Role of Fusion Energy in the 21st Century

With Thanks to Dr. Steve Koonin, BP for energy charts

Farrokh NajmabadiProf. of Electrical EngineeringDirector of Center for Energy ResearchUC San Diego

NPSS Albuquerque ChapterAugust 30, 2007

The Energy ChallengeFacts and Fiction

With industrialization of emerging nations, energy use is expected to grow ~ 4 fold in this century (average 1.6% annual growth rate)

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Energy use increases with Economic Development

Quality of Life is strongly correlated to energy use.

Typical goals: HDI of 0.9 at 3 toe/cap 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.

HDI: (index reflecting life expectancy at birth + adult literacy & school enrolment + GNP (PPP) per capita)

World Primary Energy Demand is expect to grow substantially

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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.

Energy supply will be dominated by fossil fuels for the foreseeable future

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6.5

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Source: IEA World Energy Outlook 2006 (Reference Case), Business as Usual (BAU) case

We are NOT running out of fossil fuels in the short term

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41 yrs.

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67 yrs.

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164 yrs.

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Short term issue is the distribution of fossil fuels, i.e., Energy Security.Long term issue is availability of liquid fuels for transportation.

CO2 concentration in the atmosphere is rising due to fossil fuel use

The global temperature is increasingThere is a plausible causal connection between CO2concentration and global temperature (global warming)

But this is a ~1% effect in a complex, noisy systemScientific case is complicated by natural variability, ill-understood non-linear behavior, etc.

CO2 concentration will grow geometrically!

The earth absorbs anthropogenic CO2 at a limited rateThe lifetime of CO2 in the atmosphere is ~ 1000 yearsThe atmosphere will accumulate emissions during the 21st Century

Impact of higher CO2 concentrations is uncertain~ 2X pre-industrial is a widely discussed stabilization target (550 ppm)Reached by 2050 under IEA Reference Scenario shown.

To stabilize CO2 concentration at 550 ppm, emissions would have to drop to about half of their current value by the end of this century

This in the face of a five fold increase of energy demand in the next 100 years (1.6% per year emissions growth)Modest emissions reductions only delay the growth of concentration (20% emissions reduction buys 15 years).

Reducing emissions is an enormous, complex challenge; technology development must play the central role.

Many sources contribute to the emission of greenhouse gases

It is more important to consider Emissions instead of Energy end-use.

There is a growing acceptance that nuclear power should play a major role

Emissions and Energy 1980-2004

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Large expansion of nuclear power, however, requires rethinking of fuel cycle and waste disposal, e.g., reprocessing, deep burn of actinides, Gen IV reactors.

Technologies to meet the energy challenge do not exist

Improved efficiency and lower demandHuge scope but demand has always risen faster due to long turn-over time.

RenewablesIntermittency, cost, environmental impact.

Carbon sequestrationRequires handling large amounts of C (Emissions to 2050 =2000Gt CO2)

Fissionfuel cycle and waste disposal

FusionProbably a large contributor in the 2nd half of the century

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 & Climate ChangeWill run out sooner or later

Limiting CO2 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.

Most of public energy expenditures is in the form of subsidies

Coal44.5%

Oil and gas30%

Fusion 1.5%

Fission 6%

Renewables 18%

Energy Subsides (€28B) and R&D (€2B) in the EU

Source : EEA, Energy subsidies in the European Union: A brief overview, 2004. Fusion and fission are displayed separately using the IEA government-R&D data base and EURATOM 6th framework programme data

Slide from C. Llewellyn Smith, UKAEA

Need a few good engineers!

Energy debate is dominated by activists and lobbyists.Left: “Energy challenge can be readily met by conservation and renewables alone.”Right: “Limiting greenhouse emissions are so costly that it will wreck the economy.” or “Uncertainty in the CO2 impact justifies inaction.”

Scientists and engineers are NOT involved in the debateMost proposals by activist and hyped by popular media either violate physical laws, or are beyond current technology, or would not make any sizeable impact.

No carbon-neutral commercial energy technology is available today.Solution CANNOT be legislated. Subsidies do not work! Energy market is huge (T$ annual sale, TW of power).

Get Involved and Educate!

Status of Fusion Research

Fusion is one of very few non-carbon based energy options

DT fusion has the largest cross section and lowest temperature (~100M oC). 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 recoveryPractically no resource limit (1011 TWy D; 104 (108) TWy 6Li)

D + 6Li → 2 4He + 3.5 MeV (Plasma) + 17 MeV (Blanket)

D + T → 4He (3.5 MeV) + n (14 MeV)n + 6Li → 4He (2 MeV) + T (2.7 MeV)

nT

Two Approaches to Fusion Power

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 generating, fusing ~1/3 of fuel.Several ~300 MJ explosions with large gain (fusion power/input power).

Magnetic Fusion Energy (MFE)Strong magnetic pressure (100’s atm) to confine a low density but high pressure (10’s atm) plasma.Particles confined within a “toroidal magnetic bottle” for 10’s km and 100’s of collisions per fusion event.At sufficient plasma pressure and “confinement time”, the 4He power deposited in the plasma sustains fusion condition.

Tokamak is the most successful concept for plasma confinement

R=1.7 m

JET 3m

DIII-D, General AtomicsLargest US tokamak

Fusion energy requiresHeating the plasma to ~100M oCConfining the plasma with a energy replacement time ~1 s for density of 1021 m-3

Progress in plasma confinement has been impressive

500 MW of fusion Power for 300s Construction will be started shortly in France

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ITER Burning plasma experiment

We have made tremendous progress in understanding 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.

