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)