Preliminary Parametric Analysis of First Wall, Blanket and Cycle for HAPL Power Plant

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Preliminary Parametric Analysis of First Wall,
Blanket and Cycle for HAPL Power Plant

• A. René Raffray
• UCSD
• With contribution from Wayne Meier, LLNL
• HAPL Meeting
• University of Wisconsin
• September 24-25, 2003

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Philosophy / Methodology for System Study

• Chamber system model will eventually be one part
  of an integrated system code for laser IFE that
  includes performance scaling, constraints, cost
  for all major parts of the power plant (targets,
  drivers, chambers, power plant facilities, etc.)
• Near term focus is to investigate the parameter
  space that accommodates material and design
  constraints. In each case, the corresponding
  fusion and electrical power (gross and net) will
  be estimated as a performance measure for an
  example blanket and power cycle configuration.
  This would provide some early indication (prior
  to performing a complete COE analysis) of how
  performance varies with the different design
  parameters. These parameters include chamber
  size, target yield, rep. rate, output spectrum,
  armor type and characteristics, steel wall
  characteristics, and chamber gas density). The
  constraints include maximum material
  temperatures, cyclic temperatures, stresses,
  target survival and tracking, chamber clearing,
  etc
• Methodology is to use sophisticated codes or
  detailed calculations over a range of cases
  (UCSD, UW, GA) and then develop simplified
  scaling equations appropriate for the system code
  (LLNL).
• Constraints (e.g., temperature limits) are
  parameters that can be varied in the system code
  to show the impact of our choices for base case
  assumptions.

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Integrated Chamber Armor/FW/Blanket Analysis
Required for Chamber System Studies

• Chamber engineering constraints are set by
  limits on maximum temperature and cyclic
  temperature behavior of W armor and of structural
  material (ferritic steel)
• Distinguish between transient and quasi
  steady-state conditions
• - Separation of armor function and structural
  and blanket functions
• - W armor designed to transient conditions
• - Blanket, first wall and cycle designed to
  quasi steady-state conditions
• IFE system parameters
• - e.g. fusion power (yield x rep rate), chamber
  size
• Chamber first wall and blanket design
  parameters for example configuration
• - e.g. coolant inlet and outlet temperatures,
  first wall structural material thickness,
  heat transfer coefficient at coolant,
  channel dimension

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Integrated Chamber Armor/FW/Blanket/Cycle
Analysis for Chamber System Studies

• Structural material FS or ODS FS
• Armor Material W

Develop FW/Blanket concept compatible with
structural material and armor material - Dont
re-invent the wheel utilize information from MFE
blanket design effort - Maximize
performance Choose high performance power
cycle for expected coolant temperatures Brayton
cycle Maximize cycle efficiency for given
material constraints (optimize coolant inlet and
outlet temperatures) - Design Simplicity
as a Measure of Reliability Minimize number
of coolant channels and structural
joints Minimize welds in FW area Moderate
coolant system pressure if possible - Adequate
Tritium Breeding TBR1.1 or more Active
means of adjusting TBR during operation
Choose self-cooled lithium blanket with ODS FS
and W - Maximum temperature limits (from last
first wall battle plan conference
call) Li/FS interface temperature lt
600C ODS FS maximum temperature lt
800C W maximum temperature lt 2400C FS/W
armor interface cyclic temperature swing lt 20C
(soft limit)
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Proposed Blanket Li/FS Configuration for Initial
HAPL System Study
Adapted from concepts considered in ARIES-AT
and ARIES-CS studies Li as coolant and
breeder ODS FS as structural material W as
armor 2-vertical pass flow first pass at high
velocity to cool FW and box, second pass at low
velocity through large inner channel 2 blanket
regions first replaceable region and second life
of plant region
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Proposed Blanket Module Configuration for
Parametric Analysis
Vertical length 10-20 m depending on R
2-pass flow - High velocity in FW for good
heat transfer - Slow laminar flow in inner
channel for superheating the coolant - At exit,
TcoolantgtTstructure - Use W protective layer on
FS flow divider (if required to prevent
corrosion) to allow exit Twall/Li gt Max.
allow. TLi/FS (600C) - Flow divider has no
structural function
Use HX to transfer energy from Li to Brayton
Cycle He Maximize cycle efficiency under
following constraints - TFS,maxlt 800C (minus
cyclic TFS/W swing) - TLi/FS,max lt 600C - FW
Li DP lt 0.5 MPa (soft limit, by adjusting
channel dimension) - Total cycle compression
ration lt3.5
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Integrated Chamber Armor/FW/Blanket/Cycle
Optimization Procedure

