核技术导论英文课件：Chapter 5 Thermonuclear Fusion

1、Chapter 5. Thermonuclear FusionIntroduction Thermonuclear Reactions and Energy ProductionFusion in a Hot Medium Progress Towards Fusion Power Stellar Burning Fusion2Nuclear FusionTwo nuclei combine into one nucleus plus a nucleon is called nuclear fusion, a nuclear reaction.The picture here illustra

2、tes the fusion of 2D + 3T 4He + nthat releases a lot of energy.Neutron protonPenetration through a rectangular energy barrier (height B) of a particle beam, of kinetic energy E ( 1020 s/m34. Progress Towards Fusion Power At P, the magnetic field B is uniform in the x direction and so the magnetic. f

3、orce F acts vertically downwards. However, at point Q, B has a vertical component, which results in the force having a component parallel to the x-axis directing the particle towards the region of lower fieldMagnetic Confinementplasma particles constrained in a uniform toroidal field could circulate

4、 endlesslyTokamak : 环形(toroidal)、真空室(kamera)、磁(magnit)、线圈(kotushka)Inertial Confinement Fusion(惯性约束聚变) Concept25The rate of depletion of fuel atoms dn/dt = -2RAfter a time t = , the number remaining n()certain fraction f of the fuel be consumed in the time 26For a significant burnup of f 30%, D-T at

5、 20 keV, sn Advantages:Well advanced technologyGood control of energy releaseDisadvantages:Bad energy conversionVery expensive to buildEngineering challeges at NIFPossible Drivers: Lasers (Best Shot)1000 large Optics:192 beam lines:Compare Driver to Target Sizes!real NIF targetSchematicDT capsuleMic

6、ro- PIXEPS(聚苯乙烯)靶内壳材料中掺入过渡金属元素Br11.6微米Two Different Ways to Fusion Lawson Criterion:must be achievedTemperature must be around T = 6 . 15 eVTwo ways to fulfil Lawson criterion:First solution (magnetically confined plasmas): increase confinement timeOther solution (inertial confinement fusion - ICF):

7、 increase density of fusion plasmaMany similarities, but a few decisive differences!Chapter 5. Thermonuclear FusionIntroduction Thermonuclear Reactions and Energy ProductionFusion in a Hot Medium Progress Towards Fusion Power Stellar Burning Nuclear Fusion of Protons - hydrogen cycleThe hydrogen cyc

8、le:H + H 2D (+e) + + + n2D + H 3He + 3He + 3He 4He + 2 HThe Sun derives energy from fusion of protons. There are many possibilities, but two detailed cycles were proposed.These steps take place in the deep interior of the starsnet 4 H = 4He (+ 2e) + 2+ +2 + 2 n + 26.7 MeVThe energy released is slowl

9、y transmitted to the star surface, from which energy is lost by way of radiation34Nuclear Fusion of Protons - carbon cycleThe carbon cycle:12C + H 13N + 13N 13C (+ e) + + + n13C + H 14N + 14N + H 15O + 15O 15N (+ e) + + + n15N + H 12C + 4He + net 4 H = 4He (+ 2e) + 2+ +4 + 2 n + 26.7 MeV(similar to

10、the hydrogen cycle)fusion of four hydrogen atoms to form a 4He nuclide could be accomplished with the help of the 12C nuclide. The 12C undergoes a cycle of reactions: carbon is at both the start and the end of the cycle. Thus, 12C is considered a catalyst in the fusion reaction. Fusion35Nuclear Fusi

11、on in StarsNuclear fusion reactionsThe hydrogen cycleThe carbon cycleOthers reactions 3He + 4He 7Be4 + 7Be + H 8B5 + 8B 8Be + + 8Be 2 4He + (major) 8Be + 4He 12C (minor)Additional reactions 12C + 4He 16O + 2.425 MeV 16O + 4He 20Ne + 4.73 Me 4He + 20Ne 24Mg + 9.31 MeVWhen temperatures at the center o

12、f the mass increase to 10,000,000 (ten million) K, the hydrogen fusion cycle begins. Fusion energy causes the surface to heat up, and eventually, energy escapes from the mass as radiation (heat and light). When energy released from fusion equals the energy lost by radiation, the steady state is a st

13、ar.Fusion36Nuclear Fusion in StarsStars 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.Fusion37Nuclear Fusion and the SunThe birth of the

14、 4.5e9 year old SunSun-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

15、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 3.861026 watts, 8kwatt/cm2, 0.14watt/cm2 reach the earth atmosphere (solar constant).Fusion38The SunCore: Radius = 0.25 Rsun T = 15 Million K Density = 150 g/cc Envelope: Radius

16、 = Rsun = 700,000 km T = 5800 K Density = 10-7 gLife of Star:tug-of-war between Gravity & Pressure 39Energy driving force of changeChange is the only constant in the universe.Changes: winds, rains, storms, thunders, forest fires, earthquakes, waves, plant growth, food decay, ocean tides, formation a

