Is nuclear energy a good idea or not? SNN

What is Nuclear Energy? Nuclear energy is the energy that comes from the core or the nucleus of an atom. Massive amounts of it are available to make electricity. It is released in 2 ways: Fission Fusion

Nuclear Fission Nuclear fission is the splitting of a nucleus into two roughly equal parts, usually caused by the bombardment of neutrons. It is usually accompanied by the release of large amounts of energy if the mass after the split is less than the mass before. Energy is calculated through

Chain Reaction During fission, a nucleus is split into two roughly equal fragments producing 2 or 3 neutrons. If these neutrons are slowed down, they may produce further fissions producing more neutrons. This is a chain reaction . It only occurs if a critical mass of material is available.

Nuclear Reactor The reactor consists of Fuel rods – enriched Uranium Moderator - slow down the neutrons Control rods - to absorb neutrons. (slow/stop reactions) Shielding – thick concrete walls surround it. Lead is also used. Coolant – the nuclear energy is converted to heat. The reactor core is cooled using water . Heat exchanger – takes the heat to a turbine which drives an electrical generator

Accidents in Nuclear plants. A nuclear reactor was damaged during an earthquake in Japan on March 11 2011. http://www.youtube.com/watch?v=BdbitRlbLDc An explosion is a nuclear rector caused the worst nuclear disaster in history in Chernobyl in 26 April 1986.

Nuclear Bomb If a chain reaction continues uncontrolled, a nuclear explosion occurs. A certain mass (critical mass) of fissile material is required. In the nuclear bomb, two masses of fissile material, each less than the critical mass, are brought quickly together to produce a nuclear explosion.

Nuclear Fusion Nuclear fusion is the joining together of two small nuclei to form a larger one. Two such reactions are the following To overcome Coulomb repulsion, the nuclei must hit each other with enormous velocities. Nuclei reach these velocities when heated to temperatures of around 100,000,000oC Nuclear fusion in the interior of the sun is the principal source of the sun’s energy.

Nuclear Fusion – an alternative? Advantages of fusion over fission Less radioactive No chance of a runaway chain reaction The fuel, deuterium, is readily available and cheap (in the oceans)

Hazards & Precautions of Ionising Radiation Ionisation causes atoms to lose electrons. In human tissue, this can affect the normal operation of body cells. This can cause skin burns, cancer, genetic defects or death. Precautions: Use protective clothing Minimise the time spent using them Make sure sources are properly shielded Do not eat or drink in their vicinity Use tongs for handling sources Keep sources in a safe place

Pros and Cons of Nuclear Energy Efficient – Produces a lot of electricity Waste – radioactive waste is very dangerous Reliable – not dependent on weather Cost – v. expensive to build Clean – no carbon emissions Terrorism – dangerous targets in war Plentiful – a little uranium goes a long way Danger of Nuclear Meltdown - Chernobyl

Radon and your environment The greatest health risk from radiation in Ireland is caused by radon. It is formed by decay of Uranium in rocks. The gas builds up in well insulated homes and can cause lung cancer.

Mass–Energy Einstein’s Special Theory of Relativity: mass and energy are equivalent – mass can be converted to energy and energy to mass. This is the law of Conservation of Mass-Energy A small quantity of mass can create a large amount of energy – according to the formula