© Cengage Learning 2015 LIVING IN THE ENVIRONMENT, 18e G. TYLER MILLER SCOTT E. SPOOLMAN © Cengage Learning 2015 Nonrenewable Energy-Nuclear Energy

© Cengage Learning 2015 Pros: –↓environmental impact –↓ accident risk –Potential energy = 10X10 6 times more than traditional fuel –No air pollutants if operated correctly –Low water pollution –Low disruption of land Cons: –↓ net energy –↑ $$$$$ –Fear of accidents –Long live radioactive wastes –Potential of spreading nuclear weapon technology Nuclear Energy

© Cengage Learning 2015 Simple Format: Boil water to produce steam that spins a turbine and generates electricity. Parts of a Nuclear Reactor: –Fuel Rods: contain uranium & where fission occurs Moderated by neutron-absorbing solution Control rods: lowered/raised to change the rate of the reaction Water/coolant is circulated between fuel rods to remove excess heat How Does a Nuclear Fission Reactor Work?

© Cengage Learning 2015 Parts of a Nuclear Reactor: –Reactor core: where fission occurs –Steam generator: steam/electricity generated from heat/energy from fission –Turbine: uses steam to generate electricity –Condenser: cools steam back to water for use How Does a Nuclear Fission Reactor Work?

© Cengage Learning 2015 Nuclei of isotopes with large mass #s split apart into lighter nuclei when struck by a neutron. Release energy plus 2 or 3 more neutrons Each neutron can trigger an additional fission reaction An ENORMOUS amount of energy is released in chain reactions Nuclear Fission

© Cengage Learning 2015 Mine the uranium Process the uranium to make the fuel Use it in the reactor Safely store the radioactive waste Decommission the reactor RUNNING POWER PLANT= LOW IMPACT ENTIRE CYCLE = HIGH IMPACT What Is the Nuclear Fuel Cycle?

© Cengage Learning 2015 Rods must be replaced every three or four years Cooled in water-filled pools Placed in dry casks Must be stored for thousands of years Vulnerable to terrorist attack Storing Radioactive Spent-Fuel Rods Presents Risks

© Cengage Learning 2015 Waste that results from radioactive materials –Nuclear energy –Nuclear weapons –Hospitals, universities & research labs –Industry –Mining of uranium ore Spent fuel rods Irradiated elements from reactors Radioactive coolant, gases, rods The Waste Problem

© Cengage Learning 2015 High-level radioactive wastes –Must be stored safely for 10,000–240,000 years Where can it be stored? –Deep burial: safest and cheapest option –Would any method of burial last long enough? –There is still no facility –Shooting it into space is too dangerous Dealing with Radioactive Nuclear Wastes Is a Difficult Problem

© Cengage Learning 2015 Plans in the U.S. to build a repository for high-level radioactive wastes in the Yucca Mountain desert region (Nevada) Stored below ground in steel casks lined with lead No date on construction/opening. Many problems including: –Cost of $96 billion –Rock fractures –Earthquake zone –Decrease national security –Safety concerns with transportation of wastes Dealing with Radioactive Nuclear Wastes Is a Difficult Problem

© Cengage Learning 2015 Dealing with old nuclear power plants: –Decommission or retire the power plant –Dismantle the plant and safely store the radioactive materials –Enclose the plant behind a physical barrier with full-time security until a storage facility has been built –Enclose the plant in a tomb Monitor this for thousands of years Dealing with Radioactive Nuclear Wastes Is a Difficult Problem

© Cengage Learning 2015 Nuclear power plants – no CO 2 emission Nuclear fuel cycle – emits CO 2 Opposing views on nuclear power –Nuclear power advocates –Oxford Research Group Need high rate of building new plants, and a storage facility for radioactive wastes Can Nuclear Power Help Reduce Climate Change?

© Cengage Learning 2015 Proponents of nuclear power: –Fund more research and development –Pilot-plant testing of potentially cheaper and safer reactors –Test breeder fission and nuclear fusion Opponents of nuclear power: –Fund rapid development of energy efficient and renewable energy resources New technologies –Advanced Light Water Reactors Safer –Thorium based reactors Less costly and safer Experts Disagree about the Future of Nuclear Power

© Cengage Learning 2015 Chernobyl –April 26, Considered worst nuclear plant disaster -Reactor #4 exploded, followed by additional explosions -Fires sent radioactive fallout into atmosphere -400X more fallout released than atomic bomb at Hiroshima Three Mile Island –March 28, Dauphin, PA -Partial Meltdown of Unit 2 -No deaths/injuries -Worst in US operating history Case Studies: Chernobyl & Three Mile Island

© Cengage Learning 2015 Triggered by a major offshore earthquake (8.9) and resulting tsunami Triggered explosions and widespread evacuation Four key human-related factors: –No worst-case scenarios –Seawalls too short –Design flaws –Relationship between plant owners and government Case Study: The 2011 Nuclear Power Plant Accident in Japan

© Cengage Learning 2015 Fusion –Two isotopes fused together to form a heavier nucleus –Releases energy Technology is very difficult to develop Is Nuclear Fusion the Answer?