Compact fusion reactors

Tomas LindenHelsinki Institute of Physics

NST2016, Helsinki, 3rd of November 2016

Fusion research is currently to a large extent focused on tokamak (ITER) and inertialconfinement (NIF) research. In addition to these large international or national effortsthere are private companies performing fusion research using alternative concepts, thatpotentially could result on a faster time scale in smaller and cheaper devices than ITERor NIF.

The attempt to achieve fusion energy production through relatively small and compact

devices compared to standard tokamaks decreases the costs and building time of the

reactors and this has allowed several private companies to enter the field, like EMC2,

General Fusion, Helion Energy, LPP Fusion, Lockheed Martin, Tokamak Energy and Tri

Alpha Energy. These companies are trying to demonstrate the feasibility of their

concept. If that is succesfully done, their next step is to try to demonstrate net energy

production and after that to attempt to commercialize their technology. In this

presentation a very brief overview of compact fusion reactor research is given.Tomas Linden (HIP) Compact fusion reactors 03.11.2016 1 / 24

Contents

Contents

1 Fusion conditions

2 Plasma confinement

3 The Polywell reactor

4 Lockheed Martin CFR

5 Dense plasma focus

6 MTF

7 Spherical tokamaks

8 Other fusion concepts

9 Summary

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 2 / 24

Fusion conditions

Fusion conditions

See Antti Hakolas presentation in this conference on mainline fusion.A useful fusion performance metric is the triple product

NτT (1)

that has to execeed some threshold value for the fusion reaction inquestion for the fusion power to exceed radiation and other losses andmaintain a constant plasma temperature. N is the particle density, theconfinement time is τ and the temperature is T . For DT the minimumrequired value for a thermal plasma is 3·1021 keVs/m3.

Several plasma heating methods exist.

The required temperature is defined by the desired fusion reaction

Achieving stable plasma confinement filling the triple product hasproved hard

The density and the confinement time can by varied in a largeunexplored plane

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 3 / 24

Fusion conditions

Fusion conditions

The ratio of plasma pressure to magnetic pressure β is a figure of merit ofhow well the investment in the magnetic field can be utilized.Fusion power is proportional to β2.The achievable value of β is often limited by plasma instabilities.

β = pkin/pmag (2)

where pkin = Ni kTi + NekTe , pmag = B2

2µ0. Ni (Ti ), Ne (Te) = ion-

respective electron particle density (temperature), k = Boltzmannconstant and B = the magnetic field and µ0 = the permeability of vacuum[1]. The ITER β design value is ≈ 0.03 [2]

A compact fusion reactor in this context has a significantly smallerplasma volume than a traditional tokamak because of a large value of β.

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 4 / 24

Plasma confinement

Plasma confinement

Examples of plasma confinement methods:

Magnetic Confinement Fusion (MCF)

Tokamak (JET, ITER, ...), stellarator (Wendelstein 7-X), ...N ≈ 1014/cm3, τ ≈ 1 s

Inertial Confinement Fusion (ICF)

Laser fusion (National Ignition Facility, High Power laser EnergyResearch facility (HiPER), ...)N ≈ 1025/cm3, τ ≈ 1 nsHeavy Ion Fusion (HIF)

Inertial Electrostatic Confinement (IEC)

Magnetized Target Fusion (MTF) also Magneto Inertial Fusion(MIF) (General Fusion, Helion Energy, ...) [3]

N ≈ 1019/cm3, τ ≈ 1 µs

Magnetic confinement- and laser fusion get the majority of the funding

The emphasis of laser fusion is on military applications

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 5 / 24

Plasma confinement

Plasma confinement

PlasmoidsSelf confined plasmas where the magnetic fields are mostly generated bycurrents circulating in the plasma are called plasmoids or Compact Torii[4]:

Field Reversed Configuration (FRC)

Spheromak

Plasmoid Axial- Poloidal field Toroidal field Bt

symmetry Bp Bt on surfaceFRC yes yes no noSpheromak yes yes yes no

The poloidal field is contained in planes through the symmetry axis.The toroidal field circulates the symmetry axis.FRC-plasmoids can reach β ≈ 1.

