August 17, 2000 ARIES: Fusion Power Core and Power Cycle Engineering/ARR 1 ARIES: Fusion Power Core and Power Cycle Engineering The ARIES Team Presented.

August 17, 2000ARIES: Fusion Power Core and Power Cycle Engineering/ARR

1

ARIES: Fusion Power Core and Power Cycle Engineering

The ARIES Team

Presented by A. René Raffray

ARIES Peer Review Meeting

University of California, San Diego

August 17, 2000


2

Presentation Outline

Power Core and Power Cycle Engineering:

– Power Cycle

– Blanket

– Divertor

– Material

Approach Relies on:– Detailed Analysis

• Using up-to-date analysis tools

• Developing tools for specific analytical needs

– Application of creative solutions to extend design window

– Building Block• build on previous ARIES design

experience in bettering the end product

– Community Interaction• utilize national and international

community input in evolving material properties and component parameters

• develop clear goals for R&D program showing benefits


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Power Cycle: Quest for High Efficiency

• High efficiency translates in lower COE and lower heat load

• Brayton cycle is best near-term possibility of power conversion with high efficiency– Maximize potential gain from

high-temperature operation with SiC/SiC

– Compatible with liquid metal blanket through use of IHX

ConventionalSteam Cycle:Steel/Waterη = 35%

-ARIES RS/Li V

Supercritical ( ):Rankine water

η = 45%

-ARIES STFS/ /He -17Pb LiBrayton( . ):Low Temp Heη > 45%

-ARIES AT(SiC/SiC)/ -17Pb LiBrayton( . ):High Temp Heη = 59%

RecuperatorIntercooler 1Intercooler 2

Compressor 1

Compressor 2Compressor 3

HeatRejection

HX

Wnet

Turbine

IntermediateHX

5'

1

22'

38

9

4

7'9'

10

6

T

S

1

2

3

4

5 6 7 8

9 10

PbLi Divertor +Blanket Coolant


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Brayton Cycle Based on Near-Term Technology and Advanced Recuperator Design Yields High Efficiency

Advanced Brayton cycle developed with expert input from GA and FZK, Karlsruhe • FZK/UCSD ISFNT-4 paper, 1997

• GA/UCSD ANS TOFE-14 paper, 2000

• Min. He Temp. in cycle (heat sink) = 35°C

• 3-stage compression with 2 inter-coolers

• Turbine efficiency = 0.93

• Compressor efficiency = 0.88

• Recuperator effectiveness = 0.96

• Cycle He fractional P = 0.03

• Total compression ratio set to optimize system (= 2-3)


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High Efficiency Requires High Temperature Operation

• Conventionally, maximum coolant temperature is limited by structural material maximum temperature limit

• Innovative design solutions in ARIES-ST and ARIES-AT allow the blanket coolant exit temperature to be higher than the structure temperature


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ARIES-ST Utilizes a Dual Coolant Approach to Uncouple Structure Temperature from Main Coolant Temperature

• ARIES-ST: Ferritic steel+Pb-17Li+He

• Flow lower temperature He (350-500°C) to cool structure and higher temperature Pb-17Li (480-800°C) for flow through blanket

ARIES-ST breeding zone cell

18

232

3.5

250

18

10

Pb83Li17

SiC

He-cooled Ferritic Steel


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ARIES-AT Utilizes a 2-Pass Coolant Approach to Uncouple Structure Temperature from Outlet

Coolant Temperature

• ARIES-AT: 2-pass Pb-17Li flow, first pass to cool SiC/SiC box and second pass to “superheat” Pb-17Li

• Maintain blanket SiC/SiC temperature (~1000°C) < Pb-17Li outlet temperature (~1100°C)


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Detailed Modeling and Analysis Required to Demonstrate Blanket Performance

Multi-dimensional neutronics analysis

• Latest data and code

• Tritium breeding requirement influences blanket material and configuration choices

• Blanket volumetric heat generation profiles used for thermal-hydraulic analyses


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Accommodation of Material Temperature Limits Verified by Detailed Modeling

Moving Coordinate Analysis to Obtain Pb-17Li Temperature Distribution in ARIES-AT First Wall Channel and Inner Channel under

