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COBRA-I I A//iA PROGRAM FOR THERMAL-HY DRAULICANALY SI S IN VERY LARGE BUNDLESOF FUEL PINS

BNWL-1422UC-32,Mathematicsand ComputersCOBRA-IIAA PROGRAM FOR T H E R M A L - H Y D R A U L I C A N A L Y S I S I N VERY L A R G EBUNDLES OF FUEL P I N SC. L. WheelerG. C. Main(a!D. C. Kolesar (b)August 1970BATTELLE MEMORIAL INSTITUTEPACIFIC NORTHWEST LABORATORIESRICHLAND, WASHINGTON 99352(a) Author employed by Computer Sciences Corporation(Northwest Operations), Richland, Washington(b) Author now employed by WADCO Corpprationa Subsidiary of Westinghouse Electric Corp.,under AEC Contract No. AT(45-1)-2170

P r i n t e d i n t h e U n i t e d S t a t e s o f AmericaA v a i l a b l e fromC l e a r i n g h o u s e f o r F e d e r a l S c i e n t i f i c and T e c h n i c a l I n f o r m a t i o nN a t i o n a l Bureau o f S t a n d a r d s , U . S . D e p a r t m e n t o f CommerceS p r i n g f i e l d , V i r g i n i a 22151P r i c e : P r i n t e d Copy 3 . 0 0 ; M i c r o f i c h e 0 . 6 5

COBRA-IIAA PROGRAM F O R T H E R M A L - H Y D R A U L I C A N A L Y S I S I N V E R Y L A R G EBUIVDLES O F F U E L P I N SC.L.Wheeler, G.C.M a i n a n d D.C.KolesarABSTRACTA d e s c r i p t i o n i s g i v e n o f t h e d i g i t a l computer programCOBRA-IIA.T h i s p r o g r a m i s a n e x t e n s i o n o f t h e COBRA I I c o d ew r i t t e n a t t h e P a c i f i c Northwest L a b o r a t o r i e s f o r r o d bundles u b c h a n n e l a n a l y s i s i n v o l v i n g s t e a d y - s t a t e s i n g l e o r twop h a s e f l o w . The b a s i c method o f c a l c u l a t i o n u s e d i n COBRAhas been r e t a i n e d , w i t h a f i n i t e d i f f e r e n c e s o l u t i o n o b t a i n e da t each a x i a l node.T y p i c a l l y , t h e volume t h e a x i a l nodeapproximates i s t h e e n t i r e subchannel of incremental depth.An e x t e n s i v e s e t o f r e f i n e m e n t s h a s b e e n made t o t h e COBRA 1 1c o d e t o a l l o w a n a l y s i s o f v e r y much l a r g e r b u n d l e s o f r o d s ,w i t h s i g n i f i c a n t l y l e s s complex i n p u t a n d s e v e r a l model a d d i t i o n s , including the e f f e c t s of r o t a t i n g spacer wires.Thosef e a t u r e s w h i c h d i f f e r f r o m t h e COBRA I 1 c o d e a r e d e s c r i b e d i nt h i s r e p o r t i n some d e t a i l .Program d o c u m e n t a t i o n a n d i n p u ti n s t r u c t i o n s , a s w e l l a s sample problems a r e p r o v i d e d .

T A B L E OF C O N T E N T S. . . . . . .LISTOFTABLES . . . . . . .INTRODUCTION . . . . . . . .LARGE PROBLEM SOLUTIONS . . .Parameters . . . . . . .New V e r s i o n s o f COBRA.IIA .A r r a y KCHAN . . . . . . . .A r r a y DD . . . . . . . . .A r r a y AAA . . . . . . . . .S u b r o u t i n e DIVERS . . . . .O u t p u t Save O p t i o n . . . .Time Checks . . . . . . . .Input . . . . . . . . . . .PCFDataFiles . . . . . .Form o f PCF D a t a F i l e s . .Program I n p u t L o g i c . . . .Geometry I n p u t . . . . . .SPECIAL NEW FEATURES . . . . .Wire-Wrap Model . . . . . .Flow S p l i t . . . . . . . .BypassCalculations . . . .Intrinsic Material Correlations .REFERENCES . . . . . . . . . . . . .LIST OF FIGURESAPPENDIX A :.COBRA-IIA ELEMENTS AND EXTERNAL.REFERENCES .viivii122344466888999111114171718A-1