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 6 / 24

The Polywell reactor

The Polywell reactor

Figure: An EMC2 Polywell with a sidelength of 21.6 cm built for β=1 studies.

Figure: Polywell field lines for β = 0.Simulated electron trajectories are green.

Electrons confined in a magnetic cusp accelerate and confine ions[5, 6, 7, 8, 9]

The field geometry has a stable curvature

EMC2 has shown:

1995: Electrostatic fusion in a Polywell (a potential well for ions) [10]

2013: High β together with greatly increased electron confinement [2]

To show the scientific feasibility of the Polywell for energy production,both of these have to be demonstrated at the same timeTomas Linden (HIP) Compact fusion reactors 03.11.2016 7 / 24

Lockheed Martin CFR

Lockheed Martin CFR

Lockheed Martin Compact Fusion Reactor project started in 2011T4 experiment published in February 2013 by C. Chase, aim 200 MWCFR patents published in 09/2014 [11, 12, 13, 14, 15, 16, 17, 18]T. McGuire leads the development at Skunk WorksT4 experiment 1 m * 2 m, nominal reactor core 5.2 m * 15.2 mAxisymmetric, ideas from many concepts, mirrors at ends, DT-fuelFew open magnetic field lines, good field curvature, high βheating power 15 kW (to be increased to 100 kW)Pulses ≈1 s, Te=10-25 eV, τE =4–100 µs, N=1016–1017/m3 [19, 20]

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 8 / 24

Dense plasma focus

Dense plasma focus

LPP Fusion (LPPF), led by E. Lerner [21]

Dense Plasma Focus: J.W. Mather 1960s,N.V. Filippov 1954. An electric dischargecreates the plasma, which developsthrough a series of instabilities to aplasmoidGoal P = 5 MWe, f = 200 HzLandau quantization is expected todecrease bremsstrahlungFor a DD-plasma E>150 keV has beenmeasured [22], which is enough for p11Bτ ≈ 20 ns, surpasses 8 ns goalEnergy transfer to the plasmoid surpassesgoal with 50 %ρ needs to increase with 104 for Q = 1Worked on reducing electron inducedimpurities [23]Working on reducing plasma impuritiesfrom W electrode

Figure: LPPF reactor [21].

Figure: Electrode length ≈ 15 cm.

Figure: Schematic plasma discharge.Tomas Linden (HIP) Compact fusion reactors 03.11.2016 9 / 24

MTF

SOFE 2013 2

1.00E+06

1.00E+09

1.00E+12

1.00E+15

1.00E+13 1.00E+16 1.00E+19 1.00E+22 1.00E+25

1.00E+02

1.00E+05

1.00E+08

1.00E+11

Driver Power Plasma Energy

kJ

MJ

GJ

MW

GW

TW

$ C

ost

of

Co

nfin

em

en

t

$ C

ost

of

Drive

r

ITER

$20B

NIF

$6B

GF

$150M

Plasma Density (cm-3)

Fusion Technologies

MTF

MTF

General Fusion - acoustically heated MTF [24, 25, 26, 27, 28, 29, 30, 31]

Based on LINUS concept from the 1970s

Chief scientist and founder M. Laberge

The planned reactor is a sphere with r = 1,5 m with a rotatingmolten PbLi mixture, P = 100 MWe, f = 1 Hz, Q = 6

Two plasma injectors create, accelerate and compress spheromaks

The spheromaks injected through the vortex in the middle collide

The FRC DT-plasma is heated to fusion conditions acoustically withhundreds of computer controlled pneumatic pistonsThe GF concept has several advantages compared to a tokamak:

No ”inner wall” problem, no divertor neededPbLi is a coolant and neutron multiplicator for T-generationCan be retrofitted to turbines of existing power plants

Potential problemsCompression and stability of the injected spheromaksRichtmyer-Meshkov instabilityPb,Li-impurities can cool the plasma

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 11 / 24

MTF

MTF

Figure: General Fusions 14 piston test reactor ”Mini-Sphere”, with a diameter ofone meter, is used for validating compression simulations.

