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Nuclear Fusion Powers the Universe

Nuclear Fusion Powers the Universe. Neutron proton. Two nuclei combine into one nucleus plus a nucleon is called nuclear fusion , a nuclear reaction. The picture here illustrates the fusion of 2 D + 3 T  4 He + n that releases a lot of energy. Nuclear Fusion Energy. Fusion Energy.

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Nuclear Fusion Powers the Universe

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  1. Nuclear Fusion Powers the Universe Neutron proton Two nuclei combine into one nucleus plus a nucleon is callednuclear fusion, a nuclear reaction. The picture here illustrates the fusion of 2D + 3T 4He + n that releases a lot of energy. Fusion

  2. Nuclear Fusion Energy Fusion Energy Fusion

  3. Nuclear Fusion in Stars The solar system Solar systemNASA These links may move Stars are giant fusion reactors. Nuclear fusion reactions provide energy in the Sun and other stars. Solar energy drives the weather and makes plants grow. Energy stored in plants sustains animal lives, ours included. Fusion

  4. Nuclear Fusion and the Sun The birth of the 4.5e9 year old Sun Sun-Earth Distance (149,597,870.7 km or 8.3 light minutes) is an Astronomical Unit (AU). Alpha (A+B+proxima, Centauri triple star system nearest to the sun parallax angle of 0.76-arcsec) is 4.35-4.22 light years from the Sun. Sun Mass is 333,000 times that of the Earth. The sun is a big nuclear fusion reactor, 75% H and 25% He. Sun radius (695000 km) is 109 times that of the Earth (6.4e3 km). Sun emits 3.861026 watts, ~ 8 kwatt/cm2, 0.14 watt/cm2 reach the earth atmosphere (solar constant). Fusion

  5. The Sun Core:Radius = 0.25 RsunT = 15 Million K Density = 150 g/cc Envelope: Radius = Rsun = 700,000 km T = 5800 K Density = 10-7 g Life of Star:tug-of-war between Gravity & Pressure Fusion

  6. The Sun The sun flare  The corona during an eclipse  The aurora corona during an eclipse corona during an eclipse Fusion

  7. The solar surface Fusion

  8. Nuclear Fusion Cross Sections Cross sections data from reactions studied using particles from cyclotron 7Li (p, n) 7Be3T (p, n) 3He1H (t, n) 3He2D (d, n) 3He2D (t, n) 4He3T (d, n) 4He Fusion

  9. Nuclear Fusion Energy for D-T Fusion Estimate the fusion energy for D + T 4He + n Estimate the fusion energy Q The mass excess (MeV) are given below every species. D + T 4He + n + Q 13.136 + 14.950 = 2.425 + 8.070 + QQ = 17.6 MeV/fusion This amount is 3.5 MeV/amu compared to 0.8 MeV/amu for fission. Estimating Qis an important skill. Mass and mass excess can be used, the latter is usually given to unstable nuclides. Fusion

  10. Nuclear Fusion Energy for Fusion Reactions Common fusion reactions and their Q values D + D 4He + 23.85 MeV (hypothetical) H + H D + + + n + 1.44 MeV D + T 4He + n + 17.6 MeV D + 3He 4He + p + 18.4 MeV D + D 3He + n + 3.3 MeV D + D 3T + p + 4.0 MeV See Interactive Plasma Physics Education Experience : http:// ippex.pppl.gov/ Fusion

  11. Nuclear Fusion and Plasma D and T mixtures have to be heated to 10 million degrees. At these temperatures, the mixture is a plasma. A plasma is a macroscopically neutral collection of charged particles. Ions (bare nuclei) at high temperature have high kinetic energy and they approach each other within 1 fm, a distance strong force being effective to cause fusion. Fusion

  12. Nuclear Fusion and Plasma Confinements Three confinement methods fd3.gif from ippex.pppl.gov/ippex/module_5/see_fsn.html Fusion

  13. Nuclear Fusion and Plasma - kinetic energy Kinetic energies of particles in plasma follow the Maxwell-Boltzmann distribution Fusion

