Transcript of Multiple effects for HT DCLL Presented by Neil Morley University of California, Los Angeles US-EU...
- Slide 1
- Multiple effects for HT DCLL Presented by Neil Morley
University of California, Los Angeles US-EU DCLL Workshop November
14-15, 2014 Slides from my colleagues S. Smolentsev and M. Abdou
gratefully acknowledged
- Slide 2
- Next 10 Years We are now in mostly Separate Effects stage. We
need to move to multiple effects/multiple interactions to discover
new phenomena and enable future integrated tests in ITER TBM and
FNSF Now TBMs in ITER & FNSF in FNSF Property Measurement
Phenomena Exploration Model Validation Non-Fusion Facilities: 2
Theory/Modeling Basic Separate Effects Multiple Effect/
Interactions Partially Integrated Design Codes/Data Component
Multiple Effects / Multiple Interactions bringing together
different combinations of multiple physical loads, multiple
materials and complex configurations that can drive new interacting
and synergistic phenomena Testing in Fusion Facilities
- Slide 3
- Consider a representative FW/blanket system: Dual Coolant Lead
Lithium - DCLL 3 FW Armor RAFS Structure SiC Flow Channel Inserts
Shield He Flow ARIES-ST DCLL blanket This is considered as a
leading FW/Blanket system in the US EU and China have similar
version Features and R&D issues are typical of a family of PbLi
and/or helium cooled FW/blankets Molten PbLi and helium coolants /
breeders and circulation systems Thermomechanical response of
helium cooled RAFS structures Tritium transport and control
Corrosion and activation Reliability over long operation and
transient events
- Slide 4
- Features of the High Temperature DCLL Allow high temperature
PbLi flow inside FCI while keeping the RAFM steel operating in
acceptable range for both structural and PbLi compatibility Keep
MHD pressure drop under control in a practical way that results in
acceptable inboard dP and overall flow distribution High
temperature condition can be intentional for better power
conversion or as a safety margin for temperature excursion
protection 4 FCI PbLi He
- Slide 5
- 5 Thermofluid Multiple Effect / Multiple Interactions Combined
MHD/heat/mass transfer behavior in a DCLL unit cell PbLi Flow
distribution in a complex collection of parallel channels Corrosion
and tritium mass transfer in a non- isothermal PbLi flow system
PbLi/He accident scenario evaluation Helium heat transfer and
stability in strongly heated complex flow configurations What do we
think we need to know about DCLL MHD thermofluid multiple effects /
multiple interactions
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- Combined MHD/heat/mass transfer behavior in a DCLL unit cell
Given a inflow conditions, non-uniform B-field and heating in
typical DCLL unit cells, what will be the: Material interface
temperatures, temperature gradients, thermal stresses Mass loss
rates and corrosion product concentrations Tritium transport rates
and tritium concentrations FCI performance and MHD Pressure drop
What science needs to be studied What combination of phenomena
controls flow regime / stability of the channel. What is the
sensitivity? How does the flow regime impact the heat and scalar
transport E.g. Hot spots, corrosion product source terms, tritium
leakage to helium, How does the FCI material properties and
component integrity evolve over time due to interfacial effects 6
FCI PbLi He
- Slide 7
- Spatial Gradients in Nuclear Heating and Temperature in LM
Blanket Lead to New Phenomena that fundamentally alter our
understanding of the behavior of the blanket in the fusion nuclear
environment 7 B g V UPWARD FLOW DOWNWARD FLOW Vorticity Field shows
unstable velocity affecting all transport phenomena Base flow
strongly altered possibly leading to stagnant zones and flow
reversal Buoyant MHD interactions result in Mixed Convection flow
regime with substantial impact on flow dynamics, heat transfer,
corrosion/tritium transport
- Slide 8
- The mixed-convection flow requires new rules for predicting
transition. Bottom: Flow map showing stable laminar (s) and two
turbulent regimes (wt and st) in the Ha Re plane for Gr = 5x10 7.
Top: Predictions of the critical Ha number with the linear theory.
Linear stability analysis DNS UCLA (Smolentsev) built flow maps
(Ha-Re-Gr) and determined critical Ha number to predict transitions
and specify turbulence mode. These results suggest that in DCLL
blanket (DEMO, Gr~10 12 ) poloidal flows are turbulent. These
predictions are so far limited to computations and analytical
studies. Experiments are needed. We are planning such experiments.
Pre- experimental analysis has been completed showing that
anticipated flow regimes can be reproduced in the MTOR Lab.
