Transcript Slide 1

Simplified schematic of
WDS
ISS
Looking up ISS column
ISS refrigerator, cold box
in vacuum jacket
ISS and WDS facilities at FZK
WDS
column
Water
reservoirs
R. Laesser, F4E ITER Department
4 July 2008
1
Purpose of Water
Detritiation System:
O2 gas processing:
To use the CECE
(Combined Electrolysis
• MS dryers
Catalytic Exchange)
for detritiation of water
• Wet strippers
(20 kg/h@10 Ci/kg) via
• cracking water into
hydrogen and oxygen,
Electrolyser
• stripping the residual
tritium from the
hydrogen before its
release.
The tritium is returned to
the FC via ISS.
Several potential sources
of tritiated water exist
in ITER. The largest
routine contributors to
the WDS feed streams
are the Atmosphere
and Vent Detritiation
Systems.
Emergency
tanks
R. Laesser, F4E ITER Department
4 July 2008
12 m LPCE
Water Detritiation System (EU)
Tanks for H (>100Ci/kg), M, L,
2
LL (<1.6 µCi/kg) level
water
A few topics addressed in Working Group 7
(Tritium Plant) during the ITER Design Review
Tritium Building Layout
Modification of HVAC, ADS and VDS
Tritium Tracking Strategy
R. Laesser, F4E ITER Department
4 July 2008
3
Tritium Building Layout
New building layout required due to French law for
• Compartmentalization (segregation of tritium inventories),
• Fire zoning,
• Too long escape routes,
• Missing air locks,
• Etc.
R. Laesser, F4E ITER Department
4 July 2008
4
Generic Site Tritium Plant Building Layout (ITER FDR 2001)
Dimensions
Length:
Width:
Height:
79 m
20 m
34 m
Outdated design:
New regulations:
• Escape routes not
clear and too long.
• Airlocks not included
consistently.
• HVAC to be changed.
Increase of width and
length.
Stairways: 2
3
Elevator: 0
1
R. Laesser, F4E ITER Department
4 July 2008
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12/2
New Tritium Plant Building Layout: French Rules
• Tritium inventory segregation requires
rearrangement and even splitting of
primary systems (SDS
SDS1+2).
• WDS and ISS now next to each other.
• Vacuum pumps: B1
L1.
• Confinement sector / fire sector
basically on floor by floor basis
-700 g in a “confinement / fire sector”
• Physical limitation wherever possible
-70 g in a single “fire zone” (component)
• Isotope Separation System (ISS, 250g
> 70 g) impossible to subdivide,
requires additional protection against
loss of primary confinement (fire)
R. Laesser, F4E ITER Department
4 July 2008
Up
Down
6m
B1
Up
Down
– Storage and Delivery System (SDS) &
Long Term Storage (LTS) getter beds
T12
T13
Electrical
Room
• Physical limitation wherever possible
SDS 1
TEP
WDS & ISS
Passage
Passage
T14
27 sq m
27 sq m
Local
Monitoring&Control
Room
SDS 2
Up
Passage
233 sq m
T15
TA
TB
TC
TD
TE
TF
TG
TH
TI
TJ
VPS: Vacuum Pumping System,
CPS: Coolant Purification System
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Modification of HVAC, ADS and VDS
Complexity of HVAC and confinement systems for ITER
Tokamak Complex grew over years:
• Overall configuration became very complex,
• Concept of 90% HVAC air recycle considered to be
unworkable: human access restricted due to limited fresh
air throughput of HVAC systems),
• Danger of cross contamination
R. Laesser, F4E ITER Department
4 July 2008
7
Generic ITER HVAC, Depression and Detritiation Systems Configuration:
Tokamak building
Tritium plant
Water
Detritiation
System
HVAC 2
Release
Point
Local
Air Coolers
N-VDS-1
VV Pressure
Supression
System
HVAC II
Tokamak
Exhaust
Processing
Glove box
Detritiation
System
Test
Blanket
Module
Other
Depression II
Back-up
NVDS 1
S-VDS
N-VDS-2
Vault
Neutral
Beam
Vacuum
Vessel
(VV)
Back-up
NVDS 2
Port
Plug
Port
Cell
Other
Depression I
HVAC I
Gallery
Vacuum
Vessel
Tritium plant
