March 8, ASDEX Upgrade Seminar

Report on Technical Feasibility of Fusion 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 Fusion ITER/EDA Technical Commission Council Subcommittee

Chair: Prof. N. Inoue 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 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.

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 Institute Shigetada 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 Institute Kenzo 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 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 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 : 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)

Center Solenoid Coil (7T,NbTi) Upper Maintenance Port TF Coil Design Value (16.5T,(NbTi)3Sn) Blankets Plasma Current Ip 12MA (Pressurized Water Cooling Breeder) Toroidal Field Coil Bt 9T Ring PF Coil (5.5T,NbTi) Major Radius R 7m

Inter-coil Structure Aspect Ratio A 4.1

Vacuum Chamber Elongation k95 1.85

Negative NBI Port Normalized Beta bN 3.5 (2Mev,80MW) Fusion Output PF 3GW

Divertor Maintenance Port Current Drive Power PCD 60MW Divertor Permanent Blanket Net Electric Output Power PE 1.08GW Vacuum Port Fusion Gain Q 50 5(m) Torus Sport 2 TF Coil Support Structure Averaged Neutron Wall Load Pneut. 3MW/m 5(m) 5(m) Concrete Cryostat

0 Bird's-eye view of SSTR 5 Uranium Resources

45º

Uranium is virtually inexhaustible since Uranium 40º Japan Sea extraction from sea-water is technically ready.

Concentration 3.3ppb 35º Resource in sea water 46x108tons Annual consumption 6.14x104tons

30º Resource life 75,000 years Pacific Ocean

130º 135º 140º 145º

Collection Unit

Vanadium (V2O5) Uranium (Yellow Cake) 6 Fossil Resources ( Reserves and Resource Base )

Energy Present Saturation at 12 billion persons assumed (1.67 TOE /person) 180 Nuclear/ Coal Renewable Demand of Fossil Energy Oil/Natural gas (assumed 90% of total demand) Oil + Natural Gas 150

0 500 1000 1500 2000 2500 3000(Year) Shortage due to Reserves

Resource life $10~15/bbl Past Future 100 (Coal) For reserve

Coal ; 231years ~$30/bbl (Oil) Shortage due to the Restriction of Nat.Gas ; 63years Coal Use Oil Oil ; 44years 50 $15 ~30/bbl For resource base (Coal) Coal Nat.Gas ; 452years $30/bbl~ (Gas) Oil ; 242years 0 1900 1950 2000 2100 2200 2300 2400 Year 6 CO2 Emission Rate

Fusion is environmentally attractive with its low CO2 emission rate. 300 270

200 200 178

(Fuel)

100 (Fuel) 85 81

(Fuel) (Fuel) (Fuel) 33.733.7 34.334.3 16 6-12 12 40 46 4.8 5.7 0 24 31 7 Radiological Toxic Hazard Potential Present 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.

Coal-fired power plant

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 Fusion reactor reactor I-131 power plant power plant in 3GW LWR 4.5kg of T Latent risk of the radiation exposure 8 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)

15 1020 10

13 1018 10

11 1016 10

14 109 10 Light water reactor Light water reactor Fusion reactor (SSTR) Fusion reactor (SSTR) Coal-fired power Coal-fired power 12 107 10 -4 -2 0 2 4 6 10-4 10-2 100 102 104 106 10 10 10 10 10 10 Ye ar Y e a r 9 Waste Management

Disposal cost is smaller than that for LWR spent fuel management. 10 8

10 7 10 6 Burn-up ashes 10 5 from the coal- fired plant 10 4 Fusion reactor Boiling water reactor 1000

High-level radioactive waste High bg waste Low-level radioactive waste Total Fission reactor 90 billion yen 3.84 billion yen 11.7 billion yen 10.554 billion yen with 1GW electricity / 180 m3 / 1600 m3 / 9750 m3 Fusion reactor(SSTR, - 6 billion yen 30.12 billion yen 36.12 billion yen 1.08 GW electricity) / 2500 m3 / 25100 m3

Used disposal unit prices are low-level waste (¥ 1200000/m3), high bg waste (¥ 2400000/ m3) and high-level radioactive waste (five hundred million yen/ m3) 10 Economical Efficiency