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 12 / 24

MTF

MTF

The General Fusion development plan:

Phase I - Proof of principle2002 - 2008, < 1 M$Research and development

Phase II - Show net gain≈ 50 M$

System developmentCurrent status [32]Physics validation

Full scale prototype

≈ 500 M$

Phase III - CommercializationAlpha and Beta power plants≈ 2 G$Then power production

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 13 / 24

MTF

MTF

Figure: Helion Energy, MSNW LLC Grande experiment [33, 34].

Two colliding FRCs merge to a stationary FRC

The FRC is compressed magnetically in the burn chamber

Ti ≈ 2,3 keV obtained for D-ions

A plasmoid speed of 300 km/s has been achieved

Plans to use D+D (3He) fuel

Targets 50 MWe prototype in 2019 and commercialization in 2022

ARPA-E: VENTI 12 T & FEP 20 T compression, FEP-G 40 T reactorMSNW develops a fusion driven rocket (FDR) with NIAC funding

Lithium compresses the plasma, absorbs neutrons and generates T

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 14 / 24

MTF

MTF

Figure: Tri Alpha Energy (TAE) experiment C-2U [35, 36, 37, 38, 39].

A FRC is produced by two colliding plasmoidsThe plasmoid injection speed is 250 km/sThe goal is to stabilize the FRC-state with neutral beam injection andwith external electric and magnetic fieldsThe C-2 FRC lifetime was 5 ms, Ti ≈ 1 keVWith C-2U a stable lifetime of 5 ms was reachedC2-W to be completed in mid 2017 will aim for increased temperatureTAE plans to use D3He or p11B

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 15 / 24

Spherical tokamaks

Spherical tokamaks

Mega Ampere Spherical Tokamak Upgrade (MAST-U)

National Spherical Torus eXperiment Upgrade (NSTX-U)

Affordable, robust, compact (ARC), high field compact tokamakTokamak Energy Ltd, high field spherical tokamak development

Spinoff company from Culhamn Center fo Fusion EnergyDevelops superconducting magnets based on High TemperatureSuperconductors (HTS) [40]ST40 3 T copper spherical tokamak [41]

Demonstrate HTS mechanics in a spherical tokamakStudy HH-plasma, maximize the triple product, could use DTExpected first plasma in early 2017

ST60 building planned for in 2019Cost 120 M$, building time a few years, HH-, DD- and DT- plasmasDemonstrate energy gain, 50 MW of fusion power

ST140 is the following step, 185 MW fusion power, V ≈ 40 m3

TE plans to provide power to the grid in 2030

Challenges: HTS cable construction, quality, strength and radiationprotection

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 16 / 24

Other fusion concepts

Other fusion concepts

Dynomak (Univ. Washington), spheromak fusion reactor

Fusion Power Corporation, heavy ion fusion

Farnsworth-Hirsch fusor [42, 43, 44, 45, 46] - likely the simplest fusionreactor, cannot probably be scaled up for energy production

Can be used in research and eductionFunding for constructing a fusor has been obtained the PhysicsDepartment of the University of Helsinki and Helsinki Institute ofPhysics

Phoenix Nuclear Labs, accelerator based neutron generator 3·1011 n/sfrom DD-fusion [47]

...

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 17 / 24

Summary

Summary

Company Year Funding Size Type Method Reaction P target$ m MW

EMC2; USA 1985 42 M 4 c IEC D+T 255General Fusion, Canada 2002 97 M 3 p MTF D+T(Li) 100 eLM Skunk Works, USA 2011 4 M 13 MCF D+T 200Tokamak Energy, UK 2009 15 M c MCF D+T 100–200Helion Energy, USA 2009 21,1 M 16 p MTF D+D(3He) 50 eSorlox, USA 2010 1,15M < 1 p MTF D+D 0,002-1CSI, USA 2010 120 k 7–12 c IEC p + 11B 225 eLPPF, USA 1974 4,5 M 0,15 p DPF p + 11B 5 eTri Alpha Energy, USA 1998 500 M 20 c MTF p + 11B 100

p = pulsed, c = continuous, e = electric

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 18 / 24

Summary

Summary

All possibilities of achieving fusion should be researched thoroughly byincreasing funding, becuse the potential benefits are enormous

