March 8, ASDEX Upgrade Seminar

Report on Technical Feasibility of Fusion Energy to the Special

Committee for the ITER Project

M. KikuchiFormer member of subcommittee for Fusion Development Strategy under Fusion Council

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Atomic Energy Commission

Fusion Council

Chair: Prof. N. Inoue

Special committee for the ITER ProjectChair: Prof. H. Yoshikawa

ITER/EDA Technical Subcommittee

Chair: Prof. M. WakataniPlanning and Promotion Subcommittee

Subcommittee for Fusion Development Strategy

Chair: Prof. K. Miya

Chair: Prof. N. Inoue

Structure of Fusion Program Promotion in Japan(before May 17,2000)

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Two other subcommittes are formed for answering(1) Survey of long term demand and supply of energy sources(2) Feasibility study of alternative energy sources(5) Distribution of resources for research(6) International relations.

For topic (3) above, the Special Committee additionally requested an evaluation of the feasibility of fusion energy as a safe and reliable energy source from the aspects of technical potential, management capability, and characteristics of Japanese industrial structure.

Charge to Subcommittee for Fusion Development Strategy

(3) Technical feasibility of the fusion energy(4) Extension of the program and basic supporting research

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Members of Subcommittee for Fusion Development Strategy (April 2000)

Nobuyuki Inoue (Chairman) Chairman of Fusion Council Professor, Institute of Advanced Energy, Kyoto University)

Katsunori Abe Professor, Graduate School of Engineering, Tohoku University Kunihiko Okano Research Fellow, Komae Research Laboratory, Nuclear Energy Systems

Department, Central Research Institute of Electric Power Industry,Yuichi Ogawa Professor, High Temperature Plasma Center, University of TokyoMitsuru Kikuchi General Manager, Tokamak Program Division, Department of Fusion Plasma

Research, Japan Atomic Energy Research InstituteShigetada Kobayashi Chairman of the Committee on Nuclear Fusion Research & Development,

Nuclear industry Executive Committee, Japan Electrical Manufacturers' Association(Senior Manager, Advanced Energy Design & Engineering Department, Power Systems & Services Company, Toshiba Corporation)

Satoru Tanaka Professor, Department of Quantum Engineering and Systems Science, Graduate School of Engineering, University of Tokyo

Yoshiaki Hirotani Manager, Department of Project Planning and Promotion, Japan Atomic Industrial Forum, Inc)

Masami Fujiwara Director-General, National Institute of Fusion ScienceShinzaburo Matsuda Director General, Naka Fusion Establishment,

Japan Atomic Energy Research InstituteKenzo Miya Chairman of Planning and Promotion Subcommittee under Fusion Council

(Professor, Graduate School of Engineering, University of Tokyo)

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Chapter 1 Future Prospects of the Fusion Energy1.1 Situations in the 21st century1.2 Criteria for commercialization1.3 Comparison with other power sources 1.3.1 Resources (fusion, fission, fossil) 1.3.2 CO2 Emissions and Sustainability of Atmosphere 1.3.3 Safety viewed from Biological Hazard Potential 1.3.4 Radioactive Waste and Environmental Adaptability 1.3.5 Plant Characteristics 1.3.6 Economical Efficiency 1.3.7 Use of Fusion other than Electricity1.4 Overall Assessment

Resources required for Fusion Reactor(SSTR is adopted as a reference design)

Bird's-eye view of SSTR

Torus Sport Structure

Vacuum Port

Divertor Maintenance PortDivertor

Negative NBI Port(2Mev,80MW)

Inter-coil Structure

Blankets (Pressurized Water Cooling Breeder)

Upper Maintenance PortTF Coil

Ring PF Coil(5.5T,NbTi)

Vacuum Chamber

Permanent Blanket

Concrete Cryostat

TF Coil Support

(16.5T,(NbTi)3Sn)

5(m)

5(m)

5(m)

0

Plasma Current Ip 12MAToroidal Field Coil Bt 9TMajor Radius R 7m Aspect Ratio A 4.1

Elongation κ95 1.85

Normalized Beta βN 3.5Fusion Output PF 3GW Current Drive Power PCD 60MWNet Electric Output Power PE 1.08GWFusion Gain Q 50Averaged Neutron Wall Load Pneut. 3MW/m2

Design ValueCenter Solenoid Coil

(7T,NbTi)

Resource life : Assuming present-level world electricity is produced by 1500 SSTR Deuterium : almost limitless ; 144ppm in fresh water Lithium : 1.5million years ; 233Gtons in sea-water Beryllium : 70,000 years ; 100Mtons (gross mineral resources)Niobium : 70,000 years ; 700Mtons (gross mineral resources)

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6

Uranium Resources

Uranium is virtually inexhaustible since Uranium extraction from sea-water is technically ready.

