M. Ulrickson - Mechanical Engineeringmammoli/ME217_stuff/lectures_f2011/Nuclear_F… · M....
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Nuclear Fusion Bringing a Star To Earth October 11, 2011 M. Ulrickson Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Transcript of M. Ulrickson - Mechanical Engineeringmammoli/ME217_stuff/lectures_f2011/Nuclear_F… · M....
Nuclear Fusion
Bringing a Star To Earth
October 11, 2011
M. Ulrickson
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration
under contract DE-AC04-94AL85000.
MAU 2 5/20/2003
• Nuclear Energy • Introduction • Plasma Confinement • Fusion Device Engineering • Energy Recovery and T Breeding • Chambers • Plasma Materials Interactions • Fusion Reactors • Alternate Magnetic Fusion Concepts • Inertial Fusion Energy • Additional Information
Outline
MAU 3 5/20/2003
Alternatives for Nuclear Energy - I
• Nuclear Fission – Splitting High Z nuclei increases the average
binding energy yielding net energy – Long lived radio-isotopes are produced – Actinide production poisons the fuel requiring
reprocessing or replacement – Fuel supply in a reactor is about 1 years worth – Fuel is in limited supply
• Without reprocessing (~ 50 years) • With reprocessing (hundreds of years)
MAU 4 5/20/2003
Alternatives for Nuclear Energy - II
• Nuclear Fusion – Two low atomic number atoms combined (e.g.,
D+T) – Deuterium is present in all water – Tritium is manufactured from Lithium using fusion
neutrons – Fusion fuel is widely available – Fuel supply in reactor is only a few seconds worth – With proper choice of materials, no long lived
isotopes are produced. Recycle is possible in <100 years
MAU 5 5/20/2003
Nuclear Binding Energy
Fission Energy
Fusion Energy
MAU 6 5/20/2003
Introduction
• A plasma is an ionized gas where the electrons are completely separated from the atomic nuclei (temperature about 10-100 MC). Partially ionized plasmas exist at lower temperatures (e.g., fluorescent lamp)
• Typical terrestrial plasma densities are 1012 – 1014 /cm3 (inertial fusion 100-1000 times solid density)
• Most of this talk is about magnetically confined fusion plasmas. Inertial confinement is at the end.
MAU 7 5/20/2003
Typical Plasmas
MAU 8 5/20/2003
MAU 9 5/20/2003
What is Fusion Energy? • Fusion reactions power
the sun and stars • In terrestrial fusion:
– hydrogen isotopes—deuterium and tritium
– fuse under high temperature and pressure
– produce energy, neutrons, and helium
• Requires temperatures of 100 million degrees Celsius
• Plasma or ionized gas is formed
Presenter
Presentation Notes
Much larger energy content than fission energy per unit mass. Fuel is widely distributed (no energy cartels)
MAU 10 5/20/2003
Features of a Magnetic Fusion Device
• Circular or “D” shaped coils to make field in the long direction around the torus.
• Poloidal field coils to shape the plasma and provide horizontal and vertical stability
• A vacuum vessel to protect the plasma from the atmosphere
• Plasma facing components to absorb plasma power
• Heating and fueling devices • A breeding blanket to make tritium (future)
MAU 11 5/20/2003
Terminology
• Toroidal Direction: the long direction around a torus
• Poloidal Direction: the short direction around a torus
• Ohmic Solenoid: Coil set that induces toroidal current in the plasma
• Elongation: the ratio of vertical height to horizontal width
• Triangularity: ratio of the x-point radius to the plasma radius
MAU 12 5/20/2003
Plasma Confinement
MAU 13 5/20/2003
Plasma Confinement
• Stars are confined by gravity.
• Terrestrial plasmas are confined by either magnetic fields (many configurations see later) or inertially (inward momentum confines the plasma long enough for reactions to take place)
• The most common magnetic scheme is the tokamak (bottom figure).
