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TEST RESULTS OF 60-cm BORE Nb3Sn TEST MODULE COIL (TMC-I) IN THE CLUSTER TEST
FACILITY
T. Ando, S. Shimamoto, T. Hiyama, H. Tsuji, Y. Takahashi, M. Nishi, E.
Tada, K. Yoshida, K. Okuno, K. Koizumi, et al.
To cite this version:
T. Ando, S. Shimamoto, T. Hiyama, H. Tsuji, Y. Takahashi, et al.. TEST RESULTS OF 60-cm
BORE Nb3Sn TEST MODULE COIL (TMC-I) IN THE CLUSTER TEST FACILITY. Journal de
Physique Colloques, 1984, 45 (C1), pp.C1-101-C1-104. �10.1051/jphyscol:1984122�. �jpa-00223677�
J O U R N A L DE PHYSIQUE
Colloque C I , s u p p l i m e n t a u n o 1, Tome 45, janvier 1984 page C1-101
T E S T RESULTS OF 60-cm BORE N b 3 S n T E S T MODULE C O I L (TMC-I) I N THE CLUSTER T E S T F A C I L I T Y
T. Ando, S. Shimamoto, T. Hiyama, H . T s u j i , Y. T a k a h a s h i , M. N i s h i , E. Tada, K. Yoshida, K. Okuno, K. Koizurni, T. Kato, H. Nakajima, 0 . T a k a h a s h i , M. O s h i k i r i and K. Yasukochi
F u s i o n R e s e a r c h Center, J a p a n Atomic Energy R e s e a r c h I n s t i t u t e , k%ikaiyama, Naka-Machi, Naka-Gun, Ibaraki-Ken, 311-02, J a p a n
Rdsumd - Une b o b i n e (TMC-Test Module C o i l ) d e 10 T-60 cm d e d i a m b t r e i n t d - r i e u r , u t i l i s a n t un c o n d u c t e u r Nb3Sn h 6 kA, a d t d f a b r i q u d e dans l e c a d r e d e l ' d t u d e d ' a i m a n t s toroi'daux pour Tokamaks. L ' e s s a i a p p r o f o n d i d e c e t t e b o b i n e a d t d e f f e c t u d e n a v r i l 83 d a n s l e " C l u s t e r T e s t F a c i l i t y " q u i p r o - d u i t un champ s i m i l a i r e B c e l u i d ' u n t o r e . Comme prgvu, l a b o b i n e e s t suffisamment s t a b l e m$me d a n s l a c o n d i t i o n oG une s p i r e c o m p l s t e e s t r e n - due n o r m a l e h l ' a i d e d ' u n e c h a u f f e r e t t e h 10 T-6 kA. Aucune d g t d r i o r a t i o n n ' a d t d o b s e r v g e mCme a p r s s une ddcharge r a p i d e e n 6 , 6 s e c n i s o u s l ' e f f e t d e f o r c e s e n d e h o r s du p l a n d e l a b o b i n e o b t e n u e s e n a l i m e n t a n t une s e u l e d e s b o b i n e s du " C l u s t e r " .
A b s t r a c t - An e x t e n d e d t e s t of a 60-cm-bore Nb3Sn c o i l (TMC-I), c o n s t r u c t e d a s a development of s u p e r c o n d u c t i n g t o r o i d a l c o d i n tokamak machine, h a s been c a r r i e d o u t i n t h e c l u s t e r t e s t f a c i l i t y . A 192-cm-length ( o n e t u r n ) normal zone, n u c l e a t e d by a h e a t - i n p u t i n t h e i n n e r m o s t t u r n , i s r e c o v e r e d t o s u p e r c o n d u c t i n g s t a t e a: 6 kA and 1 0 T. For t h e manual dump w i t h a d e c a y time c o n s t a n t of 6.6 s e c ( B = 1 . 0 T / s e c ) , no damage i s found on t h e TMC-I.