1) If fusionpower plants are forced to becompetitive only for the COE issue, a COEn of 0.5~0.7must be realized 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/kW 0 1.0 2.0 500 Upper value Power plants now in use Lower value (Thermal power, Photovoltaic power 10000 Ocean thermal power Hydropower, system for utility application Nuclear power) 2 GWe A 100 B Target of [Table1.3.6.2-1] Future prediction SSTR 8000 50 Wind power plant [1.3.6.2-3] Future prediction Geothermal Electricity power energy Target region of 6000 1 GWe 10 fusion power LNG-fired power plant Target of C [Table1.3.6.2-1] with CO2 sequestration 5 A-SSTR[1.3.6.2-4] Target of Coal-fired power plant 4000 CREST[1.3.6.2.-2] with CO2 sequestration A-BWR (Kashiwazaki Unit 6, Unit 7) A-BWR 1 2000 (Fukushima Power Plant I Unit 7, Unit 8), 0.1 0.5 1 5 10 50 100 future plan Normalized COE (COEn) 0 11 0 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 Fusion Reactor (inverse emission unit) 1000 100

Target for demo reactor 10 Target for commercial reactor 1 0.1 Economy Safety laxity 0.01 inverse movable BHP Inverse COEn 1.5 1.0 0.001 in reactor (linear scale) 0.5

Virtually unlimited Fuel resource R/P ratio Radiological Risk of waste BHP 20 year after decommissioning CO2 reduction effect Coal thermal plant (inverse emission unit) CO2 reduction effect with CO2 1000 LWR with sea water (inverse emission unit) sequestration 100 uranium 1000 10 100 1 Based on values for LWRs 10 0.1 1 Economy Safety laxity Based on values for ABWRs Inverse COEn 0.01 0.1 1.5 1.0 inverse movable BHP Economy Safety laxity 0.001 in reactor Inverse COEn 0.01 (linear scale) 0.5 1.5 inverse movable BHP 1.0 0.001 (linear scale) in reactor 0.5

Fuel resource Virtually unlimited R/P ratio Radiological Risk of waste Radiological Risk of waste BHP 20 year after decommissioning 13 Fuel resource R/P ratio BHP 20 year after decommissioning Chapter 2 Development Strategy based on ITER Project 2.1 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 DEMO 2.4 Summary-Placement of ITER in development strategy

14 Fusion energy development and scenarios toward the fusion power plant

Commercialization pease Second phase Third phase Fourth phase

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

Advanced and complementary Research and Development

Electricity Generation Ignition & Tokamak Tokamak Long-burn Review Experimental Prototype Reactor Economic JT-60 Reactor aspects (ITER) Decision system of prototype reactor

Development of major components with enlarge sizes and improved performances

Test using Experimental Reactor

Long-term development necessary for a fusion reactor

15 AC 2000 Experimental Reactor Phase Prototype Reactor Phase 2050 Demonstration Judgment on commercialization of Reactor fusion energy by industry world initiative /Commercial Reactor

Engineering Power Generation Expending Design Construction Demonstration Phase Performance Phase

Prototype Achievement of Basic Performance High Working Rate Reactor High Power Steady High Power Density Reflection to State Fusion Plasma the Design

CDA EDA Construction BPP EPP Experi-

mental Reflection to Self-Igniton and Long Burn Development of High Q Steady State Operation the Design Steady State Operation with Q=5 Demonstration of Integration for a Prototype Reactor Reactor of Engineering Technologies Test of Power Generation Blanket

The Break- even Physics R&D for Advanced and Experimental Reactor Complement Research Plasma Test Device Achievement of the 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 Prototype reactor Energy amplification factor (inductive) 10 - 20

Energy amplification factor (steady state) 5 30 - 50 Plasma pressure Several atm ~10 atm Maximum magnetic field 12 T 16 T Normalized beta ~2.5 ~3.5 Blanket Test module Blanket for power generation Structural material SS316 Low activation ferritic steel, etc. Neutron fluence 0.3 MWa/m2 <10 MWa/m2

