Helium Cooled Ceramic Breeder (HCCB) Blanket
Concept: Design and Test Plan
Presented by
Alice Ying
1. US HCCB efforts
With contributions to Phase 1 activities
M. Abdou, P. Calderoni, S. Reyes, R. Kurtz, S. Sharafat,
S. Willms, M. Youssef
A. Abou-Sena, Z. An, E. Kim, G. Wen
2. Working SubGroup-1 (WSG-1) TBWG presentations
WSG-1 is led by L.V. Boccaccini (FZK)
TBM Costing Kickoff Meeting
INL, August 10-12, 2005
1
Deliver TBM to ITER (in 2012) on Day-one
(office of science strategic plan)
Top Level Objectives of the Test Program
1) First integrated experimental demonstration of the
2)
3)
principles of tritium self-sufficiency
Breeding technology for producing the tritium necessary for
extended operation of ITER
Critical experimental data on the feasibility, constraints,
and potential of the DT cycle for fusion systems
(including conducting shells, passive coils, coatings/thick armors/FW
for improving plasma physics performance)
Specifics
i)
validation of TBM structural integrity theoretical predictions under
combined and relevant thermal, mechanical and electromagnetic
loads,
ii)
validation of Tritium breeding predictions,
iii) validation of Tritium recovery process efficiency and T-inventories in
blanket materials,
iv) validation of thermal predictions for strongly heterogeneous
breeding blanket concepts with volumetric heat sources, and
v) demonstration of the integral performance of the blankets systems.
2
All ITER Parties have selected HCCB concept as
one of their TBM/DEMO options
Most likely, a low temperature WCCB (water-cooled CB) blanket will be
the breeding blanket option during the 2nd phase of ITER operations if insitu tritium productions become necessary and desired
The main features of the proposed HCCB blankets are very
similar …
1.
2.
3.
4.
5.
Helium as coolant at a pressure of ~8 MPa and temperatures in the
range 300°C- 500°C.
Use of a ferritic/ferritic-martensitic steel as structural material. Its
design limit of about 550°C dictates the max temperature of
helium.
Use of the ceramic breeder in the form of a pebble bed including
single sized or binary pebble beds of Li ceramics such as Li4SiO4 or
Li2TiO3 (Li2O).
Use of Be as multiplier in the form of a pebble bed (single sized or
binary) or as a solid porous body.
Breeder material and Be are purged by a low pressure (0.1-0.2
MPa) flow of helium that extracts the T produced.
3
--- but 6 different concepts are under investigation,
characterized by different configurations
• BOT (Breeder Out of Tubes) or BIT (Breeder in Tubes)
concepts
among the BOT concepts:
– different kind of pebble bed configuration (parallel,
perpendicular to the FW),
– different bed typology (single sized or binary),
– different materials: use of graphite reflector to reduce
the amount of Be or use of Be in a porous solid form.
• Particular design requirements: use of the structural box
to withstand the full helium pressure or use of vertical
segmentations to reduce EM forces.
4
Box structure to withstand high pressure He
during accidents
BOT/pebble bed perpendicular to the FW
5
Moreover, the testing strategies vary according to
Parties’ views on DEMO’s development:
• EU proposes a strategy oriented to a “fast track” approach assuming
that ITER is the unique step to the DEMO reactor. In this strategy, the
ITER tests have a particular meaning: they have to provide as much
information as possible on the behavior of the selected system, and for
this reason, any technical expedient is adopted in order to reduce the
extrapolation gap between ITER and DEMO.
 The consequence of this strategy is the use of large TBMs (about 1 m2 of
surface exposed to the plasma) with relevant geometrical similitude and
the simulation of DEMO relevant values for the primary testing parameters.
• The US considers ITER an important fusion testing device for
performing initial fusion “break-in” tests, including calibration and
exploration of the fusion environment. Part of the fusion environment
exploration is the screening of a number of configurations. In addition,
the US believes a dedicated fusion component test facility is necessary
to reduce the high risk of initial DEMO operation.
 The US does not propose to test independently a specific configuration,
but rather to evaluate several options of blanket arrangement in cooperation with other parties.
• The other strategies proposed by the Parties fall between these two
positions.
6
Space availability requires an international
coordinated testing program
• The number of independent TBMs that can be present in one port
simultaneously strictly depends on the space availability in the port
cell area, where spaces are necessary not only for TBM pipe
penetrations but also for remote handling tools, frame coolant pipes,
and auxiliary systems.
• It is further limited by space availability in the TCWS building,
Tritium building, and Hot Cell building.
Port Plug
Port Cell
The maximum external size of
the container is 2.62 m (W) x
6.5 m (L) x 3.68 m (H).
7
Schemes to arrive at a Coordinated Testing Program
under discussion
1) An
aggressive, international co-operation with the objective
of having an international program of blanket development.