I n a d d i t i o n , a o u t - o f - p l a n e f o r c e mode o p e r a t i o n , u s i n g one of t h e c l u s t e r t e s t c o i l s , i s done w i t h no t r o u b l e . With t h e s e good r e s u l t s , t h e f i r s t s t a g e i n TMC-I t e s t was completed. And a s t h e n e x t s t a g e , up-grading t h e c l u s t e r t e s t f a c i l i t y f o r f u r t h e r TMC-I t e s t i n 1 1 T i s now going a h e a d . I - INTRODUCTION
On t h e magnetic f u s i o n machine, t h e T a b l e 1 - Design p a r a m e t e r s of t h e TMC-I.
r e a l i z a t i o n of h i g h - f i e l d and l a r g e - s i z e c o i l i s e x p e c t e d from b o t h t h e performance and t h e e c o n o m i z a t i o n . The c l u s t e r t e s t program i s now under way, a s a development of h i g h - f i e l d s u p e r c o n d u c t i n g c o i l a t JAERI / 1 / / 2 / . The f i r s t s t e p i n t h i s program i s t o d e m o n s t r a t e t h a t Nb Sn c o n d u c t o r i s f e a s i b l e f o r l a r g e - c u r r e n t 3 and h i g h - f i e l d c o i l . For t h i s p u r p o s e , a t e s t module c o i l (TMC-I) h a s been d e s i g n e d and c o n s t r u c t e d . The f i r s t t e s t of t h e TMC-I was c a r r i e d o u t i n O c t o b o r , 1982 and a magnetic f i e l d of 1 0 T was s u c c e s s f u l l y g e n e r a t e d 131.
I n A p r i l , 1983, a s t h e second t e s t of t h e TMC-I, t h e e x t e n d e d t e s t h a s been c a r r i e d o u t about t h e s t a b i l i t y , t h e manual dump, and :he o u t - o f - p l a n e f o r c e mode. I n t h i s p a p e r , t h e r e s u l t s of t h e extended t e s t a r e p r e s e n t e d .
COIL S I Z E
WINDING INNER DIA. 6 0 0 m m WINDING OUTER DIA. 1854 mm WINDING WIDTH 3 0 0 mm
WINDING CONCEPT 1 0 DOUBLE PANCAKES COOLING CONCEPT POOL COOLING a t 4.2 K GRADING CONCEPT TWO GRADES ( 10T/6.2T) MAX. MAGNETIC F I E L D 1 0 T
OPERATING CURRENT 6 k A
AVE. CURRENT DENSITY 3 0 A/mm ( i n WINDING) SELF INDUCTANCE 0.46 H
SUPERCONDUCTOR
MATERIAL Nb S n / Nb T i
S I Z E 3
12.6 mm x 73.0 m m CRITICAL CURRENT 1 0 k A a t 10T / 6.2T
Cu/NON-CU 5.36 / 10.1
STRUCTURAL MATERIAL 304L. 3 1 6 L
FINAL ASSEMBLY ELECTRON BEAM WELDING LIQ. HELIUM INVENTORY 191 liter
C O I L WEIGHT 7.71 ton
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984122
Cl-102 JOURNAL DE PHYSIQUE
11 - THE TEST MODULE COIL (TMC-I)
The t e s t module c o i l (TMC-I), which i s t h e l a r g e s t s i z e i n Nb Sn c o i l , h a s been con- s t r u c t e d w i t h t h e d e s i g n p a r a m e t e r of 10 T a t 6 kA i n a winding i n n e r d i a m e t e r of 600 mm. The d e t a i l s of t h e TMC-I have been p r e s e n t e d i n t h e p r e v i o u s r e p o r t / I / - / 3 / . I n p a r t i c u l a r , t h e f o l l o w i n g new t e c h n i q u e s a r e a p p l i e d t o t h e f a b r i c a t i o n of t h e TMC-I.
( 1 ) a p r e b e n t h e a t - t r e a t m e n t t o produce Nb Sn b e f o r e w i n d i n g . T h i s method r e a u c e s s t r a i n e f f e c t of Nb Sn.
