Roles of Fission and Fusion Energy in a Carbon- Constrained World

Transcription

1 Roles of Fission and Fusion Energy in a Carbon- Constrained World Farrokh Najmabadi Prof. of Electrical Engineering Director of Center for Energy Research UC San Diego Zero-Carbon Energy 2012 Symposium Siam City Hotel, Bangkok, Thailand May 2012

2 The Energy Challenge Scale: World energy use ~ 450 EJ/year ~ 14 TW 1 EJ = J = 24 Mtoe 1TW = 31.5 EJ/year Economics: World energy sales: $4.5T US energy sales: $1.5T Market Penetration Timing: Fastest: Nuclear power installations (~30 years to produce 8% of world energy).

3 Energy use increases with Economic Development US Primary Energy per capita (GJ) China Thailand Russia Malaysia Brazil S. Korea Mexico France Australia Japan UK Ireland 0 India 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 GDP per capita (PPP, $2000) With industrialization of emerging nations, energy use is expected to grow ~ 4 fold in this century (average 1.6% annual growth rate) Data from IEA World Energy Outlook 2006

4 Quality of Life is strongly correlated to energy use. HDI: (index reflecting life expectancy at birth + adult literacy & school enrolment + GNP (PPP) per capita) Typical goals: HDI of 0.9 at 3 toe per capita for developing countries. For all developing countries to reach this point, would need world energy use to double with today s population, or increase 2.6 fold with the 8.1 billion expected in 2030.

5 World Primary Energy Demand is expect to grow substantially World Energy Demand (Mtoe) Data from IAE World Energy Outlook 2006 Reference (Red) and Alternative (Blue) scenarios. World population is projected to grow from 6.4B (2004) to 8.1B (2030). Scenarios are very sensitive to assumption about China.

6 Energy supply will be dominated by fossil fuels for the foreseeable future Annual Growth Rate (%) Mtoe 18,000 Other Renew ables ,000 14,000 12,000 Biomass & waste Hydro ,000 Nuclear 0.7 8,000 6,000 Gas 2.0 4,000 Oil 1.3 2, Coal Total Source: IEA World Energy Outlook 2006 (Reference Case), Business as Usual (BAU) case

7 Technologies to meet the energy challenge do not exist Improved efficiency and lower demand Huge scope but demand has always risen faster due to long turn-over time. Renewables Intermittency, cost, environmental impact. Carbon sequestration Requires handling large amounts of C (Emissions to 2050 =2000Gtonne CO 2 ) Fission Fuel cycle and waste disposal Fusion Probably a large contributor in the 2 nd half of the century

8 Energy Challenge: A Summary Large increases in energy use is expected. IEA world Energy Outlook indicate that it will require increased use of fossil fuels Air pollution & Global Warming Will run out sooner or later Limiting CO 2 to 550ppm by 2050 is an ambitious goal. USDOE: The technology to generate this amount of emission-free power does not exist. IEA report: Achieving a truly sustainable energy system will call for radical breakthroughs that alter how we produce and use energy. Public funding of energy research is down 50% since 1980 (in real term). World energy R&D expenditure is 0.25% of energy market of $4.5 trillion.

9 Most of public energy expenditures is in the form of subsidies Energy Subsides ( 28B) and R&D ( 2B) in the EU Renewables 18% Fission 6% Fusion 1.5% Coal 44.5% Oil and gas 30% Slide from C. Llewellyn Smith, UKAEA Source : EEA, Energy subsidies in the European Union: A brief overview, Fusion and fission are displayed separately using the IEA government- R&D data base and EURATOM 6th framework programme data

10 Fission (seeking a significant fraction of World Energy Consumption of 14TW)

11 There is a growing acceptance that nuclear power should play a major role Emissions and Energy USA CO2 per capita (tonnes Coal France Oil Gas UK France Japan China Brazil Ireland Mexico Malaysia S. Korea Greece India Australia Russia Thailand Primary energy per capita (Gj) Large expansion of nuclear power, however, requires rethinking of fuel cycle and waste disposal, e.g., reprocessing, deep burn of actinides, Gen IV reactors.

12 Nuclear power is already a large contributor to world energy supply Nuclear power provide 8% of world total energy demand (20% of US electricity) Operating reactors in 31 countries 438 nuclear plants generating 353 GWe Half of reactors in US, Japan, and France 104 reactor is US, 69 in France 30 New plants in 12 countries under construction US Nuclear Electricity (GWh) No new plant in US for more than two decades Increased production due to higher availability 30% of US electricity growth Equivalent to 25 1GW plants Extended license for many plants

13 Evolution of Fission Reactors

14 Challenges to long-term viability of fission Economics: Reduced costs Reduced financial risk (especially licensing/construction time) Safety Protection from core damage (reduce likelihood) Eliminate offsite radioactive release potential Sustainability Efficient fuel utilization Waste minimization and management Non-proliferation Reprocessing and Transmutation Gen IV Reactors

15 Uranium Resources Note: COE is insensitive to U cost (+$100/kg U 0.25 c/kwh) 120 years at IEA expected 2030 use, 40 years if nuclear displaces 50% of fossil fuels. Unless U can be extracted from sea water cheaply, breeders are necessary within this century.

