experience with recent high field no-insulation magnets ... · k. kim experience with recent high...

K. Kim <[email protected]>

Experience with Recent High Field No-Insulation

Magnets from the Test and User Viewpoint

Kwanglok Kim and Seungyong Hahn

Applied Superconductivity Center, National High Magnetic Field Laboratory,

2031 E. Paul Dirac Dr., Tallahassee, FL, 32310, USA

Coated Conductors for Applications 2016, Aspen, CO

September 12, 2016

Experience with Recent No-Insulation Magnets: IO-06 Coated Conductor for Applications 2016, Aspen, CO (September 12, 2016) 1/32


Contents �

2.  NI Coil wound with “Metallic Cladding” REBCO Tape

4.  Summary

1.  Introduction to No-Insulation (NI) REBCO Magnet

3.  NI Coil wound with “Defect” REBCO Tape

2/32 Experience with Recent No-Insulation Magnets: IO-06

Coated Conductor for Applications 2016, Aspen, CO (September 12, 2016)

1.1. REBCO coated conductor and NI winding technique 1.2. 40 T record high field from 9 T 14 mm superconducting insert coil in a background field 1.3. “Self-protecting” behavior of 26 T 35 mm multi-width NI all-REBCO magnet

2.1. Local current sharing and quench recovery up to 700 A/mm2

2.2. “Self-protecting” behavior after a thermal runaway quench at 700 ~ 820 A/mm2

2.3. “Long-term recovery” behavior after a thermal runaway quench at 820 A/mm2

3.1. NI coil incorporated with a “Defect Irrelevant Winding” (DIW) technique 3.2. “Defect irrelevant” behavior of a NI coil


Introduction to No-Insulation (NI) REBCO Magnet�n  REBCO coated conductor ¨  In-field current carrying capacity and mechanical robustness ¨  The latest REBCO coated conductor carried 15 MA/cm2 in a 2.2 µm thick REBCO film at 30 K

under a 3 T c-axis parallel field*

* Reference: V. Selvamanickam, et al., “Critical current density above 15 MA cm-2 at 30 K, 3 T in 2.2 µm thick heavily-doped (Gd,Y)Ba2Cu3Ox superconductor tapes,” Supercond. Sci. Technol. Vol. 28, 072002 (2015)

n  No-insulation (NI) winding technique ¨  “Self-protecting” against the event of a quench ¨  “Charging delay” of NI coil

¨  Intrinsically “single strand” tape (single deposited superconducting layer)

→ Less reliable in operation than “multi strand” tape such as NbTi, Nb3Sn, Bi-2212, or MgB2




“Self-protecting” of a No-Insulation (NI) REBCO Coil �n  Unexpected event due to the thunder storm (Aug. 23) ¨  Power outage of the building during the 2nd charging test of a NI coil

(blackout)

¨  No coil damage was observed: “Self-protecting”




Researches on the NI Magnets and Applications�

n  Superconducting applications with the NI magnets ¨  2 T 94 mm NI REBCO magnet for magnetic separation (2014, Korea U.) ¨  4 kN 0.52 m × 0.42 m NI REBCO magnet for Maglev (2015, KRRI-SuNAM-CNU) ¨  300 kW 1.2 m × 0.6 m MI REBCO magnet for induction heater (2017, CNU) ¨  4 T quadruple MI REBCO magnet for rare isotope accelerator (2021, IBS-KERI)

n  Selected NI-class REBCO Magnets - Completed

* MI: Metal-co-winding

¨  0.4 T 40 m “multi-width” magnet with “bare” REBCO tapes (2011, MIT; first Magnet) ¨  3 T 35 mm insert for 16.8 T (2011, KBSI-MIT; first LHe Operation; first LTS/HTS ) ¨  4 T 240 mm 10-K cond. cooled magnet (2013, SuNAM-KPU; continuous use at SuNAM) ¨  8.7 T 91 mm insert for 1.3 GHz LTS/HTS NMR (2013, MIT; first magnet level quench) ¨  9 T 78 mm standalone magnet (2014, MIT; self-protecting at 900 A/mm2 ) ¨  26.4 T 35 mm standalone magnet (2015, SuNAM/MIT/MagLab; record field from all-HTS) ¨  3 T 100 mm all-REBCO “metallic cladding” magnet (2015, SuNAM/KBSI/MagLab, first MC) ¨  9 T insert for 24 T operation (2015, IEE-CAS) ¨  9 T 14 mm insert for 40 T operation (2016, MagLab, record field from supercond. inserts)




