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Nuclear Fusion Benjamin Harack
Nuclear Fusion Benjamin Harack
Overview
Overview
Fusion
Fusion
Fusion as a Power Source
Fusion as a Power Source
Net Energy
Net Energy
Steady State Power
Steady State Power
Energy Capture
Energy Capture
Safety Concerns
Safety Concerns
Our Focus
Our Focus
Fusion Processes
Fusion Processes
Fusion Techniques
Fusion Techniques
Analysis Tools
Analysis Tools
Ignition State
Ignition State
Lawson Criterion
Lawson Criterion
Lawson Criterion
Lawson Criterion
Lawson Criterion
Lawson Criterion
Fusion Performance Parameter
Fusion Performance Parameter
Energy Gain Factor
Energy Gain Factor
Energy Gain Factor Q
Energy Gain Factor Q
Energy Gain Factor Q Calculation
Energy Gain Factor Q Calculation
Fusion Processes
Fusion Processes
Proton-Proton Chain
Proton-Proton Chain
Proton-Proton Chain
Proton-Proton Chain
CNO Cycle
CNO Cycle
CNO Cycle
CNO Cycle
Deuterium-Deuterium (D-D)
Deuterium-Deuterium (D-D)
Deuterium-Tritium (D-T)
Deuterium-Tritium (D-T)
Deuterium-3He (D-He)
Deuterium-3He (D-He)
p-11B
p-11B
Muon Catalyzed Fusion
Muon Catalyzed Fusion
Considerations for Implementations
Considerations for Implementations
Magnetic Pressure
Magnetic Pressure
Power Density
Power Density
Direct Conversion
Direct Conversion
Direct Conversion
Direct Conversion
Direct Conversion
Direct Conversion
Materials
Materials
Implementations
Implementations
Laser Implosion
Laser Implosion
Laser Implosion Laser M
Laser Implosion Laser M
Laser Implosion National Ignition Facility
Laser Implosion National Ignition Facility
Laser Implosion Fast Ignition Systems
Laser Implosion Fast Ignition Systems
Tokamak
Tokamak
Tokamak
Tokamak
Tokamak: JET
Tokamak: JET
Tokamak: ITER
Tokamak: ITER
Inertial Electrostatic Confinement
Inertial Electrostatic Confinement
Inertial Electrostatic Confinement Fusor
Inertial Electrostatic Confinement Fusor
Inertial Electrostatic Confinement Polywell
Inertial Electrostatic Confinement Polywell
Inertial Electrostatic Confinement Polywell
Inertial Electrostatic Confinement Polywell
Fusion's Status and Future
Fusion's Status and Future
Nuclear Fusion: Status and Future
Nuclear Fusion: Status and Future
References
References
References #2
References #2
D-D, D-T, and D-He
D-D, D-T, and D-He
Plasma Beta
Plasma Beta

Презентация: «Nuclear Fusion Benjamin Harack». Автор: Ben . Файл: «Nuclear Fusion Benjamin Harack.ppt». Размер zip-архива: 2084 КБ.

Nuclear Fusion Benjamin Harack

содержание презентации «Nuclear Fusion Benjamin Harack.ppt»
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1 Nuclear Fusion Benjamin Harack

Nuclear Fusion Benjamin Harack

2 Overview

Overview

Introduction to Nuclear Fusion Analysis Tools Fusion Processes (Fuel Cycles)? Considerations for Implementations Implementation Types Fusion's Status and Future

2

3 Fusion

Fusion

Nuclear fusion refers to any process of interaction of two nuclei in which they combine to form a heavier nucleus. For light elements, this process typically emits extra particles such as electrons and neutrinos along with a relatively large amount of energy.

3

4 Fusion as a Power Source

Fusion as a Power Source

The goal of fusion power production is to harness reactions of this nature to produce electrical power. Thermal power plants convert heat into electricity via a heat engine. Direct conversion involves capturing charged particles to create a current.

4

5 Net Energy

Net Energy

We want net energy output from our fusion power plant. Later on we look at the details of the fusion energy gain factor Q, a useful quantity for describing the energy balance of a reactor.

5

6 Steady State Power

Steady State Power

In order to be producing useful electrical power, the reaction must be either in dynamic equilibrium or pulsed quickly. JET (1982-present) (Joint European Torus) ITER (~2018) (originally International Thermonuclear Experimental Reactor)? DEMO (~2033) (DEMOnstration Power Plant)?

6

7 Energy Capture

Energy Capture

Emitted energy from fusion reactions is primarily in the form of high energy neutrons and various charged particles. Charged particles skid to a halt mainly through electromagnetic interactions Neutrons deposit energy primarily through nuclear interactions. Stopping neutrons generally requires different shielding than charged particles.

