Fusion Power ppt | Fusion Energy ppt explains the benefits, approaches, fusion methods, applications and the challenges of fusion power. To Download Fusion Power ppt and PDF seminar report visit www.topicsforseminar.com
2. History: Nuclear Power
•Conceived shortly after the discovery of radioactive elements
• Released huge amount of energy per energy-mass equivalence
•Initially dismissed as impractical
• High energy radioactive elements corresponded to short half lives
•Overall it was an expensive proposition (mining/uncontrollable)
•Discovery of neutron led to more atomic experimentation
• “Induced” radioactivity changed the perceptions of radioactivity
• Discovered by Frédéric and Irène Joliot-Curie
• Made the production of radioactive elements cheaper (less mining)
• Idea of slowing neutrons down contributed to higher success in achieving
induced radiation
• Discovered in large part to work done by Enrico Fermi
[1]
3. • Tests were conducted on much heavier elements
• In 1938, Otto Hahn, Fritz Strassmann, Lise Meitner, and Otto Robert Frisch conducted experiments
bombarding uranium with neutrons, to investigate Fermi's claims
• This resulted in the roughly equal split of the nucleus into two lighter nuclei
• Differed from previous experiments that only involved small mass changes to the nuclei (think α & β decay)
• Potential for immense energy release was immediately recognized
• All occurred immediately prior toWWII
• Focus shifted to creating sustainable chain reactions
• Effective Neutron Multiplication Factor: k
• Energy Generation k = 1
• Weaponization k > 1
• Experimentation and Production continued post-war
• ColdWar contributed to exponentially increased weaponization
• Also prompted further exploration into nuclear phenomenon
• Hydrogen Bomb: First large scale man made fusion reaction
• Totally uncontrollable
• Most common type was fission initiated
• Peace time development of nuclear technology has been largely in the realm of energy
generation
[1]
4. Fusion vs. Fission
Fission
• Splitting large nuclei into smaller
pieces
• Energy release is very high
• Both parent and daughter nuclei are
highly radioactive
• Very long half lives
• Irradiates both reactor components and
the water used for cooling and heat
transfer
• Extremely dangerous
• Meltdowns
• Environmental Hazards
• Inputs and Outputs can be used to create
weapons
Fusion
• Hard to achieve
• Protons don’t like other protons
• High temps and magnetic fields are a
must
• More powerful than fission
reactions
• Large nuclei have smaller binding
energies than small
• Abundance of inputs
• Only low levels of radioactive
wastes
• Mostly just the activated interior
panels of the reaction vessel
• Input radioactivity is non-penetrative
5. Benefits of Fusion
• Abundance of input fuels
• Deuterium can be extracted from seawater
• Tritium can be made in the fusion reactor with lithium
• Helium-3 can in theory be mined from immense deposits in the lunar surface
• As opposed to fission where uranium is rare and must be mined
• Safe
• Only small amount of fuel required compared to fission reactors
• Most reactors make less radiation than the natural background
• Risk of accidental release is non-existent since plasma requires incredibly precise control
• Clean
• No combustion by products
• No weapons grade nuclear by products
6. Difficulties
•Must overcome the Coulomb barrier
• Requires incredibly high temperatures
• Simple classical calculations imply temperatures on the order of 1011 K
• Taking into account quantum effects decreases this maxima
• QuantumTunneling would lower threshold temperature to roughly 107 K
• QT is best described as the individual nuclei “leaking” through the Coulomb barrier as
opposed to overcoming it
• This means it doesn’t have to technically overcome the energy of the
Coulomb force
•PlasmaTurbulence
• Coherent plasma streams are ideal
• In reality plasma flows are incredibly complex requiring equally complex
control mechanisms and systems of stabilization
[2]
9. Magnetic Confinement
• Pinch
• Uses plasma’s electrical conductivity
• Induces a magnetic field around plasma
• Force is directed inwards causing plasma to collapse inwards and increase in density
• Chain reaction
• Denser plasma generates denser magnetic fields
• External magnetic fields required to induce the current in the plasma
• Drawbacks:
• Can produce chaotic plasma flow ranging from general instabilities and vortices to reversing the toroidal direction of flow
• Staged Z-Pinch
• Developed to reduced the instabilities that occur in normal pinch type designs
• Injects a linearly stable plasma stream that, upon reaching the critical temperature, loses stability, but keeps the
overall plasma flow stable
• Thought to be due to the instabilities being absorbed and dissipated in the stable stream
• These approaches can be thought of as steady state fusion reactions
• Requires long plasma containment time
• Confinement refers to the time τ the energy must be retained so that the fusion power released exceeds the power
required to heat the plasma
[3],[14]
10. TokAmak
• Invented in the 50’s by Soviet Physicists
• Transliteration means:
• Toroidal chamber with magnetic coils
• Toroidal chamber with axial magnetic fields
• Most common form of magnetic confinement reactor
• Most studied and promising (currently)
• Walls “capture” the heat and pass it to a heat exchanger which
produces steam to drive a turbine
• Utilizes two types of magnetic fields
• Toroidal
• Causes plasma to travel around torus
• Created by external magnets
• Poloidal
• Causes circular plasma rotation in planar cross sections
• Results from toroidal current flowing through plasma and is orthogonal to it
• ITER
• International Thermonuclear Experimental Reactor
• Being built in France
• First tokomak fusion reactor that will become productive
[5],[18]
11. Plasma Turbulence:
Edge Effects
Toroidal Coordinate
System:
• Common in plasma physics
• Red arrow - poloidal direction (θ)
• Blue arrow - toroidal direction (φ)
[5]
[12]
12. Captured by an ultra-high-speed camera, a pellet of fuel is
injected into a plasma at the ASDEX Upgrade Tokomak in
Garching, Germany. Photo: EFDA.