Area I
Tritium plant
Area II
S-ADS
Depression 1
HVAC 1
Gallery
R. Laesser, F4E ITER Department
Vacuum
Vessel
Tritium plant
Area I
Tritium plant
Area II
4 July 2008
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ITER Detritiation System Block Diagram
ITER Detritiation System
Block Diagram
R. Laesser, F4E ITER Department
4 July 2008
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17/2
Wet Stripping Column for Tritiated Water Removal
Counter current removal by exchange of
tritiated water in a wet stripping column
– Diameter about 0.7 m, length about 5 m
• Throughput about 1500 m3h-1
15 kg H2OL
fresh water
(liquid)
H2OL
– No regeneration cycles as for
molecular sieve beds
detritiated air
(saturated)
Air+H2OV
to
release
point
HTOV + H2OL 
H2OV + HTOL
• Less complicated configuration
and number of valves
• No dryer system required
• 1 column instead of 3 molecular sieve beds
• Potential cost savings
packing
– Capital costs / operational costs
– R&D ongoing at Mendeleyev University,
Moscow
– Pilot plant tests scheduled later in Japan
Air+HTOV
air / tritiated
water vapor
R. Laesser, F4E ITER Department
4 July 2008
HTOL
tritiated water
10
to ITER
WDS
18/2
ITER Ventilation and Confinement Concept
Fresh Air
Primary confinement can
include more than one
barrier
•
•
Glove box (GB) for
maintenance purposes.
GB atmosphere
detritiation.
Secondary confinement
comprises subatmospheric pressure
control and atmosphere
detritiation
HVAC supply
Release point
Secondary Confinement
Building sector/
Tritium spill
Building sector
Glove Box
Detritiation System
(GDS)
Vent
Detritiation
Primary Confinement
Surrounding Containment
(Glove Box)
Surrounding Containment
(Glove Box)
ISS
TEP
Primary
System
Primary
System
Atmosphere
Detritiation
ISS cold box
ISS
HVAC exhaust
R. Laesser, F4E ITER Department
4 July 2008
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Tritium Tracking Strategy
• Tritium inventory in Mass Balance Areas (MBA-1 for
FC, MBA-2 for LTS) must be known.
• Tritium transfer between MBAs must be measured.
• Accountancy techniques:
o pVT-c (gas)
o Calorimetry (gas and metal tritides)
o Scintillation (gas and liquid)
R. Laesser, F4E ITER Department
4 July 2008
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Tritium Inventory at any Selected Time
Assume monthly checking.
Tn = Tn-1 - TBu - TD - TL + TI + TBr
•
•
•
•
•
•
Tn-1: total tritium inventory of previous month
TBu: tritium burned
TD: tritium lost by decay
TL: tritium leaving plant in effluent streams: negligible under normal
operation
TI: tritium imported
TBr: the tritium bred: negligible
Burnrate = 5.90 10-07 mole T/s per MWF.
T burned/pulse = 0.35 g
7 g/day for 20 short pulse (450 s)
In 10 years: external tritium supply: total of 6.7 kg. Total amount burnt: 4.3 kg
R. Laesser, F4E ITER Department
4 July 2008
13
Tritium Tracking Strategy
The tritium inventory at ITER site in MBA-1 can be divided in four parts:
Tn  Min  Tin  Mex  Tex
Min: tritium mobile in-vessel; Tin: tritium trapped in-vessel;
Mex: tritium mobile ex-vessel; Tex: tritium trapped ex-vessel.
Global tritium inventory procedure will assess these categories
•
•
•
Mobile tritium external to Vacuum Vessel will be collected in SDS beds and measured.
Tritium trapped ex-vessel will be estimated/calculated.
After stop of plasma operation, mobile in-vessel tritium will be removed via wall
conditioning, baking, etc., transferred via TEP and ISS to SDS and measured by in-bed
calorimetry.
Tritium Tin trapped in-vessel after cleaning is computed by difference using
calculated Tn value.
Approximately 10 days were found to be needed for the global tritium inventory
procedure.
