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
Chapter 17, Section 2: Nuclear Energy Standards: SEV4a, e
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.
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.
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
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.
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
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?
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.
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)
2 new nuclear power plants have been approved for Georgia. Located south of Augusta
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.