Concentration 3.3ppb

Resource in sea water 46x108tons

Annual consumption 6.14x104tonsResource life 75,000 years

Vanadium (V2O5) Uranium (Yellow Cake)

Collection Unit

Pacific Ocean

Japan Sea

35º

40º

45º

145º140º135º130º

30º

2400

Year

Saturation at 12 billion persons assumed (1.67 TOE /person)180

150

100

50

0

1900 1950 2000 2100 2200 2300

Demand of Fossil Energy(assumed 90% of total demand) Oil + Natural Gas

Past Future

~$30/bbl(Oil)

Oil

$30/bbl~(Gas)

$10~15/bbl(Coal)

$15~30/bbl(Coal)

Coal

Shortage due to the Restriction of

Coal Use

Fossil Resources ( Reserves and Resource Base )

Resource life For reserve

Coal ; 231yearsNat.Gas ; 63yearsOil ; 44years

For resource baseNat.Gas ; 452yearsOil ; 242years

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0 500 1000 1500 2000 2500 3000(Year)

EnergyPresent

Coal

Oil/Natural gas

Nuclear/Renewable

Shortage due to Reserves

0

100

200

300

34.333.7

178

5.7 6-12

85 81

270

200

1634.333.7

4.831 46

(Fuel) (Fuel)(Fuel)

(Fuel)

(Fuel)

401224

CO2 Emission RateFusion is environmentally attractive with its low CO2 emission rate.

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8

Fusion reactor power plant

Coal-fired power plant

Latent risk of the radiation exposure

CO2 emission is less than 1/10.

• Radiological toxic hazard potential of T is less than 1/1000 of that of I-131.

Light water reactor

power plant

Radiological Toxic Hazard PotentialPresent large scale energy sources such as fossil plants and LWR have large risks such as Global Warming and Radiological Hazard. Fusion simultaneously reduces both risks.

I-131 in 3GW LWR

4.5kg of T

Long Term Waste Hazard Potential

Radiological toxic hazard potential of fusion plant is much smaller than fission and even lower than coal ash (Th-232,U-238)

1 07

1 09

1 01 1

1 01 3

1 01 5

1 0- 4 1 0- 2 1 00 1 02 1 04 1 06

Y e a r

1 01 2

1 01 4

1 01 6

1 01 8

1 02 0

1 0- 4 1 0- 2 1 00 1 02 1 04 1 06

Y e a r

Light water reactorFusion reactor (SSTR)

Coal-fired power

Light water reactor

Fusion reactor (SSTR)

Coal-fired power

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Used disposal unit prices are low-level waste (¥ 1200000/m3), high βγ waste (¥ 2400000/ m3) and high-level radioactive waste (five hundred million yen/ m3)

Waste Management

Disposal cost is smaller than that for LWR spent fuel management.

1000

10 4

10 5

10 6

10 7

10 8

Burn-up ashes from the coal-

fired plant

Fusion reactor Boiling water reactor

High-level radioactive waste High βγ waste Low-level radioactive waste TotalFission reactor 90 billion yen 3.84 billion yen 11.7 billion yen 10.554 billion yenwith 1GW electricity / 180 m3 / 1600 m3 / 9750 m3Fusion reactor(SSTR, - 6 billion yen 30.12 billion yen 36.12 billion yen1.08 GW electricity) / 2500 m3 / 25100 m3

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Economical Efficiency

11

Geothermal energy

0.1 0.5 1 5 10 50 1001

5

10

50

100

500104 yen/kW

Normalized COE (COEn)

Power plants now in use(Thermal power,Hydropower,Nuclear power)

LNG-fired power plant with CO2 sequestration

Coal-fired power plant with CO2 sequestration

Ocean thermal power

Wind power plant

Future prediction

Future prediction

Target region of fusion power

Photovoltaic power system for utility application

0 1.0 2.0 Upper value

Lower value

Normalized cost of electricity (COEn)

00

2000

4000

6000

8000

10000

20 40 60 80 100Unit cost of construction (x 10 kyen/kW)

