Fusion Energy Chijin Xiao and Akira Hirose Plasma Physics laboratory Physics & Engineering Physics University of Saskatchewan Supported by NSERC, CRC Trends in Nuclear & Medical Technologies April il6-7, 2009, Saskatton 1
Acknowledgement Dr. M. Dreval Mr. D. Trembach Mr. D.R. McColl Dr. R. Raman 2
Outline Fusion Basics Magnetic Confinement Fusion Research at University of Saskatchewan STOR-U Tokamak Summary 3
Fusion Basics 4
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How Fusion Works If light nuclei are fused to form a heavier one, energy is released. Examples: Hydrogen-hydrogen: 4H +2e He + 2 neutrinos (Sun, stars) Deuterium-tritium: D + T He + n. The least demanding temperature and density. Will be used in fusion reactors. Required temperature t still high: h 100 million degrees. 6
Fusion Basics Fusion reaction with the largest cross-section (probability) D + (20 kev) + T + (20 kev) He ++ (3 MeV) + n (14 MeV) Mass deficiency Δm c 2 = E Deuterium from water, 0.12 g of it can be extracted from 1 gal of water for about 4 cents Fuel consumption rate: 12 g Deuterium /h for a 3 GW reactor (100 Gallon water contains all the Deuterium needed) Tritium from Lithium through interaction D + + T + He ++ + n 6 Li + n T + 4 He + energy Fusion products are not radioactive (except neutron activation) No runaway risk, no greenhouse gas. 7
Fusion Basics (continue) He ++ ions (fusion product) collide with the fuels and deposit energy self heating (burning). A dense (10 14 /cm 3 ) D-T plasma at temperature 20 kev must be confined for more than 1 second for self sustained fusion reactions. magnetic confinement, tokamak Tokamak approach has been most successful. -- toroidal magnetic chamber in Russian. ITER = International Thermonuclear Experimental Reactor Partners: China, EU, India, Japan, Korea, Russia, USA $10B project 8
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Progress Toward Fusion Reactor Remarkable progress led to ITER. D-T burning plasma in 15 years. Fusion energy is becoming a reality. 10
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Fusion and Plasma Fusing nuclei requires a high energy = temperature. All atoms are ionized and form a plasma (ionized gas). Fusion research = confining i a high htemperature t plasma: difficult Low temperature plasmas: neon sign, plasma TV, fluorescent lamp, lightning, auroras, candle flame (weakly ionized plasma), etc. In material processing and synthesis, plasma technology is indispensible. 12
Magnetic Confinement 13
Magnetic Confinement Basics 14
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Fusion Research at UfS UofS 16
STOR-M Tokamak (PPL) R/a = 46/12 cm Mag. Field 1T Current 50 ka Temp 200 ev Density > 10 13 cm -3 Conf time 1 msec Features CT injector AC operation H-modes etc. 17
Highlights of Fusion/Tokamak Research at US-PPL Plasma Betatron achieved kev plasma temperature (1972) STOR-1M (1984): first Canadian tokamak. STOR-M tokamak (1987): for testing innovative operation scenarios, development of novel fueling technologies, and diagnostics. Compact Torus injector (1995) AC operation (1987), Ohmic H-modes (1990), plasma flow measurements (1993), horizontal ontal CT injection (1996), vertical CT injection (2004). International collaboration on CT injection and plasma flow measurements under the IAEA (Int. Atomic Energy Agency) research agreements. Theory/simulations of tokamak instabilities and suppression. 18
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STOR-U Tokamak 20
STOR-U Tokamak Conceptual Design R = 80 cm a = 36 cm Aspect ratio = R/a = 2.2 Elongation k = 1.6~1.8 Magnetic field = 1.5 T Plasma current = 1 MA 3 MW NBI n e = (1 ~ 5) 10 13 cm 3 T e = 700 ~ 1,700 ev T i = 600 ~ 3,500 ev Discharge 300 ms long Confinement time = 35~50 ms 21
Low aspect ratio tokamak Conventional large aspect ratio tokamak 22
Layout 23
Innovative Features of STOR- U Tokamak Low aspect ratio R/a = 2.2. Better confinement (simplification) Technology development and transport studies Wall lifetime (Li) Advanced fueling (Compact Torus injection) Elimination of centre solenoid (helicity injection) Understanding of electron thermal transport Toward development of more compact, steady state reactors 24
STOR-U Tokamak will be housed in the Canadian Centre for Nuclear Studies University of Saskatchewan 25 Artist s view
Summary Realization of fusion reactors is finally in sight after more than 50 years of extensive research world wide. Fusion energy is clean, safe, and abundant. STOR-M program has made significant contributions. STOR-U tokamak is needed for fusion research in Canada. 26
Plasmas, s, Plasmas, Density/Temperature Diagram 27
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ITER Objective: To demonstrate burning of DT fuel, plasma self-heating by alpha particles. Study of confinement of energetic alpha particles. Optimize i fuel lburning through hplasma pressure profile control = optimization of bootstrap current. CT injection may achieve this. Testing blanket materials and designs. 29
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