viewed as evidence of failure.

After more than forty years of study and massive amounts of spending there is no operating deep geological repository for nuclear fuel waste anywhere in the world. There is no success story.

But, there are examples of failure:

In 2012, the proponent of the Swedish DGR (deep geological repository) submitted their application for a licence, but it has repeatedly been sent back for more work due to outstanding technical concerns, particularly around the durability of the copper container and the rate of corrosion. In early 2022 the Swedish government announced its political approval, but no license or permits have been issued by the Lands and Environment Court and further safety studies must be done (as of February 2022).

During the 1990s, Yucca Mountain became the proposed site for a deep geological repository despite objections from the State of Nevada and local residents. An application for a licence to construct the repository for high-level nuclear waste was filed by the Department of Energy in June 2008. In March 2010, DOE filed a motion with the Nuclear Regulatory Commission asking to withdraw its application, which the NRC denied on June 29, 2010. The project has been stalemated by funding freezes by first the Obama and then the Trump administrations while the U.S. looks at alternatives, including centralized storage.

Asse II is a former salt mine in Germany that was used as deep repository for radioactive wastes from 1965 to 1978. In 2008, two decades after leaks were first identified, it became publicly known that the site was leaking, and two years later the government made a decision to remove the radioactive wastes; the retrieval operation is expected to be complete in 2050.

Asse II deep repository for nuclear waste - failed — Asse II deep repository failed – nuclear wastes were removed

Ontario Power Generation spent fifteen years promoting its plan for a deep geological repository for low and intermediate level radioactive waste beneath the Bruce Nuclear Generating Station in southwestern Ontario; there were several unresolved technical issues, but it was a resounding rejection through a community vote by Saugeen Ojibway Nation that ended the project

The Waste Isolation Pilot Plant is a geological repository for U.S. transuranic (nuclear weapons) waste in New Mexico and is often pointed out by waste burial proponents as an example of a successful operating DGR (note that is not for high-level nuclear fuel waste). In 2014 the use of improper packing materials caused an underground explosion, which contaminated workers, resulted in releases of radioactivity to the above-ground area, and revealed multiple failures in the repository design and in the WIPP’s system for tracking the wastes

Courtesy U.S. Department of Energy. This barrel at the Waste Isolation Pilot Project near Carlsbad breached, resulting in radioactive contamination that shut down WIPP.

The concept of burying nuclear waste failed an environmental assessment review in Canada. The NWMO’s “Adaptive Phased Management” is based on Atomic Energy of Canada Limited’s 1988 “concept” of burying nuclear waste in the Canadian Shield. After a ten-year review – which included 13 months of public hearings – the Review Panel concluded in 1998 that the AECL concept had not been demonstrated to be safe and acceptable.

Deep Geological Repositories: What are the risks?

Promoters of deep geological repositories seem very confident of their ideas, and describe DGRs as if they actually know how they will operate and have experience to point to. But they don’t.

There is no operating deep geological repository for high-level nuclear waste operating anywhere in the world.

A deep geological repository is typically described as a series of tunnels and rooms / caverns several hundred metres below the surface in a rock formation. A deep geological repository design uses a multiple-barrier system, which is described as a number of barriers – engineered and geological – that are expected to work together to contain and isolate the radioactive elements in used nuclear fuel, keeping it separate from people and the environment.

But there are unknowns and uncertainties:

Container of copper and/or steel could corrode more quickly than expected.

The ability of the backfill (bentonite or bentonite mixture) to work as a barrier could be reduced because of heat and/or physical pressures from corrosion, the generation of gases and other factors

Gas will build up in the repository because of corrosion and materials degrading; this can create pressures on the rock, causing fractures that become escape routes for radionuclides

There may be unidentified fractures and faults

There may be a poor understanding of how water and gas will flow the through the fractures and faults

Radionuclides can be released to groundwater through fractures and faults

Excavating the repository (blasting out shafts, tunnels and the caverns where the waste would be placed) can damage the surrounding rock, creating routes for radionuclide escape

In the far future, the wastes will still be dangerously radioactive, but the repository itself might be forgotten; it is conceivable that future inhabitants may accidentally dig a shaft into the rock around the repository or a well into contaminated groundwater. Also in the far future, glaciations could cause faulting of the rock, rupture of containers and penetration of surface waters or permafrost to the repository depth, leading a release of the radionuclides in the waste.

Unless and until such difficulties can be resolved, a number of scenarios exist in which a significant release of radioactivity from a deep repository could occur, with serious implications for the health and safety of future generations. In this light, the existence in a number of countries of ‘road maps’ for the implementation of deep disposal, and the rejection of other options, do not automatically mean that deep disposal of highly radioactive wastes is safe.
Rock Solid

Challenges in the review of proposed Deep Geological Repositories

Before a deep geological repository will be licensed, constructed and put into operation, it will be subject to some form of public review, mostly likely through an environmental assessment process (currently in Canada this is done through the Impact Assessment Act) and then through a licence review by the Canadian Nuclear Safety Commission. Will these reviews mean that the project will only be approved if it is safe? Maybe. Maybe not.

Here are some of the areas of uncertainty:

The main set of technical arguments are packaged together in what is called the “Safety Case”. The Safety Case relies largely on computer models; if the information going into the computer model of the assumptions the model is built on is incorrect – even slightly – the prediction will not be reliable

The NWMO has not provided the public with access to the data the NWMO is collecting during their site investigations, despite the NWMO stating that this is in the information they will be relying upon in their licence applications

The Canadian Nuclear Safety Commission has a service agreement with the NWMO and have been providing them with advice and support for several years – and are paid by the NWMO to do so; these are not public exchanges of information and the arrangement is seen by many as the CNSC coaching the NWMO on how to meet the licence requirements

Deep Geological Repositories: What are the risks?

Challenges in the review of proposed Deep Geological Repositories

Further reading

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