17、nd melting of ice, combustion, and growing old . more example please.What are physical and non-physical changes?What causes changes?Heatelasticitygravityelectromagnetic wave Identify changes and energy in everyday events40Recognizing energyEnergy plays an important partAnd its used in all this work;

18、Energy, yest energy with power so great,A kind that cannot shirk.If the farmer had not this energy,He would be at a loss,But its sad to think, this energyBelongs to a little brown horse. A school verse by Richard Feynman Nobel laureate for physicsPhoto of Feynman and Murray Gell-MenEnergy & Nuclear

19、Science41Mechanical WorkMass: m kgAcceleration: a m s-2Force: F = m a N (Newton = kg m s-2)Distance: s mWork: W = F s J (N m or kg m2 s-2)Potential energy Wp = m g h unites?Kinetic energy Wk = m v 2 work out unites0.1 kg1 NThink and deal with quantity of energy42Properties of PE and KEPE and KE are

20、state functions depending on only the final conditions not on how the conditions were arrived (path).Changes of PE and KE depend on only the initial and final conditions, not on the paths.PE and KE are inter-convertible, but not destroyed.Do you know any other properties?Energy in amusement parksExp

21、lain state functionsEnergy & Nuclear Science43The Temperature ConceptObjective comparison of energy flow potentials temperature scales.0th law of thermodynamicsTwo bodies each equal in temperature to a third body are equal in temperature to each other. Maxwell (19th century)Temperature scales led to

22、 the concept of heatThe science of heat - thermodynamics.Energy & Nuclear Science44Hot, Cold and HeatTemperatures (hot and cold) indicate potential for heat flow.They are intensive properties as are color, electrical potentials, concentrations heat capacity, pressures, etc. Temperature scales made h

23、ot-cold measurements quantitative, but they are not quantities to be added or subtracted.Heat, transfers from object to object, elusive. When heat is transferred between objects, their temperatures change.Heat is an extensive property as are electric charge, length, mechanical work, mass, mole, time

24、, etc.Heat is measurable in quantities, units being btu, cal, kcal, J, kJ, kwh, etc.An amount of heat required to raise the temperature of 1.00 g of water from 288.5 to 289.5 K is defined as 1.00 calorie or 4.184 J. What are the differences between hot-cold temperature and heat?Differentiate tempera

25、ture from heatEnergy & Nuclear Science45The Concept of HeatHeat is evidently not passive; it is an expansive fluid which dilates in consequence of the repulsion subsisting among its own particles Joseph Black (1728-1799)- is a typical additive quantity is different from hot inter-convertible to mech

26、anical work (same units)Energy & Nuclear Science46The Energy ConceptInter-conversion- discovered unexpectedlyby Ben Thompson (1753-1814) while making cannons.Conversion factor was determined by J. Joule (1818-1889) 1 cal = 4.184 JThis entity was called effort, living force, and travail, before the t

27、erm energy was coined by Thomas Young (1773-1829) Inter-conversion of Heat and WorkJoule in his 20sEnergy & Nuclear Science47EnergyHeat and work are really energy being transferred. Energy stored in a body is neither heat nor work.Kinetic energies of gases are proportional to their temperature. Once

28、 absorbed, the nature of heat has changed. Motion of gas molecules gave rise to pressure - Daniel Bernoulli (1700-1782). Rudolf J.E. Clausius (1822-1888), James Clerk Maxwell (1831-1879), W. Thomson, and Ludwig E. Boltzmann (1844-1906), studied the relationship between temperature and energy of mole

29、cular motion. Many elegant theories have been developed as a result.Energy & Nuclear Science48Forms of EnergyHeatMechanical work Waves (sound etc)Electromagnetic radiation (waves)Electrical (charge transfer)ChemicalMass (nuclear)Other driving forcesBenefitchideterminationencouragementinspirationlove

30、lawmotivationresolutionscarcityWhat are the properties of energy in these forms and how to evaluate them?Energy & Nuclear Science49Electric EnergyElectric energy, E Joulepotential, V Voltcharge, q CoulombE = V qE = hg m1 J = 1 CV = 1 N m etcBe able to evaluate quantities of electric energyEnergy & N

31、uclear Science50Simple electric energy calculationsPotential difference, V, current i ( = q / t ) and resistance R.V = i R (Ohms law)Power P, (I/o)P = V q / t = V i ( i = current ) = R i 2 (Joules law)Energy and powerE = P t ( unit kilo-watt-hour)DC and AC Electric energy, E Joulepotential, V Voltch

32、arge, q CoulombE = V qE = hg m1 J = 1 CV = 1 N m etcEnergy & Nuclear Science51eV a special energy unitElectron-volt, eV, is a very special energy unit, although we have not discussed electricity and electrons yet.Charge of an electron = 1.6022e-19 C (one of the fundamental physical constants).The en