MHD-Laminarization Effect

ARIES-AT Outboard Blanket Segment

q''plasma

Pb-17Li

q'''LiPb

Out

q''back

vback

vFW

Poloidal

Radial

InnerChannel

First WallChannel

SiC/SiCFirst Wall SiC/SiC Inner Wall


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Temperature Distribution in ARIES-AT Blanket Based on Moving Coordinate Analysis

• Use plasma heat flux poloidal profile• Use volumetric heat generation poloidal and radial profiles• Iterate for consistent boundary conditions for heat flux between Pb-17Li inner channel zone and first wall zone• Calibration with ANSYS 2-D results

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

5.50

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15Poloidal Distance from Lower Outboard (m)

OUTBOARD INBOARD

DIV.

Average Neutron Wall Load = 3.19 MW/m2

Pb-17Li InletTemp. = 764 °C

Pb-17Li Outlet Temp. = 1100 °C

Max. SiC/PbLi Interf. Temp. = 994 °C

FW Max. CVD and SiC/SiC Temp. = 1009°C° and 996°C°

700

800

900

1000

1100

1200800

900

1000

1100

1200

1

2

3

4

5

6

00.020.040.060.080.1

00.020.040.060.080.1

Radial distance (m)

Poloidaldistance(m)

SiC/SiC

Pb-17Li


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Detailed Stress Analysis Using Latest Tool for Maintaining Conservative Design Margins

Example of 2-D and 3-D Thermal and Stress Analysis of ARIES-AT Blanket

Using ANSYS

Pressure Stress Analysis of Outer Shell of Blanket Module(Max. =85 MPa)

Pressure Stress Analysis of Inner Shell of Blanket Module(Max. =116 MPa)

Thermal Stress Distribution in Toroidal Half of Outboard Blanket Module(Max. =113 MPa)

Conservative SiC/SiC stress limit from Town Meeting:Max. allowable thermal + pressure = 190 MPa


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Develop Plausible Fabrication Procedure and Minimize Joints in High Irradiation Region

Example Procedure for ARIES-AT Blanket1. Manufacture separate halves of the

SiCf/SiC poloidal module by SiCf weaving and SiC Chemical Vapor Infiltration (CVI) or polymer process;

2. Insert the free-floating inner separation

wall in each half module;

3. Braze the two half modules together

at the midplane;


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ARIES-AT Blanket Fabrication Procedure Comprises:

1. Manufacturing separate halves of the SiCf/SiC poloidal module by SiCf weaving and SiC Chemical Vapor Infiltration (CVI) or polymer process;

2. Inserting the free-floating inner separation wall in each half module;

3. Brazing the two half modules together at the midplane;

4. Brazing the module end cap;

5. Forming a segment by brazing six modules together (this is a bond which is not in contact with the coolant); and

6. Brazing the annular manifold connections to one end of the segment.


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Divertor Design Approach Relies on Community Interaction and Innovative Solution to Maximize Performance

PFC and Physics Community Interaction

– Tungsten as plasma-interactive material

– ALPS liquid divertor option collaboration

– Fully radiative divertor to maintain reasonable peak heat fluxes, ~ 5 MW/m2

Divertor Coolant Compatible with Blanket Coolant and/or Power Cycle Fluid

– ARIES-RS: Li in insulated channel (same coolant as blanket)

– ARIES-ST: He coolant (from power cycle)+high heat flux porous media (Pb-17Li as blanket coolant)

– ARIES-AT: Pb-17Li in SiC/SiC channel (same coolant as blanket)

• Assess Key Limiting Issue • Detailed Analysis and Innovative

Solution to Maximize Performance of Coolant/Material/Concept Combination

e.g. MHD Effects for Liquid Metal Cooled Divertor

– Minimize MHD effect by design choice; use of coatings, insulating inserts or SiC pipes

– However, solution must be confirmed by R&D

Provide Guidance for R&D


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ARIES-ST Divertor Designed for Thermal Expansion Accommodation

