NEA-1507: WIMSD5, Deterministic Multigroup Reactor Lattice Calculations

Program-name Package-ID Status WIMSD5A NEA-1507/01 Obsolete WIMSD5 NEA-1507/02 Obsolete WIMSD-5B(98/11) NEA-1507/03 Obsolete WIMSD-5B.12 NEA-1507/04 Tested

Machines used: Package-ID Orig.Computer Test Computer NEA-1507/04 Many Computers DEC ALPHA W.S.

3. DESCRIPTION OF PROGRAM OR FUNCTION - The Winfrith improved multigroup scheme (WIMS) is a general code for reactor lattice cell calculation on a wide range of reactor systems. In particular, the code will accept rod or plate fuel geometries in either regular arrays or in clusters and the energy group structure has been chosen primarily for thermal calculations. The basic library has been compiled with 14 fast groups, 13 resonance groups and 42 thermal groups, but the user is offered the choice of accurate solutions in many groups or rapid calculations in few groups. Temperature dependent thermal scattering matrices for a variety of scattering laws are included in the library for the principal moderators which include hydrogen, deuterium, graphite, beryllium and oxygen.
WIMSD5 is a successor version of WIMS-D/4.

4. METHOD OF SOLUTION - The treatment of resonances is based on the use of equivalence theorems with a library of accurately evaluated resonance integrals for equivalent homogeneous systems at a variety of temperatures. The collision theory procedure gives accurate spectrum computations in the 69 groups of the library for the principal regions of the lattice using a simplified geometric representation of complicated lattice cells. The computed spectra are then used for the condensation of cross-sections to the number of groups selected for solution of the transport equation in detailed geometry. Solution of the transport equation is provided either by use of the Carlson DSN method or by collision probability methods. Leakage calculations including an allowance for streaming asymmetries may be made using either diffusion theory or the more elaborate B1-method.
The output of the code provides eigenvalues for the cases where a simple buckling mode is applicable or cell-averaged parameters for use in overall reactor calculations. Various reaction rate edits are provided for direct comparison with experimental measurements.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM - As variable dimensions are used in WIMS, there are no specific limits on such parameters as number of energy groups or mesh intervals other than an overall limit on the core storage of the computer used. The library of cross-sections has only 69 energy groups. Flexibility is provided for running problems with a smaller number of groups.

6. TYPICAL RUNNING TIME -

7. UNUSUAL FEATURES OF THE PROGRAM -

9. STATUS
NEA-1507/01: 01-AUG-1997 Obsolete
NEA-1507/02: 22-FEB-1999 Obsolete
NEA-1507/03: 25-FEB-2004 Obsolete
NEA-1507/04: 25-FEB-2004 Tested at NEADB

10. REFERENCES  -
NEA-1507/04:
- ANSWERS Software Service, AEA Technology:
  WIMSD A Neutronics Code for Standard Lattice Physics Analysis
  (June 1997)
- M.J. Halsall and C.J. Taubman:
  The "1986" WIMS Nuclear Data Library
  AEEW-R 2133 (September 1986)
- T. Kulikowska:
WIMSD-5B Extensions

11. MACHINE REQUIREMENTS -

12. PROGRAMMING LANGUAGE(S) USED -
NEA-1507/04: FORTRAN-90

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED -
MVS (IBM), UNIX, VMS, MSDOS.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS -
WIMSD5 can now run on a variety of platforms such as IBMs running MVS, SUNs running UNIX and VAXes running MVS. It can be run also on PCs if compilers are used allowing extended memory.

15. NAME AND ESTABLISHMENT OF AUTHORS -
         ANSWERS Software Service
         AEA Technology
         Winfrith
         Dorset DT2 8DH, U.K.

16. MATERIAL AVAILABLE -
NEA-1507/04:
WDN29.ASC         ASCII Library                                       0 records
WILLIE.FOR        Fortran source file to convert library              0 records
/SOURCE/          Fortran Source files                                0 records
/VERIN/           Input data for test cases                           0 records
/VEROUT/          Output files for test cases                         0 records
LOADSRCNEA.BAT    Batch file to install the PC version                0 records
UPD.FOR           Update program Fortran source file                  0 records
WIMSD5B.UPD       Upd to generate srce non platform dependent         0 records
WIMSD5B.FOR       WIMSD5B source code non platform dependent          0 records

17. CATEGORIES -

- B. Spectrum Calculations, Generation of Group Constants and Cell Problems

Keywords: CELL CALCULATION, COLLISIONS, MULTIGROUP, NEUTRON TRANSPORT THEORY, REACTOR LATTICES, THERMAL REACTORS,