Progress in NI REBCO Magnet (2009 – 2016)�

2010� 2011� 2012� 2013� 2014� 2015�Year �

2016� 2017� 2018� 2019� 2020� 2021�2009�

Magn

etic f

ield [

T]�

0 �

10 �

20 �

30 �

40 �

50 �: Completed : In progress �

3.7 T, 25.4 mm �

0.16 T, 50 mm

3 T, 140 mm

26.4 T, 35 mm

24 T, 36 mm

2 T, 94 mm 3 T, 100 mm

16.8 T, 35 mm

0.45 T, 40 mm

4 T, 245 mm

8.7 T 91 mm 9 T, 78 mm

40.2 T, 14 mm

2.5 T, 686 mm

20 T, 58 mm

9.4 T, 100 mm

35, 40 mm �

>45 T, 35 mm

30.5 T, 91 mm�

30 T, 125 mm�

1.3 T ,282 mm

n  Magnetic field vs. year



* Graphically organized by Kwangmin Kim (ASC, NHMFL)


40.2 T Record High Field from Superconducting Inserts �n  9 T 14 mm all-REBCO insert ¨  Tested in the bore of a 31 T resistive

background magnet located at MagLab ¨  Consisted of 12 single pancake coils



¨  Wound with the latest 30 µm substrate REBCO tapes manufactured by SuperPower Inc.


n  Charging test results of a 9 T 14 mm all-REBCO insert ¨  Combined field of 40 T (9 T all-REBCO insert coil + 31 T resistive background magnet) ¨  Final coil temperature of 17 K (temperature limitation due to the He bubble) ¨  SuperPower’s new developed 30 µm substrate REBCO tapes

40 T Record High Field from Superconducting Inserts �



→ Current density of ~935 A/mm2


n  A 26 T 35 mm multi-width NI all-REBCO magnet ¨  Multi-width winding technique: A conductor

grading technique that enables a magnet to operate at a higher operating current

¨  26.4 T at 242 A: A record high in all-HTS magnet (tested by SuNAM)

Operation of a 26 T Multi-Width NI All-REBCO Magnet�



¨  Conductor grading was done by SuNAM


n  Charging behavior of a 26 T 35 mm NI magnet – 1st quench test

1st quench test

¨  First quench at 233.5 A (ramping rate: 0.05 A/s)

Quench test a 26 T Multi-Width NI All-REBCO Magnet�

10/32

¨  Leak current: 72.9 A (measured characteristic resistance, Rc: 9.5 mΩ)

Experience with Recent No-Insulation Magnets: IO-06 Coated Conductor for Applications 2016, Aspen, CO (September 12, 2016)

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Quench Test of a 26 T Multi-Width NI All-REBCO Magnet�

2nd quench test

¨  No magnet damages after the two quenches, i.e., self-protecting

¨  Expected center field at 235 A: 25.7 T

11/32

n  Charging behavior of a 26 T 35 mm NI magnet – 2nd quench test

¨  Leak current: 4.97 A (measured Rc: 14.8 mΩ)


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n  Electromagnetic behavior of a 26 T 35 mm NI magnet at a quench moment ¨  The quench was initiated at DP18 and then a “fast electromagnetic” quench propagation was

observed to the adjacent neighbor double-pancake coils

Initial quench

DP18

DP17

DP16

DP19

DP15

¨  The magnet was “self-protecting” from the during the full field quench tests

“Quench Propagation” of a 26 T Multi-Width NI All-REBCO Magnet�




¨  Demonstration of “fast” electromagnetic quench propagation in 26 T

M12

M2n

M1n

Equivalent L-R Circuit Model of No-Insulation Magnet with ‘n’ Number of Double-pancake Coils

DP16 DP15

DP18

DP1

DP17 DP19

* Reference: K. Bhattarai, et al., “Quench Analyses of No-Insulation REBCO Magnets,” Presented at ASC2016

¨  First magnet-level simulation of actual NI magnets n  Quench analysis of a 26 T 35 mm NI magnet

