Nuclear Power By Jordan Brown, Gynter Kotrri, Kevin Rupasinghe Vinay Jayachandiran

Nuclear Reactions – Good

Nuclear Reactions – Bad Somali Pirates Taliban North Korea Al-Qaeda China

Electricity Steam turns turbine attached to shaft Coils of copper rotate inside magnets Alternating electrical current generated

Atom Electron – Orbit (e - ) -1 charge, very small Proton – Nucleus (p + ) +1 charge, 1 amu Neutron – Nucleus (n 0 ) 0 charge, just over 1 amu Essentially one e - and one p +

4 Fundamental Forces Function/EffectRelative Strength Range GravitationalAttractive force between matter 1Infinite ElectromagneticLike charges repel, opposites attract Infinite Weak NuclearInvolved in nuclear decay Strong NuclearHolds the nucleus of an atom together 2 x

Types of Radiation Alpha Radiation Helium nuclei Beta Radiation Electrons Gamma Radiation Electromagnetic

Fission Large nuclei become unstable and break apart Decay into smaller elements and emit radiation Alpha, Beta and Gamma Radiation Neutrons break off, split into protons and electrons Happens slowly in nature Scientists can shoot neutrons at Uranium nuclei to start a reaction Mass is lost during fission and converted into energy

Chain Reaction Each reaction releases 3 neutrons These neutrons may hit other nuclei, causing a chain reaction In nature, the fissile material is not dense enough for a chain reaction Scientists can calculate a “critical mass” at which the chain reaction is sustained The equation below can be used to determine critical mass Where k is neutron multiplication factor f is the number of neutrons released in the reaction l is the number of neutrons lost from the system

Fission Reactors

Radioactive materials have to be disposed off Eventually over time these materials will loose their radioactivity Half Life Iodine 8 days Krypton 10 years Uranium 238 – 4.47 billion years Radiation causes deletions and mutations in DNA Have to be disposed of really safely Waste is stabilized before being disposed off Remove water Usually stored underground Nuclear Waste

26 April 1986 Power Surge ruptured reactor Sent radioactive material into air Many locations had to be evacuated Three Mile Island Relief Valve failed Many radioactive gases were released into air Chernobyl Nuclear Disasters

Atomic Bomb

E = mc 2 Einstein stated that mass and energy are interchangeable In nuclear reactions, mass is lost and converted into energy This change in mass yields vast amounts of energy When U-235 decays, 0.7% of its mass is converted into energy Assume 1 mole reacts: (235g) = 1.645g = kg E = ( kg)(300,000,000 m/s) 2 = x = 148 terajoules

Nuclear Fusion Used to describe the process whereby two nuclei “fuse” to form heavier nuclei The fusion of two nuclei with lower masses than iron Generally releases energy while the fusion of nuclei heavier than iron absorbs energy Naturally occurs in stars

Fusion Bombs

Hydrogen Isotopes H-1 (protium) 1 proton, no neutrons H-2 (deuterium) 1 proton, 1 neutron H-3 (tritium) 1 proton, 2 neutrons

15 million Kelvin and really high pressure 2 protons fuse to make a deuteron 1 proton and a deuteron make Helium 3 2 Helium 3 fuse and make Beryllium 6 Beryllium 6 is unstable and breaks apart into 2 protons and Helium 4 Helium 4 has less energy than its reactants, so it releases energy Also less mass, E=Δmc million tons of Hydrogen converted to helium/second Fusion on Sun Proton-Proton

Fusion on Sun 4 x Watts of Energy a day.

Have to overcome the electromagnetic force of protons Requires 100 million Kelvin (6 times temperature of Sun’s core) At this temperature atoms lose electrons and become plasma Lots of pressure needed To maintain pressure we need gas to be in container No container can survive at 100 million Kelvin Invisible Magnetic Container Plasma is magnetic Proton-Proton Fusion Fusion on Earth Magnetic Container 100 million Kelvin

DEUTERIUM - DEUTERIUM FUSION Needs less heat than proton- proton fusion 100s of millions of degrees Still needs to be highly dense Unrealistic Works at lower temperatures and Pressure Scientists think these are realistic conditions 6Li + n  4He + T Produce tritium DEUTERIUM – TRITIUM FUSION Alternative Fusion More Efficient

Run a current through plasma, creates magnetic force around plasma Run current through tube and make a donut shaped tube Contractile rings to stop plasma from moving Create Spiral magnetic coils to avoid diffusion Tokamak Fusion Reactors

Scientists think this could be the next step High intensity lasers fired at a pellet containing deuterium and tritium atoms Pellet explodes and reaction forces crushes the atoms together to create fusion Nova Lawrence Livermore National Laboratory in California The New Way Forward Laser Fusion Reactors

Implications of Nuclear Fusion Harnessing nuclear fusion on Earth could produce unlimited, clean energy for millions of years This could lead to: 1) Cheap and affordable energy 2) The deceleration of global warming 3) The total transformation of the global economy Output energy has been less than the amount of input energy

Stars – Nature’s Nuclear Reactors The energy of the stars also comes from nuclear fusion processes Big Bang created hydrogen and helium fusion created all other elements

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