Fusion Celestial to Earthbound

A Comparison 1 gallon of seawater=300 gallons of gasoline 1 gallon of seawater=300 gallons of gasoline 82,459,000 barrels per day in > 1,583,212,800 gallons of gasoline 82,459,000 barrels per day in > 1,583,212,800 gallons of gasoline 5,277,376 gallons of ocean water burned in a fusion reactor= 1,583,212,800 gallons of gasoline 5,277,376 gallons of ocean water burned in a fusion reactor= 1,583,212,800 gallons of gasoline 5,277,376 gallons of ocean water=1.5E-12% of the total volume of the ocean 5,277,376 gallons of ocean water=1.5E-12% of the total volume of the ocean Only.015% of naturally occurring hydrogen is deuterium Only.015% of naturally occurring hydrogen is deuterium

How Does Fusion Occur? Two lighter nuclei combine to form a heavier nucleus coupled with a release of energy Two lighter nuclei combine to form a heavier nucleus coupled with a release of energy Coulomb Barrier Coulomb Barrier –Heat Fuel Confinement Fuel Confinement Self Sustaining? Self Sustaining? –Lawson Criteria

The Sun Proton-Proton chain Proton-Proton chain –Beginnings 1 H + 1 H → 2 H + e + + ν e 1 H + 1 H → 2 H + e + + ν eeν e ν e 2 H + 1 H → 3 He + γ 2 H + 1 H → 3 He + γγ –pp1 3 He + 3 He → 4 He + 1 H + 1 H 3 He + 3 He → 4 He + 1 H + 1 H –pp2 3 He + 4He → 7 Be + γ 3 He + 4He → 7 Be + γ Beγ Beγ 7 Be + e− → 7 Li + νe 7 Be + e− → 7 Li + νe Liνe Liνe 7 Li + 1 H → 4 He + 4 He 7 Li + 1 H → 4 He + 4 He –pp3 3 He + 4 He → 7 Be + γ 3 He + 4 He → 7 Be + γ γ 7 Be + 1 H → 8 B + γ 7 Be + 1 H → 8 B + γ Bγ Bγ 8 B → 8 Be + e + + νe 8 B → 8 Be + e + + νe νe 8 Be ↔ 4 He + 4 He 8 Be ↔ 4 He + 4 He

The Sun (cont’d) Carbon-Nitrogen- Oxygen chain Carbon-Nitrogen- Oxygen chain – 12 C + 1 H → 13 N + γ γ – 13 N → 13 C + e+ + νe eνeeνe – 13 C + 1 H → 14 N + γ – 14 N + 1 H → 15 O – 15 O → 15 N + e+ + νe – 15 N + 1 H → 12 C + 4 He

Earthbound? Can’t use gravitational force Can’t use gravitational force –Must use electromagnetic force Magnetic confinement Magnetic confinement Limited in reaction choice Limited in reaction choice –Exothermic –Low Z nuclei Ignition Energy Ignition Energy –D-T reaction=100 million degrees Celsius

The Reactions (1)D+T → 4 He(3.5 MeV)+ n(14.1 MeV) (1)D+T → 4 He(3.5 MeV)+ n(14.1 MeV) (2i)D+D → T(1.01 MeV)+ p(3.02 MeV) 50% (2i)D+D → T(1.01 MeV)+ p(3.02 MeV) 50% (2ii) → 3 He(0.82 MeV)+ n(2.45 MeV) 50% (2ii) → 3 He(0.82 MeV)+ n(2.45 MeV) 50% (3)D+ 3 He → 4 He(3.6 MeV)+ p(14.7 MeV) (3)D+ 3 He → 4 He(3.6 MeV)+ p(14.7 MeV) (4)T+T → 4 He +2 n MeV (4)T+T → 4 He +2 n MeV (5) 3 He+ 3 He → 4 He +2 p MeV (5) 3 He+ 3 He → 4 He +2 p MeV (6i) 3 He+T → 4 He + p +n MeV 51% (6i) 3 He+T → 4 He + p +n MeV 51% (6ii) → 4 He(4.8 MeV)+ D(9.5 MeV) 43% (6ii) → 4 He(4.8 MeV)+ D(9.5 MeV) 43% (6iii) → 4 He(0.5 MeV)+ n(1.9 MeV)+p(11.9 MeV) 6% (6iii) → 4 He(0.5 MeV)+ n(1.9 MeV)+p(11.9 MeV) 6% (7)D+ 6 Li → 2 4 He MeV (7)D+ 6 Li → 2 4 He MeV (8)p+ 6 Li → 4 He(1.7 MeV)+ 3He(2.3 MeV) (8)p+ 6 Li → 4 He(1.7 MeV)+ 3He(2.3 MeV) (9)3He+ 6 Li → 2 4 He + p MeV (9)3He+ 6 Li → 2 4 He + p MeV

First Steps Hydrogen Bomb Hydrogen Bomb Radio-frequency heating Radio-frequency heating Linear Confinement Linear Confinement –Pinch effect Magnetic Mirrors Magnetic Mirrors Toroid Toroid –Stellarator

Stellarator

Problems Plasma Instability Plasma Instability Heat Loss Heat Loss

Tokamak Large toroid that produces a toroidal magnetic field Large toroid that produces a toroidal magnetic field Charged plasma also creates magnetic field Charged plasma also creates magnetic field Large external shaping magnets Large external shaping magnets Name derived from Russian: toroidalnaya kamera magnitnaya katushka Name derived from Russian: toroidalnaya kamera magnitnaya katushka

Tokamak (cont’d)

The Big Three TFTR (tokamak fusion test reactor located at Princeton University) TFTR (tokamak fusion test reactor located at Princeton University) JET (joint European torus, located in Culham, UK as part of a European collaboration) JET (joint European torus, located in Culham, UK as part of a European collaboration) JT-60 (located in Japan) JT-60 (located in Japan)

Results JET reactor produces 16MW of fusion energy JET reactor produces 16MW of fusion energy TFTR and JT-60 produce around 10.7 MW of fusion energy TFTR and JT-60 produce around 10.7 MW of fusion energy Q values of Q values of

The Future ITER (international thermonuclear experiment reactor) ITER (international thermonuclear experiment reactor) Goals Goals –400MW fusion energy –Q value of around 10

Considerations Safety Safety –Amount of fuel in reactor –Reaction sustainability Waste Waste Fuel Fuel

Sources 1) 1) 2)Fowler, T. K. The Fusion Quest, The Johns Hopkins University Press: Baltimore and London, )Fowler, T. K. The Fusion Quest, The Johns Hopkins University Press: Baltimore and London, )Braams, C.M.; Stott, P.E. Nuclear Fusion: Half a Century of Magnetic Confinement Fusion Research; Institute of Physics Publishing: Bristol and Philadelphia, )Braams, C.M.; Stott, P.E. Nuclear Fusion: Half a Century of Magnetic Confinement Fusion Research; Institute of Physics Publishing: Bristol and Philadelphia, ) 4) 5) 5) 6) 6)