The Nuclear Waste Management Organization announced in November that it has selected Wabigoon Lake Ojibway Nation (WLON) and the Township of Ignace as the host communities for Canada’s deep geological repository.  This site is over a thousand kilometers from where most of the used nuclear fuel is presently stored and thousands of kilometers from one of the sites. If road transport is to be used it could involve up to 3 shipments a day for decades.

Many people along the routes have expressed concerns that they may be exposed to radiation as a shipment passes them. Others are concerned that if a Road Traffic Accident (RTA) occurs it could lead to a “nuclear disaster” arising from a “spill” or “leak”.

These concerns are understandable. Radiation is scary because it cannot be seen or heard and lived experience tells people that RTAs are inevitable. People also know of occasions where an RTA led to spills and leaks of hazardous materials where people were harmed. This “spill or leak” idea is reinforced by the Simpsons where spills and leaks of glowing green nuclear goo are a routine occurrence.

But what are the real risks and should people be concerned?

About the size of a Firelog a CANDU fuel bundle holds ceramic fuel pellets loaded into sealed zirconium tubes.

The key to answering that question lies in the nature of the cargo. Canadian nuclear fuel is made of pellets of dry Uranium Oxide.  Uranium Oxide is a ceramic.  (he plates we eat off are typically ceramic and will give some feel for how solid a pellet is). These pellets are contained in metal tubes and the tubes are welded together into bundles the size of a fireplace log.

While in use, producing clean electricity, a tiny amount of the uranium is changed into other elements.  Most of these elements are locked into the structure of the pellet but some gases are produced and these may not be entirely locked in.  Any gas that does escape the pellet is retained in the metal tube. There are no free liquids, it is not a green goo and the vast bulk of the material cannot flow as it is solid.  

These physical properties make used nuclear fuel easy to manage and contain so that while it is hazardous, it is not especially dangerous.  This statement may sound surprising but  its true as in the entire history of the industry, across the hundreds of plants around the world, no one has been harmed by its storage. Additionally, there have been no effects on the environment outside of the physical footprint of the storage facilities.  Few other industries can claim such a record for their primary wastes.

While the metal rods will contain all the radioactive material, they do allow radiation to be emitted.  This radiation is easily stopped with “shielding”. We see shielding in use when a technician stands behind a wall while taking X-rays. Shielding is as simple and as reliable as that.

During transport shielding is provided by a container that has a thickness of steel that reduces the radiation on the outside of the container to almost nothing. No one need be concerned by a container passing them.  This can be proved by going to the NWMO reports where the doses are calculated. More convincingly, the truck will have a driver who will sit right next to the container, many hours a day, many days per week, possibly for their entire career. Health and safety restrictions prevent even that driver from being put at risk of harm by the radiation.  No one else will be more exposed.

So what about the possibility of the used fuel being involved in an RTA?

The first thing to remember is that no matter what happens the used fuel itself cannot “leak” or “spill”. The second is that the metal rods are the first containment. And as well the bundles are in a container that is already very robust because of the thickness of steel needed to shield the fuel. 

In effect, this means that even in the worst case there can be no nuclear disaster. It also means that in almost all imaginable RTA’s the bundle would remain intact and there would be no radiological consequence whatsoever. If you had a bundle of metal tubes tied down in the back of your car would you expect it to be harmed in an accident?

Based on designs that have been used internationally for decades the transport containers provide shielding and containment in all imaginable incidents.

But a fuel bundle will be in a container. It has to be to provide the shielding. Those containers are designed to act as a physical shield, an impact limiter, fire protection and a sealed containment as well as shielding.   And then they are tested to demonstrate they will not fail.  They have been dropped, had trains smashed into them, had rockets fired at them, been immersed in water and have been dumped in large pools of burning oil. All to confirm they will not fail in any circumstance.  Consideration is also given to multiple events such as being hit by an oil tanker which bursts into flame before the container tips over a bridge into a river. 

And here lies one of the many misunderstandings that may lie behind the concerns; the idea that a container may fail.  “Failure” is a poorly defined word that is largely uncalibrated.  It could mean that the whole container disintegrates and exposes the bundles. This would appear to be what some people are imagining. But when the engineers talk about failure what they mean is a breach of the seal or other loss of integrity of the containment. This is a much less significant event.  And even that never happens in the tests.

So, the overall pathway to the escape of even that small quantity of radioactivity that is mobile (the gases) is long and complex.  First, the rod in which the pellets are held would need to be broken and likely that would only happen to a few not the whole bundle.  Then the gas would need to escape from the rods to dilute into the container. Then if the seal on the container failed some of it might make it into the environment.  But not all of it; the containers are not balloons that would squeeze the activity out. 

The focus that the industry has put on ensuring the containers never fail may ironically have contributed to the idea that if they did fail a disaster would occur.  But the real reason so much attention has been given to is that the nuclear industry takes any potential adverse environmental impact very seriously.

Despite all this an ardent detractor may still say, “this has never been done before so how can we be sure that there won’t be a disaster”.  It’s not a very strong argument and it’s not even true.  It has been done before. More than 20,000 shipments of used fuel have taken place around the world.  Containers that are very similar to the ones we will use in Canada (CANDU fuel bundles are smaller than those used in most other reactors and so the containers are slightly different) have been on trucks, trains and boats. They have traveled over continents, transferred over national borders and crossed oceans. And the reason no one in Canada knows about these shipments is that they have never caused a problem.

So, can used fuel be safely transported to its final disposal site? It depends upon what you call safe, but you can be sure it’s never going to cause a nuclear disaster because that is not possible it will be a lot safer than many other things that are moving on the roads today and it has been moved safely for decades.

About the Authors

Ian Wigginton is Co-Chair of the Canadian Nuclear Society (CNS) Environment, Waste Management & Decommissioning Group and also a member of the CNS Governing Council.

Neil Alexander is the Head of Communications for the Canadian Nuclear Society

The Canadian Nuclear Society