Nuclear Glossary
Atom
- The smallest particle of an element that retains all the characteristics of the element, comprising electrons (negative charge) orbiting a nucleus which contains protons (positive charge) and neutrons (no charge)
Background radiation
- Naturally occurring radiation which every person is exposed to, resulting from radiation from the Earth’s crust and cosmic rays.
- Refers to the variety of ecosystems and animal, bird, fish and plant species.
Chain Reaction
- Where a nuclear reaction such as fission causes similar reactions that continue to cause reactions
- Term used to describe the view that the Earth’s temperature and climate will change, in part, due to the buildup of greenhouse gas emissions from human activities.
- A fluid phase in a nuclear reactor that, in cooling the reactor core, creates steam to drive turbines to generate electricity
- The state at which a reactor produces enough neutrons to maintain fission reaction
- Changes to the environment caused by an activity in combination with other past, present and reasonably foreseeable human activities.
Decommissioning
- Removal of a facility (reactor) from service, including actions to safely dismantle buildings, reclaim land and restore the site to other uses.
- A naturally occurring hydrogen isotope with one proton and one neutron
- A molecule composed of one oxygen atom and two deuterium atoms also known as heavy water
- Process to resolve conflicts in mutually beneficial ways, using techniques such as negotiation or third-party mediation instead of public hearings or courts
Fission
- The splitting of an atom in two releasing energy; induced fission occurs when a free neutron collides with a nucleus causing it to split, unlike spontaneous fission which occurs without external influence
- Bundles of tubes containing uranium dioxide pellets that fuel nuclear reactors
Generator
- An arrangement of magnets spinning inside a coil of wire to produce electricity.
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The warming of the Earth’s surface caused by the presence of carbon dioxide and other gases, known as greenhouse gases, in the atmosphere that trap the heat of the sun.
- Gases that trap heat near the Earth’s surface. These include carbon dioxide, methane, nitrous oxide and water vapor. These gases occur through natural processes (such as ocean currents, cloud cover, volcanoes) and human activities (such as the burning of fossil fuels).
- Network of high-voltage transmission lines.
Heavy Water
- A molecule composed of one oxygen atom and two deuterium atoms also known as deuterium oxide
- Used nuclear fuel that is highly radioactive and requires long-term management and storage in shielded facilities to protect people and the biosphere. Canada’s high-level waste is held in interim storage facilities at reactor sites. Canada and other countries are exploring opportunities for long-term management of this waste, including deep geologic disposal in stable rock formations.
Isotope
- Atoms of an element that have the same number of protons but differing numbers of neutrons
Low-level waste
- Consists of industrial clothing, tools and equipment, which have become slightly contaminated by radioactivity. These wastes make up most of the nuclear power industry’s waste volume. These are stored at the reactor site or at dedicated waste management facilities.
Milling
- Process to extract the uranium from the ore. Ore is crushed to fine sand and treated with chemicals that remove impurities. Uranium concentrate (“yellowcake”) is produced at the mills, and then furthered processed for use in nuclear fuel assemblies.
- Matter in a nuclear reactor used to slow the speed of neutrons in order to increase the potential for fission
National Energy Board (NEB)
- The federal regulatory agency in Canada that authorizes oil, natural gas, and electricity exports; certifies interprovincial and international pipelines, and designated interprovincial and international power lines; and sets tolls and tariffs for oil and gas pipelines under federal jurisdiction.
- Natural resources that cannot be replaced after they have been consumed. This term applies particularly to fossil fuels such as coal, oil and natural gas, but also applies to other mineral resources found in the Earth's crust.
- Waste products resulting from nuclear fission
Once-through fuel cycle
- Fuel used in only one cycle, with no reprocessing.
Public consultation
- The process of involving all affected parties in the design, planning and operation of a seismic program, an oil or gas well, pipeline, processing plant or other facility.
- Usually intended to mean the interest of the public generally as opposed to the interest of an individual or company.
Radiation
- Emission of electromagnetic particles, such as alpha particles (helium ions) released during alpha radiation
- The decay of unstable nuclei giving rise to radiation
- Radioactive materials used in cancer therapy, medical diagnostic techniques, agriculture and industry.
- Clear, odorless, radioactive gas that occurs naturally in the environment and is produced by the radioactive decay of uranium. Radon is not dangerous in open air, but in confined spaces, where it accumulates, it can be a health hazard to workers.
- Vessel in which nuclear fission is controlled and harnessed
- Naturally occurring energy sources that are continually replenished. Examples of renewable energy are wind, solar and water.
- Recycling or processing of used nuclear fuel to recover its remaining uranium and plutonium (“fissile” materials) to produce fresh fuel.
Sievert
- Unit indicating the biological damage caused by radiation.
- Fission
- People with an interest in industry activities that affect them. They may include nearby landowners, Aboriginal communities, recreational land users, other industries, environmental groups, governments and regulators.
- Ecosystem condition in which biodiversity, renewability and resource productivity are maintained over time.
- Development that meets the needs of the present without compromising the ability of future generations to meet their own needs (as defined by United Nations World Commission on Environment and Development).
Turbine
- A rotary engine that converts the energy of a moving stream of water, steam or gas into mechanical energy. Turbines are classified as hydraulic (water) turbines, steam turbines or gas turbines. Turbine-power generators produce most of the world's electricity. Windmills that generate electicity are known as wind turbines.
Uranium
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The most common fuel used to create nuclear energy. Uranium is a naturally occurring element having 92 protons.
U-238 has 146 neutrons, is mildly radioactive and forms approximately 99.3 per cent of all uranium.
U-235 has 143 neutrons, is less stable and forms approximately 0.7 per cent of all uranium.
Enriched uranium is uranium in which the U-235 content has been increased to approximately 3.5 per cent. Uranium dioxide (UO2) is processed to form ceramic pellets that are loaded into rods which are used to fuel nuclear reactors