7

8 Safety Concerns

Safety Concerns

The most popular fusion reactions produce a lot of neutron radiation. This fact has associated safety concerns: Direct Neutron Flux Activated Materials

8

9 Our Focus

Our Focus

Most of the scientific work in fusion has been focused on achieving net energy gain. Fusion for power production requires: Fusion process (fuel cycle)? a technique for bringing the fuel to a state in which fusion can progress. (Implementation)?

9

10 Fusion Processes

Fusion Processes

Fusion processes (or fuel cycles) are the possible fusion reactions. Analogous in concept and notation to chemical reactions An example of a fusion process, D-T:

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11 Fusion Techniques

Fusion Techniques

These are the different physical methods of achieving fusion conditions. Require kinetic energy to overcome the Coulomb barrier. Once the nuclei are close enough to each other, the strong nuclear force becomes stronger than the electrostatic force, and the nuclei may fuse. Some techniques we look at later include laser implosion and the tokamak.

11

12 Analysis Tools

Analysis Tools

12

13 Ignition State

Ignition State

Ignition state occurs when enough fusion energy is kept in the plasma to continue fusing other nuclei. The majority of energy leaves the plasma, becoming the energy that we capture to produce electricity.

13

14 Lawson Criterion

Lawson Criterion

First described by John D. Lawson in 1957, it is a measure of the conditions required for achieving ignition in a plasma.

14

15 Lawson Criterion

Lawson Criterion

The quantity L is defined as:

15

16 Lawson Criterion

Lawson Criterion

For D-T:

16

Wikimedia Commons (Modified)?

17 Fusion Performance Parameter

Fusion Performance Parameter

Product of ?E with plasma pressure ?. For D-T this must reach about 1MPa·s at a plasma temperature of 15keV.

17

Schumacher (2004)?

18 Energy Gain Factor

Energy Gain Factor

Energy Gain Factor is often referred to as 'Q' Q is defined as: power from fusion divided by the power of external heating required to keep fusion going.

18

19 Energy Gain Factor Q

Energy Gain Factor Q

19

20 Energy Gain Factor Q Calculation

Energy Gain Factor Q Calculation

20

21 Fusion Processes

Fusion Processes

21

22 Proton-Proton Chain

Proton-Proton Chain

Slow process in the sun for two reasons: overcoming coulomb barrier relies on quantum tunneling relies on weak interactions. Dominant energy source in stars similar to or lighter than our sun. First reaction in the process:

22

23 Proton-Proton Chain

Proton-Proton Chain

23

HyperPhysics Online (2010)?

24 CNO Cycle

CNO Cycle

CNO stands for Carbon-Nitrogen-Oxygen Four protons are converted into a helium-4 nucleus, two positrons, gamma rays, and neutrinos. A heavy nucleus acts as a catalyst. The heavy nucleus is transformed in a cycle, but is not consumed in the cycle. Dominates in stars more than 1.5 times the solar mass.

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25 CNO Cycle

CNO Cycle

25

Wikimedia Commons

26 Deuterium-Deuterium (D-D)

Deuterium-Deuterium (D-D)

Possibility for terrestrial use Reaction rate peak at 15 keV Deuterium available in the earth's oceans Two processes with equal probability:

26

27 Deuterium-Tritium (D-T)

Deuterium-Tritium (D-T)

Properties that make it more desirable than D-D: Even higher cross section than D-D Reaction rate peak at 13.6 keV Disadvantages: Blanket of Lithium required for breeding tritium Neutron carries off 80% of energy

27

28 Deuterium-3He (D-He)

Deuterium-3He (D-He)

Advantages: Comparably high energy yield (18.3MeV)? Aneutronic Direct conversion is possible Disadvantages: Helium-3 is hard to acquire currently Reaction rate peaks at 58 keV

28

29 p-11B

p-11B

Advantages Aneutronic Direct conversion possible Fuel availability Disadvantages: Reaction rate peaks at a relatively high energy of 123 keV

29

30 Muon Catalyzed Fusion

Muon Catalyzed Fusion

Muon instead of an electron orbiting a nucleus has the effect of lowering the coulomb barrier. Lower temperatures. Problem: Alpha sticking Need a cheap source of a very large number of Muons.

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31 Considerations for Implementations

Considerations for Implementations

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32 Magnetic Pressure

Magnetic Pressure

Temperatures are too high for material confinement. Charged particles tend to spiral around magnetic field lines. Magnetic fields exert a pressure on the plasma to keep it contained.