Fusion: Looking into the future

ITER will demonstrate the technical feasibility of fusion energy

Power-plant scale device. Baseline design:

500 MW of fusion power for 300sDoes not include breeding blanket or power recovery systems.

ITER agreement was signed in Nov. 2006 by 7 international partners (US, EU, Japan, Russa, China, Korea, and India)Construction will begin in 2008.

ARIES-AT is an attractive vision for fusion with a reasonable extrapolation in physics & technology

Competitive cost of electricity (5c/kWh);Steady-state operation;Low level waste;Public & worker safety;High availability.

ITER and satellite tokamaks will provide the necessary data for a fusion power plant

DIII-D DIII-D ITERSimultaneous Max Baseline ARIES-AT

Major toroidal radius (m) 1.7 1.7 6.2 5.2Plasma Current (MA) 2.25 3.0 15 13Magnetic field (T) 2 2 5.3 6.0Electron temperature (keV) 7.5* 16* 8.9** 18**Ion Temperature (keV) 18* 27* 8.1** 18**Density (1020 m-3) 1.0* 1.7* 1.0** 2.2**Confinement time (s) 0.4 0.5 3.7 1.7Normalized confinement, H89 4.5 4.5 2 2.7β (plasma/magnetic pressure) 6.7% 13% 2.5% 9.2%Normalized β 3.9 6.0 1.8 5.4Fusion Power (MW) 500 1,755Pulse length 300 S.S.

* Peak value, **Average Value

The ARIES-AT utilizes an efficient superconducting magnet design

On-axis toroidal field: 6 TPeak field at TF coil: 11.4 T

TF Structure: Caps and straps support loads without inter-coil structure;

Superconducting MaterialEither LTC superconductor (Nb3Sn and NbTi) or HTCStructural Plates with grooves for winding only the conductor.

Use of High-Temperature Superconductors Simplifies the Magnet Systems

HTS does offer operational advantages:

Higher temperature operation (even 77K), or dry magnetsWide tapes deposited directly on the structure (less chance of energy dissipating events)Reduced magnet protection concerns

Inconel strip

YBCO Superconductor Strip Packs (20 layers each)

8.5 430 mm

CeO2 + YSZ insulating coating(on slot & between YBCO layers)

Epitaxial YBCOInexpensive manufacture would consist on layering HTS on structural shells with minimal winding!

DT Fusion requires a T breeding blanket

Requirement: Plasma should be surrounded by a blanket containing Li

D + T → He + nn + 6Li → T + He

Through careful design, only a small fraction of neutrons are absorbed in structure and induce radioactivity

Rad-waste depends on the choice of material: Low-activation materialRad-waste generated in DT fusion is similar to advanced fuels (D-3He)For liquid coolant/breeders (e.g., Li, LiPb), most of fusion energy (carried by neutrons) is directly deposited in the coolant simplifying energy recovery

Issue: Large flux of neutrons through the first wall and blanket:Need to develop radiation-resistant, low-activation material: Ferritic steels, Vanadium alloys, SiC composites

Outboard blanket & first wall

ARIES-AT features a high-performance blanket

Simple, low pressure design with SiC structure and LiPb coolant and breeder.

Innovative design leads to high LiPb outlet temperature (~1,100oC) while keeping SiC structure temperature below 1,000oC leading to a high thermal efficiency of ~ 60%.

Simple manufacturing technique.

Very low afterheat.

Class C waste by a wide margin.

Modular sector maintenance enables high availability

Full sectors removed horizontally on railsTransport through maintenance corridors to hot cells Estimated maintenance time < 4 weeks

ARIES-AT elevation view

Advances in fusion science & technology has dramatically improved our vision of fusion power plants

Estimated Cost of Electricity (c/kWh)

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Major radius (m)

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After 100 years, only 10,000 Curies of radioactivity remain in the585 tonne ARIES-RS fusion core.

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.

Ferritic SteelVanadium

Radioactivity levels in fusion power plantsare very low and decay rapidly after shutdown

Fusion Core Is Segmented to Minimize the Rad-Waste

Only “blanket-1” and divertors are replaced every 5 years

Blanket 1 (replaceable)Blanket 2 (lifetime)

Shield (lifetime)

Waste volume is not large

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1270 m3 of Waste is generated after 40 full-power year (FPY) of operation.Coolant is reused in other power plants29 m3 every 4 years (component replacement), 993 m3 at end of service

Equivalent to ~ 30 m3 of waste per FPYEffective annual waste can be reduced by increasing plant service life.

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90% of waste qualifies for Class A disposal

Fusion: Why is taking so long?

There has been no urgency in developing new sources of energy

Proposed fusion development plan in 1976 aimed at fielding a fusion Demo by 2000.Recent DOE Fusion Development Plan (2003) aimed at fielding a fusion Demo by 2030.

The required funding to implement the plans were not approved.Proposals for fielding a burning plasma experiments since mid 1980s.Fusion program was restructured in mid 1990s, focusing on developing fusion sciences (with 1/3 reduction in US funding).

Fielding a fusion Demo is NOT the official goal of DOE at presentLarge interest and R&D investment in Europe and Japan (and China, India, Korea)

Development of fusion has been constrained by funding!

$M

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Demo Demo

Current cumulative funding

~ 1 week of world energy sale

In Summary, …

In a CO2 constrained world uncertainty abounds

No carbon-neutral commercial energy technology is available today.Carbon sequestration is the determining factor for fossil fuel electric generation.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 ($1T annual sale, TW of power) is huge. Solutions should fit this size market

100 Nuclear plants = 20% of electricity production$50B annual R&D represents 5% of energy sale

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 ITERLarge synergy between fusion nuclear technology R&D and Gen-IV.

Thank you!Any Questions?