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Institute of Advanced Energy, Kyoto University
High Temperature Blanket and Its
Socio-Economic Issues
Satoshi Konishi
Institute of Advanced Energy, Kyoto University
Contents
- Fast track and Development Strategy in Japan
- Power plant design
- Hydrogen production
- Safety and environmental impact
Fast Track : the next step
Institute of Advanced Energy, Kyoto University
Fusion study is in the phase to show a concrete plan for Energy.
-Power plant design and strategy following ITER are required.
Common understanding
・Resource constraint (Energy)
・Global warming problem (Environment)
・Growth in developing countries (Economy)
Energy Demonstration in 2030?
Combined Demo-Proto steps
Technical feasibility
Social feasibility
Strategy varies in each Parties due to different social requirements.
Fast
Track
Discussion
in
Japan
Institute of Advanced Energy, Kyoto University
2000
2010
Power
Demo
2020
Concept Design
BPP
Const.
Test
EPP
module1
TBM
High
Test
beta, long pulse
Tokamak
KEP
EVEDA
Const.
New line
10dpa/y
RAF
Const.
Generation
ITER
IFMIF
2030
In pile irradiation
1/2 irrad.
module2
Evolution required
In a same facility
20dpa/y
Full irrad.
Drawn from Fast track working group in Japan, 2002,Dec.
Socio-Economic
Aspect
of
Fusion
Institute of Advanced Energy, Kyoto University
・Future energy must respond to the demand of the society.
・Social and Economical feasibility of fusion depends on
high temperature blanket and its feature.
Government
Public
Government
funding
Fusion
Development
Outcome
Generation
Technically feasible
Previous Programs
Researchers’ viewpoint
funding
Fusion
Other Energy
Outcome/benefit
Damage/cost/
”Externality”
Future
Energy
Social
Supply
Demand
Socially Required
Present Programs
Social viewpoint
Power Plant Design
Institute of Advanced Energy, Kyoto University
Near Future Plants
-Reduced Activation Ferritic steels (RAFs) are expected as
blanket material candidates.
-Considering temperature range for RAFs, 500 C range
is maximum, and desirable for efficiency.
-From the aspect of thermal plant design,
ONLY supercritical water turbine is the available option
From fire-powered plant technology.
-No steam plants available above 650 degree C.
Flow diagram of indirect cycle
Institute of Advanced Energy, Kyoto University
Steam Generator
Reheater
Blanket
Turbines
Feed water heater
（divertor heat）
Tritiated water
processing
CVCS
Feed water pump
Booster pump
Thermal plant efficiency
Institute of Advanced Energy, Kyoto University
Direct cycle turbine train generates 1160MW of electricity.
Thermal efficiency is estimated to be 41%.
Comparison of Generation Cycles
Institute of Advanced Energy, Kyoto University
direct
indirect
Main steam pressure 25MPa
16.3MPa
Turbine temp.
500℃
480℃
Coolant flow rate
1250kg/s 1260kg/s
Vapor flow rate
1250kg/s 1037kg/s
Total generation
1200MW 1090MW
Thermal efficiency
41.4%
38.5%
Technical issues
tritium in
steam
coolant
generator
Other thermal Plants:
BWRs – 33% PWRs – 34%
Supercritical Fire – 47%
Combined gas turbine - >60%
He gas
10MPa
500 ℃
1865kg/s
908kg/s
1028MW
35.3%
expansion
volume
Findings
Institute of Advanced Energy, Kyoto University
-Supercritical water cycles is desirable and possible
(technically difficult).
- No gas turbine system is effective in temperature ~500 C.
- With steam generator, gas cooled is less effective than water.
- Plant design limited above 650 C.
High temperature material does not guarantee economy.
Improvements may be required in the DEMO generation.
Possible Advanced Plant Options
-High temperature cycle can be planned with He gas turbine at
~900 C.
-Only dual coolant LiPb blanket has possibility for high
temperature in ITER/TBM.
-At high temperature, use of heat for hydrogen production
may be an attractive choice.
