ReNeW PMI Theme PFC Panel Report Organization First question at the - - PowerPoint PPT Presentation

ReNeW PMI Theme PFC Panel Report

Panel team members :

• C. Wong ( GA), B. Lipschultz (MIT), T. Leonard (GA),
• R. Majeski (PPPL), D. Youchison (SNL), B. Merrill (INL)
• R. Doerner (UCSD), S. Milora (ORNL)

US Department of Energy OFES Research Needs Workshop (ReNeW) University of California, Los Angeles March 2–6, 2009

• Organization
• First question at the beginning: What are we doing?
• Technologists to physicists: What heat fluxes will the DEMO have?
• Physicists to technologists: What are your design limits?
• Both sides agreed: We have significant challenges ahead.
• The team then worked on requirements and issues of different areas.
• Generated the PFC Matrix showing issues and needs for different areas.
• We do have a draft PFC related research thrusts

PFC is a Tier 1 priority

Greenwald Priority Tier 1: solution not in hand, major extrapolation from current state of knowledge, need for qualitative improvements and substantial development for both short and long term

• Plasma Facing Components
• Materials

Plasma Facing Components: Understand the materials and processes that can be used to design replaceable components that can survive the enormous heat, plasma and neutron fluxes without degrading the performance of the plasma or compromising the fuel cycle.

ReNeW  PMI  PFC Organization

Panel member focused areas:

• Physics (Lipschultz and Leonard)
• Solid surface and design (Wong)
• Liquid metal and design (Majeski)
• Surface heat transfer and components

testing and analysis (Youchison)

• Tritium, safety and RAMI (Merrill)
• Surface materials (Doerner)
• Maintenance and development program (Milora)

Review…requirements…development… thrusts… …for the next 15-20 years

ITER design as an initial example

To project robust PFC design and development we created the ~ 1000 MWe DEMO key PFC parameters: Mid-plane Γn-max =3 MW/m2 FW φ-max= 0.5-4.0 MW/m2 (TBD) Div φ-max = 10 MW/m2 (steady state) + 20 MW/m2(10-100s) (pulses TBD)

EU Roadmap Divertor Development towards ITER & DEMO

[P. Norajitra et al.]

constant load for DEMO

* * *

For DEMO:  ELMs have to be supressed,  VDEs and disruption „unlikely events“

(Vertical Displacement Events) (Edge Localized Modes)

Intro (6): Assumptions for DEMO Design from EU

* Number of events in ITER [T. Ihli, Summer School 2007, Karlsruhe, Germany]

Intro (5): Example Divertor Cassette for Model C from EU Replacement scheme

[P. Norajitra et al.]

1-Finger module 10 MW/m2 Divertor cassette

Dome and structure (ODS RAFM) Outboard Inboard Divertor target plates with modular thermal shield (W/W alloy)

9-Finger module Reference Design: He-cooled modular divertor with jet cooling (HEMJ)

(DBTT, irr.)

1300°C 700°C 600°C 300°C 600°C inl. 700°C outl.

(RCT, irr.)

WL10 Thimble

creep rup. strength (DBTT, irr.) He coolant ODS Euro Structure

Temperature windows

18

} 5

[T. Ihli]

HEMJ-J1c

• W-tile: Non-castellated, russ. W
• WL10 thimble
• W/W joint: STEMET 1311
• W-Steel joint by Cu casting

He data:

• 10 MPa
• 13.5 g/s (∆P 0.31 MPa*)
• Tin = 520-570°C
• Tout = 550-600°C

Results:

• 10 cycles each at 4,6,10,11

MW/m2 ok

• Failure in W/W joint after 6 cycles

at ~13 MW/m2

• He Loop and thimble still intact

W-tile Detached area W-thimble Steel ring Conical Cu- cast lock

*) about 0.085 MPa equivalent at 6.8 g/s nominal

EFREMOV under FZK contract

Overall results: No suddenly and/or completely broken mock-up, i.e. no brittle failure. Nor was a recrystallisation of the thimble

• bserved in any

mock-up.