MAU 14 5/20/2003
Plasma Flux Surfaces
Nested Toroidal Flux surfaces in toroidal geometry
Helical field lines making a magnetic bottle
MAU 15 5/20/2003
Alternate Magnetic Fusion Concepts
MAU 16 5/20/2003
Alternate Concepts for MFE Spherical Torus Stellarator
Reverse Field Pinch
Spheromak
Field Reversed Configuration
MAU 17 5/20/2003
Spherical Torus
•Aspect ratio is 1.5 (compared to ~3 for a conventional tokamak
•Large ratio of rotational transform from inside to outside
•Natural divertor and elongation
•Much lower toroidal field
MAU 18 5/20/2003
The Stellarator Concept
Note large aspect ratio and complex coils
MAU 19 5/20/2003
The Compact Stellarator Concept
MAU 20 5/20/2003
Fusion Progress
20
The Fusion triple product nτET has increased by a factor of 2 every 2 years Six orders of Magnitude in 50 years is a major accomplishment The time delay for stellarators is due to technology development.
MAU 21 5/20/2003
Scientific Readiness for Burning Plasma
• The present operational boundaries are understood. • Abnormal events can be avoided or mitigated. • The required plasma purity can be obtained, including helium
removal. • Techniques exist to characterize and evaluate the important
parameters. • Plasma control techniques exist to produce and evaluate burning
plasma physics
MAU 22 5/20/2003
The Constellation of Fusion Devices
Presenter
Presentation Notes
Fusion research has led to the discovery of new types of devices, e.g., plasma divertors for clean plasmas, elongation for stability, increased size for confinement. The best features of the past devices are being incorporated into the subsequent generations. ITER is a burning plasma device being designed internationally (fusion is a great example of international cooperation for better energy supplies)
MAU 23 5/20/2003
Fusion Devices
23
MAU 24 5/20/2003
Fusion Device Engineering
MAU 25 5/20/2003
Engineering Issues for Fusion
• Super conducting coil design – “D” shape for constant tension – Wedging and overturning forces (complex
structures) • Vacuum chamber and gas removal (H/D/T and He)
– Neutron shielding (45 cm e-folding) – Breeding Blanket (Li + Be) – Cryogenic pumping and enclosure
• High heat flux removal – Thermal stress and fatigue – Erosion and fuel gas trapping
MAU 26 5/20/2003
Plasma Elongation
Standard Tokamak Divertor Configuration
TF Coil
Plasma
Solenoid
Divertor Coils
Vertical Field Coils
MAU 27 5/20/2003
Options for Defining a Plasma
MAU 28 5/20/2003
International Thermonuclear Experimental Reactor (ITER)
Central Solenoid
Outer Inter-coil Structure
Toroidal Field Coil
Poloidal Field Coil
Machine Gravity Support
Blanket Module
Vacuum Vessel
Cryostat
Port Plug
(IC Heating)
Divertor
Torus Cryopumping
Presenter
Presentation Notes
This is a cut-away view of the proposed International burning plasma device. It is the result of a seven year collaboration among scientists and engineers from the US, Russia, the European Union, and Japan Note the 2 meter tall person standing by the machine! ITER is a required step on the path to a demonstration fusion device that will produce net electricity (DEMO). Projections are that DEMO will operate in about 35 years.
MAU 29 5/20/2003
Engineering Details of Coil Structures
Compression Structure
Divertor Coils
Stability Coils
Ohmic Solenoid
Toroidal Field Coil
Coil Support Structure
MAU 30 5/20/2003
Assembly of Coil Structures
• Solenoid is placed between tensioning caps
• Poloidal field coils are mounted on tensioning caps
• Toroidal field coils rest against the solenoid
• Coil supports are placed between the TF coils
• Vacuum vessel is placed with TF coils in segments
MAU 31 5/20/2003
Plasma Heating and Fueling
• Heating Methods – Neutral beams (add hot particles 100keV-10 MeV) – Ion cyclotron radio frequency (heat the ions 50-200 MHz) – Electron cyclotron radio frequency (heat electrons 100-
200 GHz) – Ohmic heating (plasma current heats the plasma)
• Fueling Methods – Gas injection (low efficiency and increases wall recycling
and erosion) – Frozen DT pellets (good efficiency but cools plasma)
MAU 32 5/20/2003
Chambers
MAU 33 5/20/2003
Fusion Plasma Chamber
• Outer skin removed to show stiffening ribs and shielding
• Large access ports are for heating and diagnostics
• Small access ports are for pumping and divertor cooling
