3.3.2 nuclear energy
DESCRIPTION
3.3.2 Nuclear Energy. Nuclear Energy. Electricity Production by Fuel. U.S. Department of Energy, Annual Energy Review 1999. Fig 1: Nuclear Reactors in the World. Source : AIEA. By the end of 2002: 30 countries 441 reactors . 16% of electricity production 7% of primary energy. - PowerPoint PPT PresentationTRANSCRIPT
3.3.2 NUCLEAR ENERGY
NUCLEAR ENERGY
Electricity Production by Fuel
Electricity Production by Fuel
56%
9%
3%
23%
9% Coal
HydroelectricPowerOther
Nuclear
Natural Gass
U.S. Department of Energy, Annual Energy Review 1999
4
Fig 1: Nuclear Reactors in the World
By the end of 2002: 30 countries
441 reactors 16% of electricity production7% of primary energy
Source : AIEA
• Types• Alpha particles consist of 2 protons and 2 neutrons,
and therefore are positively charged• Beta particles are negatively charged (electrons)• Gamma rays have no mass or charge, but are a form
of electromagnetic radiation (similar to X-rays)• Sources of natural radiation
• Soil• Rocks• Air• Water• Cosmic rays
Radioactivity
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
• Radioactivity: Nuclear changes in which unstable (radioactive) isotopes emit particles & energy
• Radioactive decay continues until the the original isotope is changed into a stable isotope that is not radioactive
Radioactivity
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
cstl-cst.semo.edu/bornstein/BS105/ Energy%20Use%20-%203.ppt
Relative Doses from Radiation Sources
• Genetic damages: from mutations that alter genes
• Genetic defects can become apparent in the next generation
• Somatic damages: to tissue, such as burns, miscarriages & cancers
Effects of Radiation
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
The time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a different isotope
Half-time emitted Uranium 235 710 million yrs alpha, gammaPlutonium 239 24,000 yrs alpha, gamma
During operation, nuclear power plants produce radioactive wastes, including some that remain dangerous for tens of thousands of years
Half-Life
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Destructive power:[1] Small towns have been leveled by floods and landslides.[2] The same size town could be leveled by 1,000 tons of chemical explosives.
[3] Hiroshima (quarter of a million people) was destroyed by releasing the energy in 40 kg of Uranium
We know the least about the strong nuclear force.
Use of Fission Power 1945 first large scale use atomic bombs were
used by the US to knock Japan out of WWIIsince then attention
has been given to the peaceful uses of atomic energy
Nuclear Power Plants
In a conventional nuclear power planta controlled nuclear fission chain reaction
heats waterproduce high-pressure steam that turns turbines generates electricity.
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Nuclear Fission approximately 20,000
times as much heat and energy is released from uranium fuels as from an equivalent amount of coal
when a sufficient amount of fissionable material is brought together, a chain reaction occurs splitting atoms and releasing a tremendous amount of heat
Nuclear FissionControlled Fission Chain Reaction
neutrons split the nuclei of atoms such as Uranium or Plutonium
release energy (heat)
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Fusion and Fission are governed by the nuclear strong force.
Fusion: two nuclei stick together (or fuse) to form a new, larger nucleus
Two separate nuclei
One new nucleus
Fission: When a single nucleus splits to form two smaller nuclei.
Large nucleus Two smaller nuclei
Controlled Nuclear Fission Reaction
cstl-cst.semo.edu/bornstein/BS105/ Energy%20Use%20-%203.ppt
Conversion of 238U to 239Pu
Under appropriate operating conditions, the neutrons given off by fission reactions can "breed" more fuel, from otherwise non-fissionable isotopes, than they consume
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
Nuclear Fusion Fusion is combining
together the atoms are fused
together rather than split apart
possibilities for nuclear fusion are much greater than those for nuclear fission
Imagine putting a hydrogen nucleus together instead of pulling it apart. We normally write this in a special way:
n + p
H21
neutronproton Hydroge
n nucleus
This reads: a neutron and a proton fuse together to form a hydrogen nucleus.
+n p
n + p
H21
+n p
More energy Less energy
Where did the excess energy from the left-hand-side go?There must be energy released in this process!! It comes in the form of Radiant and Thermal energy
Nuclear (fusion) Energy
Thermal + Radiant Energy
Fuel for fusion fusion reactors would be
fueled by deuterium, an isotope of hydrogen
available in almost unlimited supply in sea water
FusionProblems: process is so difficult to
control that it is questionable whether commercial adaptation will ever be economically feasible
Fusion Problems fusion requires extreme
pressure and temperatures (as high as 100 million degrees)
such heat was achieved by the Hydrogen bomb by first setting off a fission explosion
Nuclear Energy Concerns
Concerns about the safety, cost, and liability have slowed the growth of the nuclear power industry
Accidents at Chernobyl and Three Mile Island showed that a partial or complete meltdown is possible
Chernobyl•April 26, 1986, reactor explosion (Ukraine) flung radioactive debris into atmosphere
•Health ministry reported 3,576 deaths•Green Peace estimates32,000 deaths;•About 400,000 people were forced to leave their homes
•~160,000 sq km (62,00 sq mi) contaminated•> Half million people exposed to dangerous levels of radioactivity
•Cost of incident > $358 billion
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Three Mile Island•March 29, 1979, a reactor near Harrisburg, PA lost coolant water because of mechanical and human errors and suffered a partial meltdown
•50,000 people evacuated & another 50,000 fled area•Unknown amounts of radioactive materials released•Partial cleanup & damages cost $1.2 billion•Released radiation increased cancer rates.
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Three Mile Island evacuation of preschool
children and pregnant women within five miles of the plant
What is Going to Happen to Spent Fuel?
Photos from :The Yucca Mountain Project:
http://www.ymp.gov/
1. Low-level radiation (Gives of low amount of radiation)• Sources: nuclear power plants, hospitals &
universities• 1940 – 1970 most was dumped into the ocean• Today deposit into landfills
2. High-level radiation (Gives of large amount of radiation)• Fuel rods from nuclear power plants• Half-time of Plutonium 239 is 24000 years• No agreement about a safe method of storage
Radioactive Waste
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Radioactive Waste1. Bury it deep underground.
• Problems: i.e. earthquake, groundwater…2. Shoot it into space or into the sun.
• Problems: costs, accident would affect large area.3. Bury it under the Antarctic ice sheet.
• Problems: long-term stability of ice is not known, global warming
4. Most likely plan for the US• Bury it into Yucca Mountain in desert of Nevada • Cost of over $ 50 billion• 160 miles from Las Vegas• Transportation across the country via train & truck
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Yucca Mountain
www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Conclusion…… “The odds of an American
dying from a nuclear power accident are 300 million to one.”
FissileResources
NuclearReactor
Electricity
Intermediate/LowLevel Waste
Conversion
Enrichment
Uranium Extraction
FuelFabrication
InterimStorage Encapsulation
WasteDisposal
HighLevelWaste
SpentFuel
Long-Term Nuclear Energy Depends on an Advanced
Nuclear Fuel Cycle
ReprocessingRecycle
Recycling TRUIn Adv. Reactor
Fissile Waste235U/233U/239Pu
Electricity& H2
MultipleReactors
FIND A PARTNER, GRAB A BOOK, AND MAKE
A CONCEPT MAP OF:The Nuclear Fuel Cycle
includingHigh level vs. low level
Nuclear Waste