- Slide 9
- Flow distribution in a complex, multi-material configuration of
parallel channels What design, flow conditions, and FCI behavior
leads to highly unbalanced flow and channel overheating? Complex
conducting structures, manifold designs and partial FCI insulation
Magnetic fields not aligned with walls and will vary front-to-back,
side-to-side and over time in large modules Heating varies strongly
back to front and vary over time FCIs motion and property changes
over time Unsteady flows that may cause pressure oscillations 9
DCLL blankets modules have 4-8 multiple channels fed from common
supply and return pipes FW Armor RAFS Structure SiC Flow Channel
Inserts Shield He Flow
- Slide 10
- The current paths in complex flow elements are difficult to
understand and predict, and will strongly impact flow distribution
10 In MHD one must always always be prepared to consider the
complete electromagnetic field. The current and magnetic fluxes
must have complete paths which may extend outside the region of
fluid-mechanical interest into locations whose exact position may
be crucial -- J A Shercliff UCLA current flow simulation in a 3
channel manifold, cut along symmetry plane down middle channel
- Slide 11
- PbLi ingress in SiC FCI can dramatically change conductivity,
increase drag in that channel and lead to severe flow redardation
15 vol% dense, 85% porosity filled with aerogel
- Slide 12
- 12 Thermofluid Multiple Effect / Multiple Interactions Combined
MHD/heat/mass transfer behavior in a DCLL unit cell PbLi Flow
distribution in a complex collection of parallel channels Corrosion
and tritium mass transfer in a non- isothermal PbLi flow system
PbLi/He accident scenario evaluation Helium heat transfer and
stability in strongly heated complex flow configurations What do we
think we need to know about DCLL thermofluid multiple effects /
multiple interactions
- Slide 13
- Next 10 Years So how do we explore, discover, understand and
accurately model multiple effect multiple interactions phenomena?
Now TBMs in ITER & FNSF in FNSF Property Measurement Phenomena
Exploration Model Validation Non-Fusion Facilities: 13
Theory/Modeling Basic Separate Effects Multiple Effect/
Interactions Partially Integrated Design Codes/Data Component
Testing in Fusion Facilities Use real materials, prototypic
temperatures Simulate surface and bulk heating and gradients
Provide large volume and use multiple channels Have more prototypic
Ha, Gr, N, Re, etc. A handful of upgraded/new experimental
facilities will be needed that:
- Slide 14
- We envision two thermofluid MHD facilities beyond near term
upgrades of existing facilities Multiple Effect/Multiple
Interactions Blanket Facility Role: Address near full size DCLL
unit cell thermofluid flow and transport issues and reduced scale
multi- channel flow control Partially Integrated Blanket Facility
Role: bring together all simulated conditions affecting
thermofluid/thermomechanical blanket/FW performance to the maximal
practical degree prior to FNSF 14 These are both non-nuclear
facilities that can be flexibly operated and instrumented to
investigate both prompt and long time scale DCLL blanket phenomena
in a controlled and well characterized fashion
- Slide 15
- Blanket MHD thermofluid test facilities Multiple
Effect/Multiple Interactions Blanket Facility. Role: Address near
full size DCLL unit cell thermofluid flow and transport issues and
reduced scale multi-channel flow control strong magnetic field, ~5T
Magnetic volume capable to accommodate full single channel size,
~0.3 x 1.5 m) controlled orientation with respect to gravity and
channel walls simulated volumetric heating and gradients PbLi and
He flow loops at prototypic temperatures (~1/2 TBM scale) 15 $20M
class facility, can be a gradual extension of MTOR/MaPLE facilities
at UCLA
- Slide 16
- Possible upgrades for MaPLE and BOB magnet Flexible B
orientation Higher flowrate and temperature PbLi Simulated
volumetric heating Online PbLi purification Instrumentation System
to switch from Horizontal to Vertical oriented BOB magnet gap
- Slide 17
- Possible upgrades for MaPLE and BOB magnet Flexible B
orientation Higher flowrate and temperature PbLi Simulated
volumetric heating Online PbLi purification Instrumentation
Secondary He coolant Higher magnetic field Larger magnetic volume
System to switch from Horizontal to Vertical oriented BOB magnet
gap Evolve into the Multiple Effect Multiple Interaction facility
just described
- Slide 18
- Blanket MHD thermofluid test facilities Partially Integrated
Blanket Facility. Role: bring together all simulated conditions
affecting thermofluid/thermomechanical blanket/FW performance to
the maximal practical degree prior to FNSF Simulated toroidal and
poloidal magnetic field Up to full size FW/blanket test modules in
multiple poloidal orientations with respect to gravity Simulated
surface and volumetric heating and gradients PbLi and He flow loop
of ~full DEMO module size Prototypic temperatures, pressures,
materials 18 $50-80M class National Laboratory facility to really
prepare for FNSF requires significant design and construction
effort
- Slide 19
- What are the principal challenges in simulating the fusion
nuclear environment? Nuclear heating in a large volume with strong
gradients, not possible to reproduce in simulation facility. Use
various techniques Embedded heaters in LM, on walls or in flow
channel inserts. Must be careful about changing the flow, FCI
behavior, etc. Integration into multiple experiments required Inlet
temperature control (e.g. flow in hot, let cool) Complex magnetic
field with toroidal field / poloidal field fidelity or transient
fields during disruptions Requires complex magnet systems, very
important for LM blankets Or utilization of modules in long pulse
confinement devices Complex mockup configuration with prototypic
size and scale Not possible in fission reactors 19 Can not bring
together all conditions in one test or adequately simulate nuclear
heating
- Slide 20
- Study on Blanket/FW Multiple Effect/Multiple Interaction and
Partially Integrated Test Strategy and Facilities 20 Why the Study
is Needed The subject of multiple effect/multiple interactions is
very complex and requires experienced blanket R&D experts But
the cost of the facility for full simulation can be very expensive
Therefore, tradeoffs between the capabilities incorporated in the
facility and COST are needed. Developing cost estimates require
mechanical design for a given set of specified parameters Requires
Blanket R&D experts as well as mechanical engineers and magnet
designers and cost professionals. There are several US institutions
interested in developing proposals to construct blanket facilities
The study could be international and a good mechanism for
collaboration