32

33 Power Density

Power Density

Power Density varies as:

33

34 Direct Conversion

Direct Conversion

Use graded positive potentials to slow down positively charged particles. Kinetic energy is transformed into potential energy as they climb potential hills. Ions strike the target electrode, stealing electrons, creating a further positive potential. Electrons are reflected to a different collection surface

34

35 Direct Conversion

Direct Conversion

35

Moir, R.W. (2009)?

36 Direct Conversion

Direct Conversion

36

Moir, R.W. (2009)?

37 Materials

Materials

Very high neutron flux for popular fuel cycles Using a divertor system, the energy flux may be tremendous As high as 100MW per square meter. No known material can handle this. Plan is to disperse the energy over wider area.

37

38 Implementations

Implementations

38

39 Laser Implosion

Laser Implosion

Also known as Inertial Confinement Fusion Pellet-based techniques have existed since the 70s High powered lasers are the key Difficulty of even laser pressure Efficiency of laser energy Ignition state may be possible

39

40 Laser Implosion Laser M

Laser Implosion Laser M

gajoule

40

CEA – Laser M?gajoule Official Website (2010)?

41 Laser Implosion National Ignition Facility

Laser Implosion National Ignition Facility

41

Wikimedia commons (2010)?

42 Laser Implosion Fast Ignition Systems

Laser Implosion Fast Ignition Systems

Use laser implosion for pressure, but other techniques for heating Single ultra high power laser burst Z-pinch Could dramatically lower the energy needed to achieve fusion conditions.

42

43 Tokamak

Tokamak

The name tokamak is a transliteration of a Russian acronym standing for a phrase similar to “toroidal chamber with magnetic coils”.

43

Wikimedia commons (2010)?

44 Tokamak

Tokamak

Poloidal magnetic field necessary. Electric current through the plasma to generate poloidal component.

44

Wikimedia commons (2010)?

45 Tokamak: JET

Tokamak: JET

45

JET Promotional Image (2010)?

46 Tokamak: ITER

Tokamak: ITER

46

47 Inertial Electrostatic Confinement

Inertial Electrostatic Confinement

Inertial Electrostatic Confinement (IEC) uses electric confinement instead of magnetic. Potential well created by an electrode at negative potential. Ions are accelerated towards central electrode.

47

48 Inertial Electrostatic Confinement Fusor

Inertial Electrostatic Confinement Fusor

48

Wikimedia commons (2010)?

49 Inertial Electrostatic Confinement Polywell

Inertial Electrostatic Confinement Polywell

Robert Bussard conducted extensive work on his own specialized version of IEC. Instead of a physical electrode, they used a cloud of electrons contained by magnetic fields. Very high energies attainable. Possibilities for aneutronic processes.

49

50 Inertial Electrostatic Confinement Polywell

Inertial Electrostatic Confinement Polywell

Ion Density varies as 1/R 2 Power Density varies as 1/R4 Well-deepening effect. New developments in 2009-2010: Funding has been approved for new prototypes. (2010-2011)? Provisional funding for later prototypes. (~2012)?

50

51 Fusion's Status and Future

Fusion's Status and Future

51

52 Nuclear Fusion: Status and Future

Nuclear Fusion: Status and Future

There has been demonstrable, though difficult progress made in the last several decades. Our understanding of the difficulties has grown, making all previous estimations of fusion's possible timeline overly optimistic. Current projections are more humble, but there may still be things we do not know. Many exciting things happening in current experiments.

52

53 References

References

Bussard, R. W. Method And Apparatus For Controlling Charged Particles. United States Patent #4826646. 1985. Maisonnier, D., et al. A Conceptual Study of Commercial Fusion Power Plants. European Fusion Development Agreement. 2005. J.D. Lawson, Some Criteria for a Power Producing Thermonuclear Reactor. Atomic Energy Research Establishment, Harwell, Berks. 1956 Post, R. F., Fowler, T. K., Killeen, J., Mirin, A. A. Concept for a High-Power-Density Mirror Fusion Reactor. Lawrence Livermore Laboratory, University of California, 1973. Post, R. F. Controlled fusion research and high-temperature plasmas. Annual Review of Nuclear and Particle Science, 1970. Ribe, F. L. Fusion Reactor Systems. Rev. Mod. Phys. 47, 7, 1975.

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54 References #2

References #2

Keefe, D. Inertial Confinement Fusion Review. Ann. Rev. Nucl. Sci. 32, 391, 1982. Schumacher, U. Status and problems of fusion reactor development. Naturwissenschaften, 88, 3, 2004. ITER and DEMO Projects Homepage: http://www.iter.org

54

55 D-D, D-T, and D-He

D-D, D-T, and D-He

55

Wikimedia Commons

56 Plasma Beta

Plasma Beta

Beta is the ratio of plasma pressure and magnetic pressure.

56

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