16 Large Expansion of Nuclear Power Requires Reprocessing of Waste From Advanced Fuel Cycle Initiative:

17 Gen IV International Forum (10 parties) has endorsed Six Gen IV Concepts for R&D Very high-temperature gas-cooled reactor (safety, hydrogen production) Lead-cooled Fast Reactor (sustainability, safety) Gas-Cooled Fast Reactor (sustainability, economics) Supercritical-water-cooled reactor (economics) Molten Salt reactor (sustainability) Sodium-cooled fast rector (sustainability) Most use closed-cycle fast-spectrum to reduced waste heat and radiotoxicity (to extend repository capacity) and to breed fuel.

18 Two High-Temperature Helium-Cooled Reactors Are Currently Operating in Asia Prismatic-Block HTTR in Japan Pebble-Bed HTR-10 in China HTTR reached outlet temperature of 950 C at 30 MW on April 19, 2004.

19 Fusion: Looking into the future ARIES-AT tokamak Power plant

20 Brining a Star to Earth T D + T 4 He (3.5 MeV) + n (14 MeV) n + 6 Li 4 He (2 MeV) + T (2.7 MeV) n D + 6 Li 2 4 He MeV (Plasma) + 17 MeV (Blanket) DT fusion has the largest cross section and lowest temperature (~100M o C). But, it is still a high-temperature plasma! Plasma should be surrounded by a Li-containing blanket to generate T. Or, DT fusion turns its waste (neutrons) into fuel! Through careful design, only a small fraction of neutrons are absorbed in structure and induce radioactivity. For liquid coolant/breeders (e.g., Li, LiPb), most of fusion energy is directly deposited in the coolant simplifying energy recovery Practically no resource limit (10 11 TWy D; 10 4 (10 8 ) TWy 6 Li)

21 Fusion Energy Requirements: Heating the plasma for fusion reactions to occur to 100 Million o C (routinely done in present experiments) Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: nτ E ~ s/m 3 Optimizing plasma confinement device to minimize the cost Smaller devices Cheaper systems, e.g., lower-field magnets (MFE) or lowerpower lasers (IFE) Extracting the fusion power and breeding tritium Co-existence of a hot plasma with material interface Developing power extraction technology that can operate in fusion environment

22 Two Approaches to Fusion Power 1) Inertial Fusion Inertial Fusion Energy (IFE) Fast implosion of high-density DT capsules by laser or particle beams (~30 fold radial convergence, heating to fusion temperature). A DT burn front is generated, fusing ~1/3 of fuel (to be demonstrated in National Ignition Facility in Lawrence Livermore National Lab). Several ~300 MJ explosions per second with large gain (fusion power/input power).

23 Two Approaches to Fusion Power 2) Magnetic Fusion Magnetic Fusion Energy (MFE) Particles confined within a toroidal magnetic bottle for 10 s km and 100 s of collisions per fusion event. Strong magnetic pressure (100 s atm) to confine a low density but high pressure (10 s atm) plasma. At sufficient plasma pressure and confinement time, the 4 He power deposited in the plasma sustains fusion condition. Rest of the Talk is focused on MFE

24 Plasma behavior is dominated by collective effects Pressure balance (equilibrium) does not guaranty stability. Example: Interchange stability Fluid Interchange Instability Outside part of torus inside part of torus Impossible to design a toroidal magnetic bottle with good curvatures everywhere. Fortunately, because of high speed of particles, an averaged good curvature is sufficient.

25 Tokamak is the most successful concept for plasma confinement DIII-D, General Atomics Largest US tokamak R=1.7 m Many other configurations possible depending on the value and profile of q and how it is generated (internally or externally)

26 T3 Tokamak achieved the first high temperature (10 M o C) plasma 0.06 MA Plasma Current R=1 m

27 JET is currently the largest tokamak in the world ITER Burning plasma experiment (under construction) R=3 m R=6 m

28 Progress in plasma confinement has been impressive ITER Burning plasma experiment Fusion triple product n (10 21 m -3 ) τ(s) T(keV) 500 MW of fusion Power for 300s Construction has started in France

29 Large amount of fusion power has also been produced ITER Burning plasma experiment DT Experiments DD Experiments

30 Fusion Energy Requirements: Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: nτ E ~ s/m 3 Heating the plasma for fusion reactions to occur to 100 Million o C (routinely done in present experiments) Optimizing plasma confinement device to minimize the cost Smaller devices Cheaper systems, e.g., lower-field magnets (MFE) or lowerpower lasers (IFE) Extracting the fusion power and breeding tritium ITER and Satellite tokamaks (e.g., JT60-SU in Japan) should demonstrate operation of a fusion plasma (and its support technologies) at the power plant scale. Developing power extraction technology that can operate in fusion environment Co-existence of a hot plasma with material interface

31 We have made tremendous progress in optimizing fusion plasmas Substantial improvement in plasma performance though optimization of plasma shape, profiles, and feedback. Achieving plasma stability at high plasma pressure. Achieving improved plasma confinement through suppression of plasma turbulence, the transport barrier. Progress toward steady-state operation through minimization of power needed to maintain plasma current through profile control. Controlling the boundary layer between plasma and vessel wall to avoid localized particle and heat loads.

