CCC-0254 ANISN-ORNL.

1. NAME OR DESIGNATION OF PROGRAM:  ANISN-ORNL.

3. DESCRIPTION OF PROBLEM OR FUNCTION

ANISN solves the one-dimensional Boltzmann transport equation for neutrons or gamma rays in slab, sphere, or cylinder geometry.  The source may be fixed, fission, or a subcritical combination of the two.  Criticality search may be performed on any one of several parame-ters.  Cross sections may be weighted using the space and energy dependent flux generated in solving the transport equation.

ANISN superseded DTF-II (NAA-SR-10951, March 1966) which followed a series of develop-mental efforts over a period of years.  An early version, DSN, was developed in the FLOCO language by Bengt Carlson of the Los Alamos Scientific Laboratory.  A revision of DSN, called DTK, was written to incorporate improved convergence technique and ease of operation.  DTF was a FORTRAN version of DTK written by UNC and LASL personnel.  DTF-II evolved from DTF at Atomics International and in turn evolved into ANISN.

In January 2007, the ANISN-ORNL package was updated to add new executables that were compiled under the Windows XP operating system using the Lahey-Fujitsu Fortran 95 version 5.7 compiler. This update was necessary because Lahey F77L3-EM/32 Version 5.1 executables in the previous release are incompatible with WindowsXP and generate stack fault errors when invoked.

Other older mainframe and workstation versions of ANISN-ORNL are retained in this package because the source files contain machine-dependent coding worth preserving. The older versions were not modified in the 2007 update.

4. METHOD OF SOLUTION

The solution technique is an advanced discrete ordinates method which represents a general-ization of the method originated by G. C. Wick and greatly developed and extended to curvilinear geometry by B. G. Carlson at Los Alamos Scientific Laboratory.

ANISN was designed to solve deep-penetration problems in which angle-dependent spectra are calculated in detail.  The principal feature that makes ANISN suitable for such problems is the use of a programming technique with optional data-storage configurations which allows execution of small, intermediate, and extremely large problems.  ANISN also includes a technique for handling general anisotropic scattering, pointwise convergence criteria, and alternate step function difference equations that effectively remove the oscillating flux distributions sometimes found in discrete ordinates solutions.  Improvements are made for the Cray and IBM RISC versions.  They include the addition of 3 arrays; 29$ (regions by interval) 59$ (unit # for input and output), and 60$ (Kword of storage).

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:  
Problem size is limited only by machine size.

6. TYPICAL RUNNING TIME

Depending on problem size, type, and convergence, running time has varied from less than one minute to several hours. Test cases run in seconds on a Pentium IV computer running Windows XP or Windows Vista.

Older versions: On the IBM 3033 the adjoint air neutron sample problem required about 45 seconds.  The other ten sample cases ran in about 30 seconds. On the Cray XMP-14, the adjoint problem ran in .2 minute.  The 10 sample problems took .11 minute. On a Northgate 486/66 PC most sample problems ran in 5 seconds or less. The IBM RS/6000 took approximately 5 seconds to run the 10 sample problems.

8. RELATED AND AUXILIARY PROGRAMS

The CCC-0650/DOORS 3.2a package includes ANISN, DORT and TORT codes and runs on WindowsXP, Linux and some unix systems. DOORS can be used for one-, two-, and three-dimensional discrete ordinates neutron/photon transport calculations. ANISN is functionally equivalent in both packages but was updated to build with different compilers and operating systems in the DOORS package, which includes a PC version built under Windows XP with the Portland Group Fortran 4.0-2 and Portland Group C 4.0-2 compilers.

10. REFERENCES

- R. Douglas O'Dell and Raymond E. Alcouffe: Transport Calculations for Nuclear Analyses: Theory and Guidelines for Effective Use of Transport Codes LA-10983-MS and UC-32 (September 1987).
- M.G. Nurdin: Ameliorations apportees a l'utilisation des codes de transport ANISN, DOT et MORSE, Note Technique No. 245 (EXPER), 40083/CAD/NUC5 (18 January 1990).
- F. Wasastjerna: Implementation of ANISN on the HP/UNIX System, VTT Technical Report RFD-19/92 (August 1992).
- D. Kent Parsons: "ANISN/PC MANUAL," EGG-2500 (December 1988). This is the manual for CCC-0514/ANISN-PC and is available upon request. Even though there are some differences for input specifications, the ANISN/PC manual can be helpful. The primary difference between the two codes is that ANISN/PC reads cross sections in CCCC ISOTXS format with a limit of 25 energy groups but cannot read an ANISN library in binary format.

- W. W. Engle Jr., and F. R. Mynatt:
"A Comparison at Two Methods of Inner Iteration Conver-gence Acceleration in
Discrete Ordinates Codes," Transactions of ANS, Volume II, No. 1 (June 1968).
- ANISN Updates and Additional Information (1971-1977).
- L. M. Petrie:
"Informal Notes on Use of ITIME Assembler Routine in IBM Version," ORNL (May
1973).
- "Modifications Included in the July 1988 ANISN Updates," ORNL Informal Notes
(July 1988).
- "README.1ST," IBM RISC Implementation Notes (4/94).
- W. W. Engle, Jr.:
"ANISN, A One-Dimension-al Discrete Ordinates Transport Code with Anisotropic
Scattering," K-1693 (March 1967).
- R. W. Roussin:
"Using ANISN to Reduce the DLC-2/100-Group Cross-Section Data to a Smaller
Number of Groups," ORNL-TM-3049 (May 1969).
- W. W. Engle, M. A. Boling, and B. W. Colston, "DTF-II, A One-Dimensional,
Multigroup Neutron Transport Program," NAA-SR-10951 (March 1966).

11. MACHINE REQUIREMENTS

ANISN-ORNL is operable on Pentium IV computers under WindowsXP. The older versions ran on IBM 3033, CRAY XMP-2, VAX family, or IBM RS/6000 computers.

Tested at the NEADB on:
- COMPUTER : Dell INTEL Duo E6550, 2.33 GHz (for Windows)
- OPERATING SYSTEM : DOS, under Windows XP Pro SP 3
- COMPILER: lahey/Fujitsu F 95 v7.1 (Windows)

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

The Windows version contains executables created on a Pentium IV under Windows XP using the Lahey-Fujitsu Fortran 95 version 5.7 compiler. The executables were tested at RSICC on a Pentium IV running Windows XP SP2 and were also tested under Windows Vista.

Also included on the distribution CD are the following unmodified, older versions. The IBM 3033 version ran under OS/VS2 (MVS) using the VS Fortran compiler with the 'LANGLVL(66)' option or a Fortran H compiler.  The CRAY version used the CFT compiler with FORTLIB under CTSS; under UNICOS, the CFT77 compiler was used.  The VAX version ran under VMS 4.6 using the VMS Fortran (version 4.7) compiler with the /NOOPTIMIZE and /NOF77 switches.

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by: Radiation Shielding Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, USA
Developed by:   ORNL, Oak Ridge, Tennessee, U.S.A (IBM 3033, CRAY, IBM RS/6000)
                Infintum Sciences Limited, Ottawa, Ontario, Canada (VAX)
                Battelle, Columbus, Ohio, U.S.A (PC 386)
                R. Tayloe Engineering. Consultancy, Inc., Upper Arlington, OH
                   (Windows)

Windows executables
Fortran source codes for all versions JCL
sample input and output
electronic documentation