HAL Id: jpa-00223680
https://hal.archives-ouvertes.fr/jpa-00223680
Submitted on 1 Jan 1984
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
DEVELOPMENT OF SUPERCONDUCTORS FOR FUSION
P. Komarek
To cite this version:
P. Komarek. DEVELOPMENT OF SUPERCONDUCTORS FOR FUSION. Journal de Physique
Colloques, 1984, 45 (C1), pp.C1-111-C1-119. �10.1051/jphyscol:1984125�. �jpa-00223680�
JOURNAL DE
PHYSIQUEColloque C1, supplCment a u no
I,
Tome 45, janvier 1984 page C1-121ASSEMBLY AND COMMISSIONING OF T H E J E T MAGNETS
M. Huguet, J . R . L a s t , R. PEhlchen, J.A. Booth, D. Cacaut and A.P. P r a t t
JET
Joint Undertaking, CuZham, U.K.
RESUME
L'assemblage d e l ' a i m a n t t o r o Z d a l d e 384 t o n n e s , 380 MW e t 5 GJ e t d e s b o b i n e s p o l o i d a l e s d e 360 t o n n e s , 3200
IN,
e t 2 G J du Tokamak JET e s t d b c r i t . La m i s e e n s e r v i c e a i n s i que l e s p r e m i s r e s d b c h a r g e s a v e c plasma s o n t bgalement p r b s e n t b e s . ABSTRACTAssembly of t h e 384 t o n s , 380 ?&V, 5 G J t o r o i c i a l magnet and t h e 360 t o n s , 3200 PIW, 2 G J p o l o i d a l c o i l s o f t h e JET Tokamak i s d e s c r i b e d . Commissioning i n c l u d i n g f i r s t plasma p u l s e s i s a l s o r e p o r t e d .
INTRODUCTION
The J o i n t European T o r u s (JET) i s t h e l a r g e s t p r o j e c t i n t h e f i e l d o f n u c l e a r f u s i o n r e s e a r c h o f t h e EAEC and i t i s f i n a n c e d and s t a f f e d by t h e c o u n t r i e s o f t h e EEC p l u s Sweden and S w i t z e r l a n d . JET i s a Tokamal. d e s i g n e d t o o p e r a t e w i t h plasmas a p p r o a c h i n g t h o s e needed f o r a f u s i o n r e a c t o r . The JET o p e r a t i o n s t a r t e d a s p l a n n e d i n June 1983 and i s e x p e c t e d t o s t o p i n 1990. During t h i s p e r i o d , a d d i t i o n a l h e a t i n g power u s i n g n e u t r a l beams and r a d i o - f r e q u e n c y w i l l b e added. I n t h e l a t e r s t a g e s o f o p e r a t i o n Deuterium-Tritium plasmas w i l l b e g e n e r a t e d s o t h a t f u s i o n r e a c t i o n s can o c c u r and t h e h e a t i n g e f f e c t o f t h e Cx p a r t i c l e s c a n b e s t u d i e d . / I / .
The main p a r a m e t e r s o f t h e machine a r e g i v e n i n T a b l e I. The t o r o i a a l m a g n e t i c f i e l d (TF) i s g e n e r a t e d by 32 D s h a p e d c o i l s which have no b e n d i n g s t r e s s e s due t o t h e magnetic f i e l d . D e t a i l s o f t h e TF c o i l s h a v e a l r e a d y been r e p o r t e d / 2 , 3 / .
The p o l o i d a l f i e l d (PF) s y s t e m i n c l u d e s t h e primary winding o r c o i l no 1 c l o s e t o t h e machine a x i s which i n d u c e s t h e c u r r e n t i n t h e plasma. The c o u p l i n g between primary and plasma i s improved by means of a t r a n s f o r m e r c o r e w i t h e i g h t r e t u r n l i m b s . The o t h e r PF c o i l s n o s 2 , 3 and 4 c o n t r o l t h e plasma s h a p e and p o s i t i o n . The PF c o i l s and magnetic c i r c u i t have a l r e a d y been d e s c r i b e d / 4 / .