2006 HHF test results (mockup #4)

Crack in thimble, growing from inside

Test conditions:

• 10 MW/m2
• 30s / 30s sharp power ramp

THe,in 550°C, 10 MPa, mfr 7 g/s

• Tile temperature rise after 89 cycles*
• -> tile probably partially detached.
• He Loop and thimble still intact.
• Post examination underway

2 4 6 8 10 12 10 20 30 40 50 60 70 time in [s] heat flux in [MW/m^2]

2007: HHF test of optimized HEMJ mockup

*n required ~ 100 - 1000 Post-examined at FZJ [T. Hirai,

• G. Ritz]

2007 overall results: successful HHF tests of optimized HEMJ mockup 10 MW/m2 (survived 100 thermal cycles, 30s-30s sharp ramp, w/o damages) Castellation: cracks parallel to heat flux, W defect

Wall loads on plasma facing components in ITER

Thermal load during ELMS:  1 GWm-2, t = 500 µs, 1 Hz  high cycle thermal fatigue critical area flat tile design

W

monoblock

CFC

• M. Roedig

ELM induced erosion of CFC and W with the 0.5 MJ/m2 limit

CFC W

energy density* E / MJm-2 0.5 1.0 1.5 heat flux factor P ·Δt / MWm-2s1/2 20 40 60 melting of tile surface droplets bridging of tiles melting of tile edges crack formation cracking of pitch fibres PAN eros. > 100 shots PAN erosion > 50 shots PAN erosion > 10 shots negligible erosion negligible damage unmitigated ELMs in ITER mitigated ELMs in ITER

* Δt = 500 µs

• M. Roedig

PFC team went through a detailed identification

• f PFC requirements and issues

Seven PFC panel areas:

• 1. Physics, 2. Solid surface and design, 3. Liquid metal and design
• 4. Surface heat transfer and components testing and analysis
• 5. Tritium, safety and RAMI, 6. surface materials, 7. maintenance and development program

ReNeW  PMI  PFC  Solid surface & design: Wong

Requirements:

• Configure surfaces to reduce peak heat flux, material erosion and deposition
• Components life time: FW 4years (TBD), divetor 2 years (TBD)
• Disruption and transient events tolerance (TBD) even for unlikely events
• Robust components to withstand all Demo operating scenarios, including all
• perational & transient E&M loads and structural and thermal stresses

(including effects from neutron irradiation, cyclic fatigue, thermal creep, fracture toughness, fracture mechanics effects), while providing a design margin of 1.3 (TBD)*

• Adjust to major divertor configuration change if recommended?
• Divertor design to maximize flexibility, surface can be shifted back and forth by ± 5°

when required by operation.

• Design with removable chamber first wall (TBD)?
• Assess the renewable low-Z surface on W option?
• Design with high thermal efficiency
• Develop predictive capability via modeling and analysis

(Not covered or provided in the Greenwald report)

Review…requirements…development… thrusts …for the next 20 years

ReNeW  PMI  PFC  Solid surface & design: Wong

Review…requirements…development… thrusts…for the next 20 years Development needs:

• Demo design: Use a projected Demo design to define the pre-conceptual design with

gradual increase of details: including physics, configuration, segmentation, routing, maintenance, structural support…etc.

• Industrial connection: Establish connections with industry on PFC components design,

fabrication and testing of different scale of PFC components

• Modeling: If necessary develop PFC relevant design codes, coupled with dedicated

analysis codes and commercial design codes

• Fusion materials design codes
• Connections: Continue to work with physicists, first wall material designers, heat transfer

and components developers and testing professionals

PFC team went through a second round on PFC requirements and issues

PFC requirements and issues were prepared for different areas We found that the two VG format was too limiting, two page write-ups of issues on each

• f the seven PFC related areas were generated.

Seven PFC panel areas:

• 1. Physics, 2. Solid surface and design, 3. Liquid metal and design
• 4. Surface heat transfer and components testing and analysis
• 5. Tritium, safety and RAMI, 6. surface materials, 7. maintenance and development program

PFC Matrix

PFC Gaps: To Develop Understanding for the Construction of Robust PFC Components

Thoeory & Modeling Existing/Upgrade/ New Test stands Existing Upgraded Confinement facilities New Confinemet Facility Chamber & Div. heat flux Steady state Transient Example 1 Solid surface design Liquid surface design Example 2 Tritium in solid, mix materials Example 3 Maintenance Innovations Example 4

• Possible temperature range: RAF/M-350 to 550 C, ODFS Tmax-700-800 C, W-alloy 700-1300 C
• Design guidelines: FW heat flux ~0.5 MW/m2, Max. heat flux ~10 MW/m2,

