Unit 4 ch 17 s2 nuclear energy


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  • In the US 70% of our energy comes from fossil fuel. Only about 20% of energy comes from nuclear power.
  • Unit 4 ch 17 s2 nuclear energy

    1. 1. Chapter 17, Section 2: Nuclear Energy Standards: SEV4a, e
    2. 2.  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.
    3. 3.  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.
    4. 4.  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
    5. 5.  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.
    6. 6.  Pros  Cons • Energy is highly • Uranium is nonrenewable concentrated- a little goes • VERY EXPENSIVE a long way so it will last  Natural gas plant = longer than fossil fuel. $600/kilowatt (kw) • Does not produce  Wind power = $1000/kw greenhouse gases  Nuclear power = $3000/kw • Good for countries that do • Low net energy yield not have good supply of because so much energy fossil fuel goes into  Ex: France- 75% of its energy mining, processing, safety, comes from nuclear power etc. • Must have complex buildings and extensive safety equipment • Nuclear waste is VERY DANGEROUS
    7. 7.  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?
    8. 8.  Site must be • Away from people • Away from water source • Geologically stable- no earthquakes Asof April 2011, government funding for Yucca Mtn facility has been suspended.
    9. 9.  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 Mutated tree. devices to conduct an Notice the unauthorized test. inner part of • Entire city evacuated the limbs are • To this day very high green (before radioactive levels in the area. explosion) & outer parts • Caused human, animal, & plant mutations as well as are blue (after numerous types of cancer. explosion)
    10. 10. 2 new nuclear power plants have been approved for Georgia. Located south of Augusta
    11. 11.  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.