Transcript Slide 1

FNST Issues, Development, and Role of
Next Step Fusion Nuclear Facility FNF
(VNS/CTF/FDF, etc.) and ITER TBM
Mohamed Abdou
Presented at FNST Meeting, UCLA August 12-14, 2008
1
FNST Issues, Development, and Role of
Next Step Fusion Nuclear Facility FNF
(VNS/CTF/FDF, etc.) and ITER TBM
Outline
1. What is Fusion Nuclear Technology?
2.
Brief Statement of Technical Issues and Role of Non-Fusion and Fusion
Testing Facilities
3.
Framework for FNT Development and Requirements
-
4.
Top Level Issues for FNT Development Facilities
-
5.
What is FNF (CTF/VNS), Why needed, main features required
Tritium Consumption and Supply and implications
Reliability / Maintainability / Availability (and Reliability Growth Strategy)
Complementary Roles of ITER TBM and FNF
-
6.
Stages
Parameters
Time, cost, schedule
International collaboration
Selected US Concepts and input to FNF design and testing strategy
2
Fusion Nuclear Technology (FNT)
Fusion Power & Fuel Cycle Technology
FNT Components from the edge of the
Plasma to TF Coils (Reactor “Core”)
1. Blanket Components (includ. FW)
2. Plasma Interactive and High Heat Flux
Components
a. divertor, limiter
b. rf antennas, launchers, wave guides, etc.
3. Vacuum Vessel & Shield Components
Other Systems / Components affected
by the Nuclear Environment
4. Tritium Processing Systems
5. Instrumentation and Control Systems
6. Remote Maintenance Components
7. Heat Transport and Power Conversion
Systems
3
Notes on FNT/FNST:
• The fusion nuclear field involves many
scientific issues and technical
disciplines as well as engineering and
component development- hence it is
often called Fusion Nuclear Science
and Technology (FNST)
• The first wall is an integral part of the
blanket. The term “Blanket” implicitly
includes the first wall.
• The Vacuum Vessel is outside the
Blanket/Shield in a low-radiation field.
• The Key Issues are for Blanket /
PFC: Highest heat and radiation
fluxes
• The location of the Blanket inside
the vacuum vessel is necessary
but has major consequences:
a- many failures (e.g. coolant leak)
require immediate shutdown
b- repair/replacement take long time
4
R&D Tasks to be Accomplished Prior to Demo
1) Plasma
- Confinement/Burn
- Disruption Control
2) Plasma Support Systems
- Superconducting Magnets
- Current Drive/Steady State
- Edge Control
- Fueling
- Heating
- Diagnostics
3) Fusion Nuclear Technology Components and Materials
[Blanket (including First Wall), Divertors, rf Launchers]
- Materials combination selection and configuration optimization
- Performance verification and concept validation
- Tritium self sufficiency in practical system
- Failure modes and effects
- Remote maintenance
- Reliability growth
- Component lifetime
4) Systems Integration
Where Will These Tasks be Done?!
• Burning Plasma Facility (ITER) and other plasma devices will address 1, 2, & much of 4
• How and Where Will Fusion Nuclear Technology (FNT) be developed?
(ITER alone?, another device?, both?)
5
Numerous technical studies were performed over the past 30
years in the US and worldwide to study issues, experiments,
facilities, and pathways for FNST development
 This is probably the most studied subject in fusion development
 This is an area where the US has played a major leadership role in the world program
and provided major contributions such as engineering scaling laws for testing,
VNS/CTF/FNF concept, and blanket designs
 These studies involved many organizations (Universities, National Labs, Industry, and
Utilities) and many scientists, engineers, and plasma physicists. Industry participation
was particularly very strong from Fission and Aerospace and they provided
substantial contributions.
 Examples of Major Studies on FNST/Blanket
– Blanket Comparison and Selection Study (1982-84, led by ANL)
– FINESSE Study (1983-86, led by UCLA)
– IEA Study on VNS/CTF (1994-96 US, EU, J, RF)
– ITER TBM (1987-present), US ITER TBM Planning and Costing(2003-2007)
 Other studies that provided important input: DEMO Study (led by ANL 1981-1983)
and many Power Plant Studies (UWMAKs, STARFIRE, ARIES, others in EU,J,RF)
 Many Planning activities discussed FNT and provided input (TPA, FESAC, etc)
These studies resulted in important conclusions and
illuminated the pathways for FNST and fusion development
6
Summary of Critical R&D Issues for
Fusion Nuclear Science and Technology (FNST)
1.