Tritium tracking accuracy will also depend on the accuracy of the tritium amounts
•
•
Known to be in the in-vessel components moved to Hot cell.
Burnt in fusion reactions (to be determined by diagnostics)
R. Laesser, F4E ITER Department
4 July 2008
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Comments to Tritium Tracking
High uncertainty in daily tritium measurements will limit significantly the availability of
ITER.
The most important error is related to the measurement of fusion power needed to
calculate the amount of tritium burnt.
2 calorimeters in the LTS will reduce the error on the imported tritium with possibility
of eliminating systematic errors in these measurement (theory of combining
measurements).
The main factor that determines the errors in tritium inventories is the analytics
employed:
– Integral measurements should always be preferred,
– Calorimetry is by far the most accurate method for tritium inventory
measurements (0.5% accuracy).
Ex-situ measurements of the tritium trapped in removed in-vessel materials should
help in the evaluation of the total tritium trapped in-vessel and reassessing this
value.
Vacuum vessel in-situ sampling techniques might be even better, but will they be
available?
R. Laesser, F4E ITER Department
4 July 2008
15
Tritium in Plasma Facing Components
JET experience clearly demonstrated that high amounts of fuel (deuterium and
tritium) are trapped in co-deposited layers with large ratios of D and T over C
((D+T)/C), especially in the shadowed areas of the machine.
Extrapolation to ITER conditions indicates that in ITER the administrative limits
for recovery of tritium would be reached after a very limited number of shots.
In conclusion: Carbon during DT phases in ITER must be avoided.
Even in a Be/W environment the number of plasma shots will be limited, however
far higher. Tritium inventories and dust production will remain critical issues.
An all metal first wall (no carbon) is also a very positive development for the ITER
Tritium Plant as the hydrocarbons will become an impurity category of minor
importance.
R. Laesser, F4E ITER Department
4 July 2008
16
Canadian + Korean
Inventory without
supply to fusion
Tritium
supply
and
consump
-tion
during
life of
ITER
Canadian + Korean
Inventory with ITER
Updated projections of Canadian + Korean tritium supply and consumption using ITER current schedule. (from
Scott Willms [March 2007]).
This slide was presented by Prof. M. Abdou in the presentation “Fusion Nuclear Technology Development and the
Role of CTF (and ITER TBM)” at the Workshop on CTF, Culham, U.K., 22-23 May 2007.
R. Laesser, F4E ITER Department
4 July 2008
17
Test Blanket Modules (TBMs) in ITER
In the present European fusion program ITER is the only interim step to
check the performance of future breeding blankets by means of
DEMO relevant Test Blanket Modules (TBMs) in a fusion
environment prior to their use in DEMO.
ITER device is a test facility for the TBMs.
R. Laesser, F4E ITER Department
4 July 2008
18
Installation and Testing of TBMs in ITER
2 EU blanket concepts (HCLL and HCPB BBs) will
be tested in ITER.
4 TBMs per concept, each dedicated to one of the
major ITER operational phases (H-H, D-D, low
D-T and high D-T), will be fabricated and tested
during the first 10 years of ITER operation.
Auxiliary systems: He purge and tritium
extraction systems, Helium Coolant System
(HCS) and Coolant Purification System (CPS)
are required.
EU TBMs shall be ready from first day of ITER
operation.
ITER Test Port
(Equatorial
plane)
FZK
EU TBMs
Coolant:
Helium at 300-500°C, 8 MPa
Structural
Material
Reduced Activation FerriticMartensitic steel: EUROFER
Breeder
Material
i) Li4SiO4 / Li2TiO3 (pebble beds)
ii) Pb-15.7at% Li (liquid metal)
CEA
R. Laesser, F4E ITER Department
4 July 2008
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Tritium Processing in TBMs
Although very small, the amount of tritium bred in TBMs needs to be extracted,
recovered and transferred into the inner DT-fuel cycle, with the main aim
of:
•
validating the theoretical predictions on tritium breeding,
•
qualifying technologies and components for tritium processing,
•
validating the theoretical predictions on tritium recovery performance and
tritium inventory in the functional/structural materials.
