Q    How does nuclear energy produce electricity?

Atoms have 2 main parts, a dense nucleus at the centre surrounded by an outer cloud of electrons orbiting the nucleus much like the planets circle the sun.  In a nuclear reactor, the nucleus of Uranium atoms is split into two or fissioned, and a great deal of energy is released in the form of heat.  This heat is used to boil water into steam; the steam is used to turn a turbine which in turn spins an electrical generator, producing electricity for the users. (see animated graphic)

Image by:  The U.S. Nuclear Regulatory Commission (NRC)

 Q    What’s the advantage of using Uranium for fuel instead of Diesel fuel?

Splitting a Uranium atom releases about 90 million times as much energy as burning an atom of Diesel or any other hydrocarbon fuel.  This is why a nuclear reactor can run for years on a single load of fuel.

Q    What is Uranium anyhow?

Uranium is a naturally occurring metal that is mined from the earth like any other metal.  It is denser than lead or gold and is about as common as Tin.

Q    Where do we get Uranium fuel from?

Canada is one of the largest Uranium producers in the world.  The richest deposits have so far been found in northern Saskatchewan, but commercial grade deposits have also been found in Labrador, Nova Scotia, Quebec, Nunavut, Northwest Territories, Ontario, Alberta and British Columbia.  Many other countries also mine Uranium.  The Uranium ore is crushed and milled and sent to fuel fabrication plants in Canada and around the world where it is manufactured into cylindrical fuel pellets about the size of a sugar cube.  The pellets are then placed in a metal structure to form a fuel bundle, which is placed in the reactor.

Q    Do we have enough Uranium?  Won’t we start running out just like oil?

There is enough proven reserves of Uranium to fuel the world’s reactors for many decades to come and new discoveries are being made all the time..  Furthermore, after Uranium has been used in the reactor, it can be re-cycled into new fuel that is burned in a different type of nuclear reactor that can extract up to 99 times more energy out of the fuel.  This fuel cycle will ensure that we will have enough nuclear fuel for centuries to come.

Q    What about radiation; aren’t nuclear reactors radioactive?

When the atoms of nuclear fuel are fissioned, the fission products typically have more internal energy than normal.  This energy is released in the form of radiation and we call this process radioactive decay.  The core of a nuclear reactor is intensely radioactive so a lot of radiation is produced there.  For this reason nuclear reactors have protective radiation shielding materials incorporated into their design to protect workers and the public.  Regulations require that nuclear power plants give off extremely low levels of radiation and in fact some public buildings are more radioactive than nuclear power plants simply because of the natural radioactivity in the building materials they are made of.

Q    What happens to the waste from a reactor?

After a period of years, the nuclear fuel becomes inefficient at producing heat and is removed from the reactor.  Commonly, although inaccurately this used fuel is referred to as waste when in fact  it is only slightly used and may be re-cycled back into fresh fuel for further energy production. 

Q    What are those huge curved towers at nuclear plants for?

Those huge curved towers are actually cooling towers.  Large quantities of water are used to cool the steam condenser in the power plant and in order to protect the environment; it must be cooled prior to return to the river or lake where it came from.  The huge towers create a natural draft that cools the water prior to its return to its source.  Although these towers are often associated with nuclear power plants, they are used at all thermal plants such as coal fired power plants.

Q     Can a nuclear plant explode like a nuclear bomb?

Absolutely No.  It is a physical impossibility for a nuclear power plant to explode like a nuclear bomb.  The concentration of the nuclear fuel in a reactor is quite different from bomb material and simply will not sustain an explosive chain reaction.

Q    What does it mean when a nuclear reactor goes critical?

A reactor that is “critical” simply means that it is in a steady state of heat production.  The energy that is released by the chain reaction in the fuel is neither increasing nor decreasing.  When the reactor is sub-critical, heat production is decreasing and when the reactor is super-critical, heat production is increasing.

Q    Does a nuclear reactor emit air pollution or greenhouse gasses?

No.  A nuclear reactor produces virtually non of the emissions that cause smog, acid rain, or greenhouse gasses.  All reaction products remain within the nuclear fuel.  The Canadian Energy Research Institute has found that the mining and fuel production, operation and waste disposal of nuclear plants produces just 1.8 grams of CO2 per kilowatt hour (g/kWh) compared with 540 g/kWh for natural gas fired generation and 1,050 g/kWh for coal fired generation. (Source:  Comparative Life-Cycle Assessment of Electricity Generation in Ontario, CERI 2008)

Q    What about the nuclear waste?

Before all the nuclear fuel is consumed, the fission product build-up in the fuel makes it inefficient at producing heat.  At this point the fuel is said to be spent, and is removed from the reactor.  Commonly, though inaccurately, referred to as nuclear waste the “waste” is actually only partially used fuel that still contains much of the nuclear energy.  This spent fuel can be sent to a processing facility where it can be recycled back into fresh nuclear fuel.  In the meantime it is held in secure storage.  For a more in-depth discussion on subject visit the Nuclear Waste Management Organization .