Fusion Contribution with hydrogen
Gton oil equivalent/year
Institute of Advanced Energy, Kyoto University
30
actual
estimated
renewables
20
gas
10
oil
0
1900
Renewable hydrogen
nuclear
Fusion hydrogen
Fusion electricity
hydro
Unconventional gas
Unconventional oil
coal
1950
2000
year
2050
2100
Hydrogen Production by Fusion
Institute of Advanced Energy, Kyoto University
Fusion can provide both high temperature heat and
electricity
- Applicable for most of hydrogen production processes
As Electricity
-water electrolysis, SPE electrolysis : renewables, LWR
-Vapor electrolysis : HTGR
As heat
-Steam reforming:HTGR(800C),
-membrane reactor:FBR(600C)
-IS process :HTGR(950C)
-biomass decomposition: HTGR
Energy Eficiency
Institute of Advanced Energy, Kyoto University
◯amount of produced hydrogen from unit heat
・low temperature（３００℃）generation
→ conventional electrolysis
・high temperature（９００℃）generation
→ vapor electrolysis
・ high temperature（９００℃） → thermochemical production
From 3GW heat
300C-electrolysis
900C-electrolysis
900C-vapor electrolysis
900C-biomass
efficiency electricity
33%
50%
50%
1 GW
1 .5 GW
1 .5 GW
ー
ー
Hydrogen
Energy
consumption production
2 8 6 kJ/ mol
25t / h
2 3 1 kJ/ mol
4 4t /h
1 8 1 kJ/ mol
5 6t /h
6 0 kJ/ mol
3 4 0t / h
Use of Heat for Hydrogen Production
Institute of Advanced Energy, Kyoto University
◯Processing capacity: 3GWt
・2500t／h waste
340t of H2
1.3x106 fuel cell vehicles (6kg/day)
or 6.4 GWe (70% fc)
Heat exchange,
Shift reaction
Fusion
Reactor
3ＧＷｔｈ
H2 340 t/h
CO2 3.7E+06 kg/h
2500 t/h biomass
CO 2.4E+06 kg/h
H2 1.7E+05 kg/h
H2O
Chemical
Steam cooler
Reactor
(770 t/h)
He
Turbine
1.38E+07 kg/h
600℃
Hydrogen from biomass and heat
Amount of hydrogen
production[mol]
The experimental results of
the change in carbon
atoms combined in
carbonized gases[mol.%]
Institute of Advanced Energy, Kyoto University
30
25
CO2
CH 4
CO
20
15
10
5
0
0.0005
0.0010
0.0015
0.0020
0.0025
H2 by calculation
H2 by measurement
0.0030
35
65
85
35
flow rate
4
steam concentration
65
[cm3/min]
5
[%]
85
Fusion safety and environmental impact
Institute of Advanced Energy, Kyoto University
BLANKET
REPROCESSING
BLANKET
PLASMA
TURBINE
GENERATOR
RELEASE
EXHAUST
DETRITIATION
SOLID WASTE
BLANKET
REPLACEMENT
DECONTAMINATION
OF SOLID WASTES
TRITIUM
EXTRACTION
DISPOSAL
EXHAUSTS
EFFLUENTS
PRIMARY LOOPS
EVACUATION
PURIFICATION
STORAGE
ISOTOPE
SEPARATION
HX
FUELING
WATER
DETRITIATION
LOADING
IN/OUT
①Solid Waste
SECONDARY
LOOPS:100g
tritium
Impact pathway ②Tritium
Release
from
Coolant
High temperature, pressure
③FuelLarge
Processing
exhaust
process
RELEASE
Out of primary enclosure
Inventory distribution compared with ITER
OFF-SITE
Institute of Advanced Energy, Kyoto University
LOAD
IN
WASTE
TEMPORARY
STORAGE
〜10g
<100g
WATER
DETRITIATION
～1 g
COOLANT
～1 g
COOLING
SYSTEMS
HOT CELL
500 g
STACK
LOAD
OUT
EFFLUENT
PROCESSING
～1 g
EFFLUENTS
<100g
FUELING
50 g
VACUUM
VESSEL
1100 g
<100g
FUEL
STORAGE
550 g*
PURIFICATION
100 g
TORUS
EXHAUST
130 g
〜10g
ISOTOPE
SEPARATION
190 g
PRIMARY FUEL SYSTEM
ITER SITE INVENTORY：2800 g
POWER REACTOR：probably less
POWER BLANKET (example)
Institute of Advanced Energy, Kyoto University
780K supercritical water
Li ceramic pebbles
He/H2 sweep for tritium
recovery
High Temperature
High Pressure
Fine tubings
Tritium Production
1st wall
Cooling tubes
Tritium Permeation could be ~100g day
Normal release from Fusion Facility
Institute of Advanced Energy, Kyoto University
・ Normal tritium will be dominated by release from coolant
・ Largest detritiation system will be for coolant
・ Fusion safety depends on ACTIVE system.