• Set thicknesses of FS region (based on structural
  function and integrity) and W region (based on
  armor requirement but minor effect here)
• - 3.5 mm and 1 mm, respectively in
  example considered
• 2. For given fusion power and chamber radius,
  estimate effective heat flux on armor due to
  photons ions
• 3. Set Brayton cycle parameters (coupled with
  blanket system)
• - DT between Li and He in HX 50C
• - Minimum He temperature in cycle (heat sink)
  35C
• - 3-stage compression
• 4. Set optimum inlet and outlet Li temperatures
  to maximize Brayton cycle efficiency for given
  thermal power subject to
• - Optimum cycle compression ratio (but lt 3.5
  not limiting for cases considered)
• - Maximum FW DPLi lt 0.5 MPa for heat-transfer
  optimized channel dimension (soft limit?)
• - ODS FS Tmax at FW Li outlet lt 780C
• - Interface ODS FS/Li Tmax at FW Li outlet lt
  600C
• - Blanket outlet Li temperature lt 850C
  (assuming 50C superheat)

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Example Results of Blanket/FW Li Temperatures and
Cycle Efficiency as a Function of Chamber Radius
from Optimization Studies
The initial variation of temperatures and cycle
efficiency with increasing chamber radius is set
by the maximum ODS FS temperature at the armor
interface lt 780C The plateau is set by the
maximum ODS FS/Li temperature lt 600 C It seems
reasonable to use the design point when the
plateau is reached to have the maximum cycle
efficiency for the smaller chamber however other
consideration such as the armor maximum
temperature would influence the choice of chamber
radius Also, even if the armor allows it only
a detailed system study could show the optimum
choice of radius (driving chamber capital cost)
and cycle efficiency (driving net electrical
power)
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Example Results of Blanket/FW Max. Li Temperature
and Cycle Efficiency as a Function of Chamber
Radius for Various Pfusion
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Example 2-D Temperature Distribution in W, FS and
Li of Armor/FW/Blanket System(Pfusion 2300 MW,
R6.5m)
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Conclusions

• System study strategy has been developed
  including armor and blanket/FW/cycle parametric
  studies
• Example blanket/FW design proposed for initial
  system analysis two-pass self-cooled Li blanket
  with ODS FS
• Material constraints assumed for initial
  analysis
• - ODS FS Tmax lt 800C
• - FS/Li Tmax lt 600C
• Consistent parametric analysis performed for
  different fusion power
• - FW Li outlet temperature determined by ODS FS
  Tmax for smaller chamber radius
• - Effective plateau then reached based on FS/Li
  Tmax
• - Effective plateau in cycle efficiency also
• - Results were used as input for armor
  parametric study presented earlier
• Armor and blanket/FW/cycle parametric analysis
  results to be used as input for overall system
  code (to be presented by Wayne)

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Additional Slides
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Example Results of Blanket/FW Li Temperatures and
Cycle Efficiency as a Function of Chamber Radius
for Pfusion2300 MW
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Example Results of Blanket/FW Li Temperatures and
Cycle Efficiency as a Function of Chamber Radius
for Pfusion 3000 MW
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Example Results of Blanket/FW Li Temperatures and
Cycle Efficiency as a Function of Chamber Radius
for Pfusion 3500 MW