Assessment of HTS for Fusion. Activities of EFDA Manel Sanmart - - PowerPoint PPT Presentation

Assessment of HTS for Fusion. Activities of EFDA

Manel Sanmartí (IREC) On behalf of EFDA-HTS Work Program AIME on Superconductivity, Ciemat, 27th-28th May 2013

• Introduction
• HTS for Fusion activities before 2011
• Why HTS for Fusion
• EFDA HTS WP2011
• Scope and objectives
• Results EFDA WP2011
• EFDA HTS WP2012-2013 Associations summary report
• Summary and Conclusions

CONTENTS

REFRAME : HTS for Fusion??

INTRODUCTION

HTS FROM DISCOVERY TO INDUSTRIAL APPLICATION HTS CABLE HTS TRANSFORMERS, FCL HTS GENERATORS AND MOTORS

*source: Walter Fietz presentation 26/03/11

INTRODUCTION

HTS for Fusion…? under evaluation since 2004

• 23rd SOFT Sept. 2004

INTRODUCTION

Why HTS for fusion?

• *source: Walter Fietz presentation

26/03/11

INTRODUCTION

HTS for fusion. Advantages

• *source: Walter Fietz presentation

26/03/11

INTRODUCTION

HTS challenges and prospects for Fusion

*source: Walter Fietz presentation 26/03/11

• HTS for Fusion: EFDA program (May 2007)

EFDA HTS WP2011

*source: Walter Fietz presentation 26/03/11

• SCOPE AND OBJECTIVES

EFDA HTS WP2011

1.- Monitoring and characterizing HTS material. Mechanical, electrical stabilization and quench, and neutron irradiation on HTS samples and cables 2.- Developing fusion cable concepts for the KA range with low ac losses 3.- Fabrication of fusion cable prototypes 4.- Cooling requirement and concepts 5.- Joint fabrication 6.- Manufacturing of winding prototypes/trial coils

• Results: 3 years Working Program

EFDA HTS WP2011

Test and studies HTS samples HTS jointing techniques Fast neutron irradiation HTS samples Preparation of the SULTAN facility

2012 2013 2014

Test and construction of Rutherford cables Tape characterization before and after irradiation Fast neutron irradiation HTS samples Test planning in SULTAN Design and manufacturing of jointing fixture Mechanical tests of the joints Construction of cable demonstrator Joint formation on SULTAN sample Cable design and manufacture

• HTS EFDA program has not been fully deployed and will

be reviewed end 2013

Planned not finished in the year Finished in the year Not started in the year

T06.- Construction and test of DEMO-relevant HTS cables

• Test of Roebel
• Test of Coaxial
• Construction and test of Rutherford

T07.- Characterisation of HTS tape test samples following neutron irradiation

• Reactor irradiation after neutron 2—1022
• Tape caractheritzation before and after irradiation

T08.- Study of the performance of HTS twisted stacked cable T09.- Study on the effect of transverse loads on RE-123 Roebel cables

EFDA HTS WP2012

• WP2012 TASKS

T10.- Design, manufacturing and testing of HTS cable joining techniques

• Evaluation of different solders
• Evaluation of different techniques

T11.- Mechanical tests of single YBCO tape joints under magnetic field Condition

• Electrical resistance. Repeatability
• Axial strength for HTS joint samples with/without magnetic field

T12.- Measurement and modelling the AC losses of coaxial cables T13.- Ic (B,T,e) characterization in relevant window for HTS tape configurations and exploring transverse load sensitivity

EFDA HTS WP2012

• WP2012 TASKS

EFDA HTS WP2013

• WP2013 TASKS

T06.)Studies testing and development of HTS samples

• Rutherford)Roebel Cables
• Strain characterization of ReBCO tapes, joints and CORC Ic and AC loss
• Twisted Stack Cables

T07.)Development and testing of HTS jointing techniques

• Manufacturing of new joints
• Electrical characterization of the joints at 77 K and self)field
• Mechanical characterization of the joints in terms of Ic magnetic behaviour
• Mechanical modelling and analysis of the stresses distribution in the joints

EFDA HTS WP2013

• WP2013 TASKS

T08.-Determination of HTS properties after fast neutron irradiation of HTS samples

• Characterization of each HTS tape shall be carried out before and after

irradiation

• Critical Temperature (Tc), Critical Current (Ic), Homogeneity of super current

flow by magnetoscan T09.-Preparation of the SULTAN facility

• Design and supply of HTS Bus Bars
• Design of counter flow heat exchanger

KIT Contribution WP2013

Different cable approaches have been investigated in the FBI (force F, magnetic field B and current I) facility of KIT. A CORC cable provided by the company "Advanced Conductor Technologies" (D. van der Laan) was investigated

Cable parameters are:

• 1160 mm long,15 tapes in 5 layers
• 4 mm wide copper stabilized SuperPower tapes
• Twist pitch of 17 mm

The results show the good performance of this type of cable.

