March 8, ASDEX Upgrade Seminar

Report on Technical Feasibility ofFusion Energy to the Special
Committee for the ITER Project
M. Kikuchi
Former member of subcommittee for Fusion
Development Strategy under Fusion Council

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

Special committee for the ITER Project
Chair: Prof. H. Yoshikawa

Atomic Energy
Commission

FusionCouncil
Chair: Prof. N. Inoue

ITER/EDA Technical
Subcommittee
Chair: Prof. M. Wakatani
Planning and Promotion
Subcommittee
Chair: Prof. K. Miya
Subcommittee for Fusion
Development Strategy
Chair: Prof. N. Inoue

1

Charge to Subcommittee for Fusion Development Strategy(3) Technical feasibility of the fusion energy(4) Extension of the program and basic supporting research
For topic (3) above, the Special Committee additionally requested anevaluation of the feasibility of fusion energy as a safe and reliableenergy source from the aspects of technical potential, management
capability, and characteristics of Japanese industrial structure.
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.

2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 Tokyo
Mitsuru 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 Science
Shinzaburo 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)

3Chapter 1 Future Prospects of the Fusion Energy
1.1 Situations in the 21st century
1.2 Criteria for commercialization
1.3 Comparison with other power sources
1.3.1 Resources (fusion, fission, fossil)
1.3.2 CO2 Emissions and Sustainability of Atmosphere1.3.3 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 Electricity
1.4 Overall Assessment

4Resources required for Fusion Reactor(SSTR is adopted as a reference design)
Resource life :Assuming present-level world electricity is produced by 1500 SSTR
Deuterium :Lithium :almost limitless ; 144ppm in fresh water

1.5million years ; 233Gtons in sea-water

Beryllium:

70,000 years ; 100Mtons (gross mineral resources)

Niobium:

70,000 years; 700Mtons (gross mineral resources)

Center Solenoid Coil
(7T,NbTi)

Design Value

Upper Maintenance PortTF Coil(16.5T,(NbTi)3Sn)

Blankets(Pressurized Water CoolingBreeder)
Ring PF Coil
(5.5T,NbTi)
Inter-coil Structure
Vacuum Chamber
Negative NBI Port
(2Mev,80MW)

Divertor

Divertor Maintenance Port

Plasma Current
Toroidal Field Coil
Major RadiusAspect Ratio

IpBtRA

12MA
9T
7m
4.1

Elongation

κ95

1.85

Normalized BetaFusion Output

βNPF
PCD
PEQ
Pneut.

3.5
3GW
60MW
1.08GW50
3MW/m2Current Drive PowerNet Electric Output Power

Permanent Blanket
Vacuum PortTF Coil Support

Torus Sport
Structure

Fusion Gain

5(m)

5(m)

5(m)

Concrete Cryostat

Bird's-eye view of SSTR

50

Averaged Neutron Wall LoadUranium Resources
45º40ºJapan Sea

35º30ºPacific Ocean

130º

135º

140º

Uranium is virtually inexhaustible since Uranium
extraction from sea-water is technically ready.
Concentration
Resource in sea water
Annual consumption
Resource life

3.3ppb46x108tons
6.14x104tons
75,000 years

145ºCollection Unit

6

Vanadium(V2O5)

Uranium (Yellow Cake)Fossil Resources ( Reserves and Resource Base )EnergyPresentSaturation at 12 billion persons assumed (1.67 TOE /person)
Nuclear/Renewable

Coal

180
Demand of Fossil Energy(assumed 90% of total demand)

Oil/Natural gas

Oil + Natural Gas

150
0500

1000

1500

2000

2500

Shortage due toReserves

3000(Year)

Resource life
For reserve
Coal100Past; 231years~$30/bbl(Oil)Nat.Gas ; 63years
Oil; 44years$10~15/bbl(Coal)

FutureShortage due tothe Restriction ofCoal Use

Oil

50

$15~30/bbl(Coal)For resource base
CoalNat.Gas ; 452years
Oil; 242years$30/bbl~
(Gas)

01900

1950

2000

62100

2200

Year2300

2400

CO2 Emission Rate
Fusion is environmentally attractivewith its low CO2 emission rate.

