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Nuclear Energy - Download as PowerPoint

VIEWS: 2 PAGES: 19

  • pg 1
									By Jasmine J Boota and Kevin Holley
 Nuclear  power uses the process of nuclear
  fission, or the splitting of Uranium 235 atoms
 This causes a chain reaction
 The reaction creates intense heat
 This intense heat boils water
 The steam from this water turns turbines,
  which provide us with electricity
                            Small amounts of radioactive gases
Uranium fuel input
(reactor core)

                                                             Containment shell

                                                                                 Waste heat              Electrical power
           Emergency core
           cooling system

                                                   Steam
      Control
      rods                                                                                               Useful energy
                                                                  Turbine        Generator
                                      Heat                                                               25 to 30%
                                      exchanger

                            Hot coolant                                     Hot water output

                                                                                 Condenser       Pump
                                      Pump
                            Coolant
                                                                            Cool water input
                                                        Black                                    Pump                Waste
                                  Moderator                                                                          heat
                                                   Water
                                  Coolant
                                  passage

                                   Pressure
                                   vessel                                                                             Waste
                                                                                              Water source            heat
                                  Shielding                                                   (river, lake, ocean)



Periodic removal                      Periodic removal
and storage of                        and storage of
radioactive wastes                    radioactive liquid wastes
and spent fuel assemblies
   The advantages to using nuclear energy include:
       Large fuel supply
       Low environmental impact (without accidents)
       Moderate land and water disruption (without accidents)
       Moderate land use
       Low risks of accidents
   The disadvantages include:
       High cost
       Low net energy yield
       High environmental impact (with accidents)
       Catastrophic accidents
       No known solution for long term storage of waste
       Spreads knowledge on building nuclear weapons
 Because of the built in safety features of
 today’s power plants,
    Exposure is extremely low
    Accident chances are low
 But, explosions are possible, like the
  Chernobyl incident
 These explosions can release radioactive
  material which can immediately kill or
  cause cancer to the recipient
 Bombs can also be created, which are
  very deadly
 Each part of the nuclear fuel cycle releases
  Low and High level radioactive waste
 Low radioactive waste is:
     Put into steel drums and buried in some
      countries
     Dumped into the Ocean by others
 High   level radioactive waste is:
     Buried deep underground
 Aftergoing through the nuclear reaction,
  nuclear wastes are:
   Put into underwater or dried casks, located in a
    separate building
   Supplied with a backup water cooling system to
    prevent the waste from catching fire
 Ifsabotaged, these wastes could catch fire and
  release airborne radioactive waste over a very
  large area
 Officials argue over the safety of the cooling
  pools and transportation, but one thing is
  certain:
      An attack is possible and deadly
•   How widespread are Contaminated
    Radioactive Sites?
•   EPA – 45,000 sites in U.S.A
•   Clean up may cost $200 billion dollars over
    next 70 years
•   144 highly contaminated sites used to
    produce nuclear power, never be completely
    cleaned up and monitored for centuries Some
    critics argue – why spend so much money if it
    is a low risk ecological problem and does not
    have high risk health problems
•   Post-Cold War in Soviet Union Areas severely
    contaminated by nuclear accidents
•   25 operating nuclear power plants with flawed
    Nuclear waste dump sites
•    Radioactive waste-processing plants
•   Contaminated nuclear test sites
•   Coastal waters- Nuclear waste dump and
    submarines 1957 explosion of nuclear waste
    storage tank at Mayak- plutonium production
    facility in Russia
•   FACT FIGURE:No one can live near 2600 sq.km’
    Nearby Lake Karachay - one hour standing fatal
    What can we do with worn out nuclear plants
    After 15-40 years –dangerously contaminated
 Extend plant life by expensive renovation
 Decommissioned or recycled
 Dismantling and Storing
 Physical barrier, 30-100 years
 Enclose in tomb and abandon for 1000 years
   YOU THINK IT IS A GOOD IDEA TO STORE
 DO
 NUCLEAR WASTE IN STORAGE FACILITIES?

 How do you feel about the Tomb and Physical
 barriers? Hilarious yes.. But what could be
 some consequences? Can you relate to
 history?
•   In the U.S. decommission costs $300 – 500 million - Many
    will be expired by 2012. Bush administration – 5-6 year
    extended license
•   1 in 3 countries (60) have nuclear weapons
•   NRC – 1700 cases in U.S.
    – Stolen or lost
    – 100 cases a year
    – What does IAEA stand for?
    – IAEA – illicit trafficking in dirty bomb materials


•   GOOD NEWS! =)
    –   Nuclear weapons in some – declined by 55% by 2012
•   BAD NEWS! =(
    –   Weapons still exist ( 30 times)
    –   Bomb grade plutonium 239- must be kept secure
•   Dirty bombs – explosives such as dynamite mixed
    with some form of radioactive material nor difficult
    or expensive to obtain.
    – Examples?
    Radioactive Materials – as much as coffee cup
    E.g. iridium, cobalt, cesium, americium
    Discuss :
    1. Where can I get Radioactive substance enough to make
      a bomb?
    Pg. 373. top Paragraph
    2. Detonating dirty bomb at street level or roof top DOES
      NOT cause a nuclear blast. But depending on amount of
      TNT?
WHAT WE MUST ANSWER ABOUT NUCLEAR ENERGY
1. Can nuclear power reduce dependence on oil.
– Yes. Il (2-3%0 oil in U.S.)
– Major use is in cars.
2. Can we afford it?
- Expensive to even boil water
- 2-3 times higher cost than other resources
- How expensive. Pg. 374. Last paragraph.
3. Can we develop New and Safer Nuclear reactors?
  -Advanced light water reactors (ALWRs)– built in
   passively to make explosions of radioactive emissions
   impossible!
- Pebble lead Modular reactors(PMBRs) – 10,000 uranium
   oxide fuel particles (pencil point), encapsulated in
   microsphere ball
 -   Melt down proof. No need for Core cooling system. Germany
     S.Africa & China
•   Crack in reactor – expose graphite to air-
    high temp – burn and release radioactive
    substance
•   Old design- not in England or Germany
•   10 times the volume of high level radioactive
    waste
•   No containment shell – terrorists can steal or
    blow it up!
•   Doesn’t eliminate
    expense/hazards/contamination & power
    plant decomissioning
 Breeder      Nuclear Fissiob reactors
    Good Breeder
        generate more nuclear fuel than consume
        Non fissionable Uranium into Plutonium239
    Uses 99% of Uranium last several 1000 years. Good or
     Bad?
    Bad Breeder
      Safety system of reactor fails – liquid sodium can escape. What
       can happen?
      Produces plutonium slowly

     US GAVE NINE BILLION FOR BREEDER RESEARCH!
ALTERNATIVE
• Nuclear Fusion – limitless source of heat and light,
  Deuterium and tritium (D-T) – 100 million degrees
• Even if it is found, small commercial reacot ris
  made:
    Cost of production                Output
•   NUCLEAR FUTURE FOR U.S.
    –   Phase out govt. subsidies/ tax breaks
    –   Use money to promote other energy source
    –   Vulnerable to attack
    –   Make electricity on small level & easily provided
    –   Other resources – electricity demand & CO2

								
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