T a b l e I - Main p a r a m e t e r s o f JET and JET magnets
Plasma minor h o r i z . r a d . 1 - 2 5 m Plasma rainor v e r t . r a d . 2 - 1 0 m Plasma major r a d i u s 2 . 9 6 m '(ax f l a t t o p of p u l s e 20 s W t of a l l TF c o i l s 384 t o n s W t o f a l l PF c o i l s 360 t o n s B t of t r a n s f o r m e r c o r e 2700 t o n s W t of vacuum v e s s e l 100 t o n s TF c o i l s ( b a s i c p e r f o r n a n c e / f u l l performance)
Peak power 250/380 MW F i e l d a t plasma c e n t r e 2 . 8 / 3 . 4 T
C o i l c u r r e n t 53/66 kA
Energy p e r p u l s e 5 G J i n 30 s / 5 G J i n 20 s
4 v e r t i c a l
2 158 1 0 . 9 1
45 20 PF c o i l s - Type Number
F i e l d t y p e Number o f c o i l s W t a l l c o i l s t o n s O u t e r d i a m e t e r m Max c u r r e n t kA Pifax v o l t a g e t o e a r t h kV
1 m a g n e t i s i n g
8 90 2 . 1 7
40 20
2 v e r t / r a d i a l
2 2 8 4.84 45/20 20/3
3 m a c / v e r t / r a d
2 84 8 . 3 7 40/45/20 20/20/3
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1984125
JOURNAL D E PHYSIQUE
I
-
ASSEMBLY OF THE TOROIDAL FIELD MAGNET -.The TF c o i l s a r e o n e component o f t h e t o r o i d a l assembly which i n c l u d e s t h e
mechanical s h e l l s t r u c t u r e which s u p p o r t s t h e c o i l s a g a i n s t e l e c t r o r . ~ e c h a n i c a l f o r c e s and t h e vacuum v e s s e l which c o n t a i n s t h e plasma. The t o r n i d n l assembly is s p l i t i n t o 8 i d e n t i c a l s e c t o r s o r o c t a n t s each c o m p r i s i n g 4 TF c o i l s and one o c t a n t of t h e mechanical s t r u c t u r e and o f t h e vacuum v e s s e l .
Assembly s t a r t e d by f i t t i n g 1/2 o c t a n t o f t h e mechanical s t r u c t u r e i n t o a c r a d l e shaped j i g . Two TF c o i l s were t h e n lowered and l o c k e d i n p o s i t i o n i n g r o o v e s on t h e i n s i d e s u r f a c e o f t h e s t r u c t u r e ( f i g u r e 1). T h i s u n i t , was t h e n l i f t e d , r o t a t e d t o an u p r i g h t p o s i t i o n and f i x e d on o n e s i d e o f t h e s l i d i n g t a b l e of t h e o c t a n t assembly f i x t u r e . T h i s p r o c e d u r e was r e p e a t e d f o r t h e o t h e r 1/2 o c t a n t .
The o c t a n t of t h e vacuum v e s s e l , was t h e n i n s e r t e d on t h e c e n t r a l s u p p o r t o f t h e assembly f i x t u r e , and t h e 2 o u t e r t a b l e s r o t a t e d s o t h a t t h e 1/2 o c t a n t s of t h e s t r u c t u r e and c o i l s e n c l o s e d t h e v e s s e l , ( f i g u r e 2 ) . The two 1 / 2 o c t a n t s were t h e n b o l t e d and keyed t o g e t h e r t o e n s u r e a s t r o n g s h e a r j o i n t . A u x i l i a r i e s s u c h a s bus b a r s , w a t e r m a n i f o l d s , h o s e s and i n s t r u m e n t a t i o n were t h e n assembled.
A t t h e same t i m e , t h e m a g n e t i c c i r c u i t and t h e c e n t r a l p a r t of t h e m e c h a n i c a l s t r u c t u r e were b e i n g e r e c t e d i n t h e Torus H a l l . These p a r t s which i n c l u d e t h e lower and u p p e r r i n g s and c o l l a r s and t h e i n n e r c y l i n d e r were o p t i c a l l y a l i g n e d a s t h e y a r e t h e mechanical r e f e r e n c e f o r t h e whole machine.