300 270

200200178(Fuel)

100(Fuel)(Fuel)

02412408581(Fuel)(Fuel)

3146734.3
33.733.7 34.3
164.8

5.7

6-12

Radiological Toxic Hazard Potential
Present large scale energy sources such as fossil plants andLWR have large risks such as Global Warming and RadiologicalHazard. Fusion simultaneously reduces both risks.
Coal-fired
power plant
CO2 emission isless than 1/10.

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

Fusion reactor
power plant
4.5kg of T

8Light water
reactorpower plant
Latent risk of the radiation exposure

I-131
in 3GWLWRLong Term Waste Hazard Potential
Radiological toxic hazard potential of fusion plant is muchsmaller than fission and even lower than coal ash (Th-232,U-238)

1 02 01 01 5

1 01 81 01 3

1 01 6

1 01 1

1 01 4

1 09

Light water reactor
Fusion reactor (SSTR)
Coal-fired power

Coal-fired power
71210

1 0- 4

Light water reactor
Fusion reactor (SSTR)

1 0- 2

1 00

1 02
Y e a r

1 04

1 06

910
1 0- 4

1 0- 2

1 00

1 02
Y e a r

1 04

1 06

Waste Management
Disposal cost is smaller than that for LWR spent fuel management.
108107106105104

Burn-up ashes
from the coalfired plant
Fusion reactor

1000High-level radioactive waste
Fission reactor
90 billion yen
with 1GW electricity/ 180 m3
Fusion reactor(SSTR,1.08 GW electricity)

High βγ waste
3.84 billion yen/ 1600 m3
6 billion yen/ 2500 m3

Boiling water reactor

Low-level radioactive waste
Total
11.7 billion yen
10.554 billion yen/ 9750 m3
30.12 billion yen
36.12 billion yen/ 25100 m3

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)

10

Economical Efficiency
1 ) I f f u s i o npower plants are f o r c e d t o b ecompetitive only for the COE issue, a C O E n o f 0 . 5 ~ 0 .must
7
berealized in future.
2) If fusion COEn will be much more than 1.5, fusion will be noncompetitive. Even if fission plants will 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.

Normalized cost of electricity (COEn)

104 yen/kW0500

100

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

Photovoltaic powersystem for utility
application

1.050

Upper value
Lower value

10000
2 GWe

B Target ofFuture prediction

A[Table1.3.6.2-1]

SSTR[1.3.6.2-3]

8000

Wind power plant

2.0Future prediction

Geothermalenergy

105

LNG-fired power plantwith CO2 sequestration

Target region offusion power

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

4000

120000.5 1

C [Table1.3.6.2-1]

Target ofA-SSTR[1.3.6.2-4]

Coal-fired power plantwith CO2 sequestration

0.1

Electricity power
1 GWe

6000

51050 100

Normalized COE (COEn)

1100

20

40

60

80

100

Unit cost of construction (x 10 kyen/kW)

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%

12Overall Assessment
Fusion can be a balanced energy source
CO2 reduction effect(inverse emission unit)

Fusion Reactor

1000
100101

Target for demo reactor
Target for commercial reactor

0.1
0.01

EconomyInverse COEn

1.51.0(linear scale)

Safety laxity
inverse movable BHP
in reactor

0.001
0.5

Virtually unlimited

Fuel resource
R/P ratio

Coal thermal plantwith CO2sequestration

Radiological Risk of waste
BHP 20 year after decommissioning

CO2 reduction effect
CO2 reduction effect(inverse emission unit)
100

1000
100uranium

101

Inverse COEn
(linear scale)

0.001
0.5

Based on values for ABWRs

Safety laxity

0.01

1.5 1.0

R/P ratio

Radiological Risk of waste
BHP 20 year after decommissioning

0.1
0.010.001

Economyinverse movable BHP
in reactor

Inverse COEn

1.5(linear scale)

Fuel resource

101

Based on values for LWRs0.1Economy(inverse emission unit)

LWR with sea water1000

131.00.5

Safety laxity
inverse movable BHP
in reactor

Virtually unlimited

Fuel resource
R/P ratio

Radiological Risk of waste
BHP 20 year after decommissioningChapter 2 Development Strategy based on ITER Project2.1 Approach - Integration and Phased Development
2.2 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 ITER
2.3 From ITER to DEMO2.4 Summary-Placement of ITER in development strategy
14