Plasma image following the injection of a
frozen deuterium pellet
[8]
[9] [11]
15. Inertial (laser) Confinement
• Implosion of micro-capsules of fuel by high
power laser beams
• Lasers cause instantaneous sublimation to plasma
• Plasma envelope collapses under the radiative pressure
• Collapse sends a shockwave through the fuel heating it to
its critical temperature
• Final stage the interior fuel reaches 20 times the density of lead
and 108 K
• Instead of having to confine the plasma for long
periods, IC confines plasma in very short bursts
• Exposed “reactor” core making energy easier to
remove from the system
• No magnetic fields also allows for a wider range
of materials for construction
• Carbon Fiber
• More resilient which decreases levels of neutron activation
[3],[5]
• Two types:
• Direct drive – Lasers focused directly on target fuel
• Hard to initiate uniform implosion
• Suffers turbulence effects similar to magnetic confinement
techniques
• Indirect drive – Fuel pellet is placed in a hollow cylindrical
cavity (a hohlraum)
• Lasers strike the metallic surface creating x-rays which are used to
heat the pellet
• Causes a much more symmetric implosion
• More stable due to its uniformity
• Still not as efficient as magnetic forms
• Improvements in laser technology and honing the
general technique could actually make it more
efficient in the long run
• Short plasma confinement times
• Less energy overall to initiate the reaction
20. D-T: Deuterium-Tritium
• Easiest and currently the most promising
• Reaction employed with the ITER fusion plant
• Requires breeding of tritium from lithium
• Advanced reactor designs utilize liberated neutrons within
the plasma to do this internally
• n + 6Li → T + 4He
• n + 7Li → T + 4He + n
• Drawbacks
• Produces lots of high energy neutrons
• Only ≈ 20% energy yield in the form of charged particles
• Rest is lost to neutrons
• Limits direct energy conversion
• Requires handling of the radioisotope tritium (τ1/2=12.32 yrs)
(write down the other facts and note card and bring up)
• Neutron Flux is 100 time higher than current fission reactors
[3], [4]
21. D-D: Deuterium-Deuterium
• More difficult to achieve than D-T
• Initiation energy is only slightly higher, but confinement times are usually 30 times longer
• Reaction has two branches:
1. D + D →T (1.01 MeV) + 1H (3.02 MeV)
2. D + D → 3He (0.82 MeV) + n (2.45 MeV)
• Occur with nearly equal probability
• Some D-T fusion will occur but no input tritium is required
• Neutrons released from (2) will have 5.76 times less kinetic energy than from D-T reactions
• Advantages
• 18% decrease in energy lost to neutrons
• Lower average neutron flux to internal components
• Decrease material stresses/damage
• Reduces the range of isotopes that may be produced within internal components
• No input lithium or tritium required
• Disadvantages
• Power produced can be as much as 68 times lower than D-T
[3], [4]
22.
23. Aneutronic Fusion
• Many potential candidate reactions
• Most can be ruled out due to very high input energies
• Two MainTypes:
• D - 3
He
• H -11B
• Fusion power where neutrons are ≤ 1% of the total energy released
• D-T & D-D reactions can release up to 80% of their energy as high velocity neutrons
• Would significantly reduce the damage to reactor wall components
• Decreases the need for measures taken to protect against ionization damage
• Specifically the need for protective shielding and remote handling safety procedures
• Pros:
• Tremendously more efficient
• Dramatic cost reductions (inputs & safety measures)
• Conversion directly to electricity (no steam turbines necessary)
• Cons:
• Incredibly difficult to initiate the reactions
[3], [4]
24. D-3He: Deuterium-Helium3
• D + 3He → p (14.7MeV) + 4He
(3.7MeV) + 18.4 MeV
• Reaction products comprised
mostly of charged particles thus
minimal damage to reactor
components
• More efficient than Neutronic
Fusion
• Higher Energy Output
• In reality though some D-D
reactions occur in the plasma
• Releases neutrons decreasing
efficiency and overall energy gain
• Still produces “wear” on internal
components
H-11B: Hydrogen-Boron
• 1H+ + 11B → 3 4He + + 8.7 MeV
• More efficient in practice than D-
3
He
• Side reactions result in ≤0.1% loss in
energy through neutron release
• Almost no damage to internal
components
• Required temperature is 10 times
higher than pure hydrogen fusion
(star fusion)
• Confinement time is roughly 500
times that of D-T
[3], [4]
26. Deep Space Applications
•NASA is currently looking into developing small-scale fusion
reactors for powering deep-space rockets
•Fusion propulsion has a nearly unlimited source of fuel
•More efficient and would ultimately lead to faster rockets
• 7 orders of magnitude (10
7
) times more energetic than the chemical
reactions
27.