D-T fuel cycle tritium self-sufficiency in a practical system
depends on many physics and engineering parameters / details: e.g. fractional burn-up
in plasma, tritium inventories, FW thickness, penetrations, passive coils, doubling time
2. Tritium extraction and inventory in the solid/liquid breeders
under actual operating conditions
3. Thermomechanical loadings and (MHD) Thermofluid response of
blanket and PFC components under normal and off-normal operation
4. Materials interactions and compatibility
5. Identification and characterization of failure modes, effects, and
rates in blankets and PFC’s
6. Engineering feasibility and reliability of electric (MHD) insulators
and tritium permeation barriers under thermal / mechanical /
electrical / magnetic / nuclear loadings with high temperature and
stress gradients
7. Tritium permeation, control and inventory in blanket and PFC
8. Remote maintenance with acceptable machine shutdown time.
9. Lifetime of blanket, PFC, and other FNT components
7
International studies on FNST have concluded:
- Testing in non-fusion facilities is necessary prior to
testing in fusion facilities.
Non-fusion facilities can and should be used to narrow material and design concept
options and to reduce the costs and risks of the more costly and complex tests in the
fusion environment. Extensive R&D programs on non-fusion facilities should start now.
~10-15 years of R&D, design, analysis, and mockup testing are required to
qualify blanket test modules for testing in any nuclear fusion facility
- However, non-fusion facilities cannot fully resolve any of the critical
issues for blankets
There are critical issues for which no significant information can be obtained from
testing in non-fusion facilities (An example is identification and characterization of failure
modes, effects and rates). Even some key separate effects in the blanket can not be
produced in non-fusion facilities (e.g. volumetric heating with blanket-typical gradients)
- Extensive Testing in Fusion Facilities is necessary prior
to DEMO.
Even the “Feasibility” of Blanket Concepts can NOT be established
prior to testing in fusion facilities
8
Types of experiments, facilities and modeling for FNT
Theory/Modeling
Basic
Separate
Effects
Property
Measurement
Multiple
Interactions
Design Codes
Partially
Integrated
Phenomena Exploration
Integrated
Component
•Fusion Env. Exploration Design
Verification &
•Concept Screening
•Performance Verification Reliability Data
Non-Fusion Facilities
(non neutron test stands,
fission reactors and accelerator-based
neutron sources)
Testing in Fusion Facilities
• Non fusion facilities (e.g. non-neutron test stands, fission reactors and neutron
sources) are essential and have important roles
• Testing in Fusion Facilities is NECESSARY for multiple interactions, partially
integrated, integrated, and component tests
9
Stages of FNST Testing in Fusion Facilities
Fusion “Break-in” &
Scientific Exploration
Engineering Feasibility
& Performance
Verification
Component Engineering
Development &
Reliability Growth
Stage I
Stage II
Stage III
0.1 – 0.3 MW-y/m2
1 - 3 MW-y/m2
> 4 - 6 MW-y/m2
1-2 MW/m2
steady state or long pulse
COT ~ 1-2 weeks
1-2 MW/m2
steady state or long burn
COT ~ 1-2 weeks
 0.5 MW/m2, burn > 200 s
Sub-Modules/Modules
• Initial exploration of coupled
phenomena in a fusion environment
• Uncover unexpected synergistic effects,
Calibrate non-fusion tests
• Impact of rapid property changes in
early life
• Integrated environmental data for
model improvement and simulation
benchmarking
• Develop experimental techniques and
test instrumentation
• Screen and narrow the many material
combinations, design choices, and
blanket design concepts
Modules
• Uncover unexpected synergistic
effects coupled to radiation
interactions in materials, interfaces,
and configurations
• Verify performance beyond beginning
of life and until changes in properties
become small (changes are substantial
2
up to ~ 1-2 MW · y/m )
• Initial data on failure modes & effects
• Establish engineering feasibility of
blankets (satisfy basic functions &
performance, up to 10 to 20 % of
lifetime)
• Select 2 or 3 concepts for further
development
D
E
M
O
Modules/Sectors
• Identify lifetime limiting failure modes
and effects based on full environment
coupled interactions
• Failure rate data: Develop a data base
sufficient to predict mean-timebetween-failure with confidence