Fusion energy development and scenarios toward the fusion power plantCommercialization pease

Fourth phase

Third phase

Second phase

Advanced confinement

Helical devise, Reverce field pinch, Mirror, Inertial confinement

Advanced and complementary Research and Development
Electricity
Generation
TokamakIgnition &Long-burnTokamak

JT-60

Review

Experimental
Reactor(ITER)

Decision system ofprototype reactor

Development of major components with enlarge sizes and improved
performances
Test using Experimental Reactor
Long-term development necessary for a fusion reactor

15

Prototype Reactor

Economicaspects

2000 Experimental Reactor Phase

ACPrototype Reactor Phase

Demonstration
Reactor/Commercial Reactor

Judgment on commercialization offusion energy by industry world initiative

Engineering
Construction
DesignPrototype
Reactor

Reflection to
the Design

CDA

Experimental
Reactor

2050

EDA

Construction

Reflection to
the Design

BPP

EPP

Self-Igniton and Long Burn

Development of High Q
Steady State Operation
for a Prototype Reactor

Steady State Operation with Q=5
Demonstration of Integrationof Engineering Technologies

Power Generation
Expending
Demonstration Phase Performance Phase
Achievement of BasicHigh Working Rate
PerformanceHigh Power SteadyHighPower Density
State Fusion Plasma

Test of Power Generation Blanket

The Breakeven
PlasmaTest Device

Physics R&D forExperimental Reactor

Advanced andComplement Research

Achievement ofthe Break-even conditions

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

16

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

ITER

Energy amplification factor (inductive)

Prototype reactor

10 - 20

Energy amplification factor (steady state)

530 - 50

Several atm~10 atm

Maximum magnetic field

12 T

16 T

Normalized beta~2.5~3.5

Test moduleBlanket for power generation

Structural material

SS316

Low activation ferritic steel, etc.

Neutron fluence

0.3 MWa/m2<10 MWa/m2

Plasma pressureBlanket

Power flow in SSTR
(Generated electric power 1.08GW)
Reduced plasma current
Fusion plasma
Plasma current
12MA
Q = 5060MW

Plant efficiency 30%
NominalGenerated power 1.28GW generated power
1.08GW
Electricity generation
Thermal power 3.7 GW
efficiency 34.5%
Plasma thermal power
300GW
Blanket power
0.7GW
Steam turbine Generator

N-NB current drive equipment

High current
High plasma
drive efficiencypressure andhigh bootstrap
Efficiency 50%
currents
Steady state fusion power plant

Circulating power
120MW
Station power
80MW

17

Chapter 3 Technical Issues and Future Prospects
3.1 Fusion plasma technology
3.2 Fusion reactor technology
3.3 Blanket and material development
3.4 Safety related technology
3.5 Operation and maintenance
3.6 View from Industry
3.7 Competitiveness in the Market
3.8 Summary-Technological Prospects
18

A-SSTR

432

1

Pulse Operation

0

Steady State Operation

0101010

Steady State Operation

6

Steady StateOperation~1000s2
1~3months~9months

800
600

CREST

A-SSTR

SSTR

4002000

CREST

CREST

10A-SSTR

Required Radiative Cooling Power
Acceptable
Divertor Heat Flur
A-SSTR

15SSTR

5SSTR

01.0

Bt-max.

0.5

Steady State Operation
CREST

Bt(0)

Pulse Operation
0105

Pulse Operation

10
Steady State Operation
0

A-SSTR

01day~1monthPulse Operation ~300s

520

SSTR

1000

10025
2015
105030

Ideal MHD Stability Limit
A-SSTR
SSTR
Ideal MHD Stability Limit in a casewithout Wall Stability Effect
Ideal MHD Stability Limit when n=1
RWM is Stabilized
Medium-Sizetokamaks Pellet Inj.
CREST

CREST842Transient

1Pulse Operation
0A-SSTRSSTR50

104CREST

2CREST

6SSTR

3 large
Exp.Reactor
tokamaks etc.

Demonstration
ReactorPhase

A-SSTRSSTRRFNBINBIARIES-IRF

03 large
Exp.Reactor
tokamaks etc.