• Tungsten Armor

• High-temperature He coolant

• Advanced high heat flux porous media

• Several SBIR proposals based on similar configuration

• Initial high heat flux testing at Sandia indicate high heat flux capability for this material combination (~30 MW/m2)

3-D stress analysis • Moderate stresses in high heat flux region

• High local stress at attachment, can be relieved by flexible joint

16 mm

2 mm 1 mm

3 mm

HOT COLD

ARIES-ST Divertor Tube Cross Section


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MHD Effects Influence Both Pressure Drop and Heat Transfer Even in Insulated Channels

MHD Accommodation Measure for ARIES-AT Divertor Design • Minimize Interaction Parameter (<1) (Strong Inertial Effects)• Flow in High Heat Flux Region Parallel to Magnetic Field (Toroidal)• Minimize Flow Length and Residence Time• Heat Transfer Analysis Based on MHD-Laminarized Flow

Pb-17Li Poloidal Flow in ARIES-ATDivertor Header

PoloidalDirection

ToroidalDirection

Example schematic illustrationof 2-toroidal-pass schemefor divertor cooling

Plasma q''

A ACross-Section A-A


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Temperature Distribution in Outer Divertor PFC Channel Assuming MHD-Laminarized Pb-17Li Flow

δBTPFC

LiPb LiPb

• Moving Coordinate Analysis• Inlet Temperature = 653°C• W Thickness = 3 mm• SiC/SiC Thickness = 0.5 mm• Pb-17Li Channel Thickness = 2 mm• SiC/SiC Inner Wall Thick. = 0.5 mm• Pb-17Li Velocity = 0.35 m/s• Surface Heat Flux = 5 MW/m2

• Max. SiC/SiC Temp. = 1000°C

700

800

900

1000

1100

1200

600

700

800

900

1000

1100

0

0.005

0.01

0.015

0.02

00.001

0.0020.003

0.0040.005

0.0010.002

0.0030.004

0.0050.006

Radial distance (m)

Toroidal distance (m)Tungsten

SiC/SiC

Pb-17Li


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Divertor Design Optimized for Stress Limit Accommodation and Acceptable Coolant Pressure Drop

0.00

0.50

1.00

1.50

2.00

0 0.01 0.02 0.03 0.04 0.05

Toroidal Dimension of Divertor Channel (m)

Inner Channel

Orifice

PFC Channel

Total

δBTPFC

LiPb LiPb

Example ARIES-AT Divertor Analysis• For 2.5 mm tungsten, SiC/SiC pressure stress ~ 35 MPa

(combined SiC/SiC pressure +thermal stress ~ 190 MPa)• P is minimized to ~0.55 MPa


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Close Interaction with International Material and Blanket Design and R&D Communities

Combination of Low Activation Structural Material + Liquid Breeder Result in Attractive, High Performance Blankets

– ARIES-RS: Li + Vanadium; ARIES-ST: Pb-17Li+FS+He; ARIES-AT: Pb-17Li+SiC/SiC

Recent Example of Interaction with International Material and Design Communities• Organize International Town Meeting to bring together international (US, EU and Japan)

material and design SiC/SiC communities (ORNL, Jan 2000)– Current material development and characterization status

– Latest SiC/SiC-based blanket design: TAURO(EU), DREAM(Japan(), ARIES-AT(US)

– Key SiC/SiC issues affecting blanket performance

– Detailed info on website (http://aries.ucsd.edu/PUBLIC/SiCSiC/)

• Town Meeting was very successful; achievements include:– Develop list of properties and parameters for design study

– Clear R&D need for high temperature high performance blanket• Need better-quality material with reasonable thermal conductivity-stoichiometry goal

• Temperature limit: Compability between Pb-17Li and SiC at high temperature

– Included in US R&D plan and being carried out in Europe

– Paper deriving from meeting submitted to FE&D

August 17, 2000 ARIES: Fusion Power Core and Power Cycle Engineering/ARR 1 ARIES: Fusion Power Core and Power Cycle Engineering The ARIES Team Presented.

Documents

power cycle engineeringarr

fusion power core

aries team

structure temperature

lower temperature

blanket sicsic temperature

hightemperature operation

high temperature operation