• Iterative design / test / fail / analyze /
improve programs aimed at reliability
growth and safety
• Obtain data to predict mean-time-toreplace (MTTR) for both planned
outage and random failure
• Develop a database to predict overall
availability of FNT components in
DEMO
10
FNST Requirements for Major Parameters for Testing in Fusion Facilities with
Emphasis on Testing Needs to Construct DEMO Blanket
- These requirements have been extensively studied over the past 20 years, and they have been agreed to internationally
(FINESSE, ITER Testing Blanket Working Group, IEA-VNS, etc.)
- Many Journal Papers published (>35), e.g. IEA-VNS Study Paper (Fusion Technology, Vol. 29, Jan 1996)
Parameter
a
Neutron wall load (MW/m2)
Plasma mode of operation
Minimum COT (periods with 100% availability) (weeks)
Neutron fluence at test module (MW·y/m2)
Stage IC: initial fusion break-in (less demanding requirements than II & III)
Stage II: concept performance verification (engineering feasibility)
d
Stage III : component engineering development and reliability growth
Total “cumulative” neutron fluence experience (MW·y/m2)
Total test area (m2)
Total test volume (m3)
Magnetic field strength (T)
Value
1 to 2
b
Steady State
1 to 2
~0.1- 0.3
1 to 3
d
4 to 6
>6
>10
>5
>4
a - Prototypical surface heat flux (exposure of first wall to plasma is critical)
b - For stages II & III. If steady state is unattainable, the alternative is long plasma burn with plasma duty cycle >80%
c - Initial fusion break-in has less demanding requirements than stages II & III
d - Note that the fluence is not an accumulated fluence on “the same test article”; rather it is derived from testing “time”
on “successive” test articles dictated by “reliability growth” requirements
11
Critical Factors in Deciding where to do
Blanket / FNT Fusion Testing and that have Major
Impact on FNT (and Fusion) Development Pathway
1. Tritium Consumption / Supply Issue
2. Reliability / Maintainability / Availability Issue
3. Cost, Risk, Schedule
The idea of a Fusion Nuclear Facility, FNF (also called VNS, CTF, etc)
dedicated to FNST testing was born out of the analyses of these
critical factors
12
What is FNF (CTF/VNS)?
• The idea of FNF (also called VNS, CTF) is to build a
small size, low fusion power DT plasma-based device in
which Fusion Nuclear Science and Technology (FNST)
experiments can be performed in the relevant fusion
environment: 1- at the smallest possible scale, cost, and
risk, and 2- with practical strategy for solving the tritium
consumption and supply issues for FNST development.
- In MFE: small-size, low fusion power can be obtained in a low-Q (driven)
plasma device.
- Equivalent in IFE: reduced target yield (and smaller chamber radius?)
• This is a faster, much less expensive approach than
testing in a large, ignited/high Q plasma device for which
tritium consumption, and cost of operating to high fluence
are very high (unaffordable!, not practical).
13
FNF (CTF/VNS) MISSION
The mission of FNF is to test, develop, and qualify Fusion Nuclear
Components (fusion power and fuel cycle technologies) in
prototypical fusion power conditions.
The FNF facility will provide the necessary integrated testing environment of high
neutron and surface fluxes, steady state plasma (or long pulse with short dwell
time), electromagnetic fields, large test area and volume, and high “cumulative"
neutron fluence.
The testing program on FNF and the FNF device operation will
demonstrate the engineering feasibility, provide data on reliability /
maintainability / availability, and enable a “reliability growth”
development program sufficient to design, construct, and operate
blankets, plasma facing and other FNST components for DEMO.
FNF will solve the serious tritium supply problem for fusion
development by a- not consuming large amounts of tritium, bbreeding much of its own tritium, c- accumulating excess
tritium (in later years) sufficient to provide the tritium inventory
required for startup of DEMO, and d- developing the blanket
technology necessary to ensure DEMO tritium self sufficiency 14
The issue of external tritium supply is serious and has major
implications on FNST (and Fusion) Development Pathway
Production & Cost:
CANDU Reactors: 27 kg from over 40 years,
$30M/kg (current)
Fission reactors: 2–3 kg/year
$84M-$130M/kg (per DOE Inspector General*)