( 2 ) a roughened and o x i d i z e d c o p p e r c o o l i n g 3 s u r f a c e t o o b t a i n h i g h h e a t f l u x t o l i q u i d h e l i u m . The s u r f a c e h a s been a l r e a d y u s e d f o r t h e J a p a n e s e LCT c o i l . ( 3 ) no j o i n t of c o p p e r s t a b i l i z e r a t
g r a d i n g c o n n e c t i o n of s u p e r c o n d u c t o r t o a v o i d t h e e x i s t e n c e of m e c h a n i c a l
weak p a r t i n t h e c o n d u c t o r . F i g . 1 - The TMC-I b e i n g i n s t a l l e d i n The d e s i g n p a r a m e t e r s of t h e TMC-I a r e t h e c l u s t e r t e s t f a c i l i t y .
p r e s e n t e d i n T a b l e 1 . I11 - COOLING-DOWN
The TMC-I i s t e s t e d i n t h e c l u s t e r t e s t f a c i l i t y , which i s composed of a h e l i u m l i q u e f i e r / r e f r i g e r a t o r , a power s u p p l y w i t h p r o t e c t i o n , a vacuum v e s s e l , a computer, and a p a i r of t h e c l u s t e r t e s t c o i l s (CTC). The CTCs p r o d u c e t o r o i d a l m a g n e t i c f i e l d on t h e TMC-I which i s i n s t a l l e d between them i n s e c t o r c o n f i g u r a t i o n . F i g . 1 shows t h e TMC-I b e i n g i n s t a l l e d i n t h e c l u s t e r t e s t f a c i l i t y . The c o i l s y s t e m i n c l u d i n g t h e TMC-I was c o o l e d down t o 4 K i n 140 h o u r s by u s i n g t h e r e f r i g e r a t o r h a v i n g t h e maximum r e f r i g e r a t i o n c a p a c i t y o f 220 W a t 4 . 4 K / 4 / . The cooling-down t i m e i n t h i s t e s t i s s h o r t e n e d by around 30 h o u r s i n comparison w i t h t h e f i r s t t e s t , by improving t h e h e a t - e x c h a n g e between i n l e t c o o l a n t g a s and l i q u i d n i t r o g e n . During t h e
cooling-down, f l o w r a t e and t e m p e r a t u r e o f h e l i u m g a s s u p p l i e d t o t h e c o i l s were c o n t r o l l e d by t h e computer, PDP-11/34, t o a v o i d e x c e s s i v e t h e r m a l s t r e s s i n e a c h c o i l and between t h e c o i l s . The performance o f t h e c o i l s d u r i n g cooling-down and c h a r g i n g were m o n i t o r e d w i t h t h e computer s y s t e m t h r o u g h s e n s o r s o v e r 500 i n t h e c o i l system.
I V - CHARGING TEST
1 1 i ~ t h e e x t e n d e d t e s t , t h e TMC-I was c h a r g e d up t o 6 k A w i t h t h r e e s e p a r a t e modes, ( 1 ) s i n g l e o p e r a ~ e node : t h e TMC-I c h a r g e o n l y f o r a f a s t c h a r g i n g t e s t . ( 2 ) t o t a l o p e r a t i o n mode : t h e TMC-I and t h e CTCs c h a r g e f o r s t r a i n measurement . ( 3 ) f a u l t o p e r a t i o n mode : t h e TMC-I and one of t h e CTCs c h a r g e f o r t h e TMC-I performance t e s t i n a o u t - o f - p l a n e f o r c e c o n d i t i o n .
I n t h e s i n g l e o p e r a t i o n mode, a m a g n e t i c e n e r g y o f 8 . 5 1400 MJ w i t h 6 kA was c h a r g e ~ p i n t w e l v e m i n u t e s . T h i s i s
t h e h i g h e s t speed w i t h t h e p r e s e n t power s u p p l y . I n t h e t o t a l o p e r a t i o n mode, t h e s t r a i n v a l u e s o f t h e c o n d u c t o r were o b t a i n e d a s a f u n c t i o n of t r a n s p o r t Z c u r r e n t i n t h e TW-I w i t h t h e f u l l back-up f i e l d of t h e 2 600
CTCs. The r e s u l t s a r e shown i n F i g . 2. The maximum " 400 s t r a i n i n t h e winding i s 0.12 % (110 MPa) a t 6 kA and
10 T i n t h e i n n e r m o s t t u r n (SC1). 2 0 0
I n t h e f a u l t o p e r a t i o n mode, 323 MPa i s t h e o r e t i c a l l y O 0 1 2 3 4 5 6 7 c a l c u l a t e d a t t h e c o r n e r i n t h e o u t e r r i n g of t h e h e l i u m CURRENT l k A l
v e s s e l . T h i s v a l u e i s 8 0 % of y i e l d s t r e n g t h of F i g . 2 - S t r a i n v a l u e s of S.S.316L a t 4 K. I n t h e p r a c t i c a l e x p e r i m e n t , t h e TMC-Ithe conductor in the winding.
