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What is radiation?

Response

Last updated 10/18/2016

Radiation is energy travelling through space.

We are exposed to low levels of radiation every day from numerous sources, including many of our daily activities. Low levels of radioactivity are even present in certain common household objects.

All radiation takes the form of either electromagnetic waves or high-speed particles. Electromagnetic waves have energy, but no mass, and include things like microwaves, radio waves, visible light, X-rays and gamma rays. High-speed particles, on the other hand, have both energy and mass. This type of radiation includes neutrons, alpha particles and beta particles.

Excessive exposure to radiation can be harmful to people and other living things. Radiation is either “ionizing” or “non-ionizing” depending on how it affects matter. Examples of non-ionizing radiation are heat, light, radio waves and microwaves. Examples of ionizing radiation are gamma rays, X-rays and alpha particles.

Exposure to radiation can be controlled by using protective barriers. For example, a sheet of paper can stop alpha particles. A sheet of aluminum can stop beta particles. Gamma rays are much more penetrating and require dense barriers to keep them contained.

Used nuclear fuel gives off radiation. It is a potential health and safety hazard unless properly managed. It is subject to multiple layers of safeguards designed to protect people and the environment.

Radiation Risk and SafetyIs radiation from used fuel the same as natural radiation?

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What is used nuclear fuel?

Response

Last updated 8/13/2018

Used nuclear fuel is a by-product of electricity generation by nuclear power plants. Canadian nuclear power plants are fuelled by uranium pellets that are sealed inside zirconium tubes and arranged into fuel bundles.

Once a fuel bundle has been used to generate electricity, it is highly radioactive and must be carefully managed for a very long period of time, essentially indefinitely.

Used nuclear fuel in Canada is safely managed on an interim basis in licensed facilities at nuclear reactor sites. The NWMO is responsible for its long-term management.

This is an image of the components of a fuel bundle.
Canada's Used Nuclear Fuel

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What is the radioactivity of the used fuel over time?

Response

Last updated 10/18/2016

When used fuel is removed from the reactor, it is highly radioactive and requires careful management.

This radioactivity naturally decreases with time. Initially, the radioactivity decreases very rapidly. However, the residual radioactivity (together with chemical toxicity) persists, and the used fuel remains a potential health risk for a very long period of time.

It will take about one million years for the radioactivity level to reach that of an equivalent amount of natural uranium.

Radiation Risk and Safety

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How does radiation affect human health?

Response

Last updated 10/18/2016

Exposure to high levels of radiation can be dangerous. Measures to protect the public and workers from radiation and other hazards are being incorporated into all phases of our management of used nuclear fuel. This includes the safe transport of used fuel from current storage facilities, to its inspection and repackaging at surface facilities, and its long-term placement in the deep geological repository.

Used nuclear fuel contains radioactive nuclides which can emit ionizing radiation, and is most radioactive when it is first removed from the reactor. While the radioactivity diminishes over time, the used nuclear fuel remains hazardous, essentially indefinitely.

Radiation can either be ionizing or non-ionizing. The forms of ionizing radiation are alpha particles, beta particles and neutrons, as well as X-rays and gamma rays. Ionizing radiation have enough energy to change the makeup of materials at their most basic level, the atom. If the exposure is beyond the body's natural repair processes, it may lead to uncontrolled growth of cells (i.e., cancer) or more serious health effects. Non-ionizing radiation does not have enough energy to cause atomic changes. The Canadian Nuclear Safety Commission provides a helpful and informative summary of the impacts of radiation on human health.

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How will people and the environment be protected?

Response

Last updated 9/5/2018

Canada's plan for the safe, long-term management of used nuclear fuel involves containing and isolating it in a deep geological repository.

Safety of people and the environment is the top priority in the process for selecting a repository site. We will need to demonstrate that any site selected can safely contain and isolate used nuclear fuel for a very long period of time. There cannot be any credible risk from the repository to the public or the environment.

The repository will be located deep underground in a suitable rock formation, which must meet site selection technical criteria for the development of a robust safety case. This approach is consistent with international best practice, and is the culmination of more than 30 years of research, development, and demonstration of technologies and techniques.

The repository uses multiple barriers that include the waste form, container, sealing materials, and host rock. The system is designed such that the failure of one component would not jeopardize the safety of the containment system as a whole.

The project will also be subject to a thorough regulatory review process, including an environmental assessment and a licensing review to ensure that it is implemented in a manner that protects people and the environment.

Once placed in the repository, the used nuclear fuel will be monitored for an extended period of time.

Safety: Protecting People and the EnvironmentMultiple-Barrier System

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Is radiation from used fuel the same as natural radiation?

Response

Last updated 10/18/2016

The types of radiation emitted by used nuclear fuel are the same as those emitted by natural sources.

All radiation takes the form of either electromagnetic waves or high-speed particles. Electromagnetic waves have energy, but no mass, and include such things as microwaves, radio waves, visible light, X-rays and gamma rays. High-speed particles, on the other hand, have both energy and mass. This type of radiation includes neutrons, alpha particles and beta particles.

Used nuclear fuel emits both types of radiation, in the form of gamma rays, alpha particles and beta particles, and to a lesser extent, neutrons.

Radiation Risk and Safety

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Will health and safety of drivers or rail workers transporting used fuel be at risk?

Response

Last updated 10/18/2016

To ensure worker health and safety, the Canadian Radiation Protection Regulations set limits on the amount of radiation a nuclear energy worker can receive. These regulations set an annual dose limit of 50 mSv per year to a maximum of 100 mSv over a five-year period. Before any transportation of used nuclear fuel can begin, we will be required to demonstrate our operations will not result in any worker or member of the public being exposed to radiation that would result in exceeding regulatory limits.

A generic study was completed of the potential occupational dose to transportation workers involved in used fuel transportation using the Used Fuel Transportation Package. Transportation activities assessed in this study focused on worker activities from the time a used nuclear fuel shipment leaves the interim storage facilities to its arrival at the repository site. The study showed doses to workers would be lower than the regulatory public dose limit of 1 mSv per year.

Drivers and train crews would receive training that meets the Transportation of Dangerous Goods Regulations for ensuring safety and security. Shipments of used nuclear fuel will be continuously monitored by a transportation command centre and will have a security escort.

TransportationPublic and Worker Safety

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Will people be exposed to radiation when you transport used nuclear fuel? How much?

Response

Last updated 10/18/2016

The Canadian Nuclear Safety Commission regulates the use of nuclear energy and radioactive materials to protect the health, safety and security of people and the environment, including setting regulatory limits on radiation exposures. The regulatory limit for a member of the public is 1 milliSievert (1 mSv) per year.

The average natural background radiation dose received by Canadians is about 1.8 mSv per year.

A recent generic study was conducted to determine the potential exposure to individuals along transportation routes using the Used Fuel Transportation Package. The study considered individuals including residents living along or in the vicinity of the transport route, people sharing the transport route, and people at rest stops along the route. The annual dose to these people is expected to be lower than the regulatory public dose limit.

As part of the package and transportation certification and licensing process, and before any shipment of used nuclear fuel is authorized by the regulator, we will have to demonstrate that radiation levels from the package will be below the regulatory limit for transport packages.

Transportation Regulations and OversightSafe ContainmentGeneric Transportation Dose Assessment Study

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