“Quench Propagation” of a 26 T Multi-Width NI All-REBCO Magnet�




Contents �

2.  NI Coil wound with “Metallic Cladding” REBCO Tape 2.3. “Long-term recovery” behavior after a thermal runaway quench at 820 A/mm2 2.1. Local current sharing and quench recovery up to 700 A/mm2



4.  Summary

1.3. “Self-protecting” of 26 T multi-width NI all-REBCO magnet 1.  Introduction to No-Insulation (NI) REBCO Magnet 1.1. REBCO coated conductor and NI winding technique 1.2. 9 T record high field from superconducting insert coil in a background field 1.3. “Self-protecting” of 26 T multi-width NI all-REBCO magnet

3.  NI Coil wound with “Defect” REBCO Tape 3.1. NI coil incorporated with a “defect irrelevant” (DI) winding technique 3.2. Charging test of a DI coil in a bath of liquid nitrogen at 77 K




NI Coil with “Metallic Cladding” REBCO Tape�n  Metallic cladding (MC) REBCO tape ¨  Firstly proposed by SuNAM in 2015

¨  “Thin (1 ~ 2 µm)” metal layer is hermetically clad on the REBCO tape

Substrate

Superconductor

Stabilizer

→ Increasing turn-to-turn contact resistance without sacrificing “self-protecting”

Iθ IR

Ip

LHTS Rc

* Reference: S. Hahn, et al., “HTS Pancake Coil without Turn-to-Turn Insulation,” IEEE Trans. Appl. Supercond., vol. 21, pp. 1592 – 1595, 2011.



NI coil MC coil


n  Charging time comparison between NI and MC coils

Did It Work?: (1) Faster Charging; (2) Self-Protecting �

* Reference: J. Kim, S. Yoon, K. Cheon, K. H. Shin, S. Hahn, D. L. Kim, S. G. Lee, H. Lee, and S. H. Moon, “Effect of Resistive Metal Cladding of HTS Tape on the Characteristic of No-Insulation Coil,” IEEE Trans. Appl. Supercond. 26 (2016), 4601906

¨  ~ 4 times faster charging time showed at MC coil

NI coil MC coil

~ 24 sec ~ 6 sec

¨  Inner diameter: 58.0mm, Turns: 276 (NI coil), 275 (MC coil)

¨  Coil fabrication and test was conducted by SuNAM




¨  Inner diameter; turns: 58.0 mm; 140

Current leads

MC coil

* Y. Hwang, a report for a KBSI-SuNAM-NHMFL project entitled “400 MHz High-Resolution All-REBCO NMR Magnet,” April, 2016.

Burnt-out! �

n  Over-current test results of a MC coil

Did It Work?: (1) Faster Charging; (2) Self-Protecting �

¨  The coil was burnt-out at 1055 A/mm2

¨  The coil survived at 305 A/mm2

¨  Coil fabrication and test was conducted by KBSI

What we trying to do is…...




Local Current Sharing and Quench Recovery of the MC Coil�n  Electrical behavior of the MC coil ¨  Heater induced quench tests were performed at 4.2 K ¨  “Local current sharing” observed at 680 A/mm2

Current leads �

Hall sensor�

MC coil �

680 A/mm2

~4 µV�

~34 µV�




Local Current Sharing and Quench Recovery of the MC Coil�n  Electrical behavior of the MC coil Current leads �

Hall sensor�

MC coil �

¨  Heater induced quench tests were performed at 4.2 K

700 A/mm2

¨  “Local current sharing” observed at 680 A/mm2

¨  No thermal runaway observed at 700 A/mm2




¨  “Self-protecting” of the MC coil was confirmed ¨  Current decreased from 336 A to 50 A within < 0.5 sec ¨  Starting heat diffusion as the heater was turned-on

< 0.5 sec ~1.5 sec

n  Thermal runaway quench moment at 700 A/mm2

700 A/mm2

t = 1680 sec�

Heater�

t = ~1681.5 sec�t > ~1681.5 sec�

Thermal Runaway Quench of the MC Coil�



700 A/mm2 750 A/mm2


n  Multiple thermal runaway quench operations of the MC coil

Survival against the Multiple Thermal Runaway Quenches at 700 ~ 750 A/mm2 �




n  Multiple thermal runaway quench operations of the MC coil ¨  “Self-protecting” against the multiple thermal runaway quenches