Generalized fusion plant
building confinement
secondary confinement
GENERATION
SYSTEM
PRIMARY LOOP
TRITIUM
RECOVERY
BLANKET
PLASMA
PRIMARY
COOLANT
reactor boundary
COOLANT
PROCESSING
SECONDARY LOOPS
AIR DETRITIATION
tritium flow
tritium leak/permeation
PRIMARY
LOOP
TRITIUM INVENTORY(kg)
TRITIUM THROUGHPUT(kg/day)
TOTALTHROUGHPUT(kg/day)
COOLANTPROCESS
1
0.5
30
0.5
60
500000
Generalized
detritiation
system
Institute of Advanced Energy, Kyoto University
・Detritiation for power train will depends on blanket types.
・Normal detritiation for coolant will handle emergency spill.
・Safety control with active system is not site specific.
Turbine
Heat
HX
tritium
Blanket
tritium
Heat
Heat
Heat
Tritium recovery
Low concentration
Large throughput
Once through
Tritium recovery
Large enrichment
-broad concentration range
Closed cycle cascade
Tritium recovery
High concentration
Quick return
Detritiation systems of Plant
Institute of Advanced Energy, Kyoto University
Processes large throughput, lower concentration
Controls environmental release
Operational continuously (including maintenance)
Air Detritiation :
- 1000 m3 / hour, possibly ci/m3 level
- leak from generator, secondary loops, hot cell
Water Detritiation : (isotope separation)
- 100 m3 / day, possibly 1000 ci/m3 level, 100g/day?
- driving turbine
Solid Waste Detritiation :
- 1 ton / day, possibly g / piece?
- materials (lithium, berylium, Steel) recycle
- needed both for resource and waste aspects.
Tritium confinement
Institute of Advanced Energy, Kyoto University
TRITIUM IS CONFINED WITHIN
ENCLOSURES AND
DETRITIATION SYSTEMS
Power train will be driven with
tritium containing medium.
High temperature blanket will
require improved permeation
control.
BUILDING
D ETR ITIA TIO N
S YS TEM
VACUUM
VESSEL
Cryostat
D ETR ITIA TIO N
S YS TEM
H X TUR B IN E
Expansion pool
Pressurized gas may require
additional expansion volume.
For gas driven system,
large Expanson volume
FUEL LOOP may be needed.
Expansion pool
Emission
from Fusion
and
Dose
Institute of Advanced
Energy, Kyoto
University
Impact pathway of tritium suggests ingestion will be dominant.
Findings
Institute of Advanced Energy, Kyoto University
-Fusion plant detritiation will be dominated by power
plant configuration.
- Normal tritium release will be controlled actively.
- Off-normal spill can be recovered with normal detritiation.
- High temperature plant will require improved tritium system.
-Measurable tritium will be released in airborne form.
-Tritium accumulates in environment (far smaller natural BG).
-Ingestion dose will be dominant.
-For long run, C-14 may be a concern.
Conclusion
Institute of Advanced Energy, Kyoto University
Fusion development is in the phase to study market
・Fusion must find customers and meet their requests.
・Fusion must satisfy environmental and social issues.
Development of advanced blanket is a key issue for fusion
・Economy - not just temperature, but to maximize market
・Environment - not just low activation, but best total cost
and social value / least risk(Externality)
Development strategy (road map) for blanket is needed.
・ITER and DEMO require 2 or more generations of blankets.
・staged improvement of blanket is planned with water-PB,
and LiPb dual coolant concepts.
Conclusion 2
Institute of Advanced Energy, Kyoto University
Possible blanket improvement
・Independent from large increment of plasma
・Continuous improvement
can be reflected in blanket
change.
(Improvement in DEMO phase)
・Multiple paths to meet
various needs are possible.
・Flexibility in development of
entire fusion program is
provided by blanket
development.
Fast Track