A Faster Way to Fusion Our Mission “To deliver to mankind a cheap, safe, secure and practically limitless source of clean energy – fusion power” “a sustainable oil well” The Challenge • Traditional view for fusion power & tokamaks is that bigger is better (ITER) • Huge investment and timescales to progress • Spherical Tokamaks are much more efficient than traditional ‘doughnut’ shape tokamaks. • This allows for smaller more compact designs • But: there are space constraints at the centre of spherical tokamaks • conventional (copper / low temperature superconducting) magnets cannot create conditions required to produce fusion energy The Tokamak Energy Solution Spherical Tokamaks High Temperature Squashed shape Superconductors Highly efficient High current at high field Fusion Power smaller, cheaper, faster Our approach • Rapid development of: • Working prototype devices • Know-how & Patents • A path to energy break even supported by experimental data • Supportive sources of capital • A plan to rapidly deliver a sustainable source of energy to replace fossil fuels CONFIDENTIAL Endorsements • Selected by the International Energy Agency “as one of three most promising innovative fusion concepts” 2017 • Recognised as a Technology Pioneer 2015 by the Davos World Economic Forum • Our peer-reviewed article “On the power and size of tokamak fusion pilot plants and reactors” is the most downloaded paper ever from the Nuclear Fusion journal • Collaborations with MIT whose ARC Reactor combines HTS magnets and tokamak reactors MIT’s “ARC” Fusion • Jointly authored paper with Princeton Plasma Physics Laboratory: Power Plant concept “Fusion nuclear science facilities and pilot plants based on the spherical tokamak” • Director of Princeton Plasma Physics Laboratory gave evidence to Congress in April 2016 and selected spherical tokamaks with HTS magnets as the most promising route to fusion power PPPL / Tokamak Energy ST concept The Tokamak • Magnetic Confinement Fusion uses strong magnetic fields to hold an extremely hot fuel mixture known as a plasma • The Tokamak is by far the most established device for controlled fusion • Over 200 devices have been operated • More than £30Billion invested to develop a robust scientific understanding • Tokamaks have already produced 16MW of fusion power and have been close to a major breakthrough – energy breakeven • where more power is produced in fusion reactions than is required to sustain the plasma • Only spherical tokamaks can be self-sustaining for plasma current and plasma heating • The compressed plasma geometry of the spherical tokamak allows high performance in a compact device Our People • A world class team of over 40 full time scientists and engineers with expertise in the field of fusion and high temperature superconducting magnets • Dr David Kingham, Chief Executive Officer • PhD Theoretical Physics • Ex-MD Oxford Innovation • VG Instruments • Dr Mikhail Gryaznevich, Chief Scientist • PhD Fusion Physics • World-leading expert in small tokamaks • Ex - Culham Centre for Fusion Energy • Paul Noonan, R&D Director • Ex Technical Architect – Agilent Technologies • Ex Chief Engineer – Oxford Instruments • 30 years’ experience in superconducting and cryogenic technology Scientific Advisory Board • Lord Hunt of Chesterton, FRS • Leader in Applied Mathematics of turbulence; House of Lords Science and Technology committee • Professor George Smith, FRS • Leader in Materials Science of Nuclear Reactors • Professor Jack Connor, FRS • Leader in theoretical plasma physics • Professor Colin Windsor, FRS • Leader in neutronics • Professor Bill Lee, FREng • Director of Centre for Nuclear Engineering, Imperial College Leading Consultants & Collaborators Consultants Collaborators • Dr Melanie Windridge • Dr Paul Thomas • Dr David Hawksworth • Professor Valery Chuyanov • Dr Alan Costley • Professor Jan Hugill • Dr Guy Morgan • Dr Martin Wilson • Dr Elwyn Baynham Competitive Landscape In the last decade privately low physics funded companies have risk emerged Prompted by a lack of progress in mainstream publicly funded fusion and the recognition that fusion needs to happen sooner $500M – 1Bn of investment Slow, big fast, small, Capital intensive Low capital Competition pursuing high risk, low technology readiness, designs that require scientific validation The Tokamak Energy approach is alone in having established theoretical and high physics experimental foundation risk CONFIDENTIAL ‘Compact Fusion’ concepts Lockheed Martin ‘skunkworks’ General Fusion Helion All deviate significantly from the well characterized tokamak route Tri-alpha All have very low nT τ at present HIT SI3 (Jarboe, UW) Fusion 2H 4He + 3.5MeV 3H n + 14.1MeV Lawson criterion Balance cooling against reaction rate for self