Magnetic Confinement Fusion-Status and Challenges

Transcription

1 Chalmers energy conference 2012 Magnetic Confinement Fusion-Status and Challenges F. Wagner Max-Planck-Institute for Plasma Physics, Greifswald Germany, EURATOM Association RLPAT St. Petersburg Polytechnic University Sun Fusion supplies the universe with energy In the core of the sun: 15 Mill C Matter: in the plasma state Energy-mass equivalence: E=mc 2 4 Mill tons of mass/sec to energy Fusion energy maintains fusion conditions: self-sustained burn 1

2 Energy 2050 From the sun to the 1st fusion reactor Sun confinement by gravity ITER tokamak magnetic confinement 4p He 4 + energy D + T He n + energy 2

3 Energy 2050 From the sun to the 1st fusion reactor Sun confinement by gravity ITER tokamak magnetic confinement 4p He 4 + energy D + T He n + energy 3

4 Energy 2050 From the sun to the 1st fusion reactor Sun confinement by gravity ITER tokamak magnetic confinement 4p He 4 + energy D + T He n + energy 4

5 Fusion basics Chalmers energy conference 2012 Technical fusion: hydrogen istopes deuterium (D) and tritium (T) D+T He 4 +n MeV (1 g fusion fuel = 10 tons coal) T from breeding reaction: n + 7 Li 4 He + T + n MeV He (α-particle; E α = 3.5 MeV) provides the internal heating; maintains the power producing plasma state. When cooled down: ash ash removal n carries its energy (E n = 14.1 MeV) to the outside. 5

6 Chalmers energy conference 2012 pros and cons of fusion energy Pro: D from sea water Li from earth crust inexhaustable energy source equal distribution of fuel on earth no CO 2 poduction no uncontrollable power excursions no critical afterheat no radio-active fusion products Con: (1) tritium is radio-active BUT: the production of tritium is in situ (2) neutrons activate structural materials BUT: radio-active by-products are well confined Their decay time is about 100 years 0.08 g D und 0.2 g Li put in a fusion reactor would supply a family of 4 with electricity for a year Source: FZJ 6

7 The task Confine a hot, high-pressure D-T plasma Chalmers energy conference 2012 Heat it to high temperatures externally till inner α-particle heating takes over ( self-sustained burn) Provide plasma equilibrium, stability and good confinement Exhaust the He ash and maintain high plasma purity Breed tritium within a Lithium-blanket via the fusion neutrons Remove the neutron-heat deposited into the blanket Produce electricity by standard steam techniques Realisation: Inertial confinement (use e.g.lasers to compress pellets) Magnetic confinement 7

8 Magnetic confinement Energy p gravity 8

9 Magnetic confinement Energy 2050 sphere torus - p gravity 9

10 Magnetic confinement Energy p gravity Magnetic force - p 10

11 Energy 2050 Tokamak: The most advanced system Strong current inside the plasma Tokamak (1951 Sacharov und Tamm) тороидальная камера в магнитных катушках toroidal chamber within magnetic coils induced like in a transformer Plasmaring with magnetic field 11

12 The stellarator Energy

13 Chalmers energy conference 2012 JET: the largest tokamak 13 13

14 Chalmers energy conference 2012 Devices of the Asian fusion programme KSTAR - Korea EAST- China SST-1 India JT-60 SA Japan 14 14

15 Chalmers energy conference 2012 Wendelstein 7-X, Greifswald 15

16 Status of Fusion Research Chalmers energy conference MW fusion power from JET H 200 Mill C in the core of JET 16 16

17 Status of Fusion Research Chalmers energy conference 2012 Fusion triple product nt i τ E (10 20 m -3 sec kev) Central ion temperature T i (kev) After 50 years of fusion research there is no evidence for a fundamental obstacle in the basic physics But, of course, still many problems have to be overcome 17

18 The first fusion reactor: ITER Chalmers energy conference 2012 Fusion power 500 MW Power amplification Q=10 External heating 70 MW Pulse lenght > 8 Min. Plasma current 15 MA International partnership China, Europe, India, Japan, Korea, Russia, USA Plasma volume 840 m 3 Plasma energy 350 MJ Magnetic field 6 T (12 T) Energy of the field 10 GJ Size 18

19 Why so large? Energy 2050 centre 19

20 Why so large? Energy 2050 centre 20

21 Why so large? Energy 2050 centre 21

22 Why so large? Energy 2050 centre 22

23 Physics: Chalmers energy conference 2012 Challenges for the fusion programme Confine a plasma magnetically with 1000 m 3 volume Maintain the plasma stable at 2-4 bar pressure and 150 Mill C in core With 15 MA current running in a fluid (tokamak) Find methods to maintain the plasma current steady-state (tokamak) Tame plasma turbulence to get the necessary confinement time Technology: Build a system with 200 Mill K in the plasma core and 4K about 2 m away Build magnetic system at 6 T (max. Field 12 T) with 50 GJ energy Handle n-fluxes of 2 MW/m 2 leading to 100 dpa Handle α-particle power of 10 MW/m 2 onto divertor targets Develop low activation material Develop T breeding technology Provide high availability of a complex system 23

24 Plasma physics Chalmers energy conference 2012 Does fusion come too late? road map to a fusion power station Tokamak physics programme Stellarator development Electricity production Decision point Commercial availability Installatoins JET ITER IFMIF, 14 MeV neutron source DEMO Technology ITER- Technology DEMO Technology

25 Chalmers energy conference 2012 Does fusion come too late? Change in technology from red to blue Increase in world population Increase in energy consumption Increase of CO 2 Oil peak Blue: RE, fission with breeder fusion The 1st half of this century will experience dynamic developments There are many uncertainties keep all options open now

26 Chalmers energy conference 2012 Final comment Research into high temperature plasmas is an intellectually rewarding field Fusion has a tremendous potential facing the future uncertainties - the risks of fission, storage of RE the fusion development has to be accelerated There is a clear road-map to commertialize fusion (of course, there is still no guarantee of final success) ITER will answer open physics questions related to burning plasmas W7-X will demonstrate the quality expected from stellarator optimisation ITER, IFMIF, DEMO: The programme will move away from plasma science more toward technology orientation After the ITER physics and technology programme - if successful fusion can be placed into national energy supply strategies With fusion, we hand over to future generations a clean, safe and - in our expectations - economic power source 26