28. References:
1) "Nuclear Power." Wikipedia. Wikimedia Foundation, 21 Sept. 2012. Web. 21 Sept. 2012. <http://en.wikipedia.org/wiki/Nuclear_power>.
2) "How Nuclear Fusion Reactors Work." HowStuffWorks. N.p., n.d. Web. 18 Sept. 2012. <http://science.howstuffworks.com/fusion-reactor.htm>.
3) "Fusion Power." Wikipedia. Wikimedia Foundation, 18 Sept. 2012. Web. 18 Sept. 2012. <http://en.wikipedia.org/wiki/Fusion_power>.
4) "Nuclear Fusion." Wikipedia. Wikimedia Foundation, 22 Sept. 2012. Web. 22 Sept. 2012. <http://en.wikipedia.org/wiki/Nuclear_fusion>.
5) "Nuclear Fusion." , Fusion Reactors. N.p., n.d. Web. 21 Sept. 2012. <http://www.splung.com/content/sid/5/page/fusion>.
6) "Reversed Field Pinch." Wikipedia. Wikimedia Foundation, 18 Sept. 2012. Web. 22 Sept. 2012.
<http://en.wikipedia.org/wiki/Reversed_field_pinch>.
7) "Laser Fusion." --Â Kids Encyclopedia. N.p., n.d. Web. 23 Sept. 2012. <http://kids.britannica.com/comptons/art-124938/Laser-fusion-is-an-
experimental-method-for-harnessing-the-energy>.
8) "The TFTR Project at Princeton Plasma Physics Laboratory." TFTR Public Home Page. N.p., n.d. Web. 23 Sept. 2012. <http://w3.pppl.gov/tftr/>.
9) "ITER - the Way to New Energy." ITER - the Way to New Energy. N.p., n.d. Web. 23 Sept. 2012. <http://www.iter.org/sci/plasmaheating>.
10) "Peering Inside an Artificial Sun -- Science & Technology -- Sott.net." SOTT.net. N.p., n.d. Web. 23 Sept. 2012.
<http://www.sott.net/articles/show/202102-Peering-Inside-an-Artificial-Sun>.
11) "High Frequency Pellet Injector Project." EFDA. N.p., n.d. Web. 23 Sept. 2012. <http://www.efda.org/jet/jet-iter/high-frequency-pellet-injector-
project/>.
12) "Plasma Research: Fusion Research, Plasma Confinement, Plasma Turbulence, Plasma Waves." Plasma Research: Fusion Research, Plasma
Confinement, Plasma Turbulence, Plasma Waves. N.p., n.d. Web. 23 Sept. 2012. <http://www.ipf.uni-
stuttgart.de/gruppen/pdd/pdd_driftwaves.html>.
13) "Noscope." Fusion Power. N.p., n.d. Web. 23 Sept. 2012. <http://noscope.com/2004/fusion-power>.
14) "Aneutronic Fusion." Wikipedia. Wikimedia Foundation, 18 Sept. 2012. Web. 23 Sept. 2012. <http://en.wikipedia.org/wiki/Aneutronic_fusion>.
15) "Image Gallery - Chairman of National People's Congress of China Visits ITER." Image Gallery - Chairman of National People's Congress of China
Visits ITER. N.p., n.d. Web. 23 Sept. 2012. <http://www.iter.org/gallery/pr_2010_07_bangguo>.
16) "S&TR | September 2005: How One Equation Changed the World." S&TR | September 2005: How One Equation Changed the World. N.p., n.d.
Web. 23 Sept. 2012. <https://www.llnl.gov/str/September05/Aufderheide.html>.
17) Sample, Ian. "California Fires up Laser Fusion Machine." The Guardian. Guardian News and Media, 28 May 2009. Web. 23 Sept. 2012.
<http://www.guardian.co.uk/environment/2009/may/28/national-ignition-facility-fusion-energy>.
18) "Tokomak." Wikipedia. Wikimedia Foundation, 09 Dec. 2012. Web. 23 Sept. 2012. <http://en.wikipedia.org/wiki/Tokomak>.