APPENDIX D:. . .O S E D I T . OUTPUT-SAVED E D I T PROGRAM . . . . .INPUT INFORMATION . . . . . . . . . . . . .APPENDIX E :SAMPLE PROBLEMSAPPENDIX 3 :APPENDIX C :LDATA . L I S T AND PREPARE DATA PROGRAM. . . . . . . . . . . . . .B- 1C-1D- 1E- 1

L I S T OF F I G U R E ST y p i c a l Run t o C r e a t e L a r g e Problem V e r s i o n fromS t a n d a r d COBRA-IIA5T y p i c a l I n p u t DeckCOBRA-IIA I n p u t and PCF F i l e O u t p u t L o g i cS i g n i f i c a n c e of D i r e c t i o n o f Wire R o t a t i o n on Model13I l l u s t r a t i o n o f A r b i t r a r y N a t u r e o f R o t a t i n g WireC o o r d i n a t e System15Example o f R o t a t i n g W i r e C o o r d i n a t e S y s t e m16C a r d I n p u t S e q u e n c e f o r LDATAB-3217-Pin Bundle1 / 1 2 S e c t i o n ModelE-2217-Pin Bundle1 / 2 S e c t i o n ModelE-3L I S T OF TABLES1P a r a m e t e r s Used i n Two V e r s i o n s o f COBRA-IIA

COBRA-I I AA PROGRAM FOR T H E R M A L - H Y D R A U L I C A N A L Y S I S I N VERY L A R G EBUNDLES O F FUEL P I N SC.L . Wheeler, G .C.M a i n and D.C.KolesarINTRODUCTIONThe COBRA-IIA d i g i t a l computer program i s an e x t e n s i o no f COBRA 11.A s w i t h t h e p a r e n t code, a s o l u t i o n i s foundf o r an i n i t i a l v a l u e problem i n a m u l t i c h a n n e l g e o m e t r y .Time i n v a r i a n t s i n g l e and t w o - p h a s e f l o w i s p e r m i t t e d .Thec o o l a n t i n e a c h c h a n n e l i s d e s c r i b e d by a lumped model i nwhich t h e f l u i d i n e a c h n o d a l c e l l i s presumed t o b e i n auniform s t a t e .Energy and most o f t h e momentum i s t r a n s f e r -r e d according t o t h e impressed g r a d i e n t s .Then mass i sd i v e r t e d a p p r o p r i a t e l y t o s a t i s f y c o n t i n u i t y o f mass andmomentum r e q u i r e m e n t s w i t h a n u p d a t i n g o f t h e e n e r g y b a l a n c e .The COBRA I 1 program p o s s e s s e s t h e d i s a d v a n t a g e of b e i n gl i m i t e d i n t h e s i z e o f t h e problems i t c a n c o n s i d e r .Further-more, a s t h e problem s i z e i n c r e a s e s , t h e i n p u t c o m p l e x i t yl e a d s t o l o n g p r e p a r a t i o n t i m e s and e x t e n s i v e i n p u t . Thesel i m i t a t i o n s , a s w e l l a s t h e a v a i l a b i l i t y of c e r t a i n f e a t u r e sp r e v i o u s l y b u i l t i n t o a v e r s i o n of COBRA u s e d f o r FFTF d e s i g n ,l e d t o t h e development o f a s p e c i a l i z e d Univac 1108 v e r s i o n ,COBRA- I IA.COBRA-IIA employs a scheme t o t r a n s l a t e f u l l b u n d l ed e s c r i p t i o n t o a d e q u a t e program d e s c r i p t i o n o f a s m a l l e r s e g ment c u t a l o n g l i n e s o f symmetry b u t e x c l u s i v e o f c o n n e c t i o n s .F u r t h e r m o r e , a s p e c i a l i z e d w i r e wrap model i s i n c l u d e d . T e s t i n g o f t h i s model h a s been l i m i t e d by t h e s c a n t e x p e r i m e n t a ldata available.to date.However, t h e r e s u l t s have been e n c o u r a g i n g