R. Laesser, F4E ITER Department
4 July 2008
20
Integration of TBM in the ITER Fuel Cycle
TES
He: 0.4 g/s
TBM
He: 0.4 g/s
He: 1.4 kg/s
33 mg/d HT*
257 g/d H2
a
c
co
u
n
t
an
c
y
to T storage
and delivery (SDS)
Q2
TEP
ISS
HCS
CPS
He: 0.35 g/s
1.3 mg/d HT
1.9 g/d H2
TEP: Tokamak Exhaust Processing
HCS: Helium Cooling System
TES: Tritium Extraction System
CPS: Coolant Purification System
VDS: Vent Detritiation System
WDS: Water Detritiation System
ISS: Isotope Separation System
R. Laesser, F4E ITER Department
VDS
Q2 O
WDS
Off-gas release
* High duty DT phase; 1.16E-6 g/s of T produced in HCPB-TBM
4 July 2008
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Conceptual Design of TES for HCPBTBM
Main components
- Adsorption column for
Q2O removal operates at
RT in adsorption phase
- Two bed TSA system for
Q2 removal
- U metal getter as
scavenger bed in a bypass line to be used
mainly in the low duty DT
phase
R. Laesser, F4E ITER Department
mol. sieve
beds (TSA)
HCPB
TBM
U-getter
mol. sieve bed
4 July 2008
22
Conceptual Design of CPS for HCPBTBM
Three Step Process
1) oxidation of Q2 to Q2O
and of CO to CO2 by an
oxidising reactor (Cu2OCuO)
operated
at
280°C;
cat. ox., step 1
2) removal of Q2O by two
bed PTSA operated at RT
and 8 MPa and at
300°C and 0.1 MPa in
regeneration;
3)
removal
of
the
impurities in HCS by a
two-bed cryogenic PTSA
cryo-mol. sieve
beds (PTSA), step 3
mol. sieve bed
(PTSA), step 2
No Q2O is released from
CPS to TEP (or VDS)
because of the presence
of metallic reducing beds
in the PTSA regeneration
loop
R. Laesser, F4E ITER Department
4 July 2008
23
Tritium Processing in DEMO
DEMO relies on enough tritium production in
breeding blankets (Tritium Breeding Ratio
(TBR): >1.0)
R. Laesser, F4E ITER Department
4 July 2008
24
The DEMO Fuel Cycle: A few Numbers
In ITER DT fuel flow rates:
120 Pam3/s (up to 200 Pam3/s.
In DEMO, despite the 7 times
larger power than in ITER, only
slightly higher feed flow rates
are expected due to the better
burn-up efficiency.
In DEMO:
o ~35 kg tritium per day to
be supplied for plasma
operation
o ~500 g of tritium burnt per
day
o ~550 g of tritium bred in the
BBs (TBR=1.1) per day
o 50 g of tritium can be added
to the long-term storage
each day
R. Laesser, F4E ITER Department
ITER
DEMO
Fusion power
0.5 GW
3.7 GW
Electrical power
--
1.5 GWel
Tritium burn-up
72 g/d
500 g/d
Burn-up efficiency
0.5 %
1.5 %
Tritium throughput
3.5 kg/d
~35 kg/d
DT feed flow rate
120 Pam3/s
~300 Pam3/s
Tritium inventories
in different
subsystems of
ITER and DEMO
< 4 kg in FC
< 1 kg in inner loop
< 1 kg in SDS
< 1 kg in vessel
< 1 kg in HC
< 5 kg in FC
< 1 kg in inner loop
< 4 kg in SDS
< 1 kg in vessel
< < 1 kg in HC
Tritium bred in
ITER TBMs and in
DEMO BBs
25 mg/d
~550 g/d
4 July 2008
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Simplified block diagram of DEMO Fuel Cycle
External
T needed
for start
Fuelling Systems (FS):
Pellet Injection, Gas Puf.
D from
external
sources
Storage and Delivery
System (SDS)
Neutral Beam Injection
(NBI), Cryo Pumps
Protium
Release
BB
WDS
BB tritium recovery syst.
DEMO
Tritiated Water
Torus
Breeding Blanket
Tritium Recovery Syst.
