In-Depth: Transportation Risks

Definitions, links to data, studies and reports on the risks of long-distance transportation of high-level nuclear waste.

Radiation exposure due to the transportation of nuclear fuel waste falls into three categories: routine transportation operations; accidents including severe accidents during transportation or transfer; and terrorist attack during transportation, with possible catastrophic results.

Routine Exposure during Transportation of Nuclear Waste

During routine transportation operations, radiation is continuously emitted through cask walls. These are not high levels of radiation, but there is no safe level of exposure. The effects of radiation exposure are cumulative, so exposures from being near a transportation cask are added to your background exposure and other exposures such as medical imaging and air travel.

There are three different scenarios for exposure during routine transportation operations:

  1. members of the public residing or working at locations near the transportation routes;
  2. vehicle occupants trapped in traffic gridlocks or construction or other road stoppages;
  3. worker exposure (e.g., of drivers) during transport or inspections.

Transportation Accidents

Photo of jack-knifed truck in a snowstorm on the TransCanada Highway west of Thunder Bay

In severe transportation accidents, the container’s (cask’s) radiation shielding could be damaged, resulting in higher – possibly much higher –  radiation levels around the damaged container and possibly in the release of some portion of container contents, which could cause contamination of the surface and adjacent waterways.

Dangers of Cesium

In the event of an accident along the transportation route (or at the burial site during repackaging – or within the Deep Geological Repository itself), Cesium-137 could be released into the environment.

Radioactive Cesium-137 (an isotope of Cesium) is present in used nuclear fuel, and is of special concern because it is water soluble. It has a half-life of 30 years, and remains significantly radioactive for more than 100 years. Ingesting/absorbing Cesium-137 from contaminated water or food-chain organisms could have negative health impacts for human beings and other life. Organisms absorb Cesium easily; it mimics Potassium and is readily incorporated into soft tissues and organs, including the pancreas. Along with Stontium-90, Cesium-137 continues to be a major source of radiation in the zone of alienation around the former Chernobyl reactor. It is currently a major health threat near Fukushima.

Water-soluble Cesium-135 is also present in used nuclear fuel. It poses a smaller immediate danger as its rate of disintegration is much slower – yet, with a half-life of 2.3 million years, it remains a danger for much longer.


The NWMO currently proposes transporting only waste from Canada’s CANDU reactors to its potential DGR site. Although CANDU waste contains Plutonium, which is used to make nuclear bombs, the major terrorism concern with CANDU waste is simply its radioactivity, which could be exploited by terrorists threatening to use an explosive to scatter the waste over a large area, causing profound radioactive contamination. Waste travelling by truck or train could be vulnerable to such a scheme.

Also of concern is the possibility that the NWMO may in the future transport the nuclear fuel waste from SMRs (small modular reactors) to a DGR site. Some SMR designs will generate waste that contains fissionable material (capable of sustaining a fission reaction, or “going critical”; the Canadian nuclear industry has insisted this cannot happen with used the CANDU fuel waste generated by the current fleet of Canadian reactors).

Further reading:

Know Nuclear Waste website: Transportation

Excerpts from Northwatch’s 2019 Submission regarding Whiteshell Laboratories Relicensing: Transportation Safety Issues

Excerpts from Northwatch’s 2019 Submission regarding Whiteshell Labaoratories Relicensing: Canadian Nuclear Laboratories’ Proposed Use of NWMO Used Fuel Transportation Package (cask)

RADIOACTIVE ROADS website: Transporting nuclear waste – by road, by rail, by barge – is a risky business. Accidents can be catastrophic, but even “normal” operations will expose those along the transportation route to low doses of ionizing radiation.