sustaining equilibrium e.g. 5x10 21 m-3 s keV at 150x10 6 K Magnetic confinement Larmor radius (1 ͦ = ⏊ " , • mm for ions • 10s of µm for electrons Ideal magnetic pressure (i.e. no instabilities) ̼2 ͕ͤ͛͡ = 20 5T ⇒ ~100 bar at 100% efficiency (β) Early days The 1946 Fusion Reactor patent of Thompson & ZETA 1957/8 Blackman [1] (Imperial College 1946) was indeed Compact Fusion - But all sorts of instabilities appeared.. A conducting vessel helped, but … Early announcement of success proved wrong τ ~ 1ms → T~ 0.17keV A small ‘pinch’ device: R / a = 1.30m / 0.3m, Ip = 0.5MA classical confinement was assumed : but all sorts of instabilities appeared → τ = 65s →T = 500keV Hence DD----DD fusion would be achievable 20 msec Add a strong toroidal field The tokamak is born The tokamak In 1969 the T-3 tokamak was claimed to be much hotter than the pinches studied in the Western world. A team of Culham scientists spent a year at the Kurchatov, proving this was indeed the case, using a Thomson Scattering diagnostic. The rest of the World began building tokamaks! Developments and improvements of the Tokamak have controlled all the major plasma instabilities. But energy confinement still poor; scaling approximately as 2 1.5 τ ~ R x B T To obtain a Gigawatt size power plant, leads to the ITER project 3 R = 6.2m, Vol ~ 850m , B T (at R) = 5.3T Tokamak progress Tokamak progress Triple product, n x T x τ, vs time Progress has been impressive, but at the expense of building ever larger machines Why a toroidal current? 6 4 (1⏊ Gradient + ͦ" = => drift , 2 Toroidal flux density Toroidal Current → poloidal ‘twist’→ cancellaon 0 Why spherical? Flux density At high field ions are more tightly bound to field lines => 8 1 ̼α ͦ ͨ ͌ ͊!0. = β ̼͐ [1] 6 4 ST40 at R = 0.4m is modest compared to JET maj JET with Rmaj = 2.96m 2 … but has a region of higher flux density close S to the centre column ST40 How is this of use? Flux density [T] 0 Normalised major radius 1 On the fusion triple product and fusion power gain of tokamak pilot plants and reactors. Nucl. Fusion 56 (2016). Costley et al Efficiency Ideal magnetic pressure (i.e. no instabilities) ͦ ͤ = ͕͛͡ ͦ[ͤ RECORD βββ ON START (achieved through NB Heating) but not in practice (i.e. there are 50 1996 instabilities), so we define: 6 1997 = β N + 1998 β = ģğĔĦĠĔ 40 +ĠĔĚ And this is high in spherical 30 .5 tokamaks DIII-D, #80108 3 β , % = it) T β N lim on 20 oy conventional Tr • High magnetic flux density and ( tokamak sheer gradients supress the propagation if instabilities 10 ͦ ͨ • ‘Good curvature’ dominates ͊!0. = β ̼͐ the ions' trajectory 0 o High ‘safety factor’ 0 2 4 6 8 10 o High natural elongation normalised plasma current, I p/aB T Current drive Magnetic mirror Current drive High field gradient ⇒ high bootstrap current ⇒ steady state with minimum external drive ST summary • High field in compact device ͦ ͨ ͊!0. = β ̼͐ • High β • Good scaling compensates for low volume ⇒ Power production in smaller machine • High bootstrap current ⇒ Reduced capital cost and recycled power for current drive Development cycle time and cost/cycle reduced ⇒ Faster route to market So what’s the catch? So far we have: 22.4MA • high β • enhanced stability ͤ ∗ ̓ but B has been low (~0.5T) due to the slender copper centre column ̼ = T 2ͦ 3.2T at 1.4m ͦ ͨ ͊!0. = β ̼͐ Low temperature superconductors? Space is required for a neutron radiation shield … shield plasma centre column 18T For the previous example field on a 0.5m diameter centre column is ~18T BT α 1/R so there is only enough room for shielding to reduce the neutron heat load to several 10’s kW Challenging at LTS temperatures of 2 ~ 5K ͎*' ͉̽͊ **'$)" = ͎#*/ − ͎**'$)" … and it gets worse 1000000 Can get ~2T improvement by further cooling, but the practical 100000 limit is ~20T BT α 1/R 10000 NbTi With shielding low B T in plasma ] ] 4.2K at 2 Internal tin [A/mm 1000 c J Nb 3Sn 100 Bronze route 10 0 5 10 15 20 25 30 35 40 45 Tesla LTS performance in field HTS Even with shielding we can have high B T in plasma Business case Spherical tokamak + HTS ⇒ the possibility of small modular fusion reactors of ~100MWe Rapid, affordable, development Then the size of the deployed reactor becomes a choice …. HTS key technologies REBCO conductors Quench protection ~100 kA cable design • I surface • Current sharing C • AC losses • Boundary resistance • Detection • % copper content • Tape construction • Dump • Cooling • Quality / variability Joints Mechanical design • Size, shape, position • PF / TF coil locations • Heatload - many or • Forces few ? • Demountable coils ? I degradation Cryogenics C Power supplies • Neutron damage • Neutron heating Current leads • Thermal cycling • • Joint heating Dump circuits • Mechanical • • Suspension Cold rectification ? • Fatigue • • Vacuum