Leak detection system
Roughing Pumps (RP)
DT
Isotope Separation
System (ISS)
Analytical
System (ANS)
Q2
Tokamak Exhaust
Processing (TEP)
Tritium Plant
Release of detritiated
gas via VDSs, HTO of
VDSs to BB WDS
Main changes with respect to ITER inner Fuel Cycle: main Q2 bypasses ISS and SDS. No
WDS in inner FC (all HTO treated in BB Tritium collection loop. No cryopumps (with exception
of NBI) shown (needs to be assessed). BB tritium recovery systems will be discussed later.
R. Laesser, F4E ITER Department
4 July 2008
26
Main Parts of Inner D/T DEMO Fuel Cycle
DEMO Cryopumps: If higher pressures in the DEMO divertor can be tolerated, the
cryopumps could be replaced by mechanical (Roots) pumps with the benefits of
continuous vacuum operation (lower inventories, smaller cryoplant). To be assessed.
DEMO Impurity Processing System: will be similar to ITER TEP, however smaller.
o The Q2 permeated through the first stage of TEP will be transferred directly to
the Fuelling System bypassing ISS and SDS.
o The Q2 gases from the second and third stages of TEP will be sent to ISS and
after isotope enrichment to SDS.
DEMO Isotope Separation System (ISS):
o DEMO ISS of inner loop will be smaller than in ITER ISS as most of the recycled
Q2 will bypass ISS.
o Due to the lower throughput and lower inventories it should be possible to
produce pure H2, D2 and T2 gases. In this way isotopic composition changes of
gas mixtures during delivery from metal tritide storage beds will be avoided.
DEMO Storage and Delivery System: The tritium and deuterium storage beds could be
very similar to the ones of ITER (designed for in-situ calorimetry and high supply
rates).
DEMO Analytical System: will serve the inner and the BB loop.
DEMO Fuelling Systems: similar in design as in ITER (wait for ITER experience).
The inner DEMO fuel Cycle loop may not need a Water Detritiation System (WDS). All
water created there can be treated in the WDS of the BB loops.
R. Laesser, F4E ITER Department
4 July 2008
27
Simplified Block Diagram for the Blanket Tritium Processing in DEMO
DEMO
Blanket
He + (Q2 + Q2O)
0.4 kg/s, 0.11 MPa
Q2 = 110 Pa; HT = 016 Pa
Q2O = 0.16 Pa
Pth= 3.0 GW
GT= 385 g/d
Tperm= 15 g/d
Q2O 2 kg/d
49500 Ci/kg
TES
η=0.9
He + (Q2 + Q2O)
0.4 kg/s, 0.11 MPa
Q2 = 110 Pa; HT = 1.6 Pa
Q2O = 1.6 Pa
HCS
He + Q2 + Q2O
2.4 kg/s, 8 MPa,
H2 = 1000 Pa; HT = 0.08 Pa
H2O = 50 Pa
R. Laesser, F4E ITER Department
4 July 2008
Q2 17.1 kg/d
HT: 202000 Ci/kg
BB ISS
Tritiated impurities
BB TEP
He+(Q2+Q2O)
2400 kg/s, 8 MPa
Tin 300ºC
Tout 500ºC
He + (Q2 + Q2O)
2.4 kg/s, 8 MPa,
Q2 = 1000 Pa; HT = 0.8 Pa
Q2O = 50 Pa
BB TEP
Main subsystems of
breeding blanket
tritium recovery
loops in DEMO:
CPS
η=0.9
• Collection of HTO
• Collection of HT
• Processing of highly
tritiated HTO
• ISS, WDS and TEP
BB WDS
Q2O 122 kg/d
1100 Ci/kg
28
Acknowledgements
Many thanks to the colleagues and principal investigators in
the Associations and Industry who contributed to the
development of the DT Fuel Cycle.
Thanks to the contributors to this presentation, in particular: M.
Abdou, N. Bekris, I. Cristescu, I.R. Cristescu, Ch. Day, M.
Glugla, S. Grünhagen, D. Murdoch, G. Piazza, Y. Poitevin and
I. Ricapito.
END
R. Laesser, F4E ITER Department
4 July 2008
29