*www.ig.energy.gov/documents/CalendarYear2003/ig-0632.pdf
 A Successful ITER will exhaust most
of the world supply of tritium, but
5-10 kg will be needed to start one DEMO
(one DEMO? Other countries will compete for tritium!)
 Any future long pulse burning plasma device
will need tritium breeding technology
 The availability and cost of external tritium
supply is a serious issue for FNST
development
 FNST engineering development and
reliability growth stages must be done in a
small fusion power device to minimize
tritium consumption (only stage I fusion
break-in can be done in ITER)
Projected Ontario (OPG) Tritium Inventory (kg)
Tritium Consumption in Fusion is HUGE! Unprecedented!
55.6 kg per 1000 MW fusion power per year
30
Tritium decays at
5.47% per year
CANDU
Supply
w/o Fusion
25
20
15
10
1000 MW Fusion
10% Avail,
TBR 0.0
5
ITER-FEAT
(2004 start)
See Table S/Z
0
1995 2000 2005
2010 2015 2020 2025 2030 2035 2040 2045
Year
Tritium Breeding Blankets must be developed in
the near term to solve the serious issue of
external tritium supply We cannot wait very long
for blanket development
15
Updated projections of Canadian + Korean tritium supply
and consumption using ITER current schedule
Canadian + Korean Inventory
without supply to fusion
Canadian + Korean
Inventory with ITER
(From Scott Willms [March 2007]). Notes & assumptions given on a separate slide.
16
Tritium Breeding Requirements for FNF
•
•
•
•
•
•
Available External Supply after ITER use is very limited (and very expensive)
FNF has to breed tritium to:
a- supply most or all of its consumption
b- accumulate excess tritium (in later years) sufficient to provide the tritium
inventory required for startup of DEMO
The required TBR in FNF depends on:
– FNF fusion power
– start date of FNF
– start date of ITER and whether ITER extended phase (second 10 yrs) will be
approved
Assuming that the entire tritium inventory from Canada and Korea not used by ITER
is available for use in FNF, the required TBR in FNF is:
– to supply its consumption: TBR < 1 (and increases with FNF fusion power)
– to supply consumption plus DEMO startup inventory: TBR > 1 (and is higher for
smaller power for DEMO inventory >> 5Kg)
A scenario for FNF in which TBR is low initially (when availability is low) and higher
in later years (when availability is ~30%) is worth considering
See M. Sawan Presentation for detailed results
17
Reliability / Availability / Maintainability (RAM)
• RAM, particularly for nuclear components, is one of the most challenging
issues for DEMO and Power Plants.
• A primary goal of FNF is to solve the RAM issue by providing for
“reliability growth” testing and maintenance experience
• But achieving a reasonable Availability in the FNF device is by itself a
challenge
•
RAM has a MAJOR impact on :
– Defining the FNST Testing Requirements to achieve given goals for DEMO.
This directly defines FNF major parameters e.g. Fluence, number of test
modules , test area, availability, and testing strategy in FNF
– Design and Development of FNF to achieve its availability goals
•
RAM is a complex topic for which the fusion field does not have an R&D program
or dedicated experts. A number of fusion engineers tried over the past 3 decades
to study it and derive important guidelines for FNST and Fusion development
18
Device Availability is reduced by two types of outages
Scheduled Outage: (This you design for)
Planned outage (e.g. scheduled maintenance of components, scheduled
replacement of components, e.g. first wall at the end of life, etc.).
This tends to be manageable because you can plan scheduled maintenance /
replacement operations to occur simultaneously in the same time period.
Unscheduled Outage: (Can kill your DEMO and your future)
Failures do occur in any engineering system. Since they are random they are
much worse than scheduled outages and tend to have the most serious impact
on availability.
This is why “reliability/availability analysis,” reliability testing, and
“reliability growth” programs are key elements in any engineering
development.
19
Some RAM terminology
Device Availability or Device Duty Factor= AS x AU
AS = Availability Due to Scheduled Outage
Au = Availability Due to Unscheduled Events
1
i represents a component
1   Out age Risk
i
(Outage Risk) i = (failure rate) i • (mean time to repair) i=
Au =
MT T Ri
MT BFi
MTBF = mean time between failures = 1/failure rate
