Status of Tritium Processing for ITER - UCLA Dept. of ......2008/08/14 · UCLA August 12-14, 2008...
Transcript of Status of Tritium Processing for ITER - UCLA Dept. of ......2008/08/14 · UCLA August 12-14, 2008...
Presented by Scott Willms (LANL)
Fusion Nuclear Science and Technology Meeting
UCLAAugust 12-14, 2008
Status of Tritium Processing for ITER
Outline
• Tritium Plant• TEP Design• TEP R&D• TEP Modeling
--The TEP project is being performed as a partnership between SRNL and LANL.
The ITER Tritium Plant is a small chemical plant consisting of seven systems built by multiple PTs
TEP components have been tested at about 1/10th
ITER scale
PMR-US
Caper-FzK
JFCU-JA(US)
ITER Detailed Design Description of TEP process outline – under review
DESIGN
“Build-to-Spec” Design Process
PerformanceSpecifications
Identify Technology Set
Develop PFD andComponent Sizing
Develop P&ID and Equipment List
Glovebox Layout
“SRD”
“Procurement Arrangement”
TEP Interfaces
• GEP stream flows to VDS.
• LTEP stream flows to NB permeators.
• HTEP stream flows to FEP.
• LTEP, HTEP and other interfaces determine IP requirements.
Most major gas streams originate on cryopumps and come to TEP through the Roughing Pump System
Torus
TorusCPs
RoughingSystem
TEPHe (GDC)
ISSSDS
D/T
Wasteto VDS
NeutralBeam CPs
Fueling
Cryopump regeneration separates gas species (thermal desorption spectroscopy)
DT Burn & Dwell – Scenario optimization considerations
DDD calls for two separate systems to process gases from torus and NB cryopumps. Perhaps one is sufficient.
Four standard considerations are:• Sequence: NB CP
regen shifted to follow Torus CP regen.
• T Inventory: N/A• Cooling/Heating:
NB CP regen is not totally constrained.
• Change Needed? Flow from NB CP is “design controlling”. It can be reduced by extending the evacuation period.
Burn Dwell
Minimum NB CPCooling Period
1000 sec B&D with NB Cryopump
TOTAL
Q2
He, Ne
Seq 1 2 3
D2
175 g T ~ 0 g T
Minimum NB CPHeating Period
DT Burn and Dwell – Result of scenario optimization
• Sequence:• T Inventory:• Cooling/Heating:
Extended as much as possible.
• Change Needed?NB CP was “design controlling”, now it is not.
Burn Dwell
1000 sec B&D with NB Cryopump
TOTAL
Q2
He, Ne
Seq 1 2 3
D2
Minimum NB CPHeating Period
Minimum NB CPCooling Period
Present design activities
• Technology evaluation and selection• Process flow diagram preparation and detail
R&D
Reactions
Water gas shift
Methane steam reforming
Catalysts tested
• Catalyst 1: United Catalyst, 60-70% Ni/Al2O3, 1/16” extrusion
• Catalyst 2: Degussa, 0.15% Pt/ 0.15% Pd onAl2O3, 2 mm spheres
• Catalyst 3: NIKKI, 50% Ni on diatomaceous earth, 2 mm pellets
Hydrogen Processing Laboratory
Methane steam reforming – Ni (typical)MSR-NiA-20070214-51 CH4 : 1.99 H2O500 C
Water gas shift – Ni (typical)WGS-NiA-20070125-41.05 CO : 1 H2O500 C
Methane-steam reforming and water-gas shift - Key equations
Arrhenius plot for forward MSR reaction (k1f)
0.0011 0.0012 0.0013 0.0014 0.0015 0.0016 0.00171E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
10900 850 800 750 700 650 600
PtA NiK NiA
k1f (
m3/
mol
/s)
1/T (1/K)
T (K)
Example comparison of model to experiment-MSR over NiA
0.0 0.5 1.0 1.5 2.0 2.5 3.00.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 MSR-NiA-20070214-51 CH4 : 2 H2O500 C
Model Exp H2O H2O H2 H2 CO CO CH4 CH4
CO2 CO2
Mol
e Fr
actio
n
Residence Time (s)
By removing hydrogen as it is produced, thermodynamic barriers are circumvented and process can be greatly simplified
MODELING
TEP modeling phases
• Outline Model (Complete)– Evaluate the capabilities of Aspen Dynamics– Provide a basic understanding of system behavior
• Evaluation Model (Current Emphasis)– Support technology selection– Support process flow diagram development
• System Model– Support PI&D development
• TEP-Wide Control Model– Support control system design– Support operating procedure development
• Tritium Plant Model (Proposed)– Develop a model of the entire ITER tritium plant
Present modeling activities
• Aspen unit operations models– Plug-flow reactor model– Permeator model– Palladium membrane reactor (PMR) model– Pump models
• TEP system modeling• Support of TEP technology evaluation• Tritium Plant model• Component modeling (if time permits)
– PERMCAT model
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Retentate Material Balance
• Aspen Dynamics model contains a transient material balance equation for a plug-flow reactor
• Aspen uses a sub-model to calculate net generation rate or consumption of each species from all reactions in the model
• Need to add a term to account for permeation
ε ⋅ ∂Ci∂t
= − 1V⋅ ∂Fi∂ξ
+ ri −AmV
⋅Gi
for i = H2 : GH2 =2 ⋅ K p
Dout ⋅ ln Dout Din( )⋅ PH2 +ε − PH2 ,perm( )for i ≠ H2 : Gi = 0
Permeation term added to Aspen Dynamics model
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Benchmark Test Results
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Response to 50°C Temperature Decrease
38% CO2
14% CO
0.44% H2O
0.33% H2
0.04% CH4
0.42% H2O
0.38% H2
0.65% CH4
13% CO
Conclusions
• The ITER TEP project is– successfully addressing many practical tritium processing issues– solving a number of long-standing issues– changing traditional views of ITER and fusion tritium processing
systems• The ITER TEP project does not have the mission or
time/funding to– study the science behind some of the behaviors being observed– study promising directions for improvement