Roles of Fission and Fusion Energy in a Carbon-Constrained WorldFarrokh NajmabadiProf. of Electrical EngineeringDirector of Center for Energy ResearchUC San Diego

Zero-Carbon Energy 2012 SymposiumSiam City Hotel, Bangkok, Thailand22-23 May 2012

The Energy Challenge

Scale:World energy use ~ 450 EJ/year

~ 14 TW1 EJ = 1018 J = 24 Mtoe1TW = 31.5 EJ/year

Market Penetration Timing:Fastest: Nuclear power installations (~30 years to produce 8% of world energy).

Economics:World energy sales: $4.5T US energy sales: $1.5T

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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0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000

Prim

ary

Ener

gy p

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apita

(GJ)

GDP per capita (PPP, $2000)

US

Australia

Russia

Brazil

China

India

S. Korea

Mexico

IrelandFrance

UKJapan

Malaysia

Energy use increases with Economic Development

Data from IEA World Energy Outlook 2006

Thailand

Quality of Life is strongly correlated to energy use.

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.

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

World Primary Energy Demand is expect to grow substantially

Wor

ld E

nerg

y D

eman

d (M

toe)

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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Mtoe OtherRenewables

Biomass &waste

Hydro

Nuclear

Gas

Oil

Coal

’04 – ’30 Annual Growth

Rate (%)

Total

6.5

1.3

2.0

0.7

2.0

1.3

1.8

1.6

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

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 CO2)

Fission Fuel cycle and waste disposal

Fusion Probably 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 & Global Warming Will 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%

Renewables18%

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 dataSlide from C. Llewellyn Smith, UKAEA

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

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

Emissions and Energy 1980-2004

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Primary energy per capita (Gj)

CO2

per c

apita

(ton

nes)

USAUKFranceJapanChinaBrazilIrelandMexicoMalaysiaS. KoreaGreeceIndiaAustraliaRussiaThailand

Coal Oil

Gas

France

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

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

1990 1994 2000 2001 20020

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Nuc

lear

Ele

ctric

ity (G

Wh) 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 plantsExtended license for many plants

Evolution of Fission Reactors

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

Uranium Resources

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.

Note: COE is insensitive to U cost (+$100/kg U → 0.25 c/kWh)

Large Expansion of Nuclear Power Requires Reprocessing of Waste

From Advanced Fuel Cycle Initiative: http://www.nuclear.gov/AFCI_RptCong2003.pdf

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.

Two High-Temperature Helium-Cooled Reactors Are Currently Operating in Asia

HTTR reached outlet temperature of 950°C at 30 MW on April 19, 2004.

Prismatic-Block

HTTR in Japan

Pebble-BedHTR-10 in

China

Fusion: Looking into the future

ARIES-AT tokamak Power plant

Brining a Star to Earth

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 recovery

Practically 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

Fusion Energy Requirements:

Heating the plasma for fusion reactions to occur to 100 Million oC (routinely done in present experiments)

Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: ntE ~ 1021 s/m3

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 Co-existence of a hot plasma with material interface Developing power extraction technology that can operate in

fusion environment

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).

Two Approaches to Fusion Power –2) Magnetic Fusion

Rest of the Talk is focused on MFE

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 4He

power deposited in the plasma sustains fusion condition.

Plasma behavior is dominated by “collective” effects

Pressure balance (equilibrium) does not guaranty stability. Example: Interchange stability

Impossible to design a “toroidal magnetic bottle” with good curvatures everywhere.

Fortunately, because of high speed of particles, an “averaged” good curvature is sufficient.

Outside part of torus inside part of torusFluid Interchange Instability

Tokamak is the most successful concept for plasma confinement

R=1.7 m

DIII-D, General AtomicsLargest US tokamak

Many other configurations possible depending on the value and profile of “q” and how it is generated (internally or externally)

T3 Tokamak achieved the first high temperature (10 M oC) plasma

R=1 m

0.06 MAPlasma Current

JET is currently the largest tokamak in the world

R=3 m

ITER Burning plasma experiment (under construction)

R=6 m

Progress in plasma confinement has been impressive

500 MW of fusion Power for 300s Construction has started in France

Fusi

on tr

iple

pro

duct

n (1

021 m

-3) t

(s) T

(keV

)

ITER Burning plasma experiment

Large amount of fusion power has also been produced

ITER Burning plasma experiment

DT Experiments

DD Experiments

Fusion Energy Requirements:

Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: ntE ~ 1021 s/m3

Heating the plasma for fusion reactions to occur to 100 Million oC (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

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.

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.

Fusion Energy Requirements:

Confining the plasma so that alpha particles sustain fusion burn Lawson Criteria: ntE ~ 1021 s/m3

Heating the plasma for fusion reactions to occur to 100 Million oC (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

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)

Irradiation leads to a operating temperature window for material

Additional considerations such as He embrittlement and chemical compatibility may impose further restrictions on operating window

Radiation embrittlement

Thermal creep

Zinkle and Ghoniem, Fusion Engr. Des. 49-50 (2000) 709

Carnot=1-Treject/Thigh

Structural Material Operating Temperature Windows: 10-50 dpa

Several blanket Concepts have been developed

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%.

Dual coolant with a self-cooled PbLi zone, He-cooled RAFS structure and SiC insert

Flow configuration allows for a coolant outlet temperature to be higher than maximum structure temperature

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ARIES-STARIES-RS

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ivit

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Time Following Shutdown (s)

1 mo 1 y 100 y1 d

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

Level in Coal Ash

Waste volume is not large

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Blanket Shield VacuumVessel

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1270 m3 of Waste is generated after 40 full-power year (FPY) of operation. Coolant is reused in other power plants 29 m3 every 4 years (component replacement), 993 m3 at end of service

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

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90% of waste qualifies for Class A disposal

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

Estimated Cost of Electricity (c/kWh)

02468

101214

Mid 80'sPhysics

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Late 90's Physics

AdvancedTechnology

Major radius (m)

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Early 90'sARIES-I

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2000 ARIES-AT

In Summary, …

In a CO2 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).

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.

Thank You