Each completed o c t a n t w e i g h t i n g 120 t o n s was t r a n s f e r r e d i n t o t h e T o r u s H a l l by means o f a l a r g e C-shaped frame a b l e t o l i f t and h o l d t h e o c t a n t i n t h e u p r i g h t p o s i t i o n . The frame l i f t s an o c t a n t from t h e bottom and m a i n t a i n s i t i n an a c c u r a t e v e r t i c a l p o s i t i o n by means o f an a d j u s t a b l e r e s t r a i n i n g arm a t t h e t o p . The v e r t i c a l i t y of t h e c o i l s and t h e o c t a n t a s a whole h a s t o b e a c c u r a t e l y a d j u s t e d t o p e r m i t t h e i n s e r t i o n o f t h e o c t a n t i n t o i t s f i n a l p o s i t i o n ( f i g u r e 3 ) . The upper p a r t o f t h e C frame s t r u c t u r e w i t h t h e c r a n e hook a t t a c h m e n t i s above t h e u p p e r PF c o i l s t h u s a l l o w i n g t h e assembly o r d i s m a n t l i n g of an o c t a n t w i t h t h e PF c o i l s i n t h e i r p a r k e d p o s i t i o n .
The s t r a i g h t p a r t of e a c h TF c o i l f i t s i n t o a c y l i n d r i c a l groove on t h e i n n e r . c y l i n d e r , s o t h a t e a c h c o i l i s l o c a t e d and s u p p o r t e d . The c o i l s were i n i t i a l l y p r e s s e d mechanicalJy and t h e n m a g n e t i c a l l y u s i n g c u r r e n t s up t o 1 5 kA, a g a i n s t t h e i n n e r c y l i n d e r . I n t h i s way c e n t r e p e t a l f o r c e s o f 100 t o n s p e r TF c o i l were produced. A d d i t i o n a l shims which l o c a t e t h e c o i l s a l o n g t h e i r o u t e r c o n t o u r s were t h e n i n s e r t e d . The a c c u r a c y o f p o s i t i o n i n g i s a b o u t 0 . 4 mm f o r t h e s t r a i g h t p a r t and 1 mm f o r t h e o u t e r c o n t o u r . T h i s a c c u r a c y was n o t d i c t a t e d by f i e l d
p e r t u r b a t i o n s o r a s s o c i a t e d f o r c e s b u t by a s s e n b l y r e q u i r e m e n t s . I 1
-
ASSEMBLY OF THE POLOIDAL FIELD COILSC o i l 1 c o n s i s t s o f 8 i d e n t i c a l s u b c o i l s s t a c k e d v e r t i c a l l y a t t h e c e n t r e of t h e machine. A f t e r m a n u f a c t u r e t h e c o i l s were s t a c k e d and shimmed u s i n g an epoxy p a s t e on t h e i r h o r i z o n t a l f a c e s t o g i v e good c o n t a c t and e n s u r e v e r t i c a l i t y . The 6 c e n t r a l c o i l s of t h e 8 were t h e n machined on t h e i r o u t s i d e d i a m e t e r on a v e r t i c a l a x i s l a t h e t o g i v e an a c c u r a t e s u r f a c e ( c y l i n d r i c a l w i t h i n 0 . 2 mm) f o r t h e i n n e r c y l i n d e r and TF c o i l s t o p r e s s a g a i n s t . A f t e r d e l i v e r y t h e 8 c o i l s were s t a c k e d i n t h e Assembly H a l l and d i m e n s i o n a l l y checked ( o u t e r s u r f a c e v e r t i c a l w i t h i n 0 . 5 mm) and b u s b a r s and w a t e r p i p e s were f i t t e d ( f i g u r e 4 ) . The complete s t a c k was
t r a n s p o r t e d by c r a n e t o t h e T o r u s H a l l and i n s e r t e d i n t o t h e c e n t r e of t h e Tokamak.