ELMs with rise time of 125-250 µs, energy flux ~0.5 MJ/m2

• Inputs to be developed jointly with PWI and other panels
• Inputs to be developed jointly with other panels

PFC Matrix Example 1 (physics)

PFC Gaps: To Develop Understanding for the Construction of Robust PFC Components (Physics) Theory & Modeling Define chamber spatial and temporal heat loads 1st principles modeling Chamber & Divertor heat flux Conventional Extended channel(s) (e.g. SXD, snowflakes) Divertor physics, integrated with PMI effects, 1st principles modeling Transients: Startup/shutdown Define start/up & shutdown parameters Model suppression and elimination of high ELMs power ELMs Disruption Model disruption avoidance and mitigation, Other off normal events: eliminate off normal events MARFE, Improve neutral and photon modeling H-L transition Model avoidance of MARF, H-L transition heat load Heat dumps Define occasional ELMs and heat dump locations and parameters by 1st principles modeling

PFC Matrix Example 2

PFC Matric Example 1

PFC Gaps: To Develop Understanding for the Construction of Robust PFC Components Existing/Upgraded/New Test Stands Liquid surface design issues Configuration (Ext. chan., e.g. SXD,snowflakes) Construct high B-field facilities for In chamber MHD effects fast flow and capillary flow Fluid flow MHD Perform high heat flux LM experiments Heat flux limits at tokamak-relevant high B-field Liquid surface substrate design Study feed, drain manifolds Thermal limits Study eroion and corrosion lifetime Engineering design margin Study T retention/migration Impurity control and cleanup IFMIF to test substrate material Plasma performance modifications Study impurity control and cleanup

PFC Matrix Example 3

PFC Gaps: To Develop Understanding for the Construction of Robust PFC Components Existing/Upgraded Confinement Facilities Tritium in solid, mix materials Tritium permeation/migration Validate understanding of tritium transport and inventory on PFC materials Materials/irradiation Experiments with innovative and irradiated PFC materials Safety limits Testing of tritium diagnostics Accountancy Develop and test permeation barriers Test interface joining materials, initiate material qualification

PFC Matrix Example 4

PFC Gaps: To Develop Understanding for the Construction of Robust PFC Components Theory & Modeling Innovations: Advanced structural materials Model advanced materials: SiC/SiC, refractory alloys (e.g. W, Mo..) Surface materials innovation Model C, B coating and BW-surface Advanced heat removal designs Model new innovative heat removal proposals, e.g. liquid metal heatpipes

Potential PFC panel recommended Research Thrusts, version 5, 2/19/09

Small Medium Large

• 1. Liquid surface options

1,3,5,4 2,6*

• 2. W surface option

2,3,6,1,4

• 3. Helium heat transfer

1,2,8,5

• 4. PFC diagnostics

development 1,2,3,8,5,4 6*

• 5. Existing/Upgraded/New

Test Stands: He- loops, heat flux, materials 2 1,3,8,5,4

• 6. New confinement

facility (Does it need to be DT?) 1,3,8,5,6,4

• 7. Upgrade existing

confinement device for hot walls 3,6,4

• 8. Modeling for predictive

capability 1,6,4 Very rough range: Small $2-3 M, medium $10-30 M, large ~$100M per year *Some of the research thrusts could cost in the small scale but they will need a medium cost device to work on or demonstrate

• 1. Wong, 2. Majeski, 3. Doerner, 4. Merrill, 5. Milora, 6. Leonard, 7 Lipschultz ,8. Youchison

Conclusions

• We have identified that with presently available materials for ITER water cooled PFC

components are already pushed to the edge of acceptable performance

• When extended to DEMO with RAFM steel as structural material and He as the

coolant, disruptions will have to be avoided and ELMs will have to be mitigated or

• eliminated. Generation of robust PFC design will be a significant challenge, and could

be by itself a major Research Thrust.

• Requirements and issues for physics, solid and liquid surface design, heat transfer

and components testing and analysis, tritium, safety and RAMI, PFC surface material, maintenance, RAMI and development program areas have been identified.

• Innovative approaches on structural material, PFC material and heat removal will be

needed

• A PFC matrix and a first collection of research thrust have been generated.
• We will continue to assess research thrust as a tool to meet our goal of have robust

DEMO PFC components. PFC remains a Greenwald Priority Tier 1 area: solution not in hand, major extrapolation from current state of knowledge, need for qualitative improvements and substantial development for both short and long term