Inadequate funding has affected the rate of developement

Fusion break even is a very hard problem

The development of plasma physics, instrumenting, software and computershas enabled some ten (privately funded) companies to do fusion research

Compact fusion reactors have several advantages in terms of developmenttime, cost, placement, applications (mobile, space, medical, material physics)

Fusion reactions have been commercialized as neutron generators

Small fusion reactors can be developed for medical isotope generation

Pulsed fusion reactors could be simpler than continuous reactors

MTF/MIF could provide a promising path to practical fusion

CSI, LPPF and Tri Alpha Energy try to develop aneutronic p11B fusion

GF, HE, LM, LPPF & TE aim for Q ≥ 1 within the next few years

If Q � 1 is reached, then commercialization is the next goal

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 19 / 24

Additional material

Additional material

A longer version of this talk:

T. Linden, Compact fusion reactors, CERN Colloquium 26th of March2015, https://indico.cern.ch/event/382453/

Articles on the same topic:

Wayt W. Gibbs, The fusion underground, Scientific American,November 2016

Lev Grossman, Inside the Quest for Fusion, Clean Energy’s Holy Grail,Time magazine, November 02, 2015

T. Linden, Kompakta fusionsreaktorer, Arkhimedes 5-6, 2014,p. 16-23

D. Clery, Fusion’s restless pioneers, Science 345 6195, 25.7.2014p. 370-375

M. M. Waldrop, The Fusion Upstarts, Nature 511, 24.7.2014p. 398-400

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 20 / 24

Additional material

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[2] J. Park et al., High Energy Electron Confinement in a Magnetic Cusp Configuration, Phys. Rev. X 5, 021024

[3] I. R. Lindemuth, R. E. Siemon, The fundamental parameter space of controlled thermonuclear fusion, Am. J. Phys. 77, pp.407-416, May 2009

[4] P. M. Bellan, Spheromaks : a practical application of magnetohydrodynamic dynamos and plasma self-organization, London: Imperial College Press, 2000

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[7] Nicholas Krall, Fusion Technology, Volume 22, August 1992, The Polywell: A Spherically Convergent Ion Focus Concept

[8] Robert W. Bussard, November 9, 2006, Should Google Go Nuclear?

[9] J. Park, POLYWELL - Electric Fusion in a Magnetic Cusp, talk at Microsoft January 22, 2015

[10] Robert W. Bussard, The Advent of Clean Nuclear Fusion: Superperformance for Space Power and Propulsion, Proc. 57thInternational Astronautical Congress, Valencia, Spain October 2-6 2006

[11] T. McGuire, ACTIVE COOLING OF STRUCTURES IMMERSED IN PLASMA, Patent publication WO/2014/204553A3

[12] T. McGuire, SYSTEM FOR SUPPORTING STRUCTURES IMMERSED IN PLASMA, Patent publicationWO/2014/204554A3

[13] T. McGuire, MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION REACTOR, Patent publicationWO/2014/204555A8

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 21 / 24

Additional material

[14] T. McGuire, ENCAPSULATING MAGNETIC FIELDS FOR PLASMA CONFINEMENT, Patent publicationWO/2014/204556A3

[15] T. McGuire, HEATING PLASMA FOR FUSION POWER USING NEUTRAL BEAM INJECTION, Patent publicationWO/2014/204557A2

[16] T. McGuire, HEATING PLASMA FOR FUSION POWER USING MAGNETIC FIELD OSCILLATION, Patent publicationWO/2014/204558A2

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[18] T. McGuire, MAGNETIC FIELD PLASMA CONFINEMENT FOR COMPACT FUSION POWER REACTOR, Patentpublication WO/2014/165641A1

[19] T. McGurie, The Lockheed Martin Compact Fusion Reactor

[20] T. McGurie, Overview of the Lockheed Martin Compact Fusion Reactor (CFR) Program