Type 2 c o i l s were completed a t t h e f a c t o r y r e a d y f o r assembly o n t o t h e Tokamak e x c e p t t h a t t h e l o w e r c o i l had t o b e t u r n e d o v e r u s i n g a s p e c i a l l y d e s i g n e d t o o l . Type 3 and 4 c o i l s were manufactured a s h a l f p a n c a k e s , p r e a s s e m b l e d a t t h e f a c t o r y , d i s m a n t l e d and d e l i v e r e d t o JET a s h a l f p a n c a k e s . The pancakes were s t a c k e d on an a l i g n m e n t t o o l i n t h e Assembly H a l l , c o a t i n g t h e m a t i n g s u r f a c e s w i t h epoxy r e s i n and a p o l y e s t e r o r g l a s s wool mat. When s t a c k i n g was c o m p l e t e , t h e pancakes were clamped and t h e epoxy r e s i n a l l o w e d t o c u r e a t room t e m p e r a t u r e . A f t e r c o m p l e t i o n o f w a t e r m a n i f o l d s and c o n n e c t i o n s t h e c o i l was h e a t e d , by c i r c u l a t i n g h o t w a t e r , a t 60 OC f o r 24 h o u r s , t o complete c u r i n g o f t h e pancake a d h e s i v e . The pancakes w e r e a l i g n e d w i t h i n
+
o r - 2 . 5 mn o f nominal r a d i u s and c o i l mounting p l a t e s were p o s i t i o n e d w i t h i n+
o r-
0 . 5 mm. To move t h e s e c o i l s t h e JET c r a n e i s equipped w i t h4 s e p a r a t e r o p e s which f i t i n t o s p e c i a l l i f t i n g p o i n t s s p a c e d around t h e c o i l p e r i p h e r y . The c o i l s were moved t o t h e T o r u s H a l l u s i n g t h i s 4 r o p e l i f t , which can a l s o b e u s e d f o r r a i s i n g and l o w e r i n g t h e c o i l s f o r m a i n t e n a n c e o p e r a t i o n s on t h e Tokamak.
I 1 1 - COMMISSIONING
F o r t h e t e s t s , of t h e TF magnet t h e c u r r e n t was p r o g r e s s i v e l y i n c r e a s e d u p t o 2 5 kA u s i n g a r e c t i f i e r u n i t f e d d i r e c t l y from t h e m a i n s , t h e n up t o 40 kA u s i n g t h e TF
f l y w h e e l g e n e r a t o r . A t t h i s c u r r e n t l e v e l each c o i l i s p r e s s e d towards t h e a x i s o f t h e machine w i t h a f o r c e o f 700 t o n s and an e n e r g y o f 1 . 2 GJ i s d e l i v e r e d d u r i n g a s i n g l e p u l s e t o t h e magnet, c a u s i n g a t e m p e r a t u r e r i s e of 1 5 OC a l o n g t h e narrow s t r a i g h t n o s e o f t h e c o i l s . The c o o l i n g w a t e r t e m p e r a t u r e peaks a p p r o x i m a t e l y one minute a f t e r t h e s t a r t o f t h e p u l s e and r e t u r n s t o i t s a v e r a g e l e v e l w i t h i n 3 m i n u t e s . The c o i l e x p a n s i o n h a s been measured i n t h e v e r t i c a l and r a d i a l d i r e c t i o n s and conforms t o c a l c u l a t e d v a l u e s c o n f i r m i n g t h a t b e n d i n g s t r e s s e s a r e e f f e c t i v e l y e l i m i n a t e d by t h e D s h a p e . During t h e s e t e s t s t h e c o i l s were p r o t e c t e d a g a i n s t e a r t h f a u l t s by a n e a r t h l e a k a g e d e t e c t o r , and a g a i n s t i n t e r n a l s h o r t c i r c u i t by a s y s t e m which compares t h e v o l t a g e o f a d j a c e n t c o i l s .
The PF c o i l s were t e s t e d a t 4 5 kV t o e a r t h and a t i n t e r t u r n v o l t a g e s between 565 and 2800 v o l t s / t u r n . The i n t e r t u r n t e s t was made by d i s c h a r g i n g a 4 5 VF c a p a c i t o r i n t o t h e c o i l . The ground i n s u l a t i o n t e s t s w i l l b e r e p e a t e d a f t e r t h e c o i l s have been f i l l e d w i t h w a t e r .
