NESC0393 XSDRN.

1. NAME OR DESIGNATION OF PROGRAM:  XSDRN.

3. NATURE OF PHYSICAL PROBLEM SOLVED

XSDRN uses the Nordheim integral  treatment, narrow resonance, or infinite mass approximation to process resonance data on a master cross section library and thus obtain microscopic fine-group cross sections for a large number of nuclides. The code will then use these cross sections in an independent calculation to solve for fluxes, eigenvalues, critical dimensions, etc., using discrete ordinates, diffusion, or an infinite medium theory calculation. The fine-group fluxes thus obtained can then be used to collapse the fine-group cross section data to a more tenable broad-group structure for use in several independent computer codes.

4. METHOD OF SOLUTION

The principal calculations performed by XSDRN (resonance calculation and flux calculation) both employ numerical finite-difference techniques. For the resonance calculation, this involves a Simpsons integration to solve for the collision density in the resonance range. The flux calculations employ a multigroup energy structure, an arbitrary spatial structure and a mechanical angular quadrature, all of which must be used in the various integration and differencing schemes in the code.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The principal restriction is the availability of adequate core storage to build required arrays. The code is flexibly dimensioned which means that array sizes are set for the particular problem at execution time. (Provisions are also available for storing certain large data arrays out of core, if need be.)

6. TYPICAL RUNNING TIME

Typical resonance calculations have been run on the IBM360/75 in from one-half to one minute per nuclide.
A typical flux calculation (S4 P3, 25 space points, 123 energy groups, cylinder, K-calculation, reduce cross sections, 4 resonance  nuclides) generally runs in 10 to 12 minutes. A fixed source calculation for the same system would take approximately the same time.

7. UNUSUAL FEATURES OF THE PROGRAM

The flexible dimensioning scheme employed by XSDRN allows one to make optimal use of core storage.
A unique method of storing cross sections is employed to eliminate input of unnecessary transfer cross sections.

8. RELATED AND AUXILIARY PROGRAMS

The master library tape for XSDRN is produced by XLACS. Cross section tapes can be generated for ANISN (ACC abstract 151), DOT, CITATION (ACC abstract 387), ROD, or the EXTERMINATOR2 (ACC abstract 156) codes.

10. REFERENCES

- N. M. Greene and C. W. Craven, Jr.:
  XSDRN, A Discrete Ordinates Spectral Averaging Code.
  ORNL-TM-2500, July 1969, and Errata
- N. M. Greene:
  XLACS, Cross Section Production Package for XSDRN.
  CTC Report (to be published).
- Description of XSDRN Tape Contents, ACC Note, May 1970.

- N.M. Greene and C.W. Craven, Jr.:
  XSDRN - A Discrete Ordinates Spectral Averaging Code
  ORNL-TM-2500.
- L.L. Bennett:
  Recommended Fission Product Chains for Use in Reactor Evaluation
  Studies
  ORNL-TM-1658
- M.L. Tobias and G.W. Cunningham III
  A Simple Method fo Listing Data Sets in Readable Form
  ORNL-CF-72-7-32

11. MACHINE REQUIREMENTS

On the IBM360/65 approximately 90k words of directly addressable core storage must be available for the program. The various calculational options require from 4 to 13 input/output  devices, depending on the problem. At least one direct-access device is required.

13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED:  OS/360.

14. ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

XSDRN is presently used in a four-level overlay structure consisting of 14 separate links. Subroutine DA must be compiled with the FORTRAN G compiler.

15. NAME AND ESTABLISHMENT OF AUTHOR

                 N. M. Greene
                 Computing Technology Center
                 P. O. Box P
                 Oak Ridge, Tennessee  37830

                 C. W. Craven, Jr.
                 Oak Ridge National Laboratory
                 P. O. Box Y
                 Oak Ridge, Tennessee  37830

File name	File description	Records
NESC0393_02.001	INFORMATION	1
NESC0393_02.002	X-SECTION LIBRARY - BCD	182380
NESC0393_02.003	XSDRN SOURCE PROGRAM	6666
NESC0393_02.004	XSDRN OVERLAY CARDS	30
NESC0393_02.005	XSDRN DD CARDS	20
NESC0393_02.006	XSDRN SAMPLE PROBLEM INPUT	96
NESC0393_02.007	X-SECTION CONVERTER PROGRAM - F4 EBCDIC	177
NESC0393_02.008	X-SECTION CONVERTER PROGRAM DD CARDS & DATA	10
NESC0393_02.009	X-SECTION LISTING PROGRAM - F4 EBCDIC	301
NESC0393_02.010	X-SECTION LISTING PROGRAM DD CARDS & DATA	6
NESC0393_02.011	PRINTED OUTPUT OF XSDRN	8610
NESC0393_02.012	PRINTED OUTPUT OF CONVERTER PROGRAM	193
NESC0393_02.013	PRINTED OUTPUT OF LISTING PROGRAM	4275