NEA-1516 DANCOFF-MC.

1. NAME OR DESIGNATION OF PROGRAM:  DANCOFF-MC.

3. DESCRIPTION OF PROGRAM OR FUNCTION

DANCOFF-MC program was designed to calculate, by Monte Carlo method, the Dancoff factor which is used to determine the flux reduction in resonance integral calculations. DANCOFF-MC allows almost arbitrary arrangement of cylindrical or spherical fuel elements: different fuel region diameters, clads and gaps with different sizes, annular rods, arbitrary positions of rods or spherical pellets, and different macroscopic cross sections for each fuel element and its clad are all permitted. Optionally, it is also possible to calculate the Dancoff factor in a lattice of "grey", i.e., partially transparent,  fuel lumps.

4. METHOD OF SOLUTION

Calculation of Dancoff factors is based on its  collision probability definition. The program calculates the probability that a neutron emitted isotropically from the surface of the fuel region of the fuel element under consideration will have its next collision in the fuel region of any other surrounding fuel  element. This probability is calculated by Monte Carlo method which  is equally applicable in simple and in complicated geometries. Using the Monte Carlo method in the case of DANCOFF-MC means to select randomly the position where the neutron is emitted and the direction in which it travels. The lengths traveled in different material regions and the transport probabilities along any given path are calculated according to analytical formulae.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Fuel rods and pellets cannot be mixed in the same arrangement. The cylinders'axes  must be parallelly positioned in rod arrangements. Calculation of "grey-effect" for annular geometries is not available.

6. TYPICAL RUNNING TIME

Being a Monte Carlo calculation, the running  time depends on the required accuracy. The calculation of one Dancoff factor with 100,000 histories, providing typically a statistical accuracy not worse than 0.001, takes 3 to 10 s on a DEC  AXP 3000/400 computer and 50 to 60 s on a 66 MHz 486 PC if the number of surrounding lumps taken into account lies in the range between 20 to 40.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- S. Feher et al.:
Monte Carlo Calculation of Dancoff Factors in Irregular Geometries
  Nucl. Sci. Eng. 117, 227-238 (1994)

- S. Feher and P.F.A. de Leege:
  DANCOFF-MC - A Computer Program for Monte Carlo Calculation
  of Dancoff Factors in Irregular Geometries
  IRI-131-95-003 (June 1997)

11. MACHINE REQUIREMENTS

DANCOFF-MC runs on DEC AXP, IBM RISC/6000, and IBM 486 personal computers. The main storage (RAM) requirement depends on the number of neighbouring lumps taken into account. Typical problems need 500 Kbytes of main storage.
NEA 1516/01: The NEA Data Bank compiled and ran the program on the following computers: (1)DEC VAX 4000; (2)DEC ALPHA 200-4/166; (3)PC  DELL Optiplex GXi with Pentium 166MHz and 32MB of RAM; (4)HP 9000/7xx; (5)IBM RISC/6000; (6)SUN SPARC sun4u.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

DEC Open VMS Version 6.1 on DEC AXP, S-DOS 6.2 on IBM 486 PC, and IBM AIX Version 3.2 on IBM RISC/6000.
NEA 1516/01: The tests at the NEA Data Bank were performed on the different computers under the following respective platforms: (1) OpenVMS 6.1; (2) OSF1 3.2 62 (DEC UNIX); (3) Windows NT 4.0 (MSDOS window); (4) HP-UX 0.05 & HP-UX 10.20; (5) AIX V4 R1; (6) Solaris 2.0 (SunOS 5.5.1). The following respective compilers were used to compile the source codes: (1) DEC/VMS FORTRAN; (2) DEC FORTRAN f77 and f90; (3) Lahey Fortran 90 V3.5 and MS-FORTRAN Powerstation 4.0; (4) HP f77 Rel. 10.0; (5) IBM f77 (xlf); (6) SUN f77 and f90.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

- S. Feher
  Technical University of Budapest, Institute of Nuclear Techniques
  Budapest, Hungary
- P.F.A. de Leege
  Delft University of Technology, Interfaculty Reactor Institute
  Delft, The Netherlands

PACKING.LST  Packing list
DCMCDOC.PDF  Dancoff-MC User Manual
README.TXT  Description of installation and changes
DCIM_F90.EXE  PC executable for DCMCI
DC37_F90.EXE  PC executable for DCMC37
DCIM_F90.FOR  Complete program source DCMCI
DC37_F90.FOR  Complete program source DCMC37
DC_I_F90.FOR  Subroutine to calculate regular (infinite) lattices
DCMC_F90.FOR  Nucleus subroutine of the Dancoff-MC method
DCIS_F90.FOR  Subrout. to make the subrout. DCMCI callable from SCALE sys.
SMPI1.INP  Sample input 1  for the program DCMCI
SMPI1.OUT  Sample output for SMPI1.INP
SMPI2.INP  Sample input 2  for the program DCMCI
SMPI2.OUT  Sample output for SMPI2.INP
SMPI3.INP  Sample input 3  for the program DCMCI
SMPI3.OUT  Sample output for SMPI3.INP
SMPI4.INP  Sample input 4  for the program DCMCI
SMPI4.OUT  Sample output for SMPI4.INP
SMP371.INP  Sample input 1  for the program DCMC37
SMP371.OUT  Sample output for SMP371.INP
SMP372.INP  Sample input 2  for the program DCMC37
SMP372.OUT  Sample output for SMP372.INP
dcmcim  Script to run the main program DCIM_F90 on UNIX
dcmc37  Script to run the main program DC37_F90 on UNIX
runall  Script to run all sample problems on UNIX
DCMCIM.BAT  Script to run the main program DCIM_F90 on PC
DCMC37.BAT  Script to run the main program DC37_F90 on PC
RUNALL.BAT  Script to run all sample problems on PC