The PF c o i l s have been t e s t e d (and u s e d f o r plasma p r o d u c t i o n ) c o n n e c t e d t o t h e main power s u p p l y a t up t o h a l f t h e maximum c u r r e n t i n c o i l 1 and a t r e l a t i v e l y low c u r r e n t i n t h e o u t e r c o i l s w i t h o u t w a t e r c o o l i n g and w i t h o u t complete i n s t r u - m e n t a t i o n . These t e s t s showed f i e l d c o n f i g u r a t i o n s i n agreement w i t h c o m p u t a t i o n s . When t h e c o i l s a r e f i n a l l y t e s t e d a t f u l l power t h e f o l l o w i n g w i l l b e measured - v o l t a g e , c u r r e n t , ampere t u r n s , f l u x , f o r c e s , s t r e s s e s , d i s p l a c e m e n t s and tempera- t u r e - a t o t a l o f 250 measurement c h a n n e l s . The c o i l s w i l l a l s o have a s h o r t c i r c u i t d e t e c t o r which compares ampere t u r n s i n s i m i l a r c o i l s .
IV - COMBINED TESTS AND FIRST PLASMAS
Combined t e s t s o f t o r o i d a l and p o l o i d a l f i e l d s , which g i v e r i s e t o t w i s t i n g moments on t h e TF c o i l s , have o n l y been c a r r i e d o u t a t low l e v e l due t o t h e l i m i t e d t i m e a v a i l a b l e i n t h e e a r l y commissioning p h a s e . A t t h e s e l e v e l s (2000 t o n - m e t e r s , i . e . 1/10 of t h e maximum e x p e c t e d ) t h e o v e r a l l t w i s t i n g motion o f t h e machine i s i n a c c o r d a n c e w i t h c a l c u l a t i o n s .
On 25-26 J u n e 1983 t h e f i r s t plasma d i s c h a r g e s were g e n e r a t e d and peak plasma c u r r e n t s o f 100 kA o f d u r a t i o n 100 m s were measured. O p t i m i z a t i o n o f plasma c o n t r o l p a r a m e t e r s and improvements o f t h e vacuum v e s s e l i n t e r n a l w a l l c o n d i t i o n i n g l e d t o d i s c h a r g e s w i t h c u r r e n t s up t o 230 kA on 9 J u l y and 600 kA on 26 J u l y .
REFERENCES
/1/ The JET Design p r o p o s a l
-
EUR 5516e, 1976/2/ The d e s i g n o f t h e TF c o i l s f o r t h e J o i n t European T o r u s , POHLCIIEN R . , HUGUET M . , BOOTH J . , 6 t h I n t . Conf. on Magnet Technology (fifT6) - B r a t i s l a v a 1977.
/3/ The m a n u f a c t u r e of t h e TF c o i l s f o r t h e J o i n t European T o r u s . POHLCHEN R . , BOOTH J . , HUGUET M., LEHR K . , BIEDER H . , SEILER D i r . 7 t h I n t . Conf. on Magnet Technology (MT7)
-
K a r l s r u h e (1980)./4/ P o l o i d a l c o i l s and t r a n s f o r m e r c o r e f o r JET - Design and Manufacture LAST J . R . , CACAUT D . , PRATT A.P., RAUCH J . C . , FERRY P . J . , ARENSMANN U . , ALVAREZ A . , 1 2 t h SOFT, J f l l i c h .
Cl-124 JOURNAL
DE
PHYSIQUEF i g . 1 Assembly o f a TF c o i l i n F i g . 2 O c t a n t u n d e r c o n s t r u c t i o n . The t h e m e c h a n i c a l s t r u c t u r e . h a l f o c t a n t s a r e now r e a d y t o b e c l o s e d
around t h e vacuum v e s s e l i n t h e m i d d l e .
F i g . 3 T r a n s f e r o f a completed o c t a n t . The F i g . 4 PF c o i l 1 b e i n g s t a c k e d i n D shaped TF c o i l s a r e c l e a r l y v i s i b l e . On Assembly H a l l . The o u t e r s u r f a c e i s t h e r i g h t t h e o u t e r PF c o i l s a r e lowered i n c o v e r e d w i t h a low f r i c t i o n
a p a r k e d p o s i t i o n . m a t e r i a l .
F i g . 5 PF c o i l 4 b e i n g lowered o n t o t h e F i g . 6 The JET machine.
machine u s i n g t h e 4 r o p e f e a t u r e o f t h e c r a n e . A v e r t i c a l limb o f t h e magnetic c i r c u i t i s i n t h e f o r e g r o u n d .