800 A/mm2

820 A/mm2

Survival against the Multiple Thermal Runaway Quenches at 800 ~ 820 A/mm2 �



Power supply turned-off


“Long-Term Recovery” Behavior after a Thermal Runaway Quench�n  Electrical behavior of the MC coil after a thermal runaway quench

¨  Quench recovery of the MC coil

820 A/mm2

¨  Multi-turn to single-turn transition




Contents �

2.  NI Coil wound with “Metallic Cladding” REBCO Tape 2.1. Local current sharing and quench recovery up to 700 A/mm2



4.  Summary

1.  Introduction to No-Insulation (NI) REBCO Magnet 1.1. REBCO coated conductor and NI winding technique 1.2. 9 T record high field from superconducting insert coil in a background field 1.3. “Self-protecting” of 26 T multi-width NI all-REBCO magnet

3.  NI Coil wound with “Defect” REBCO Tape 3.1. NI coil incorporated with a “defect irrelevant” (DI) winding technique 3.2. Charging test of a DI coil in a bath of liquid nitrogen at 77 K




NI Coil with “Defect Irrelevant Winding”�n  “Defect Irrelevant Winding” (DIW) technique ¨  Concept: Portion of the coil current bypasses the defect spots ¨  DIW technique may enable…

* Reference: S. Hahn, et al., ““Defect irrelevant” Behavior of a no-insulation pancake coil wound with REBCO tape containing multiple defects,” Accepted in Supercond. Sci. Technol. (2016)

…the improvement of operational reliability of NI REBCO magnet on the partial damage of the REBCO coated conductor

…the construction cost reduction of high field NI REBCO magnets




n  Specifications of a single pancake DI coil

NI coil with “Defect” REBCO Tape �

¨  Ic measurement by YateStar: 6 major defects (Ic is less than 80 % of the lengthwise average) ¨  Length of 6 defects: 6 ~ 11 cm




n  Specifications of a single pancake DI coil

NI coil with “Defect” REBCO Tape �

¨  Inner diameter; turns: 20 mm; 135 turns ¨  Charging test was performed in a bath of liquid nitrogen at 77 K

¨  Ic measurement by YateStar: 6 major defects (Ic is less than 80 % of the lengthwise average) ¨  Length of 6 defects: 6 ~ 11 cm




Charging Test Result of a DI coil at 77 K�n  Step charging of a DI coil in a bath of liquid nitrogen ¨  Ic criteria: 0.23 mV with 0.1 µV/cm; 2.3 mV with 1 µV/cm ¨  No substantial DC voltage measured during steady-state operations at < 60 A




n  Comparison of the measured and expected Ic values of a DI coil ¨  Measured Ic value was 68 A (0.1 µV/cm criterion)

Ic Measurement of a DI Coil�




n  Comparison of the measured and expected Ic values of a DI coil ¨  Measured Ic value was 68 A (0.1 µV/cm criterion) ¨  Ic of “defect-free” coil was estimated to be 72 A (field angle: 67 °, field strength: 0.4 T)

Ic Measurement of a DI Coil�




Summary �

n  No-insulation (NI) REBCO Magnet

¨  9 T 14 mm insert for 40 T: Current density of ~935 A/mm2

¨  The 26 T 35 mm multi-width NI magnet survived against two consecutive quenches

n  Quench Behavior of a “Metallic Cladding” (MC) NI Coil ¨  Local current sharing and quench recovery of the MC coil was observed up to the current

density of 700 A/mm2

¨  The coil can operate “safely” at ≤ 680 A/mm2 without thermal runaway quench ¨  The coil survived against the multiple thermal runaway quenches at 700 ~ 820 A/mm2

¨  “Long-term recovery” behavior observed after a thermal runaway quench at 820 A/mm2

n  Charging Test of a “Defect Irrelevant” (DI) NI Coil

¨  No substantial DC voltage measured during steady-state operations at < 60 A ¨  Expected to enable the magnet’s construction cost reduction and substantial improvement

the operational reliability upon the partial damage of the REBCO coated conductor



32/32 K. Kim

<[email protected]>

Thank you for your attention!�


experience with recent high field no-insulation magnets ... · k. kim experience with recent high...

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