32 Fusion Energy Requirements: Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: nτ E ~ s/m 3 Heating the plasma for fusion reactions to occur to 100 Million o C (routinely done in present experiments) Optimizing plasma confinement device to minimize the cost Smaller devices Cheaper systems, e.g., lower-field magnets (MFE) or lower-power lasers (IFE) Extracting the fusion power and breeding tritium Developing power extraction technology that can operate in fusion environment Co-existence of a hot plasma with material interface

33 New structural material should be developed for fusion application Fe-9Cr steels: builds upon 9Cr-1Mo industrial experience and materials database (9-12 Cr ODS steels are a higher temperature future option) SiC/SiC: High risk, high performance option (early in its development path) W alloys: High performance option for PFCs (early in its development path)

34 Irradiation leads to a operating temperature window for material Structural Material Operating Temperature Windows: dpa Radiation embrittlement η Carnot =1-T reject /T high Thermal creep Zinkle and Ghoniem, Fusion Engr. Des (2000) 709 Additional considerations such as He embrittlement and chemical compatibility may impose further restrictions on operating window

35 Flow configuration allows for a coolant outlet temperature to be higher than maximum structure temperature Several blanket Concepts have been developed Dual coolant with a self-cooled PbLi zone, He-cooled RAFS structure and SiC insert Simple, low pressure design with SiC structure and LiPb coolant and breeder. Innovative design leads to high LiPb outlet temperature (~1,100 o C) while keeping SiC structure temperature below 1,000 o C leading to a high thermal efficiency of ~ 60%.

36 Radioactivity levels in fusion power plants are very low and decay rapidly after shutdown Activity (Ci/W th ) Vanadium 1 d ARIES-ST ARIES-RS Ferritic Steel 1 mo 1 y 100 y Time Following Shutdown (s) SiC composites lead to a very low activation and afterheat. All components of ARIES-AT qualify for Class-C disposal under NRC and Fetter Limits. 90% of components qualify for Class-A waste. After 100 years, only 10,000 Curies of radioactivity remain in the 585 tonne ARIES-RS fusion core. Level in Coal Ash

37 Waste volume is not large 1270 m 3 of Waste is generated after 40 full-power year (FPY) of operation. Coolant is reused in other power plants 29 m 3 every 4 years (component replacement), 993 m 3 at end of service Equivalent to ~ 30 m 3 of waste per FPY Effective annual waste can be reduced by increasing plant service life. Cumulative Compacted Waste Volume (m3) Blanket Shield Vacuum Vessel Magnets Structure Cryostat Cumulative Compacted Waste Volume (m3) Class A 90% of waste qualifies for Class A disposal Class C

38 Advances in fusion science & technology has dramatically improved our vision of fusion power plants Major radius (m) Estimated Cost of Electricity (c/kwh) Mid 80's Pulsar Early 90's ARIES-I Late 90's ARIES-RS 2000 ARIES-AT Mid 80's Physics Early 90's Physics Late 90's Physics Advanced Technology

39 In Summary,

40 In a CO 2 constrained world uncertainty abounds No carbon-neutral commercial energy technology is available today (except nuclear power). A large investment in energy R&D is needed. A shift to a hydrogen economy or carbon-neutral syn-fuels is also needed to allow continued use of liquid fuels for transportation. Problem cannot be solved by legislation or subsidy. We need technical solutions. Technical Communities should be involved or considerable public resources would be wasted The size of energy market ($4.5T annual sale, TW of power) is huge. Solutions should fit this size market 100 Nuclear plants = 20% of electricity production of US $75B annual R&D represents 5% of energy sale of $1.5T (US sales).

41 Status of fusion power Over 15 MW of fusion power is generated (JET, 1997) establishing scientific feasibility of fusion power Although fusion power < input power. ITER will demonstrate technical feasibility of fusion power by generating copious amount of fusion power (500MW for 300s) with fusion power > 10 input power. Tremendous progress in understanding plasmas has helped optimize plasma performance considerably. Vision of attractive fusion power plants exists. Transformation of fusion into a power plant requires considerable R&D in material and fusion nuclear technologies (largely ignored or under-funded to date). This step, however, can be done in parallel with ITER Large synergy between fusion nuclear technology R&D and Gen- IV.

42 Thank You