Measurements in FBI-facility

Schematic drawing of the FBI test facility for the characterization of superconductor cables at temperatures from 4.2 K up to 80 K under magnetic field up to 12 T and current up to 10 kA..

2 4 6 8 10 12 1 2 3 4 5 6 7 8 CORC cable 1 µV/cm criteria Ic / kA B / T

Tsurface: 4.2 K 10.0 K 12.5 K 15.2 K 18.1 K 21.4 K 25.0 K 29.0 K 33.5 K 38.3 K 43.8 K

For a measurement of a ROEBEL assembled cable such a cable was sealed in G10 for mechanical support. The joints to the Cu contacts were very homogeneous, no degradation by handling was observed. During measurement a degradation by Lorentz force was observed under higher magnetic

• fields. However, external experiments at CERN demonstrated that currents even at 10 T

are possible, but to cope with mechanical forces is the critical point for the ROEBEL cable.

Measurements in FBI-facility

Individually measured voltage/current characteristic of the ROEBEL cable Overall voltage/current characteristic of the ROEBEL cable at 2 T and 20 K.

KIT will test optimized ROEBEL cable and other cable approaches in 2013

KIT Contribution

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1 2 3 4 5 R contact:

• verall: 48 nΩ

tape1 tape2 tape3 tape4 tape5 tape6 tape7 tape8 tape9 tape10

• verall

E / (µ

µ µ µV/cm)

I / kA 10 strand Roebel - individually contacted LN2 (77 K), self-field

1 2 3 4 5 2 4 6 8 10 RACC cable 2 T - 20 K surface temp. E / (µ

µ µ µV/cm)

I / kA

University of Twente

• Association Focus Activity: Strain, Stability & Cable AC loss

Transverse stress and torsion under controlled axial tensile load on tape at 77 K or 4.2 K with or without applied magnet field. Ic vs axial strain, B & T

0.2 0.4 0.6 0.8 1 1.2 1.4 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1

ε [%] Ic/Ic0 Behaviour of I c/Ic0 for SCS4050 tape during torsion test

Vtap1 Vtap2 Vtap3 Vtap4 Vtap5 Vtap1rev Vtap2rev Vtap3rev Vtap4rev Vtap5rev

University of Twente University of Twente

Calorimetric & PU-Coil AC loss measurements for fusion spectra on stacked tape wire from CRPP, (D. Uglietti), CORC cable samples, Advanced Conductors (D. van der Laan)

EPFL-CRPP

Association Focus Activity: T06 - Twisted Stack Cables

At 0.6% bending strain (0.25 m bending radius): reversible reduction less than 2%

NEW, BIGGER STRAND 6.2 mm Ø Expected Ic : ~3000 A at 5 K, 15 T CABLE 26 strands Ic = 80 kA at 15 T, 5 K Cu cross-section: 650 mm2

Sample length = 500 mm Assembled strand Assembled strand after soldering

Bending Test

2012 2013 OUTCOME: coated conductor tapes can be assembled in a soldered stacked cable

EPFL-CRPP

In SULTAN sample currents up to 100 kA are supplied by a NbTi transformer, which has to be

• perated at a temperature close to 4.5 K.

On the other hand, the region of interest for testing the HTS sample is between 4.5 K and ~40 K. In this task, it has been proposed to limit the heat flux between transformer and HTS test conductor to a reasonably small value by means

• f a High Temperature Superconducting (HTS)

bus bar, which is similar to the HTS module of an HTS current lead.

• Association Focus Activity:
• WP2013 T09 - Preparation of the SULTAN facility

HTS conductor under test Variable temperature:

5 K – 40 K 4.5 K

HTS bus bar Superconducting transformer 1 m 0.4 m 4 m

TU WIEN Radiation resistance of coated conductors

2 4 6 8 10 12 14 16 1 10 100

H||c

Ic (A) µ0H (T)

(Y,Dy)-123

2 4 6 8 10 12 14 16 0.1 1 10 100

H||c

unirr. 77 K 64 K 50 K 10

22m

• 2

77 K 64 K 50 K 10

22m

• 2 in Gd-screen

77 K 64 K 50 K Ic (A) µ0H (T)

Gd-123

ITER fluence: 1022 Am-2 ITER design fluence: no degradation of Jc. Gadolinium might be problematic because of (n,γ)-reaction, which induces significant additional disorder. (Neutron energy distribution has to be known.) Future work: irradiation to DEMO relevant fluences (3-5·1022 Am-2).

Strain dependence of the critical currents

ITER fluence: 1022 Am-2 push rods pull rod carriage

• YBCO/RABiTS: strain dependence hardly changes/sligthly increases after irradiation.
• GdBCO/IBAD: strain dependence strongly increases at large level of disorder (change in Tc!).