MTTR = mean time to repair
Burn time
Plasma Duty Factor =
(Burn time Dwell time)
(Plasma duty factor = 1 for steady state operation)
Fluence (integrated neutron wall load) = Neutron wall load x Calendar years x
(Device Duty Factor x Plasma Duty Factor)
20
Availability (Due to Unscheduled Events)
1
i represents a component
Availability: =
1   Out age Risk
i
(Outage Risk) i = (failure rate) i • (mean time to repair) i=
MT T Ri
MT BFi
MTBF = mean time between failures = 1/failure rate
MTTR = mean time to repair
• A Practical Engineering System must have:
1. Long MTBF: have sufficient reliability
- MTBF depends on reliability of components.
One can estimate what MTBF is NEEDED from “availability allocation
models” for a given availability goal and for given (assumed) MTTR.
But predicting what MTBF is ACHIEVEABLE requires real data
from integrated tests in the fusion environment.
2. Short MTTR: be able to recover from failure in a short time
- MTTR depends on the complexity and characteristics of the system (e.g.
confinement configurations, component blanket design and configuration,
nature of failure). Can estimate, but need to demonstrate MTTR in fusion
test facility.
21
DEMO Availability of 50% Requires Blanket Availability ~88%
(Table based on information from J. Sheffield’s memo to the Dev Path Panel)
Fraction of
Outage Risk Component
Component Num Failure
MTBF in MTTR MTTR
ber
rate in
for
for Minor failures that
Availability
years
-1
hr
16
5 x10-6
23
Major
failure,
hr
104
8
5 x10-6
23
5x103
240
0.1
0.025
0.97
4
1 x10-4
1.14
72
10
0.1
0.007
0.99
2
100
32
4
1
1
2 x10-4
1 x10-5
2 x10-5
2 x10-4
3 x10-5
1 x10-4
0.57
11.4
5.7
0.57
3.8
1.14
300
800
500
500
72
180
24
100
200
20
-24
0.1
0.05
0.1
0.3
1.0
0.1
0.022
0.135
0.147
0.131
0.002
0.005
0.978
0.881
0.871
0.884
0.998
0.995
3
5 x10-5
72
6
0.1
2.28
Conventional equipment- instrumentation, cooling, turbines, electrical plant ---
0.002
0.05
0.624
0.998
0.952
0.615
Toroidal
Coils
Poloidal
Coils
Magnet
supplies
Cryogenics
Blanket
Divertor
Htg/CD
Fueling
Tritium
System
Vacuum
TOTAL SYSTEM
failure, hr are Major
240
0.1
0.098
0.91
Assuming 0.2 as a fraction of year scheduled for regular maintenance.
Demo Availability = 0.8* [1/(1+0.624)] = 0.49 (Blanket Availability must be .88
and blanket MTBF must be > 11 years!)
22
800
ed
(R
)
600
5
400
200
0
Expected
0
1
2
C
A
0
3
MTBF per Blanket Segment(FPY)
10
N
ee
d
MTBF per Blanket System(FPY)
Current confinement concepts have long blanket MTTR > 1 month because of a- complex
configuration, and b- the blanket is INSIDE the vacuum vessel. (compared to replacement
time of ~ 2 days of fuel in fission reactors) This leads to reliability requirements on the
Blanket/FW that are most challenging. These must be seriously addressed as an integral
part of the R&D pathway to DEMO. It is one of the key DRIVERS for FNF/CTF/VNS.
MTTR (Months)
A = Expected with extensive R&D (based on mature technology and no fusion-specific failure modes)
C = Potential improvements with aggressive R&D
23
“Reliability Growth”
Upper statistical confidence level as a function of test time in
multiples of MTBF for time terminated reliability tests (Poisson
distribution). Results are given for different numbers of failures.
1.0
Number of F ailures 0
Confidence Level
0.8
Example,
TYPICAL
TEST
SCENARIO
1
To get 80% confidence
in achieving a particular
value for MTBF, the
total test time needed
is about 3 MTBF (for
case with only one
failure occurring during
the test).
2
0.6
3
0.4
4
0.2
0.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
T est T im e in Multiplies of Mean-T ime-Between-F ailure (MT BF )
Reference: M. Abdou et. al., "FINESSE: A Study of the Issues, Experiments and Facilities for Fusion Nuclear
Technology Research & Development, Chapter 15 (Figure 15.2-2.) Reliability Development Testing Impact on Fusion
Reactor Availability", Interim Report, Vol. IV, PPG-821, UCLA,1984. It originated from A. Coppola, "Bayesian
Reliability Tests are Practical", RADC-TR-81-106, July 1981.
24
Obtainable Blanket System Availability (%)
Obtainable Blanket System Availability with 50%
Confidence for Different Testing Fluences and Test Areas
MTTR = 1 month
1 failure during the test
80 blanket modules in
blanket system
70
60
6 MW.yr/m2
Experience factor =0.8
3 MW.yr/m2
50
Test area per test
article =0.5 m2
40
30
1 MW.yr/m2
20
10
0
Neutron wall load = 2 MW/m2
0
2
4
6
Test Area (m2)