Power flow in SSTR (Generated electric power 1.08GW) Reduced plasma current Plant efficiency 30% Fusion plasma Nominal Plasma current Generated power 1.28GW generated power 1.08GW 12MA Thermal power 3.7 GW Electricity generation efficiency 34.5% Q = 50 Plasma thermal power 300GW Blanket power 0.7GW Steam turbine Generator 60MW N-NB current drive equipment High plasma High current pressure and drive efficiency Circulating power 120MW high bootstrap Efficiency 50% currents Station power Steady state fusion power plant 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 4 CREST SSTR 6 Transient 3 Ideal MHD Stability Limit CREST 4 2 SSTR A-SSTR 2 1 Pulse Operation Ideal MHD Stability Limit in a case 0 without Wall Stability Effect 0 Steady State Operation Ideal MHD Stability Limit when n=1 RWM is Stabilized A-SSTR Medium-Size SSTR 2 50 tokamaks Pellet Inj. CREST Pulse Operation 1 CREST SSTR A-SSTR 0 0 8 Steady State Operation 10 1000 6 800 CREST A-SSTR 10 Steady State ~3months ~9months Operation~1000s 600 4 1day SSTR Required Radiative Cooling Power 10 400 ~1month Acceptable 2 200 10 Pulse Operation ~300s Divertor Heat Flur 1 0 A-SSTR 10 15 CREST 10 5 CREST A-SSTR SSTR 5 SSTR 0 0 25 1.0 20 15 Bt-max. Steady State Operation 0.5 CREST 10 Bt(0) Pulse Operation 5 0 0 30 10

20 SSTR A-SSTR Pulse Operation 5 RF NBI 10 NBI ARIES-I RF Steady State Operation 0 0 3 large Exp.Reactor Demonstration Commercial 3 large Exp.Reactor Demonstration Commercial tokamaks etc. Reactor Reactor tokamaks etc. Reactor Reactor Phase Phase 19 100

FY1999-2002 Demo reactor TF coil 90 1 Niobium Aluminum Conductor development 2 Development of 20-K operation high (16.5T, 80kA) 80 temperature superconductor 3 Optimization of design technique from limitation experiment results of CS model 70 coil

60 ITER-TF(12.5T, 60kA) 50

40 ITER-CS(13T, 40kA) US-DPC 30 DPC-U Target for Demo reactor LCT 20 DPC-EX Demonstration in model coil LHD Coil for Current status 10 magnetic TMC levitation train Tore Supra TMC TRIAM 0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 21 22 Magnetic field (T)

Fig. 3.2.3-2 Development Step of Conductor for Demo Reactor Coil 20 1000 SiC/SiC composote material (Target)

Vanadium Alloy (Target) (Target) Reduced Activation Ferritic/Martensitic Steels 500 ODS

(Current Refinement of Microstructure Level) By the Improvement of Design Methods

Demo Reactor Austenitic Steel Blanket 0 5 10 15 20 Neutron Fluence (MWa/m2 ~ 10 dpa)

Fig.3.3.2-4 Development of Structural Materials and their Target Performances in Feasible Temperature and Neutron Fluence 21 Year Item 2000 2010 2020 2030 2040 Power Generation Demo Construction Verification Reactor Design

Construction ITER C&R Basic Performance Extended Performance EDA Power Generating Blanket Module Test

Ferritic Steel Tokamak Test

Component Technology Development (Structure, Tritium Breeding) Engineering Data 100~200dpa Engineering Data Materials Selection several 10dpa 10~20dpa Low Activation Characteris Candidate Ferritic Steel tics Data Improvement

V, SiC Advanced Maerials

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

Technology Intense Engineering Phase Demonstration 250mA Fusion Phase Deuteron Beam Neutron CDE 50mA 125mA Source Construction Upgrade * 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-up system

Vacuum Vessel Operable region Clean-up system

Fuelling Tritium Plant shutdown shutdown Exsaust • low fuelling • excess fuelling • poor confinement • instability by over pressure

23 Operation and Maintenance

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.

350 Rail support 300

250

Rail expander and 200 storage equipment Module receiver 150

100

rail Vehicle type 50 manipulator 0 0 100 200 300 400 500 600 700 800 24 Module number 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 examined in experiments to date.

It is difficult to predict burning plasma behavior with the present knowledge base since fusion self-heating simulation using external power is difficult. Therefore, without understanding this burning plasma behavior, it is difficult to clearly predict the technical feasibility of fusion energy.

Nonetheless, fusion energy development can be achieved by advancement of existing technologies if the control of burning plasma becomes possible. Thus, the understanding 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 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 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 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.

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-temperature blanket 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 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.

27 5.9 Conclusion of Part 1 The 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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