• Vessel is lined with copper plates for passive stability
• Forces can be several atmospheres
MAU 34 5/20/2003
Energy Recovery and T Breeding
MAU 35 5/20/2003
Breeding Blanket Concept
MAU 36 5/20/2003
Breeding Blanket Module
MAU 37 5/20/2003
Liquid Breeding Blanket Concept
MAU 38 5/20/2003
Plasma Materials Interactions
MAU 39 5/20/2003
Plasma Edge Region
• Transport along field lines is much more rapid than perpendicular transport
• The confined plasma is surrounded by open field lines that carry plasma leaking from the confined region to either a limiter or the divertor
• The width of the edge region is very narrow (~ few cm in a reactor)
• Implies high heat and particle fluxes
MAU 40 5/20/2003
Limiter vs. Divertor Operation
MAU 41 5/20/2003
Divertor Edge Plasma Details
MAU 42 5/20/2003
Magnetic Fusion Energy Heat Fluxes
10-4 10-3 10-2 10-1 100 101 102 103 104 105 106
Duration (s)
10-1
100
101
102
103
104
105
106
Hea
t Flu
x (M
W/m
2 )
Fusion Divertor
Radiant Flux at Sun SurfaceFast Breeder
Fission Reactor
Fusion First Wall
Fusion Disruption
Fusion ELM
Rocket Nozzle
Presenter
Presentation Notes
This slide shows a comparison of the heat flux found in magnetic fusion devices to the heat flux in nuclear reactors, space flight, and the sun. The fusion divertor absorbs the alpha particle power from the DT reaction (about 20% of the fusion power). The first wall sees the neutron flux and a portion of the alpha power (up to one half). The disruption heat flux is generated when the plasma current suddenly terminates and the plasma stored energy is dumped to the plasma facing components. The survival of both normal operation and disruptions represent the main challenge of plasma facing components.
MAU 43 5/20/2003
Fusion Plasma Materials Interactions
• The core plasma must be kept clean of impurities and He ash
• The plasma facing component surface sees high density and temperature plasma and must remove high heat flux
• Key issues are hydrogen trapping, erosion, and thermal fatigue
• Spans science from ionized gases to materials science Core
Plasma Boundary Plasma
Plasma Facing Material
20-100 M K 0.1-2 M K 800-3500 K
Energy and particles
Fuel and impurities
Ionization and transport
Trapping
Sputtering Evaporation
Presenter
Presentation Notes
Plasma facing components must survive in an very challenging environment where the temperature gradients are very large and must not contaminate the plasma because of erosion. Transport processes from the surface to the plasma are very rapid and very damaging. The challenge is to engineer materials and components that can meet the challenge. Sandia’s specialty!
MAU 44 5/20/2003
Plasma Facing Components
Heat Sink
Coolant
Fatigue. Creep, Fracture
Heat Flux
Critical Heat Flux
Heat removal
Erosion, Melting & Evaporation
Joint
MAU 45 5/20/2003
Materials Choices for PFCs
• Divertor applications – Only W and C are acceptable for the highest heat
flux (C limited because of T retention and neutron damage)
– With some radiation in the divertor W, C, Mo, Ta, and Nb? are candidates (Cu is not acceptable because of erosion)
• For first wall applications – Iron alloys (ferritic steel), V, Be, and all the divertor
materials
MAU 46 5/20/2003
Heat Flux Capability
Al Be C PyC Cr Co Cu Au Fe Mg Mo Ni Nb Pt Ag Ta Ti W V ZrMaterial
0
10
20
30
40
50
Lim
iting
Hea
t Flu
x (M
W/m
2 )
Typical Maximum
Normal Operation
Typical Minimum
MAU 47 5/20/2003
Recycling feasibility (from INEEL) 1
H
3
Li4
Be
41
Nb
5
B
6
C
8
O
2
He
10
Ne
65
Tb
63
Eu
nostable
isotopes
77
Ir
nostable
isotopes
cd<10 10Šcd<102 102Šcd<103 103Šcd<104 104Šcd<105 105Šcd<106 106Šcd<107
72
Hf
44
Ru
7
N
75
Re
76
Os
80
Hg
58
Ce
67
Ho
71
Lu
9
F
11
Na
12
Mg
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
19
K
20
Ca
21
Sc
22
Ti
23
V
24
Cr
31
Ga
32
Ge
33
As
35
Br
39
Y
40
Zr
42
Mo47
Ag
48
Cd
49
In
52
Te
53
I
57
La
59
Pr
60
Nd
68
Er
69
Tm70
Yb
74
W
79
Au
81
Tl
82
Pb
83
Bi
µSv/hTop half of box: µSv/h after 10 yearsBottom half of box: µSv/h after 100 years
34
Se
51
Sb
25
Mn
26
Fe
27
Co
28
Ni
29
Cu
30
Zn
36
Kr
37
Rb
38
Sr
45
Rh
46
Pd
107Šcd
50
Sn
54
Xe
55
Cs
56
Ba
62
Sm
64
Gd
66
Dy
73
Ta
78
Pt
Based on C. B. A. Forty, et al., Handbook of Fusion Activation Data; Part 1. Elements Hydrogen to Zirconium, AEA FUS 180, May 1992. Assumes 4.15 MW/m2 for 25 years.