8
10
Level of Confidence based on Figure 15-2.2 in "FINESSE: A Study of the Issues, experiments and Facilities for Fusion Nuclear Technology Research &
Development, Chapter 15 Reliability Development Testing Impact on Fusion Reactor Availability", Interim report, Vol. IV, PPG-821, UCLA, 1984.
Reliability Growth Testing Requires:
1- “Cumulative” testing fluence of > 6 MW∙y/m2
2- Number of test modules per concept ~ 10-20
25
How Many Modules/Submodules Need to Be Tested For Any
Given One Blanket Concept?
Never assume one module. Engineering science for testing shows the need to account for:
1. Engineering Scaling
2. Statistics
3. Variations required to test operational limits and design/configuration/material options
---------------------------------------------------------------------------------------------------------------US detailed analysis indicates that a prudent medium risk approach is to test the
following test articles for any given One Blanket Concept:
- One Look-Alike Test Module
- Two Act-Alike Test Modules
(Engineering Scaling laws show that at least two modules are required, with each
module simulating a group of phenomena)
- Four supporting submodules (two supporting submodules for each act-alike module
to help understand/analyze test results)
- Two variation submodules (material/configuration/design variations & operation limits)
These requirements are based on “functional” and engineering scaling
requirements. There are other more demanding requirements for “Reliability
26
Growth” as discussed earlier (10-20 modules per concept)
Complementary Roles for ITER TBM and FNF lead to optimal FNST pathway
Role of FNF (CTF/VNS)
Role of ITER TBM
Component Engineering
Development &
Reliability Growth
Fusion “Break-in” &
Scientific Exploration
Engineering Feasibility
& Performance
Verification
Stage I
Stage II
Stage III
1 - 3 MW-y/m2
> 4 - 6 MW-y/m2
1-2 MW/m2,
steady state or long pulse
COT ~ 1-2 weeks
1-2 MW/m2,
steady state or long burn
COT ~ 1-2 weeks
0.1 – 0.3 MW-y/m2
 0.5
MW/m2,
burn > 200 s
Sub-Modules/Modules
• Initial exploration of coupled
phenomena in a fusion environment
• Uncover unexpected synergistic effects,
Calibrate non-fusion tests
• Impact of rapid property changes in
early life
• Integrated environmental data for
model improvement and simulation
benchmarking
• Develop experimental techniques and
test instrumentation
• Screen and narrow the many material
combinations, design choices, and
blanket design concepts
Modules
• Uncover unexpected synergistic
effects coupled to radiation
interactions in materials, interfaces,
and configurations
• Verify performance beyond beginning
of life and until changes in properties
become small (changes are substantial
2
up to ~ 1-2 MW · y/m )
• Initial data on failure modes & effects
• Establish engineering feasibility of
blankets (satisfy basic functions &
performance, up to 10 to 20 % of
lifetime)
• Select 2 or 3 concepts for further
development
D
E
M
O
Modules/Sectors
• Identify lifetime limiting failure modes
and effects based on full environment
coupled interactions
• Failure rate data: Develop a data base
sufficient to predict mean-timebetween-failure with confidence
• Iterative design / test / fail / analyze /
improve programs aimed at reliability
growth and safety
• Obtain data to predict mean-time-toreplace (MTTR) for both planned
outage and random failure
• Develop a database to predict overall
availability of FNT components in
DEMO
27
Analysis of benefits, costs, risks, and schedule shows that
TBM testing in ITER, combined with FNF, clearly provides
the best approach for FNT development for DEMO
• Best Approach to FNT Development:
• Role of ITER TBM: Perform Stage I
– Fusion Break-in and scientific exploration and initial blanket concept
screening
• Role of FNF: Perform Stages II and III
– Stage II: Engineering Feasibility and Performance Verification
– Stage III: Component Engineering Development and Reliability Growth
28
TBM Tests in any fusion facility need a whole TBM System
(TBM + “Ancillary Equipment”)
For example: PbLi loop with heat exchanger, tritium extraction system, He-coolant
circuits with pumps and heat exchangers, etc.
For FNF / CTF such Ancillary Equipment will also be needed for each
module of base breeding blanket and for each test module
TBM Port
Frame
He pipes to
TCWS
PbLi
loop
VV Port
Extension
TBM
Bioshield
Transporter
29