Electricity power1 GWe

2 GWe Target ofSSTR[1.3.6.2-3]

[Table1.3.6.2-1]A

C [Table1.3.6.2-1]

Target of CREST[1.3.6.2.-2]

A-BWR(Kashiwazaki Unit 6, Unit 7)

A-BWR(Fukushima Power Plant I Unit 7, Unit 8),future plan

B

A-SSTR[1.3.6.2-4]Target of

1) I f fusion power plants are forced to be competitive only for the COE issue, a COEn of 0 .5~0.7 must be realized in future. 2) I f fusion COEn wil l be much more than 1.5, fusion wil l be noncompetit ive. Even i f f ission plants wil l be unavailable for one reason or other, the fossil power plants with CO2 sequestration systems will need lower cost than the fusion plants. Furthermore, the cost of CO2 sequestration will be reduced in future.

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Target for Commercial Use

COE : designed value of 10yen/kWh or less 15yen/kWh as upper limit

Stability : less than 1%

Forced outage : 0.5/unit year ( including disruption-induced outage)

Load-following : at least partial load operation in case of emergency

Site requirement : near high demand area if possible

Generation capacity : <2GW/unit

Capacity factor : ideal design value of 85%, initial target 70%

Overall Assessment

Coal thermal plant with CO2 sequestration

EconomyInverse COEn

(linear scale)

Fuel resourceR/P ratio Radiological Risk of waste

BHP 20 year after decommissioning

Safety laxityinverse movable BHP

in reactor

CO2 reduction effect(inverse emission unit)

1.5 1.0

0.50.001

0.01

0.1

1

10

100

1000 LWR with sea water

uranium

1.5 1.00.5

0.0010.01

0.1

110

100

1000

Virtually unlimited

Based on values for ABWRs

Based on values for LWRs

Safety laxityinverse movable BHP

in reactor

CO2 reduction effect(inverse emission unit)

EconomyInverse COEn

(linear scale)

Fuel resourceR/P ratio

Radiological Risk of waste BHP 20 year after decommissioning

Fusion Reactor

1.5 1.00.5

0.001

0.01

0.1

110

100

1000

Target for demo reactor

Target for commercial reactor

CO2 reduction effect(inverse emission unit)

Safety laxityinverse movable BHP

in reactor

EconomyInverse COEn

(linear scale)

Fuel resourceR/P ratio Radiological Risk of waste

BHP 20 year after decommissioning

Virtually unlimited

Fusion can be a balanced energy source

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Chapter 2 Development Strategy based on ITER Project2.1 Approach - Integration and Phased Development2.2 ITER as an Experimental Reactor 2.2.1 ITER 2.2.2 What will be realized on ITER 2.2.3 Significance and cost sharing phylosophy 2.2.4 Value of hosting ITER to Japan 2.2.5 Tokamak research insupport of ITER2.3 From ITER to DEMO2.4 Summary-Placement of ITER in development strategy

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Fusion energy development and scenarios toward the fusion power plant

Prototype Reactor

Ignition &Long-burn

Third phaseSecond phase Fourth phase

Tokamak

Commercialization pease

JT-60

Decision system of prototype reactor

Electricity Generation

Advanced and complementary Research and Development

Helical devise, Reverce field pinch, Mirror, Inertial confinement Advanced confinement

Tokamak

Development of major components with enlarge sizes and improvedperformances

Test using Experimental Reactor

Long-term development necessary for a fusion reactor

Economicaspects

ExperimentalReactor(ITER)

Review

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16fig2.1.2-2 : An example of Development Program on a Tokamak Fusion Reactor

Experi-mental Reactor

Prototype Reactor

AC

The Break-even PlasmaTest Device

Reflection to the Design

Demonstration Reactor/Commercial Reactor

Engineering Design

Expending Performance Phase

High Working Rate

CDA EDA Construction BPP EPP

Reflection to the Design

20502000 Experimental Reactor Phase

Self-Igniton and Long Burn

Physics R&D for Experimental Reactor

Advanced and Complement Research

Achievement ofthe Break-even conditions

Development of High Q Steady State Operation for a Prototype Reactor

Judgment on commercialization offusion energy by industry world initiative

Achievement of Basic Performance

High Power Density

Test of Power Generation Blanket

Prototype Reactor Phase

ConstructionPower Generation Demonstration Phase

High Power Steady State Fusion Plasma

Steady State Operation with Q=5

Demonstration of Integration of Engineering Technologies

Table 2.3.2-1 Parameter gaps from experimental reactor ITER to a prototype reactor

Item

Energy amplification factor (inductive)

Energy amplification factor (steady state)

Plasma pressure

Maximum magnetic field

Normalized beta

Blanket

Structural material

Neutron fluence

ITER

10 - 20

5

Several atm

12 T

~2.5

Test module

SS316

0.3 MWa/m2

Prototype reactor

30 - 50

~10 atm

16 T

~3.5

Blanket for power generation

Low activation ferritic steel, etc.

