Nuclear energy
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Transcript of Nuclear energy
NUCLEAR ENERGY
Ch. 11
Nuclear fission process
Splitting atom, releases heat Uncontrolled: explosion Controlled: make heat to produce steam
that turns generator to produce electricity
Electricity production
US produces most energy, but France produces highest percentage of countries electricity (78%), and Japan
Potential energy 10 million times more than ff
1960s-1980s – many plants built Concerns – safety, cost, nuclear waste Current renewed interest
Electricity shortages, ff prices, global warming
Nuclear fuel
THE BIG PICTURE
1/6 CO2 as fossil fuels
Less land disruption = less habitat loss
Decrease foreign oil dependence
No other air pollution
Difficult to store radioactive waste
Safety issue Expensive to build Tie to nuclear weapons Use CO2 when mining
uranium Thermal water pollution
PROS CONS
Radiation and human health
How nuclear reactors work
PRESSURIZED WATER REACTOR(3 WATER LOOPS)
safety issues – containing radiation
Radioactive wastes
Storing radioactive wastes Biggest issue (US stored on site) Ideas: deep underground, aboveground mausoleums,
ocean disposal prohibited Needs:
Isolation Geological stability Little/no water
Issues: NIMBY Yucca Mountain
Nuclear Waste Policy Act – burden on federal government Transporting nightmares
Environmental
No air pollutants Little CO2 Little water
pollution Land disruption
minimal
Nuclear wastes take thousands of years to degrade; how to store them
Safety and malfunction issue
advantages disadvantages
Radioactive decay Radioactive half life: time
it takes for ½ the amount to change into different substance
Nucleus goes from unstable to stable Ex: U-235 lead The half-life of polonium-
210 is 138.4 days. How many milligrams of polonium-210 remain after 415.2 days if you start with 2.0 mg of the isotope?
p. 252 #15
The half-life of polonium-210 is 138.4 days. How many milligrams of polonium-210 remain after 415.2 days if you start with 2.0 mg of the isotope? The half-life of polonium-210 is 138.4 days. How many milligrams of polonium-210 remain after 415.2 days if you start with 2.0 mg of the isotope? The half-life of polonium-210 is 138.4 days. How many milligrams of polonium-210 remain after 415.2 days if you start with 2.0 mg of the isotope? The half-life of polonium-210 is 138.4 days. How many milligrams of polonium-210 remain after 415.2 days if you start with 2.0 mg of the isotope?
Nuclear reactor types
BOILING WATER REACTOR (2 WATER LOOPS)
Boiling Water Reactor Schematic: 1. Reactor pressure vessel (RPV) 2. Nuclear fuel element 3. Control rods 4. Circulation pumps 5. Engine control rods 6. Steam 7. Feedwater 8. High pressure turbine (HPT) 9. Low pressure turbine 10. Generator 11. Exciter 12. Condenser 13. Coolant 14. Pre-heater 15. Feedwater pump 16. Cold water pump 17. Concrete enclosure 18. Mains connection
Nuclear fusion
Future??? Fuel = isotopes of hydrogen; waste is
helium (deuterium and tritium)