US Selected Concepts and Strategy
In 2003 an extensive effort by the US community was devoted to selection of
reference US Blanket Concept(s).
Two concepts, the Dual-Coolant Lead-Lithium (DCLL) and the HeliumCooled Ceramic Breeder (HCCB) have been selected.
Key Reasons for Selection of the TWO Concepts:




DCLL provides pathway toward high temperature, high performance blankets
using ferritic steel structure
HCCB is modest performance, but less feasibility issues and is of interest to
all world programs
The US plays a lead role for DCLL and supporting role for HCCB in the world
program
Two different classes of blanket concepts that have substantially different
feasibility issues to avoid the situation where a fatal flaw may eliminate the
only concept.
The selected two concepts (DCCL and HCCB) are the
REFERENCE concepts for the US program. So, these are the
concepts to consider for testing on ITER TBM and FNF/CTF TBM.
30
Highlights of the two US Reference Blanket concepts
• The Dual-Coolant PbLi Liquid
Breeder Blanket (DCLL)
concept with helium-cooled
structure and self-cooled PbLi
breeding zone with flow
channel inserts (FCIs) as
MHD and thermal insulator.
– “Pathway” to higher outlet
temperature/higher thermal
efficiency while using ferritic
steel.
• The Helium-Cooled Ceramic
Breeder Blanket (HCCB)
concept with ferritic steel
structure and beryllium
neutron multiplier
– Likely near term breeding
blanket - all parties interested
DCCL Module
Poloidal flow
PbLi channel
Purge gas pipe
He-cooled
RAFS FW
HCCB Module
SiC FCIs
Ceramic
breeder
pebbles
 Helium (~8 MPa) coolant
operating (350C-500C)
 Low pressure (0.1-0.2
MPa) helium/H2 purge
gas to extract tritium
He-cooled
RAFS FW
Be
Pebbles
31
Blanket Concepts Proposed by 7 Parties for ITER Testing
Concept
Acronym
Materials
Proposing Party
HCCB