<10 MWa/m2

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Power flow in SSTR(Generated electric power 1.08GW)

Plant efficiency 30%Nominal generated power 1.08GW

Steady state fusion power plant

Thermal power 3.7 GW Electricity generationefficiency 34.5%

Generated power 1.28GW

Q = 50

Fusion plasmaPlasma current 12MA

Efficiency 50%

N-NB current drive equipment

GeneratorSteam turbine

Reduced plasma current

High currentdrive efficiency

High plasma pressure and high bootstrapcurrents

60MW

Circulating power120MW

Station power

80MW

Plasma thermal power 300GWBlanket power 0.7GW

Chapter 3 Technical Issues and Future Prospects

3.1 Fusion plasma technology3.2 Fusion reactor technology3.3 Blanket and material development3.4 Safety related technology3.5 Operation and maintenance3.6 View from Industry3.7 Competitiveness in the Market3.8 Summary-Technological Prospects

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410 610 8

2

Steady State Operation~1000s

Pulse Operation ~300s

1day ~1month

~3months ~9months

10

101

05

10152025

Bt-max.

Bt(0)

0

0

1

2

3

4

Pulse Operation

Steady State Operation

SSTR

CREST

A-SSTR

Pulse Operation

Steady State Operation0

50

CREST

SSTRA-SSTR

0

10

5 CREST

SSTR

A-SSTR

Exp.Reactor

Phase

3 large tokamaks etc.

DemonstrationReactor

CommercialReactor

Pulse Operation

Steady State Operation

30

10

20

0

Transient

Ideal MHD Stability Limit in a case without Wall Stability Effect

6

4

2

0

Ideal MHD Stability Limit when n=1 RWM is Stabilized

CREST

SSTR A-SSTR

Medium-Size tokamaks Pellet Inj.

0

2

1SSTR

CREST

A-SSTR

Acceptable Divertor Heat Flur

0200400

600800

1000

Required Radiative Cooling Power

CREST

SSTR

A-SSTR

15

10

5

CREST

SSTR

A-SSTR

0

0.5

1.0

Pulse Operation

Steady State OperationCREST

Phase

3 large tokamaks etc.

Exp.Reactor DemonstrationReactor

CommercialReactor

0

5

10

SSTR A-SSTR

NBIRF

RF

NBIARIES-I

Ideal MHD Stability Limit

19

20

10

20

30

40

50

60

70

5 6 7 8 9 10 11 12 13 14

Demonstration in model coil

Current status

Magnetic field (T)

ITER-TF(12.5T, 60kA)

ITER-CS(13T, 40kA)US-DPC

DPC-U

DPC-EXLCT

LHD

TMCTRIAM

TMCTore Supra

80

90

100

15 16 170 18 21 22

Demo reactor TF coil

(16.5T, 80kA)

Target for Demo reactor

FY1999-20021 Niobium Aluminum Conductor development2 Development of 20-K operation high temperature superconductor3 Optimization of design technique from limitation experiment results of CS model coil

Fig. 3.2.3-2 Development Step of Conductor for Demo Reactor Coil

Coil for magnetic levitation train

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Neutron Fluence (MWa/m2 ~ 10 dpa)

SiC/SiC composote material(Target)

0 5 10 15 20

1000

500

Vanadium Alloy (Target)

Reduced Activation Ferritic/Martensitic Steels

Demo ReactorBlanket

ODS

(Target)

Refinement of MicrostructureBy the Improvement of Design Methods

Austenitic Steel

(Current Level)

Fig.3.3.2-4 Development of Structural Materials and their Target Performances in Feasible Temperature and Neutron Fluence