[21] Eric J. Lerner, S. Krupakar Murali, A. Haboub, Theory and Experimental Program for p + 11B Fusion with the DensePlasma Focus J Fusion Energy (2011) 30:367-376

[22] Eric J. Lerner et al., Fusion reactions from >150 keV ions in a dense plasma focus plasmoid, Phys. Plasmas 19, 033704(2012)

[23] Eric J. Lerner and Hamid R. Yousefi, Runaway electrons as a source of impurity and reduced fusion yield in the denseplasma focus, Phys. Plasmas 21, 102706 (2014)

[24] M. Laberge, An Acoustically Driven Magnetized Target Fusion Reactor, J Fusion Energ (2008) 27:65-68

[25] S. Howard, M. Laberge, L. McIlwraith, D. Richardson, J. Gregson, Development of Merged Compact Toroids for Use as aMagnetized Target Fusion Plasma, J Fusion Energ (2009) 28:156-161

[26] M. Laberge, Experimental Results for an Acoustic Driver for MTF J Fusion Energ (2009) 28:179-182

Tomas Linden (HIP) Compact fusion reactors 03.11.2016 22 / 24

Additional material

[27] P. J.F. Carle, S. Howard, J. Morelli, High-bandwidth polarimeter for a high density, accelerated spheromak, Rev SciInstrum 84, 083509 (2013)

[28] V. Suponitsky, A. Froese, S. Barsky, Richtmyer-Meshkov instability of a liquid-gas interface driven by a cylindricalimploding pressure wave, Computers & Fluids 89 (2014) 1-19

[29] M. Laberge, S. Howard, D. Richardson, A. Froese, V. Suponitsky, M. Reynolds, D. Plant, Acoustically driven MagnetizedTarget Fusion, Proc. Fusion Engineering (SOFE), 2013 IEEE 25th Symposium on Fusion Engineering, June 10-14, 2013,San Francisco, California, USA, http://dx.doi.org/10.1109/SOFE.2013.6635495

[30] M. Lindstrom, S. Barsky, B. Wetton, Investigation into Fusion Feasibility of a Magnetized Target Fusion Reactor: APreliminary Numerical Framework, J Fusion Energ (2015) 34:76-83

[31] M. Lindstrom, Assessment of the Effects of Azimuthal Mode Number Perturbations upon the Implosion Processes ofFluids in Cylinders, arXiv:1602.01865 [physics.flu-dyn]

[32] M. Laberge, Acoustically driven Magnetized Target Fusion at General Fusion

[33] J. Slough, G. Votroubek and C. Pihl, Creation of a high-temperature plasma through merging and compression ofsupersonic field reversed configuration plasmoids, Nucl. Fusion 51 (2011) 053008

[34] A. Pencotti, Electromagnetically Driven Fusion Propulsion, NASA’s Innovative Advanced Concepts symposium 4-6.2.2014

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Tomas Linden (HIP) Compact fusion reactors 03.11.2016 23 / 24

Additional material

[39] M. W. Binderbauer et al., A high performance field-reversed configuration, Phys. Plasmas 22, 056110 (2015)

[40] A. Sykes et al., Compact Fusion Energy based on the Spherical Tokamak

[41] M. Gryaznevich, Overview and status of construction of ST40

[42] Tom Ligon, The World’s Simplest Fusion Reactor, And How to Make It Work

[43] Philo T. Farnsworth, Electric Discharge Device for Producing Interactions Between Nuclei, U.S. Patent Number 3,258,402June 28, 1966

[44] Robert L. Hirsch, Inertial-Electrostatic Confinement of Ionized Fusion Gases, J Appl Phys 38 (1967) 4522-4534

[45] Robert L. Hirsch; Erratum: Inertial-Electrostatic Confinement of Ionized Fusion Gases, J Appl Phys 39, (1968) 4047

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[47] G.L.Kulcinski, Recent Progress at Phoenix Nuclear Labs and SHINE Medical Technologies, 15th Workshop on InertialElectrostatic Confinement Fusion, October 6-9 Uji, Kyoto, Japan

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