  14. Nuclear Fusion and Plasma - particle motion Charged particles avoid crossing magnetic lines. Fusion

  15. Nuclear Fusion using Magnetic Plasma Confinement A Magnetic Bottle for Plasma Confinement A plasma distorts magnetic field or bends magnetic lines. Fusion

  16. Nuclear Fusion using Tokamak The Tokamak technology for plasma confinement in fusion fd4.gif<=ippex.pppl.gov/ippex/module_5/see_fsn.html Fusion

  17. Nuclear Fusion using Magnetic Confinement JET:The Joint European Torus Program Tokamak shapes like a donut confining the plasma in a circular motion inside the Tokamak. PSFC: MIT Plasma Science and Fusion Center fd6.gif<=ippex.pppl.gov/ippex/module_5/see_fsn.html Fusion

  18. Nuclear Fusion Bombs A thermonuclear Bomb consists of explosives, fission fuel, and D, T, and Li. A thermonuclear bomb begins with the detonation of small quantities of conventional explosives. The explosion starts fissionable chain reaction that heats to 1e7 K to ignite a chain of fusion reactions. 2D + 3T 4He + n + 17.6 MeV n + 6Li  T + 4He ( = 942 b) n + 7Li  T + 4He + n ( = 0.045 b) A neutron bomb is a fusion bomb designed to release neutrons. A cobalt bomb is a dirty bomb to kill using radioactive 60Co. Fusion

  19. Nuclear Fusion Energised the Cold War During WW2, the USSR competed with UK and US for military superiority. The Cold War started. Sept. 23, 1949, President Truman told the world about the Soviet explosion of A-bomb. The US stepped up to develop the H-bomb. 1952, Nov. 1. US tested the first H-bomb at Enewetak 1953 the USSR tested an H-bomb Britain, France, and China also have tested H-bombs. The cold war was red hot until the former USSR disintegrated. Fusion

  20. H-bomb Nov. 1, 1952, the first H-bomb Mike tested,mushroom cloud was 8 miles across and 27 miles high;the canopy was 100 miles wide, 80 million tons of earth was vaporized. H-bomb exploded Mar. 1, 1954 at Bikini Atoll yielded 15 megatons and had a fireball 4 miles in diameter.USSR H-bomb yields 100 megatons. Fusion

  21. Nuclear Fusion under Controlled Conditions Humans had controlled fission chain reactions before testing bombs. 1952, Nov. 1. US tested the first H-bomb at Enewetak, controlled sustained fusion reactor has yet to be achieved. High temperature and high particle density for long period of time are the conditions for fusion. Magnetic and inertia confinements keep particle density high. Lawson criterion requires confinement time times particle density reach 1e20 s m-3. Fusion Links: http:// www. physics.auburn.edu/~plasma/fusion/fusion_lab/links.html Fusion

  22. Nuclear Fusion Research Nuclear fusion research is costly, requiring an international effort. Plasma confinement by torus offers a hope for success. 1968, the USSR reported achieving 1.0e7 K in Tokamak, and and later reached 1.0e8 K in Tokamak fusion test reactor (TFTR). Tokamak technology is used in JET and Princeton Large Torus. Tokamak in the Soviet achieved 5e6 K and density 5e19 p m-3 for D plasma in 1996. Strong magnetic field using superconductors is also used. Laser heating frozen pellets in inertia confinement had some success. Break even points have been reached in 1995. Fusion

  23. Fusion Research – cont. The Princeton Large Torus achieved 510 million K, before decommissioned Oct. 2002. Simulations made possible by advances in parallel processing allow us to realistically visualize plasma behavior predicted by advanced models. Improved heat retention achieved by plasma flow toward the outside, instead of flowing close to the center (theory and experiment). Shear flow pattern also made higher temperature possible. Understanding of plasma led to National Spherical Torus Experiment (NSTX) at PPPL, and perhaps other places. NSTX may achieve self-sustaining. Fusion

  24. Fusion Research – cont. In addition to optimizing the plasma configuration, future fusion research these are likely to include a burning (self-heated) plasma experiment, an engineering test facility, facilities for testing fusion materials and components, and then a demonstration plant, which would put net electricity onto the grid. It may be possible to eliminate one step by combining the burning plasma experiment and engineering test facility into one device. The spherical torus configuration, being developed through NSTX, may provide an excellent test bed for the development of materials and components for the demonstration power plant. Fusion