MAU 48 5/20/2003
Qualify for Class C waste (from INEEL) 1
H
3
Li4
Be
11
Na
12
Mg
19
K
20
Ca
21
Sc
22
Ti
23
V
37
Rb
39
Y
40
Zr
41
Nb
55
Cs
56
Ba
57
La
73
Ta
24
Cr
42
Mo
74
W
25
Mn
26
Fe
28
Ni
46
Pd
47
Ag
30
Zn
48
Cd
5
B
31
Ga
49
In
6
C
14
Si
32
Ge
50
Sn
15
P
33
As
8
O
52
Te
9
F
53
I
69
Tm68
Er
66
Dy
65
Tb
63
Eu
60
Nd
59
Pr
no stable
isotopes
83
Bi
82
Pb
81
Tl
79
Au
77
Ir
no stable
isotopes
70
Yb
72
Hf
27
Co
45
Rh
44
Ru
13
Al
7
N
17
Cl
16
S
29
Cu
34
Se
38
Sr
51
Sb
75
Re
76
Os
78
Pt
80
Hg
58
Ce
62
Sm
35
Br
64
Gd
67
Ho
71
Lu
unlimited 10% 1% .1% .01% .001% .0001%
Top half of box: hard spectrum Bottom half of box: soft spectrum
.00001%
From: S. J. Piet, et al., Fusion Technology, Vol. 19, 1991, pp. 146-161. Assumes 5 MW/m2 for 4 years; and E. T. Cheng, Journal of Nuclear Materials, Vol. 258-263, 1998, pp. 1767-1772.
MAU 49 5/20/2003
Fusion Reactors
MAU 50 5/20/2003
The ARIES Reactor Concept
Fusion Energy Device (1000 MW)
MAU 51 5/20/2003
FESAC 35 Year Roadmap
MAU 52 5/20/2003
Inertial Fusion Energy
MAU 53 5/20/2003
Inertial Fusion Energy Characteristics
• All involve heating a small (few mm to few cm) DT ice pellet by compression to much greater than solid density
• Four drivers are under investigation – Uniform laser driven implosion – Above with small very high power laser trigger – Particle beam driven x-ray source (indirect drive) – Z-Pinch driven implosion
• Burn duration is about 10 ns and the repetition rate is 0.1 to a few Hz (high peak to average power)
MAU 54 5/20/2003
Inertial Fusion Energy
MAU 55 5/20/2003
Indirect Drive Capsule
• Driver can be either laser light or heavy ion beams
• The x-rays generated in the cylinder heat and compress the fuel capsule in the center
• The outer cylinder shields the pellet from ambient conditions
MAU 56 5/20/2003
Photon Drivers For IFE
• Diode pumped solid state lasers are one option for repetitive laser drives (work at LLNL)
• KrF lasers use electron beams to stimulate the gas in the laser (work at NRL)
• Z-Pinch can also create an x-ray source for pellet compression (Sandia work)
MAU 57 5/20/2003
Additional Information
MAU 58 5/20/2003
Interesting Places to Visit
• fire.pppl.gov • fusion.gat.com • science.doe.gov • fusionpower.org • fusion.ucla.edu • nrl.gov • llnl.gov
MAU 59 5/20/2003
Books and Journals
• “The Plasma Boundary of Magnetic Fusion Devices” Peter Stangeby, Institute of Physics Publishing, 2000
• “Introduction to Plasma Physics”, Rutherford and Goldston • “Burning Plasma, Bringing a Star to Earth”, National
Academy Press, 2003 • Nuclear Fusion Journal • Journal of Nuclear Materials • Fusion Engineering and Design • Fusion Technology