This is of course the most effective method, but also the most difficult
to implement. It requires a broader official agreement among the
involved IPs, with the goal of developing this line of blanket components
up to the DEMO reactor.
2) Partial international agreements for co-operation especially
during the first couple of years of ITER operations. The
objective can be to design common TBM objects to produce data that
can be used for the development of later independent TBMs or DEMO
blanket concepts. Some proposals in this direction have been already
presented.
3) Time sharing of a testing place, allowing the IPs to test their
own concepts independently. This strategy allow the testing of
more concepts, but has the consequence of reducing the testing time
available for each IP.
A common effort is in any case necessary to develop and operate part of 8
the fixed equipment like the HCS or common standardized interfaces.
Testing strategy calls for different issues to be
addressed in alignment with ITER operational plan
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7
8
9
EM/S
First wall structural
response and transient
EM/ disruption tests
0.0
High Duty D-T
5
0.0
4
0.0
3
2
1
0.0
Low Duty D-T
DD-plasma
0.006
0.008
0.012
0.020
0.024
10
HH-plasma
0.024
(Passive methods on
tritium production rate,
energy spectrum)
NT
(local magnetic field, eddy
Neutronics and
current distribution,
tritium production
forces, and torques)
rate prediction tests
Look-Alike/ITER Optimized
Act-Alike/ITER Constraint
TM
Tritium release,
thermomechanical
interaction and
design evaluation tests
3 to 4 unit cell arrays
/submodules will be placed in
ITER over the first 10 years of
ITER testing
PI
Initial study of
irradiation
effects on
performance
9
Example coordinated testing program under discussion
• Each TBM is assumed to occupy half a port and can be replaced at most
once per year
• Modules with common helium feeds, but containing sub-modules of
different party’s design, or designed in co-operation with different parties,
are considered as examples for Locations 1 and 2, respectively.
• In Location 3, the example shown assumes that only home TBMs will be
tested (consequently, a full time sharing approach.)
This example assumes that three half ports are dedicated to this line of blanket
testing (two half-port positions in port A plus a half-port position in port C.)
10
We proposed two collaboration schemes to help to
achieve a coordinated testing program
Scheme No. 1: inserting
three “US” unit cells into the
EU HCPB structural box
Each unit cell size~ 0.2 x 0.2
x 0.4 m3
Scheme No. 2: Co-Design and
Fabrication of Submodule/module
TBM
In this scheme, the submodule would
have to be expanded to a module due
to a limited space for penetration 11
KO has expressed a similar interest in a
collaborative testing program in ITER
Test Plan of KO HCSB submodule and TBM
Test
Description
Modules
Electro Installation for day one operation
Magnetic
 Size : to be determined through discussion with host TBM
Sub-module  Utilizing HCS of host TBM
 Installation in D-D and D-T phase operation
Neutron
 Size : to be determined through discussion with host TBM
Tritium Sub Ancillary systems are to be shared with host TBM
module
 NMS & TMS
ThermoMechanical
TBM 1
 Installation in D-T phase operation
 Size : ½ port
 Ancillary systems are to be shared with other party
ThermoMechanical
TBM 2
 Installation in D-T phase operation (for the last 2 years)
 Size : ½ port
 Ancillary systems are to be shared with other party
12
JA has not yet explicitly expressed its role in the
collaborative testing program
• BOT/Layered configuration
• 3 sub-module structure for
internal pressure durability
and structure similarity with
DEMO blanket (slit
structure for electromagnetic force reduction).
JA Solid Breeder He Cooled TBM
1st breeder
1st multiplier
2nd breeder
• The concept is not practical
due to the numbers of
service pipes.
2nd multiplier
3rd breeder
3rd multiplier
Horizontal View
EBW at rear wall
3 x Large penetrations/pipes (up to ~100 mm OD)
1 x penetration for Instrumentation (up to ~80 mm OD)
7 x small penetrations (~35 mm OD)
13
China hopes to equally share space with other ITER parties
under TBWG framework, and expects to deliver a HCCB
TBM to ITER on day one.
Structural Material: EUROFER 97 Within WSG-1’s content, this
TBM program is illustrated as
664mm
Location 3 of the draft Table
630mm
890mm
9 (3 x 3)
Sub-modules
–0.260m in poloidal
–0.190m in toroidal
–0.420m in radial
14
Integration view of structure design
Straight BIT option
RF concepts emphasizing BIT
approach
1
2
Coil BIT option
7
6
Pebble bed + pellet option
3
Within WSG-1’s content, this
TBM program is illustrated as
Location 3 of the draft Table
4
3
4
1
2
1-beryllium briquette; 2-ceramic pebble-bed;
3-ceramic pellets; 4-gauze elements.
