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Direct Fusion Drive for distributed terrestrial power

Michael Paluszek and Stephanie Thomas

PFRC-­‐2  Experiment  at  PPPL  

3/26/15

DFD Terrestrial

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DFD: Small AND Clean

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!  A 1-20 MW reactor is the size of a mini-van !  Low radioactivity

-  Little shielding required to prevent neutron escape -  Disposal at end of life is to move the DFD to a disposal site

!  Mass produced in a factory !  Come with fuel for their design life !  Multiple units provide higher power !  Fixed base or portable units

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DFD Fuel

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!  Selected fuel is D + 3He (deuterium and helium-3) -  Low neutron reactions (low radiation), aka aneutronic

!  Terrestrial helium-3 production enough for 100 MW power generation/year

!  Additional sources -  Plenty of 3He on the moon -  An operating DFD would spur lunar mining -  D-D breeding reactors

!  Option is to use just deuterium -  More neutrons but there may be ways of minimizing the

increase

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PFRC Ongoing Research

3/26/15

!  Princeton Plasma Physics Laboratory performing experiments with DOE funding -  Concluded PFRC-1 a, b, c in 2011; breakthrough achieved in FRC electron heating

methods -  PFRC-2 operating now; goal is to demonstrate keV plasmas with pulse lengths to 0.3 s -  MNX studies on plasma detachment via nozzle

!  Princeton Satellite Systems performing mission and trajectory design, space balance of plant studies under IR&D -  Four joint PPPL/PSS patents

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DFD Phased Development

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!  Complete PFRC-2 experiments – ion heating

!  Design PFRC-3 and conduct experiments -  Fast Track – design PFRC-3

subsystems to production standards

!  Design and build PFRC-4 -  Burning plasma reactor -  Would produce fusion power

!  Build prototype power reactor !  Production !  Roughly $50M to get to 3B

3/26/15

Nuclear Fusion Background

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Magnetic Fusion Energy Background

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!  Fusion power has been produced in D-T tokamaks -  PPPL Tokamak Fusion Test Reactor (TFTR) 10.7 MW -  Joint European Torus (JET) 16.1 MW

with a fusion energy gain (Q) of 0.6 -  Japanese JT-60 has effective Q (if DT were used) of 1.25

!  ITER will develop the engineering needed for baseload power generation from D-T tokamaks -  Prototype D-T reactor DEMO would follow ITER

!  Several other D-T-fueled configurations under study -  Stellarators, spherical tokamaks, etc

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Comparison of Reactors

ITER research reactor: 60 m tall

PFRC reactor: 8 m long

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PFRC: Small and Clean

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ITER PFRC

!  1-10 MW !  Separatrix radius 30 cm !  1e-3 volume and mass !  5e-4 radioactivity (0.2

MW) !  Tritium exhausted

!  Simple solenoid and no breeding blanket

!  Ordinary materials

!  0.5 GW !  Separatrix radius 8 m !  Machine 60 m tall !  400 MW radiation !  Tritium fuses,

producing high-energy neutrons

!  Complex coils and T breeding blanket

!  Hazardous lithium ➨ ~1/1000  cost  

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Fusion Core: D-3He (low level of neutrons)

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!  Field Reversed Configuration (FRC) -  Simple geometry

!  Heating with odd-parity rotating magnetic fields -  Limits size to 20 MW

!  Confinement with high temperature superconducting coils !  Burns D and 3He

-  Could use just D for terrestrial power !  Field Reversed Configuration is a toroidal plasma with

closed magnetic fields -  Small FRC not prone to tilt instabilities

!  Odd-parity rotating magnetic fields heat the plasma -  The symmetry of this heating method improves confinement

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What is Next?

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Challenges of Direct Fusion Drive

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!  Need to demonstrate a burning plasma -  PFRC-3A or PFRC-4

!  Need to get or breed helium-3 -  Not that much needed, terrestrial sources have enough to support small-

scale implementation -  Moon and gas giants, D-D breeding are future sources

!  Need all the supporting hardware to be have high reliability -  Minimal maintenance

!  Radiation shielding -  Neutrons (but not too many) -  Bremsstrahlung – x-rays -  Synchrotron

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Ongoing Work

3/26/15

!  Numerical plasma models using LSP -  PIC code

!  Ion heating experiment in PFRC-2 -  Expect additional grad students this year

!  Design of RF heating system

Growing commitments

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For More Information

3/26/15

Michael Paluszek map@psatellite.com

Stephanie Thomas sjthomas@psatellite.com

Dr. Samuel Cohen scohen@pppl.gov

Princeton Satellite Systems 6 Market St. Suite 926 Plainsboro, NJ 08536

(609) 275-9606 http://www.psatellite.com

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3/26/15

Additional Information

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Possible Fusion Reactions

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p +11 B !3 4He + 8.7 MeV

D+3 He !4He (3.6 MeV) + p (14.7 MeV)

D + T !4He (3.5 MeV) + n (14.1 MeV)

D + D !T (1.01 MeV) + p (3.02 MeV)

D + D !3He (0.82 MeV) + n (2.45 MeV)

D-3He reactors will also have D-D reactions, hence D-T reactions, unless the T fusion products are quickly removed.

Boron - proton produces very few neutrons

DFD

T0kamak

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Reaction Rates

3/26/15 Princeton Satellite Systems

Reaction Rates

100 101 102 10310−40

10−38

10−36

10−34

10−32

10−30

10−28

10−26

10−24

10−22

10−20

Mea

n Si

gma

V (m

3 /sec

)

Temperature (KeV)

D−D−nD−D−pD−TD−He3p−B11

D-T

D-3He D-D

p-11B

x x x

Reactor operating temperatures

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Rotating Magnetic Fields

3/26/15

!  Parity refers to the RMF dipole vector symmetry

!  Odd means it flips at z=0 !  Frequency is a fraction of the

ion cyclotron frequency for the helium-3

!  Provides all the startup power and a fraction of the heating power during operation

!  Would be 0.6 to 6 MHz !  Antennas shown to the right

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Reactor Crosssection

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15 cm 10B4C shielding

Hi-T superconducting

M. Walsh, K. Griffin