Ic

irr = 0.76 Ic unirr

Ic

irr = 0.1 Ic unirr

Self-field Ic at 77 K

TU WIEN

Flux penetration into model Roebel loops

Time resolved Scanning Hall probe measurements. Supports modelling of coupling losses

TU WIEN

Development and testing of HTS jointing techniques 1.Complete the WP12 task by:

• Manufacturing of new joints
• Electrical characterization of the joints at 77 K and self-field
• Mechanical characterization of the joints in terms of Ic, contact resistance and n -index

after tensile stress and bending

• Analysis of magnetic behaviour of joints
• Mechanical modelling and analysis of the stresses distribution

in the joints

• 2. Analysis of joints on a stack of tapes and Roebel cable (if available)
• Manufacturing of new joints
• Electrical characterization of the joints at 77 K and self-field
• Mechanical characterization of the joints in terms of Ic, contact resistance and n -index

after tensile stress and bending

• Mechanical modelling and analysis of the stresses distribution in

the joints of stacks

ENEA

• Low heat capacity system

for high heating warm)up and cool)down rate (> 60 °C /min);

• max = 100 W; max >

250°C;

1300 1400 1500 1600 1700 1800 Fixture Temperature (a.u.) Time (s) I

fixture = 2.5 A

I

fixture = 5 A

I

fixture = 2.5 A

fan-assisted cool down (0.6 ° C/s) slow cool down T

Max

Solder T

melting

solder time

size: 8 x 3 x 3 cm

Joint manufacturing

Conditions for joints SCS4050:

• = 170 °C
• = 200°C
• tapes cleaned with citric acid (510)3 M, pH≈2.7)

@ 170°C;

• load applied melting < < Max
• Solder time=75)90 seconds

Simple lap configuration: YBCO sides are facing each

• ther ()

Joint specific resistance sJ = J ×

YBCO side Substrate side YBCO side Substrate side

Solder

• SuperPower tapes SCS4050;
• commercial solder Sn60Pb40 (m=183°C) with flux core;
• Joint manufacturing using a dedicated fixture;
• Joint Length () and applied load () were changed;

ENEA

Spring with known constant, !

• Pressure range: 0.4 – 15 MPa (by varying both joint length and applied load

);

• the pressure was applied by a T)shaped hammer with the force applied on a

sphere;

• Applied load was controlled by the compression of the spring

Applied force, "#

Joint manufacturing ENEA

Results: sJ vs P

• decreases with $, applied load, for all the investigated J following a general

trend;

• reaches a plateau within the range 2 MPa < $ < 13 MPa;
• this behaviour explained considering the solder thickness reduction with $;

SJ = × (w J) = 2 (ρcu cu + Si) + ρsolder solder =

• SJ decreases because of the

dependence of solder≈ 1/$ SJ = 2 (ρcu cu + Si) + ρsolder !$

• solder≈ ;

SJ = 2 (ρcu cu + Si) + ρsolder

ENEA

Joint #22: p=4.27 MPa, sJ=37 n—cm2 The joint area was coated by Sn)Pb alloy by standard electrochemical deposition. The coating thickness was about 1 µm.

Results: SEM analysis of cross)section

= 10 m

ENEA

IREC-ICMAB/CSIC

• HTS spliced joints.
• Voltage-current function on stress. Joint resistance

IREC-ICMAB/CSIC

• Strain in the joint at different strengths

Spliced region 39 mm 1st modeling 2013

IREC-ICMAB/CSIC

• Magnetic behavior joints at 77 K

Joint critical current function on external field and stress

NEXT STEPS

• Review HTS for Fusion Work Program
• Pending tasks:
• Construction of cable demonstrator

Joint formation on SULTAN sample HTS DEMO conductors based on a detailed cable design and the performance of a next generation of industrially fabricated RE-123 tapes with artificial pinning centers Sequential reactor irradiation to a fast neutron fluence of 6x1022 m-2 Cable design and manufacture

CONCLUSIONS

• European Fusion Road Map

HTS magnets offer the opportunity for higher magnetic fields at higher operating temperatures and margins This in turn would lead to a higher overall efficiency from the fusion power plant due to higher energy density and lower cryogenic power requirements respectively In addition, if demountable TF magnets could be developed, they would offer a potentially transformative technological innovation with simpler maintenance methods (i.e. larger access ports) and improved availability Design and R&D work should continue in Horizon 2020 with the intention to build and test full-scale HTS cables at relevant field, current and temperature conditions. This activity will focus mainly on the manufacture and testing of small-scale and full- scale HTS cables prototypes including jointing techniques and investigation of the response to neutron irradiation.

• Industry-Academia collaboration is mandatory

EFDA HTS COLLABORATION A joint work in the frame of by