8
5
1-beryllium briquette; 2-cooling channel; 3ceramic breeder; 4-holes for attachment rods;
5-coolant inlet; 6-coolant outlet; 7-purge-gas
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outlet; 8-purge-gas inlet
Scheme 1: inserting three “US” unit cells into the EU HCPB structural box
Added complexity could be manageable:
Four pipes are added into the piping system to
provide separate cooling and purge gas lines to
the test units
Associated ancillary components to be arranged
in the port cell area
Cooling to each unit cell is done by unit cell array
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manifold
Neutronics Unit Cell Design Details
Providing a range of tritium production profiles for verifying
neutronics code calculation procedures
• To achieve a good spatial
resolution on local tritium
production rate
measurement
• To freeze tritium during
ITER testing
• Helium 8 MPa
• Tin: 100oC
• Tout: 300oC
Tritium measurements:
1. Pellet specimens are
used for local tritium
production rate
measurements
2. Run hot helium into the
breeding zones to
collect tritium (global)
17
during ITER dwell
Thermomechanics Unit Cell Design Details
Skelton View
DEMO act-alike design approach:
reproducing temperature
magnitude and gradient within the
blanket pebble bed regions
• Helium 8 MPa
• Tin: 350oC
• Tout: 500oC
• Total heat generation inside
the unit cell ~ 35.8 kW
• He-coolant flow rate: 0.046
kg/s per unit cell
18
A larger scale of participation is to co-design and
fabrication of a TBM module with other party(ies)
Can be one of the three submodules of the JA’s TBM
 Neutronics and tritium
production rate
prediction (NT) tests
• Low T operation during
ITER burn: He Tin/Tout:
100/300oC
• Low temperature
helium cools breeder
zone first before
cooling the first wall;
breeder zone < 350oC
The design combines layer and edge-on
configurations in one physical unit with its
own first wall structural box
Tritium measurements:
1. Pellet specimens are used for
local tritium production rate
measurements
2. Run hot helium into the breeding
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zones to collect tritium during
ITER dwell
Modification to a typical DEMO FW coolant routing scheme is
needed in designing the ITER TBM FW
Max Temp: 523 oC
h=5890
W/m2-K
• In general, ITER TBM is smaller
in size than a typical DEMO
module (short flow path, larger
flow area per M2 FW)
• Uncertain ITER surface flux
distribution
• Disproportional heat distribution
between surface heat and
neutron loads: By-pass flow is
considered to further increase
h=5890 W/m2-K
He velocity (for TM/PI Modules)
ITER FW heat flux at the midplane:
Nominal: 0.11 MW/m2
Peak: 0.5 MW/m2
Average: 0.3 MW/m2
5 coolant channels per flow
path connected in series
20
Engineering scaling rules are applied for TBM design in order
to achieve DEMO-like operating conditions under a reduced
neutron wall load (0.78 vs 2- 3 MW/m2)
Beryllium
zone
Predicted high stress zone (~20MPa)
occurs at the corner of the coolant plate
Breeder zone
MARC Model
von Mise’s stresses (focused
on beryllium PB region)
Elastic modulus (MPa)
EC B  314 x 0.75
Temperature profile
at 400 s
E B e  1772 x 0.83
Finite element based pebble bed
thermomechanics analysis
21
A “qualified” structural material
fabrication technology is also
needed for breeder zone coolant
plates in addition to FW box
Layer Design Configuration
Edge-on Design Configuration
(2 paths)
22
Purge-gas delivery and collection systems are
integrated into the bottom and upper end caps
Upper end cap
91 cm
Not only heat but
also tritium
produced inside the
breeder zone needs
to be brought out
[more structural
fabrication issues]
Purge gas flows
vertically and radially
through different
breeding zones to
remove tritium
Bottom end cap
23
There will be ancillary conditioning equipment and
measurement systems located in the port cell area
• A coordinated test program requires a standardization of the TBM/frame
interface and an integrated layout of the port cell equipments.
24
Summary
• An initial framework to achieve a coordinated testing program
for HCCB blanket TBMs has been established. This
includes:
– Cooperation in the design/manufacturing/testing of “common” TBMs.
– Use of sub-modules inside the testing program of another IP; this will
allow testing of different concepts in smaller test objects, but will
require strong cooperation among partners in the design of a common
supporting structure.
– Preparation of common tests that can be useful for different program;
design of common equipment and sharing of results
– Standardization of the TBM/frame interface
– Common use of the port cell equipment (integrated layout);
– Common use of one or more helium coolant systems.
• The US is expected to play a strong supporting role in the
ITER WSG-1 testing program through cost sharing of
common auxiliary systems and delivery of about one-third of
half-port size helium-cooled ceramic breeder unit
cells/submodule.
• Need “routes” to realize formal collaborative agreements
25
among the parties (Bilateral or multi-lateral).