RAFS Structure
Be multiplier
Ceramic breeder (Li2TiO3, Li4SiO4, Li2O)
Helium coolant and purge
Water-Cooled
Ceramic Breeder
WCCB



RAFS structure
Be multiplier, Ceramic breeder (Li2TiO3, Li2O)
Water coolant, He purge
Helium-Cooled
Lead-Lithium
HCLL



RAFS structure
Molten Pb-17Li breeder/multiplier
Helium coolant
DCLL




RAFS structure
SiC flow channel inserts
Molten Pb-17Li breeder/coolant/multiplier
Helium coolant
HCML



RAFS structure
Lithium breeder
Helium coolant
KO
Li/V



Vanadium alloy structure
Insulator barrier (e.g., AlN)
Lithium breeder/coolant
RF
LLCB



RAFS structure, PbLi multiplier/breeder/coolant
Dual Helium Coolant
Dual Ceramic Breeder
IN
Helium-Cooled
Ceramic Breeder
Dual-Coolant
Lead-Lithium
Helium-Cooled
Molten Lithium
Self-Cooled
Lithium
Lead-Lithium
Ceramic Breeder
EU, KO, CN
(JA,US, RF, IN)*
*Supporting/Submodule
Role
JA
EU, CN
US, CN
(EU, JA, IN)*
*Supporting Role
- Proposed 12 designs for TBM’s representing 7 classes of concepts
- But there is much common R&D (e.g. for ferritic steel, ceramic breeder, PbLi)
among the concepts
32
Conclusions
Conclusions will be given AFTER Discussion
33
Discussion Topics

Discussion on Base Blanket for FNF:
•
•
•

What are the options for a base breeding blanket (structural materials, coolants,
breeding materials, etc.)?
Are there good reasons for using a non-breeding base blanket rather than a
breeding base blanket?
Is there a base breeding blanket option for which there will be more
data/experience/confidence than those for the primary blanket concepts for the
test modules?
Discussion on Divertor Options for FNF:
•
•
•
What are the expected heat and particle loads on FNF divertor, and how do they
compare to ITER?
What are the preferred material and coolant options?
What database/experience is required?
34
Discussion Topics (cont.)

Discussion on Reliability/Maintainability/Availability in FNF:
•
•
•
•

Discussion on testing strategies on FNF:
•
•
•
•
•

What availability goals are required for FNF? What are the corresponding MTBF and
MTTR for various components and for base blanket?
What are the requirements on periods of continuous operations (test campaigns)? What
are the requirements on the plasma duty cycle during these test campaigns?
What is the minimum achievable plasma dwell time? Maximum burn time during a
pulse? Maximum plasma duty cycle?
What is needed to realize the above goals for the device availability factor and plasma
duty factor?
What are the preferred blankets options for testing on FNF and what are the
implications for R&D?
Comparison of strategies for testing space allocation on FNF:
• a) all or most outboard occupied by test modules/test sectors
• b) base blanket with test modules in test ports (ITER type)
Number of blanket concepts to be tested in FNF in 2 cases:
• a) Assuming ITER TBM is carried out
• b) With no US ITER TBM
R&D required to place a test module on FNF (how does it compare to ITER TBM?)
R&D required for base blanket
Discussion on Mapping into Greenwald Gaps for FNST
35