  25. Nuclear Fusion of Protons - hydrogen cycle The Sun derives energy from fusion of protons. There are many possibilities, but two detailed cycles were proposed. The hydrogen cycle: H + H 2D (+e–) + + + n2D + H 3He + 3He + 3He 4He + 2 Hnet 4 H = 4He (+ 2e–) + 2+ +2 + 2n + 26.7 MeV The carbon cycle will be described next. Fusion

  26. Nuclear Fusion of Protons - carbon cycle The hydrogen cycle. The carbon cycle: 12C + H 13N +  13N 13C (+ e–) + + + n13C + H 14N +  14N + H 15O +  15O 15N (+ e–) + + + n 15N + H 12C + 4He + net 4 H = 4He (+ 2e–) + 2+ +4  + 2 n + 26.7 MeV (similar to the hydrogen cycle) Fusion

  27. Nuclear Fusion in Stars Nuclear fusion reactions The hydrogen cycleThe carbon cycle Others reactions 3He + 4He 7Be4 + 7Be + H 8B5 + 8B 8Be + +8Be  2 4He +  (major) 8Be + 4He 12C (minor) Additional reactions 12C + 4He 16O + 2.425 MeV16O + 4He 20Ne + 4.73 Me 4He + 20Ne 24Mg + 9.31 MeV Life of a Star Condense mass Protostar Star (stable situation) Red Giant White Dwarf & Planetary Nebula Nova or Supernova Neutron Star or Black Hole Fusion

  28. Nuclear Fusion Catalysed by Muons Muons, m– and m+ are 2nd generation leptons, 207 time the mass of electron, and holds 2 D 74/207 (= 0.35) pm apart. Frank and Sakharov independently suggested muons would help two deuterium nuclei to fuse. 2D23He + n + 3.3 MeVor2D23T + p + 4.0 MeV Alvarez and colleagues suggested a muon catalysed reaction 2D–1H + 3He +  with weak evidence. Fusion

  29. Nuclear Fusion and Electrolysis - cold fusion Cold fusion refers to fusion reactions at room temperature. Pons and Fleischmann electrolyzed a basic lithium oxide solution containing 0.1 mol of LiOD per litter of D2O solution, using palladium electrodes. Unexpected amount of heat destroyed their experiment equipments, and they claimed palladium catalyzed cold nuclear fusion. Evidence was not sufficient, and no one else has reproduced the result yet. Jones and co-workers also claimed cold fusion as energy source in the Earth interior. Fusion

  30. Fusion Research in U.S.A. • Princeton Plasma Physics Laboratory (PPPL). • Oak Ridge National Laboratory (ORNL). • Massachusetts Institute of Technology, Alcator C-Mod. • University of Wisconsin, HSX. • University of Texas, Fusion Research Center. • Max Planck Institut fur Plasmaphysik, Wendelstein 7-AS Fusion

  31. Fusion Research World Wide • UK: EFDA-JET, START, MASTSmall Tight-Aspect Ratio Tokamak - operational at Culham from 1991 until 1998. This 'baby' tokamak was the first high temperature spherical tokamak • MAST - Mega Amp Spherical Tokamak - START's bigger brother (approximately twice as big), now operating at Culham. • JAPAN: JT-60 • RUSSIA: ? • CANADA: Canadian Fusion Fuels Technology Project (CFFTP)http:// epub.iaea.org/ fusion/public/ws97/node42.html • March 2002, bubble fusion was reported in Science, unconfirmed. • International collaboration called ITER expected to produce fusion energy at the rate of a commercial power plant by the year 2010 Fusion

  32. Nuclear Fusion in Summary Recognize possible fusion reactions Evaluate fusion energy for fusion reactions Describe properties of plasma and principle of magnetic confinement Discuss inertia and other confinements for fusion reaction Appreciate and anticipate difficulties in fusion experiments Understand weapons and their social and international impact Judge claims of fusion reaction and designs of fusion experiment Develop an interest in fusion and keep up-to-date with fusion research Fusion Timeline: informationheadquarters.com/List_of_themed_timelines/nuclear_fusion.shtml Fusion

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