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Nonrenewable Energy. Chapter 17, Section 2: Nuclear Energy Standards: SEV4a, e. What is nuclear energy?. Nuclear energy is the energy within the nucleus of an atom. This energy is very powerful & can be harnessed thru fission reactions.
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Nonrenewable Energy Chapter 17, Section 2: Nuclear Energy Standards: SEV4a, e
What is nuclear energy? • Nuclear energy is the energy within the nucleus of an atom. • This energy is very powerful & can be harnessed thru fission reactions. • Uranium is the element used as a source of nuclear energy.
What is nuclear fission? • Neutrons are fired into atoms of uranium. • Uranium atoms split & release their neutrons and tons of energy. • These uranium neutrons go on to split more uranium atoms • This creates a chain reaction • Chain reaction of energy can easily get out of control and cause explosion. • Constant monitoring and safety measures must be taken to prevent explosions.
How does a nuclear power plant work? • A nuclear reactor is a large concrete structure that houses the uranium fuel assembly. • Has concrete walls that are 30 cm thick with steel inner lining to contain potential explosions. • Has large vat of water that has uranium fuel rods submerged in it. • Vat of water also contains control rods. • Control rods of cadmium or boron absorb neutrons and control the uranium chain reaction. • Uranium chain reaction occurs, heats water, creates steam, turns turbine which turns a generator to create electricity
Why are water and control rods important in a nuclear power plant? • Water absorbs heat and slows the neutrons. • Control rods control the rate of the reaction. • During peak energy demands control rods are raised out of water so reaction can happen faster and create more energy. • During nonpeak periods control rods are submerged to slow the reaction. • If reaction appears to get out of control, the control rods are slammed into the reactor vessel to stop the reaction.
What are the advantages and disadvantages of using nuclear power? • Pros • Energy is highly concentrated- a little goes a long way so it will last longer than fossil fuel. • Does not produce greenhouse gases • Good for countries that do not have good supply of fossil fuel • Ex: France- 75% of its energy comes from nuclear power • Cons • Uranium is nonrenewable • VERY EXPENSIVE • Natural gas plant = $600/kilowatt (kw) • Wind power = $1000/kw • Nuclear power = $3000/kw • Low net energy yield because so much energy goes into mining, processing, safety, etc. • Must have complex buildings and extensive safety equipment • Nuclear waste is VERY DANGEROUS
What are the problems with nuclear waste? • Nuclear waste consists of used fuel rods, water, mining waste, & clothing of workers. • Exposure can cause cancers or tumors • Radioactive for 1000’s of years • Must have container to store it in that will last that long. • Currently most radioactive nuclear waste is stored onsite in huge concrete vaults underground. • A site at Yucca Mtn, Nevada is being developed to house all nuclear waste • Many people do not want waste traveling thru their towns to Nevada • New containers have been developed to prevent risk of nuclear waste accidents during travel. • Do you think it is safe to store all radioactive waste in one location?
Why is Yucca Mountain the site for nuclear waste disposal? • Site must be • Away from people • Away from water source • Geologically stable- no earthquakes • As of April 2011, government funding for Yucca Mtn facility has been suspended.
What is a nuclear meltdown? • When the chain reaction gets so out of control it causes an explosion • Worst nuclear accident was in 1986 in Chernobyl in the Ukraine. • Workers turned off safety devices to conduct an unauthorized test. • Entire city evacuated • To this day very high radioactive levels in the area. • Caused human, animal, & plant mutations as well as numerous types of cancer. Mutated tree. Notice the inner part of the limbs are green (before explosion) & outer parts are blue (after explosion)
What is the future of nuclear power in Georgia? • 2 new nuclear power plants have been approved for Georgia. • Located south of Augusta
Is nuclear FUSION possible? • Nuclear fusion- combining of nuclei to make heavier atom and releases large amounts of energy. • Same energy as in sun & stars • Safer only b/c less dangerous radioactive byproducts • Technology not developed yet to harness power safely.