VLT Topical Area Fuel Cycle

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VLT Topical AreaFuel Cycle
Scott Willms Los Alamos National
Laboratory Presented at DOE Germantown August
25, 2005
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Fuel Cycle VLT Mission and Scope

• Mission
• To research, develop and design safe and
  effective tritium processing systems needed to
  accomplish the OFES mission

• Scope
• Separations Many unique separations are required
  for tritium impurities processing, isotope
  separation, purification, and gas and water
  detritiation
• Storage and delivery Isotopes must be safely
  stored and delivered to systems as needed
• Effluent cleanup High efficiency cleanup systems
  are needed to prevent worker public exposure
• Analysis A variety of analyses are required for
  process monitoring, inventory control and
  contamination control
• Handling Tritiums unique properties lead to
  materials compatibility and containment issues
• Control Unique control issues arise from the
  challenge of producing on-spec product with this
  radioactive material while maintaining minimal
  inventory

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Key RD thrust areas over the next five years

• Thrust 1 Fuel cycle dynamic modeling
• Thrust 2 Permeation-based separations
• Thrust 3 TEP supporting research
• Thrust 4 Tritium separation and control in
  blanket systems
• Thrust 5 Continuously regenerable cryopump
• Thrust 6 Water detritiation
• Thrust 7 In-vessel tritium removal/processing
• Thrust 8 Tritium accountability

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Description of RD Thrusts
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Thrust Area 1 Fuel cycle dynamic modeling

• ITER Tritium Plant risk assessment performed
• The most striking observation is that, compared
  to present experience, the ITER Tritium Plant is
• 10xs flowrate (or more)
• 10xs inventory (or more)
• 1/10th the processing time

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Industrial-class dynamic simulation needed

• Roles for a Tritium Plant dynamic model
• Process design
• Scale-up
• Control
• Tritium inventory
• Fundamental understanding
• Knowledge capture
• Training

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Thrust Area 2 Permeation-based separations

• Baseline has been cryogenic molecular sieve.
  Considerable work performed on this.
• However, cryogenic molecular sieve is 77 K and
  blanket is around 700 K
• During ITER EDA discovered that Pd/Ag permeators
  can be used to remove small amounts of tritium in
  inert gases

• Equipment layout needed now
• Experimental testing needed at blanket conditions
• Tritium migration in TBM needs evaluation

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Thrust Area 2 Permeation-based separations

• Low concentration tritium from helium
• Primary stream e.g. ceramic breeder
• Secondary stream e.g. heat exchanger permeate
• Low concentration tritium in liquid breeder (e.g.
  PbLi)
• Tritium bound in chemical forms (link to Thrust
  area 4)
• Membrane reactor
• Superior membranes
• Superior geometries

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Dual Coolant Lead Lithium TBM tritium processing
overview
Recover tritium from He
Tritium control important throughout
Also use as test station
Use He to strip T from PbLi
PbLi loop
He loop
T permeation thru HX tubes
Recover tritium from He
Avg. T2 breeding rate 0.024 sccm
He loop
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Task Area 3 TEP supporting research

• Current TEP design has only been tested at FzK,
  and they have not performed integrated testing
  (this is planned)
• Indications that fundamental parameters have not
  been tested
• These parameters are particularly important for
  scale-up
• May need H/D testing of reactor/permeator train
  to determine parameters

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Palladium Membrane Reactor

• CD-1 review encouraged considering alternates to
  present ITER TEP design. PMR possibly shrinks
  and simplifies the TEP.
• PMR recently chosen for industrial application
  and design completed
• New industrial membranes may improve performance

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Task Area 4 Tritium separation and control in
blanket systems

• Primary separation method evaluation Bubble
  column, permeator, disengager, oxidation/adsorptio
  n, etc.
• Fate and control evaluation System design,
  barriers, etc.

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Extraction strategy depends on tritium
migration paths

• Large surface area in heat exchanger (req. for
  heat exchange) results in large loss of tritium
  through heat exchanger
• Must process cool side of heat exchanger
• Need tritium extractor in main loop?

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Task Area 5 Continuously regenerable cryopump

• Completed initial tests of pump with H and D, and
  He
• Successfully fed up to 40 SLPM (current ITER
  exhaust rate is 91 SLPM)

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Task areas 6-8

• Thrust Area 6 Water detritiation (EU?)
• Thrust Area 7 In-vessel tritium
  removal/processing (mostly other program
  elements/other parties)
• Tritium removal
• Tritium processing
• Thrust Area 8 Tritium accountability (EU/ITER?)

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Current spending on RD Thrusts

• No VLT fuel cycle funding

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Characterization of RD thrusts to VLT missions
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Summary

• Fuel cycle research is needed
• To ensure the success of ITER
• To learn from the opportunities afforded by ITER
• To face the new challenges of tritium breeding
• To lay the groundwork for future machines
• Work in many of the fuel cycle areas requires a
  unique skill set. This skill set is broadly
  applicable to other subsystems.