33、ergy required to increase the electric potential of an electron by 1 V is 1 eV = 1.6022e-19 J (J = C V).Other units used in nuclear energy arekeV (1000 eV)MeV (1e6 eV)GeV (1e9 eV)Be able to inter-convert energy quantities in various unitsEnergy & Nuclear Science52What is light?Wave properties? Parti

34、cle properties?MasslessInterferenceNewton ringdiffractionLaw of reflection law of refractionmove in straight line?Energy & Nuclear Science53Electromagnetic RadiationElectromagnetic radiation is transfer of energy by EM waves via no medium(?).EM waves travel in empty space at constant speed (c = 2.99

35、7925e8 m/s constant).EM waves are characterized by wavelength (or frequency )Light is part of the EM spectrum.EM radiation has a very wide spectrum ( or ).Energy & Nuclear Science54The EM SpectrumLong-wave RadioBroadcast radio bandShort wavelength radioInfraredVISIBLEUltravioletX-raysGamma raysThe E

36、M Radiation Spectrum 600 m 600 - 200 m200 m - 0.1 mm0.1 - 0.0007 mm0.7 - 0.4 um0.4 um - 1 nm1 nm - 0.1 pm0.1 nmRemember the order of these regionsEnergy & Nuclear Science55The EM Wave SpectrumEnergy & Nuclear Science56The Visible SpectrumDouble rainbowEnergy & Nuclear Science57Photons, E = hMax Plan

37、ck assumption, E = h , was shown to be true by Einsteins photoelectric experiment. Speed of light, c = 3e8 m s-1wavelength, frequency of light, = c / Planck constant, h = 6.62619e-34 J senergy of a photon E = h . A photon is a bundle of energy, and its like a particle of light.Use wave to show and .

38、Max Planck(1858-1947)Nobel Prize (1918)Energy & Nuclear Science58The Photon StoryMax Planck assumption, E = h, was shown to be true by Einsteins photoelectric experiment. Explain the photoelectric effect.Energy & Nuclear Science59Photon EnergyTypical red light, = 4.69e14 s-1 (Hz), = c / = 3e8 m s-1

39、/ 4.69e14 s-1 = 640 nm Wave number = 1 / = 1 / 6.40e11 m = 1.56e6 m-1 E = h = 6.62619e-34 J s * 4.69e14 s-1 = 3.1 x 1019 J (1 eV / 1.6 x 10-19 J) = 1.9 eV per photonfind wavelength or frequency of a violet photon and carry out similar evaluations.Energy & Nuclear Science60LaserLight Amplification by

40、 Stimulated Emission of Radiation (LASER)Energy & Nuclear Science61Chemical EnergyenthalpyUnderstand these terms on energy or enthalpyBond energyenergy of reactionenergy related to temperatureenergy related to states melting, vaporization, phase transitionmass loss in chemical reactionsEnergy & Nucl

41、ear Science62Relative and Zero MassesSpecial theory of relativity (by Einstein) shows that mass m of a particle with velocity, v relates to the mass when v = 0, which is called zero mass, mo.Energy & Nuclear Science63Mass and EnergyEinstein further showed that the relativistic mass, m, of a particle

42、 exceeds its rest mass mo (m = m - mo). The increase in kinetic energy E and increase in mass are related by: E = m c 2or E = m c 2Implication:Mass and energy are equivalent. Mass can be expressed in energy unit and vice versa.241800 J = 241800/c 2 = 2.7x10-12 kg = 3 ngEnergy & Nuclear Science64Powe

43、r rate of energy transferThe SI unit for power P is watt named after James Watt, 1 watt = 1 J s1 Work out by heart 1 kilowatt-hour = _ J = _ cal = _ BTUEnergy & Nuclear Science65The law of Conservation of EnergyEnergy converts among various forms without any loss or gain.Energy cannot be created nor

44、 destroyed.Conversions of energy in various forms have definite rates. These rates never change, and we have energy conversion factors.1 amu = (12 kg/k mol)/12 = (1 kg/k mol)/(6.022e26 (k mol)-1) = 1.661e-27 kg = 931.5 MeV1 amu = 1/12th of mass of a C12 atomSome conversion factors1 eV = 1.602 x 1019

45、 J1 eV/molecule = 23045 cal/mol1 MeV = 1.602 x 1013 J1 amu = 1.66043 x 1031 J= 931.4812 MeV1 cal = 4.184 J1 atm L = 101.3 J1 J = 1 coulombvolt1 joule = 107 ergs1 BTU = 252 calEnergy & Nuclear Science67Transmitting Energy by SoundSound intensity (I, watt/m2), level (SIL) is SIL (dB) = SILo + 10 log (I/Io )At 1000 Hz, the threshold SILo=0dB, I0 = 10-12 watt / m2)When I = 1 watt / m2 SIL = 120 dB (work out)Comfortabl