S p e c i a l programming h a s b e e n employed t o r e d u c e t h e comp l e x i t y of i n p u t .F o r e x a m p l e , v a r i o u s d a t a c a n b e s t o r e d ona t a p e o r on a F a s t r a n d Drum f i l e t o b e u s e d a s p a r t i a l i n p u tf o r a problem.C o n s e q u e n t l y , t h e t i m e t o s e t up a p r o b l e m i sreduced s i g n i f i c a n t l y .Special "fixes"t o o b t a i n a s t a b l e s o l u t i o n have beenr e q u i r e d i n some p r o b l e m s .LARGE PROBLEM SOLUTIONSOne o f t h e p r i n c i p a l g o a l s i n t h e development o f t h i sprogram was t h e economic s o l u t i o n o f l a r g e p r o b l e m s w i t h o u tcompromising a c c u r a c y o r any of t h e c a l c u l a t i o n a l d e t a i l s i nCOBRA.For example, t h e 217-pin h a l f - b u n d l e problem r e q u i r e df o u r t o f i v e t i m e s t h e a v a i l a b l e Univac 1108 memory when u s i n gCOBRA 11.I n o r d e r t o be a b l e t o s o l v e t h e p r o b l e m , s e v e r a l ofLt h e l a r g e r e c t a n g u l a r a r r a y s were e l i m i n a t e d o r r e s h a p e d t oe x c l u d e a l l u n n e c e s s a r y z e r o e s , and t h e b a s i c m a t r i x s o l u t i o nwas reprogrammed.Because o f t h e b u l k o f o u t p u t d a t a , p r o v i -s i o n i s made t o c o l l e c t c h a n n e l o u t p u t d a t a on t a p e f o r p r i n t i n g and e d i t i n g i n t h e same o r a l a t e r r u n .Misjudgment ofprogram r u n n i n g t i m e may l e a d t o p r e m a t u r e e x e c u t i o n t e r m i n a tion.The a d v e r s e e f f e c t s o f t h i s have b e e n c i r c u m v e n t e d byc l o c k w a t c h i n g ( s u b r o u t i n e TCHEK) and i n c o r p o r a t i n g DumpRestart options.PARAMETERSTwo F o r t r a n V c o m p i l e r f e a t u r e s a r e u s e d i n COBRA I 1 t oa l l o w t h e u s e r t o r e s h a p e d a t a memory.The f i r s t f e a t u r e i sone which a l l o w s DIMENSION s t a t e m e n t s t o b e g i v e n i n t e r m s o fparameter v a r i a b l e s .The DIMENSION s t a t e m e n t s a r e p r e c e d e d i nc o m p i l a t i o n by a PARAMETER s t a t e m e n t a s s i g n i n g v a l u e s t o e a c hof t h e p a r a m e t e r s .The F o r t r a n V INCLUDE s t a t e m e n t ( u s e d w i t ha n FCOPY b l o c k i n a PDP e l e m e n t ) e n a b l e s t h e same copy of t h ePARAMETER, DIMENSION, and o t h e r common s t a t e m e n t s t o b e u s e d.x

i n a l l subprograms when t h e y a r e c o m p i l e d .Table 1 l i s t s t h ep a r a m e t e r v a l u e s c o m p i l e d i n t o two s t a n d a r d i m p l e m e n t a t i o n so f COBRA- I IA.TABLE 1.ParameterNameParameters Used in Two Versions of lueMA1010MB55MC45227Use o f P a r a m e t e rNumber o f a r e a v a r i a t i o n t y p e sNumber o f b y p a s s c o n n e c t i o n sNumber o f c h a n n e l sNumber o f s p a c e r t y p e sNumber o f g a p s ( c o n n e c t i o n s )Number o f n o d e s , f o r t a b u l a rdataNumber o f columns i n AAANumber o f p r o p e r t y t a b l e e n t r i e sNumber o f r o d sNumber o f gap v a r i a t i o n t y p e sNumber o f w i r e - w r a p t y p e sNumber o f a x i a l nodes i n c o r ea t one t i m eMutual t o t a l d i m e n s i o n f o r AAAi n DIVERT and DIVERSMAAASNumber o f c h a n n e l s p e r r o dNEW V E R S I O N S O F C O B R A - I I AA l l o f t h e program c h a n g e s made t o accommodate l a r g ep r o b l e m s have b e e n i n c o r p o r a t e d i n t o t h e s t a n d a r d v e r s i o n o fCOBRA-IIA, a l t h o u g h some a r e n e c e s s a r y o n l y i n l a r g e - p r o b l e mversions.The p u r p o s e was t o c r e a t e one working program w i t hc a p a b i l i t y t o h a n d l e r o u t i n e l y a l a r g e number o f a n t i c i p a t e dneeds.A change i n one p a r a m e t e r c a r d i n t h e s h a r e d PDPe l e m e n t BASIC and r e c o m p i l a t i o n o f t h e s e t o f F o r t r a n s u b programs which u s e COMMON s t a t e m e n t s i s t h e o n l y s t e pr e q u i r e d t o go from s t a n d a r d COBRA-IIA t o a l a r g e - p r o b l e m