was s t a b l y o p e r a t e d u n d e r h i g h s t r e s s c o n d i t i o n .
V - STABILITY TEST
The TMC-I has been designed to satisfy a stability requirement that the coil recovers to fully superconducting state following the occurence of a sufficiently long
normalcy. In this case, the temperature of the normalcy is specified to be more than
2 0 K. In order to confirm this requirement, eighteen heaters are installed in the
conductor. Each heater has a length of 32 cm, corresponding to one sixth turn.
Voltage taps and thin film carbon thermometers are attached on the conductor. The stability test was carried out with changing the heating length from one sixth turn to one turn and wlth increasing the transport current.
Fig. 3 shows the voltage and the temperature profiles of the conductor in the innermost turn at 6 kA after one turn heating. In this case, the highest magnetic field is 1 0 T. After the innermost turn becomes normal and the temperature reaches more than 2 0 K by heating, the normalcy recovered spontaneously to the super- conducting state in 5.7 sec, as shown in Fig. 3. This result shows that the stability requirement is completely satisfied. A heat flyx, calculated from the generated voltage and the transport current, is 1 . 0 8 W/cm .
Fig. 4 - Normal front velocity in each zone as a function of transport current.
Fig. 4 shows a normal front velocity in each zone as a function of transport current with the back-up field from the CTCs. These values were calculated from the voltage gradient (dV/dt) during shrinking. The velocity
COII Current
at 6 kA is 0.1. - 0 . 4 m/sec. And from Fig.4, the minimum propagation current is predicted to be
6.5 IrA at 1 0 . 7 T. This will be verified by up-
grading the field with two more supplementary >
5 0
back-up coils in the next experiment. S
W
>
neater Stycast Rovphened and CuO
5
i-
1-0.5
3 o z
Temperature of the Conductor (~nnermost turn1
051Bm,,x 5j5 6kg 7b3 867 '.
Bmin 382 4.96 6 10 7 24 837
- ( T I TRANSPORT CURRENT (ka)
1 3 4 5 6 , 2
-
-
. VH4 v~5p VH3 *,:,
T I M E ( s e c l T I M E (secl
i * - 1 0 -
Fig. 3 - Voltage and temperature profiles Fig. 5 - Temperature and pressure rise
on the innermost one turn in the middle due to manual. dumping from 5 . 4 k A with a
pancake at 6 M after heater input. time constant of 4 . 0 sec.
JOURNAL DE PHYSIQUE
V I - MANUAL DUMPING TEST
A manual dumping t e s t o f t h e TMC-I was c a r r i e d o u t t o c h e c k p o s s i b l e damage due t o h i g h v o l t a g e , and
t o measure t h e dump l o s s e s , t h e t e m p e r a t u r e r i s e of 150- t h e c o n d u c t o r and t h e p r e s s u r e r i s e of h e l i u m i n t h e
c o i l due t o t h e l o s s e s g e n e r a t e d by t h e c h a n g i n g
f i e l d . The dumping t e s t was performed w i t h c h a n g i n g -
t h e t i m e c o n s t a n t and w i t h i n c r e a s i n g t h e t r a n s p o r t - 2 100- c u r r e n t . The t i m e c o n s t a n t i s v a r i e d by c h a n g i n g a
a dump r e s i s t a n c e . The TMC-I was dumped w i t h two ",
1
s e p a r a t e modes: (1) s i n g l e dump mode (TMC-I o n l y ) ,
a( 2 ) t o t a l dump mode (TMC-I and CTCs). 5
D
