NESC0713 SYN3D

1. NAME OR DESIGNATION OF PROGRAM:  SYN3D

3. DESCRIPTION OF PROBLEM OR FUNCTION

SYN3D solves  the direct  and
adjoint, diffusion theory, static eigenvalue  equations in two and
three dimensions.   The geometries available  are x-y,  r-z, x-y-z
and triangular-z.

4. METHOD OF SOLUTION

SYN3D   uses  single-channel   spatial   flux
synthesis to  calculate   approximate  solutions  to   the  three-
dimensional  (or  two-dimensional)   diffusion  theory  difference
equations.  Synthesis expansion functions must  be supplied by the
user from  two-dimensional (or  one-dimensional) finite-difference
calculations  performed by  some other  code.  SYN3D  sets up  the
synthesis  equations  and  solves them  by  power  iteration  with
Wielandt acceleration.   Each iteration is  an exact  inversion of
the block-tridiagonal synthesis  equations by forward-elimination,
backward-substitution.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The  only  serious
limitation  is on  the product  of the  number of  groups and  the
maximum number of expansion functions used at any particular axial
elevation.

6. TYPICAL RUNNING TIME

Exclusive of the time  required to generate
expansion functions,  SYN3D will  solve an  11-group, 12,000  mesh
point model with  two expansion functions in 0.9  minutes of Model
195 CPU  time.  A  28-group, 30,000  mesh point  model with  three
expansion functions requires 8.9 minutes of  CPU time on the Model
195.  Each 370 sample problem was executed in 1 minute of CPU time
on an  IBM3033.  All  four 7600 sample  problems were  executed in
less than 1 minute of CP time on a CDC7600.

7. UNUSUAL FEATURES OF THE PROGRAM

The  difference equations  SYN3D
solves are  the mesh-interval-centered type.   Expansion functions
should be generated using diffusion  theory codes solving the same
equations.  The code  is designed with restart  capabilities which
reduce, on the average, the  running times for individual problems
when a  series of similar problems  is to be run.   SYN3D requires
input   cross   sections,  expansion   functions,   and   geometry
descriptions in  the Version III formats  defined by the  ERDA RDD
Reactor  Physics  Branch  Computer   Code  Coordination  Committee
(CCCC).  Special options  include group collapsing and  the use of
different  expansion functions  in different  axial  zones of  the
model.

8. RELATED AND AUXILIARY PROGRAMS

SYN3D requires binary input files
containing  cross  sections,  expansion  functions,  and  geometry
descriptions.  Although a small program  is provided with the code
to read  these data  from cards, the  user may  wish to  use other
programs which  generate CCCC files.   LASIP3 (NESC  Abstract 691)
can  be  used  to  generate CCCC  standard  interface  files  from
specially formatted  card input.   A finite-difference,  diffusion
theory  program  is  required  to  generate  expansion  functions.
VENTURE (NESC Abstract 686) is one such program.

10. REFERENCES

C. H. Adams,  SYN3D - A Single-Channel,  Spatial Flux
Synthesis Code for Diffusion  Theory Calculations, ANL-76-21, July
1976.
             B.  M.  Carmichael,  Standard   Interface  Files  and
Procedures  for Reactor  Physics Codes,  Version III,  LA-5486-MS,
February 1974.

11. MACHINE REQUIREMENTS

The 370  version requires as a  minimum 35K
full-word  storage  to  execute  small   problems  and  runs  more
efficiently  with increased  storage capacity.   Depending on  the
complexity of  the problem,  SYN3D may  require up  to 45  logical
units.  To execute the 370's sample problems, 470K words of memory
are needed.   The 7600  version requires  55,000 (octal)  words of
small core memory (SCM).

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  OS/370 (IBM370)
and SCOPE (CDC7600).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

                 C. H. Adams
                 Applied Physics Division
                 Argonne National Laboratory
                 9700 South Cass Avenue
                 Argonne, Illinois  60439

File name	File description	Records
NESC0713_01.001	INFORMATION	28
NESC0713_01.002	SYN-3D SOURCE (F4,EBCDIC)	19216
NESC0713_01.003	BPOINTER,DINAMIC ALLOCATION ROUTINES (ASS.)	501
NESC0713_01.004	CDFILE SOURCE (F4,EBCDIC)	665
NESC0713_01.005	INTERFACE FILES INPUT FOR CDFILE (S.P.1-4)	12
NESC0713_01.006	INPUT DATA FOR CDFILE	1418
NESC0713_01.007	BCD INPUT FOR SYN-3D,S.P.1	7
NESC0713_01.008	BCD INPUT FOR SYN-3D,S.P.2	10
NESC0713_01.009	BCD INPUT FOR SYN-3D,S.P.3	22
NESC0713_01.010	BCD INPUT FOR SYN-3D,S.P.4	26
NESC0713_01.011	PRINTED OUTPUT OF SYN-3D FOR S.P.1	302
NESC0713_01.012	PRINTED OUTPUT OF SYN-3D FOR S.P.2	149
NESC0713_01.013	PRINTED OUTPUT OF SYN-3D FOR S.P.3	813
NESC0713_01.014	PRINTED OUTPUT OF SYN-3D FOR S.P.4	1577
NESC0713_01.015	CDFILE/SYN-3D JCL AT ARGONNE	108
NESC0713_01.016	CDFILE/SYN-3D JCL AT NEA D.B.	122
NESC0713_01.017	OVERLAY FILE	26