16.2 – Nuclear Energy

Objectives Explain how a nuclear reactor converts nuclear energy to thermal energy. Describe the advantages and disadvantages of using nuclear energy to produce electricity. Discuss nuclear fusion as a possible energy source.

Power Plants How do they work

Electricity About 20% in the USA comes from nuclear power plants Power plants convert an extremely small amount of mass into an enormous amount of energy using nuclear fission Overall, nuclear power plants produce about eight percent of all the energy consumed in the United States.

Nuclear Reactors A fuel that can be made to undergo nuclear fission Control rods that are used to control the nuclear reactions A cooling system that keeps the reactor from being damaged by the heat produced

Nuclear Reactors Heat is produced by nuclear fission Energy is released when U-235 nucleus split into two smaller nuclei after being split by a neutron Special rods absorb excess neutrons to prevent dangerous chain reactions

Nuclear power plants Use the heat of nuclear fission to produce steam Steam drives a turbine Turbine rotates an electric generator

Nuclear Power Plants Do not produce the air pollutants that are released by fossil-fuel burning power plants Produce nuclear waste Radioactive by-products from radioactive materials Low-level wastes contain only a small amount of radioactive material

Nuclear power plants High-level wastes must be disposed of extremely carefully because they will remain radioactive for tens of thousands of years The mining of the uranium can cause environmental damage Water that is used as a coolant in the reactor core must cool before it is released into streams and rivers

Nuclear fusion The joining together of nuclei Process uses hydrogen as fuel Hydrogen is abundant on Earth Product of the reaction is helium Helium is not radioactive and is chemically non-reactive

Nuclear fusion Not practical energy source due to the high temperature it requires Consume more energy to reach and maintain these temperatures than they produce Difficult to contain a reaction that occurs at such extreme conditions Disasters

In-class Assignment/Homework Pg. 500 #1-5, do not do #6 “Muddiest point” You will write out the concept (related to electricity, nuclear power, fossil fuels) that is most confusing to you I will evaluate the responses and modify future lesson to reteach or reinforce the concepts.