Commercial
Reactor19

Demonstration
Reactor
Phase

Commercial
Reactor100
Demo reactor TF coil

FY1999-2002
1 Niobium Aluminum Conductor development
2 Development of 20-K operation hightemperature superconductor
3 Optimization of design technique fromlimitation experiment results of CS modelcoil

90807060(16.5T, 80kA)

ITER-TF(12.5T, 60kA)

5040ITER-CS(13T, 40kA)
US-DPC

30

DPC-U
LCT

DPC-EX

20

Coil formagnetic
levitation train

100

Target for Demo reactor

567

Demonstration in model coil

LHD

Current status

Tore Supra

TMC

8109

TMC
TRIAM

1112131415161718

Magnetic field (T)Fig. 3.2.3-2 Development Step of Conductor for Demo Reactor Coil

202122

1000

SiC/SiC composote material(Target)

Vanadium Alloy (Target)(Target)Reduced Activation
Ferritic/Martensitic Steels
ODS

500

Refinement of Microstructure
By the Improvement of DesignMethods(CurrentLevel)

DemoReactorBlanketAustenitic Steel

05101520

Neutron Fluence (MWa/m2 ~ 10 dpa)
Fig.3.3.2-4 Development of Structural Materials andtheir Target Performances in Feasible Temperature and Neutron Fluence21

ItemYear

2000

2010

2020

DemoReactor

2030

2040

Construction

Power Generation
Verification

DesignConstruction

C&R

ITER

Basic Performance

Extended Performance

EDA
Power Generating Blanket Module Test

Ferritic SteelTokamak Test
Component Technology Development(Structure, Tritium Breeding)Materials Selection
10~20dpa
Low Activation
Ferritic SteelCharacteristics Data

Engineering Data
100~200dpa

Engineering Data
several 10dpa

CandidateImprovement

V, SiC Advanced Maerials
Prototype Reactor Materials Candidate(Engineering Research)(Engineering Verification)

Key Element

IntenseFusion
NeutronSource

TechnologyPhase

Engineering
Demonstration
Phase

250mA

Deuteron Beam
50mA

CDE

125mA

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

Figure 3.3.2-5 A schedule of fusion materials development

22

Fusion Safety
Inherent safety of fusion

Containment/confinement concept
Building
Stack

Clean-upsystemVacuumVessel

Operable
regionClean-upsystem

Tritium
Plant

Fuelling

shutdown• low fuelling• poor confinement

shutdownExsaust• excess fuelling• instability byover pressure

23

Operation and Maintenance
SSTR: 400 modules
200 modules will be changed every 3 years if RAF neutron fluencecan be increased to 200dpa.
Period of exchange 28days for 200 modules with improvementfrom ITER technology.
350

Rail support
300

250

Rail expander andstorage equipment

200

150

Module receiver

100Vehicle typemanipulator

rail

50

0

240100

200

300

400

500

Module number

600

700

800

5.4 Control of burning plasma and technologies addressed in ITER
Control of burning plasma
Self-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, without
understanding 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 energy
research.

25

New developments for DEMO
Technologies required for DEMO should be developed in parallel withthose 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 scheme
The 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 throughthe most productive use of existing tokamak devices and to apply theirperformances to ITER operation, especially to the burning plasma in ITER.
At the same time, it is important to establish operational methods thatavoid plasma disruptions, which preclude steady-state operation.

26

(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-temperatureblanket is required. Developed in ITER, its design will be available for DEMO.
(3) Neutron irradiation test
Development 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 andbeyond have been identified. However, performance of these materials should beconfirmed by neutron irradiation tests, as the material database has not beensatisfactorily completed at present. Neutrons produced in ITER can be used forirradiation tests at low fluence and for component tests.

27

5.9 Conclusion of Part 1
The technical feasibility of fusion energy will be confirmed bydemonstrating control of burning fusion plasma, by establishing the technicalfeasibility of an integrated fusion device, and by accomplishing safety andreliability in ITER.
Furthermore, a high-performance fusion reactor will be realized byestablishing steady-state operation. Most major technologies required for theDEMO reactor and beyond can be developed as an extension of ITER.
Therefore, the prospects of fusion development for the DEMO reactor andbeyond will become clearer during the ITER program, as compared to thepresent situation where clarification of physical phenomena receives moreemphasis.
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, technologicalinnovations, and the progress of plasma physics. A similar possibility could
apply to a commercial fusion power station that would follow DEMO.

28