ConstructionBasic Performance Extended Performance

ItemYear

DemoReactor

ITER

IntenseFusionNeutronSource

ConstructionPower Generation

Verification

C&R

EDA

Ferritic Steel Tokamak Test

Component Technology Development(Structure, Tritium Breeding)

Low Activation Ferritic Steel

Characteristics Data

Construction

Candidate Improvement

V, SiC Advanced Maerials

Prototype Reactor Materials Candidate (Engineering Research) (Engineering Verification)

Materials Selection10~20dpa

Engineering Dataseveral 10dpa

Engineering Data100~200dpa

CDE

Key Element

Technology

PhaseEngineering

DemonstrationPhase Deuteron Beam

50mA 125mA250mA

Upgrade

* dpa: integrated neutron damage parameter to study the effect of neutron irradiation on the materials characteristics

2000 2010 2020 2030 2040

Power Generating Blanket Module Test

Design

Figure 3.3.2-5 A schedule of fusion materials development

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Fuelling

Exsaust

BuildingStack

Vacuum Vessel

Tritium Plant

Clean-up system

Clean-up system

Fusion Safety

Inherent safety of fusion Containment/confinement concept

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shutdown shutdown• low fuelling• poor confinement

• excess fuelling• instability by over pressure

Operable region

Operation and Maintenance

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SSTR: 400 modules 200 modules will be changed every 3 years if RAF neutron fluence can be increased to 200dpa.

Period of exchange 28days for 200 modules with improvement from ITER technology.

0

50

100

150

200

250

300

350

0 100 200 300 400 500 600 700 800

Module number

Vehicle type manipulator

Rail expander and storage equipment

rail

Rail support

Module receiver

5.4 Control of burning plasma and technologies addressed in ITER

Control of burning plasmaSelf-heating power produced by the fusion reaction will be applied to the burning

plasma itself, while only plasma heating from the external sources has been examinedin experiments to date.

It is difficult to predict burning plasma behavior with the present knowledge basesince fusion self-heating simulation using external power is difficult. Therefore, withoutunderstanding this burning plasma behavior, it is difficult to clearly predict the technicalfeasibility of fusion energy.

Nonetheless, fusion energy development can be achieved by advancement ofexisting technologies if the control of burning plasma becomes possible. Thus, theunderstanding and control of burning plasma is the last big challenge of fusion energyresearch.

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New developments for DEMO

Technologies required for DEMO should be developed in parallel with those needed for ITER. By confirming them in ITER, one major ITER design guideline, a "single step to DEMO," can be realized. Major issues of concern are discussed below.

(1) Development of steady-state operation schemeThe basic principle of steady-state operation in tokamaks has been

proven at a number of research institutions in Japan and other countries.

It is important to fully develop steady-state operation methods through the most productive use of existing tokamak devices and to apply their performances to ITER operation, especially to the burning plasma in ITER.

At the same time, it is important to establish operational methods that avoid plasma disruptions, which preclude steady-state operation.

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(2) Development of high-temperature blanket test modules The blanket plays three important roles, neutron shielding, tritium breeding,

and extraction of high-temperature thermal energy. The latter will produce steam for generation of electricity.

To accomplish the technologies relevant to these roles, a high-temperature blanket is required. Developed in ITER, its design will be available for DEMO.

(3) Neutron irradiation testDevelopment of reduced activation materials that allow intense high-energy

neutron irradiation and high-temperature operation is required to enhance safety and economics of fusion.

Leading candidates for blanket structural materials to be used in DEMO and beyond have been identified. However, performance of these materials should be confirmed by neutron irradiation tests, as the material database has not been satisfactorily completed at present. Neutrons produced in ITER can be used for irradiation tests at low fluence and for component tests.

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5.9 Conclusion of Part 1The technical feasibility of fusion energy will be confirmed by

demonstrating control of burning fusion plasma, by establishing the technical feasibility of an integrated fusion device, and by accomplishing safety and reliability in ITER.

Furthermore, a high-performance fusion reactor will be realized by establishing steady-state operation. Most major technologies required for the DEMO reactor and beyond can be developed as an extension of ITER.

Therefore, the prospects of fusion development for the DEMO reactor and beyond will become clearer during the ITER program, as compared to the present situation where clarification of physical phenomena receives more emphasis.

In addition, it is possible that the construction cost of the DEMO reactor will be lower than that of ITER due to development of materials, technological innovations, and the progress of plasma physics. A similar possibility could apply to a commercial fusion power station that would follow DEMO.

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